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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 
     18 #ifndef ANDROID_AUDIO_CORE_H
     19 #define ANDROID_AUDIO_CORE_H
     20 
     21 #include <stdbool.h>
     22 #include <stdint.h>
     23 #include <stdio.h>
     24 #include <sys/cdefs.h>
     25 #include <sys/types.h>
     26 
     27 #include <cutils/bitops.h>
     28 
     29 __BEGIN_DECLS
     30 
     31 /* The enums were moved here mostly from
     32  * frameworks/base/include/media/AudioSystem.h
     33  */
     34 
     35 /* device address used to refer to the standard remote submix */
     36 #define AUDIO_REMOTE_SUBMIX_DEVICE_ADDRESS "0"
     37 
     38 /* AudioFlinger and AudioPolicy services use I/O handles to identify audio sources and sinks */
     39 typedef int audio_io_handle_t;
     40 #define AUDIO_IO_HANDLE_NONE    0
     41 
     42 /* Audio stream types */
     43 typedef enum {
     44     /* These values must kept in sync with
     45      * frameworks/base/media/java/android/media/AudioSystem.java
     46      */
     47     AUDIO_STREAM_DEFAULT          = -1,
     48     AUDIO_STREAM_MIN              = 0,
     49     AUDIO_STREAM_VOICE_CALL       = 0,
     50     AUDIO_STREAM_SYSTEM           = 1,
     51     AUDIO_STREAM_RING             = 2,
     52     AUDIO_STREAM_MUSIC            = 3,
     53     AUDIO_STREAM_ALARM            = 4,
     54     AUDIO_STREAM_NOTIFICATION     = 5,
     55     AUDIO_STREAM_BLUETOOTH_SCO    = 6,
     56     AUDIO_STREAM_ENFORCED_AUDIBLE = 7, /* Sounds that cannot be muted by user
     57                                         * and must be routed to speaker
     58                                         */
     59     AUDIO_STREAM_DTMF             = 8,
     60     AUDIO_STREAM_TTS              = 9,
     61 
     62     AUDIO_STREAM_CNT,
     63     AUDIO_STREAM_MAX              = AUDIO_STREAM_CNT - 1,
     64 } audio_stream_type_t;
     65 
     66 /* Do not change these values without updating their counterparts
     67  * in frameworks/base/media/java/android/media/AudioAttributes.java
     68  */
     69 typedef enum {
     70     AUDIO_CONTENT_TYPE_UNKNOWN      = 0,
     71     AUDIO_CONTENT_TYPE_SPEECH       = 1,
     72     AUDIO_CONTENT_TYPE_MUSIC        = 2,
     73     AUDIO_CONTENT_TYPE_MOVIE        = 3,
     74     AUDIO_CONTENT_TYPE_SONIFICATION = 4,
     75 
     76     AUDIO_CONTENT_TYPE_CNT,
     77     AUDIO_CONTENT_TYPE_MAX          = AUDIO_CONTENT_TYPE_CNT - 1,
     78 } audio_content_type_t;
     79 
     80 /* Do not change these values without updating their counterparts
     81  * in frameworks/base/media/java/android/media/AudioAttributes.java
     82  */
     83 typedef enum {
     84     AUDIO_USAGE_UNKNOWN                            = 0,
     85     AUDIO_USAGE_MEDIA                              = 1,
     86     AUDIO_USAGE_VOICE_COMMUNICATION                = 2,
     87     AUDIO_USAGE_VOICE_COMMUNICATION_SIGNALLING     = 3,
     88     AUDIO_USAGE_ALARM                              = 4,
     89     AUDIO_USAGE_NOTIFICATION                       = 5,
     90     AUDIO_USAGE_NOTIFICATION_TELEPHONY_RINGTONE    = 6,
     91     AUDIO_USAGE_NOTIFICATION_COMMUNICATION_REQUEST = 7,
     92     AUDIO_USAGE_NOTIFICATION_COMMUNICATION_INSTANT = 8,
     93     AUDIO_USAGE_NOTIFICATION_COMMUNICATION_DELAYED = 9,
     94     AUDIO_USAGE_NOTIFICATION_EVENT                 = 10,
     95     AUDIO_USAGE_ASSISTANCE_ACCESSIBILITY           = 11,
     96     AUDIO_USAGE_ASSISTANCE_NAVIGATION_GUIDANCE     = 12,
     97     AUDIO_USAGE_ASSISTANCE_SONIFICATION            = 13,
     98     AUDIO_USAGE_GAME                               = 14,
     99 
    100     AUDIO_USAGE_CNT,
    101     AUDIO_USAGE_MAX                                = AUDIO_USAGE_CNT - 1,
    102 } audio_usage_t;
    103 
    104 typedef uint32_t audio_flags_mask_t;
    105 
    106 /* Do not change these values without updating their counterparts
    107  * in frameworks/base/media/java/android/media/AudioAttributes.java
    108  */
    109 enum {
    110     AUDIO_FLAG_AUDIBILITY_ENFORCED = 0x1,
    111     AUDIO_FLAG_SECURE              = 0x2,
    112     AUDIO_FLAG_SCO                 = 0x4,
    113     AUDIO_FLAG_BEACON              = 0x8,
    114     AUDIO_FLAG_HW_AV_SYNC          = 0x10,
    115     AUDIO_FLAG_HW_HOTWORD          = 0x20,
    116 };
    117 
    118 /* Do not change these values without updating their counterparts
    119  * in frameworks/base/media/java/android/media/MediaRecorder.java,
    120  * frameworks/av/services/audiopolicy/AudioPolicyService.cpp,
    121  * and system/media/audio_effects/include/audio_effects/audio_effects_conf.h!
    122  */
    123 typedef enum {
    124     AUDIO_SOURCE_DEFAULT             = 0,
    125     AUDIO_SOURCE_MIC                 = 1,
    126     AUDIO_SOURCE_VOICE_UPLINK        = 2,
    127     AUDIO_SOURCE_VOICE_DOWNLINK      = 3,
    128     AUDIO_SOURCE_VOICE_CALL          = 4,
    129     AUDIO_SOURCE_CAMCORDER           = 5,
    130     AUDIO_SOURCE_VOICE_RECOGNITION   = 6,
    131     AUDIO_SOURCE_VOICE_COMMUNICATION = 7,
    132     AUDIO_SOURCE_REMOTE_SUBMIX       = 8, /* Source for the mix to be presented remotely.      */
    133                                           /* An example of remote presentation is Wifi Display */
    134                                           /*  where a dongle attached to a TV can be used to   */
    135                                           /*  play the mix captured by this audio source.      */
    136     AUDIO_SOURCE_CNT,
    137     AUDIO_SOURCE_MAX                 = AUDIO_SOURCE_CNT - 1,
    138     AUDIO_SOURCE_HOTWORD             = 1999, /* A low-priority, preemptible audio source for
    139                                                 for background software hotword detection.
    140                                                 Same tuning as AUDIO_SOURCE_VOICE_RECOGNITION.
    141                                                 Used only internally to the framework. Not exposed
    142                                                 at the audio HAL. */
    143 } audio_source_t;
    144 
    145 /* Audio attributes */
    146 #define AUDIO_ATTRIBUTES_TAGS_MAX_SIZE 256
    147 typedef struct {
    148     audio_content_type_t content_type;
    149     audio_usage_t        usage;
    150     audio_source_t       source;
    151     audio_flags_mask_t   flags;
    152     char                 tags[AUDIO_ATTRIBUTES_TAGS_MAX_SIZE]; /* UTF8 */
    153 } audio_attributes_t;
    154 
    155 /* special audio session values
    156  * (XXX: should this be living in the audio effects land?)
    157  */
    158 typedef enum {
    159     /* session for effects attached to a particular output stream
    160      * (value must be less than 0)
    161      */
    162     AUDIO_SESSION_OUTPUT_STAGE = -1,
    163 
    164     /* session for effects applied to output mix. These effects can
    165      * be moved by audio policy manager to another output stream
    166      * (value must be 0)
    167      */
    168     AUDIO_SESSION_OUTPUT_MIX = 0,
    169 
    170     /* application does not specify an explicit session ID to be used,
    171      * and requests a new session ID to be allocated
    172      * TODO use unique values for AUDIO_SESSION_OUTPUT_MIX and AUDIO_SESSION_ALLOCATE,
    173      * after all uses have been updated from 0 to the appropriate symbol, and have been tested.
    174      */
    175     AUDIO_SESSION_ALLOCATE = 0,
    176 } audio_session_t;
    177 
    178 /* a unique ID allocated by AudioFlinger for use as a audio_io_handle_t or audio_session_t */
    179 typedef int audio_unique_id_t;
    180 
    181 #define AUDIO_UNIQUE_ID_ALLOCATE AUDIO_SESSION_ALLOCATE
    182 
    183 /* Audio sub formats (see enum audio_format). */
    184 
    185 /* PCM sub formats */
    186 typedef enum {
    187     /* All of these are in native byte order */
    188     AUDIO_FORMAT_PCM_SUB_16_BIT          = 0x1, /* DO NOT CHANGE - PCM signed 16 bits */
    189     AUDIO_FORMAT_PCM_SUB_8_BIT           = 0x2, /* DO NOT CHANGE - PCM unsigned 8 bits */
    190     AUDIO_FORMAT_PCM_SUB_32_BIT          = 0x3, /* PCM signed .31 fixed point */
    191     AUDIO_FORMAT_PCM_SUB_8_24_BIT        = 0x4, /* PCM signed 7.24 fixed point */
    192     AUDIO_FORMAT_PCM_SUB_FLOAT           = 0x5, /* PCM single-precision floating point */
    193     AUDIO_FORMAT_PCM_SUB_24_BIT_PACKED   = 0x6, /* PCM signed .23 fixed point packed in 3 bytes */
    194 } audio_format_pcm_sub_fmt_t;
    195 
    196 /* The audio_format_*_sub_fmt_t declarations are not currently used */
    197 
    198 /* MP3 sub format field definition : can use 11 LSBs in the same way as MP3
    199  * frame header to specify bit rate, stereo mode, version...
    200  */
    201 typedef enum {
    202     AUDIO_FORMAT_MP3_SUB_NONE            = 0x0,
    203 } audio_format_mp3_sub_fmt_t;
    204 
    205 /* AMR NB/WB sub format field definition: specify frame block interleaving,
    206  * bandwidth efficient or octet aligned, encoding mode for recording...
    207  */
    208 typedef enum {
    209     AUDIO_FORMAT_AMR_SUB_NONE            = 0x0,
    210 } audio_format_amr_sub_fmt_t;
    211 
    212 /* AAC sub format field definition: specify profile or bitrate for recording... */
    213 typedef enum {
    214     AUDIO_FORMAT_AAC_SUB_MAIN            = 0x1,
    215     AUDIO_FORMAT_AAC_SUB_LC              = 0x2,
    216     AUDIO_FORMAT_AAC_SUB_SSR             = 0x4,
    217     AUDIO_FORMAT_AAC_SUB_LTP             = 0x8,
    218     AUDIO_FORMAT_AAC_SUB_HE_V1           = 0x10,
    219     AUDIO_FORMAT_AAC_SUB_SCALABLE        = 0x20,
    220     AUDIO_FORMAT_AAC_SUB_ERLC            = 0x40,
    221     AUDIO_FORMAT_AAC_SUB_LD              = 0x80,
    222     AUDIO_FORMAT_AAC_SUB_HE_V2           = 0x100,
    223     AUDIO_FORMAT_AAC_SUB_ELD             = 0x200,
    224 } audio_format_aac_sub_fmt_t;
    225 
    226 /* VORBIS sub format field definition: specify quality for recording... */
    227 typedef enum {
    228     AUDIO_FORMAT_VORBIS_SUB_NONE         = 0x0,
    229 } audio_format_vorbis_sub_fmt_t;
    230 
    231 /* Audio format consists of a main format field (upper 8 bits) and a sub format
    232  * field (lower 24 bits).
    233  *
    234  * The main format indicates the main codec type. The sub format field
    235  * indicates options and parameters for each format. The sub format is mainly
    236  * used for record to indicate for instance the requested bitrate or profile.
    237  * It can also be used for certain formats to give informations not present in
    238  * the encoded audio stream (e.g. octet alignement for AMR).
    239  */
    240 typedef enum {
    241     AUDIO_FORMAT_INVALID             = 0xFFFFFFFFUL,
    242     AUDIO_FORMAT_DEFAULT             = 0,
    243     AUDIO_FORMAT_PCM                 = 0x00000000UL, /* DO NOT CHANGE */
    244     AUDIO_FORMAT_MP3                 = 0x01000000UL,
    245     AUDIO_FORMAT_AMR_NB              = 0x02000000UL,
    246     AUDIO_FORMAT_AMR_WB              = 0x03000000UL,
    247     AUDIO_FORMAT_AAC                 = 0x04000000UL,
    248     AUDIO_FORMAT_HE_AAC_V1           = 0x05000000UL, /* Deprecated, Use AUDIO_FORMAT_AAC_HE_V1*/
    249     AUDIO_FORMAT_HE_AAC_V2           = 0x06000000UL, /* Deprecated, Use AUDIO_FORMAT_AAC_HE_V2*/
    250     AUDIO_FORMAT_VORBIS              = 0x07000000UL,
    251     AUDIO_FORMAT_OPUS                = 0x08000000UL,
    252     AUDIO_FORMAT_AC3                 = 0x09000000UL,
    253     AUDIO_FORMAT_E_AC3               = 0x0A000000UL,
    254     AUDIO_FORMAT_MAIN_MASK           = 0xFF000000UL,
    255     AUDIO_FORMAT_SUB_MASK            = 0x00FFFFFFUL,
    256 
    257     /* Aliases */
    258     /* note != AudioFormat.ENCODING_PCM_16BIT */
    259     AUDIO_FORMAT_PCM_16_BIT          = (AUDIO_FORMAT_PCM |
    260                                         AUDIO_FORMAT_PCM_SUB_16_BIT),
    261     /* note != AudioFormat.ENCODING_PCM_8BIT */
    262     AUDIO_FORMAT_PCM_8_BIT           = (AUDIO_FORMAT_PCM |
    263                                         AUDIO_FORMAT_PCM_SUB_8_BIT),
    264     AUDIO_FORMAT_PCM_32_BIT          = (AUDIO_FORMAT_PCM |
    265                                         AUDIO_FORMAT_PCM_SUB_32_BIT),
    266     AUDIO_FORMAT_PCM_8_24_BIT        = (AUDIO_FORMAT_PCM |
    267                                         AUDIO_FORMAT_PCM_SUB_8_24_BIT),
    268     AUDIO_FORMAT_PCM_FLOAT           = (AUDIO_FORMAT_PCM |
    269                                         AUDIO_FORMAT_PCM_SUB_FLOAT),
    270     AUDIO_FORMAT_PCM_24_BIT_PACKED   = (AUDIO_FORMAT_PCM |
    271                                         AUDIO_FORMAT_PCM_SUB_24_BIT_PACKED),
    272     AUDIO_FORMAT_AAC_MAIN            = (AUDIO_FORMAT_AAC |
    273                                         AUDIO_FORMAT_AAC_SUB_MAIN),
    274     AUDIO_FORMAT_AAC_LC              = (AUDIO_FORMAT_AAC |
    275                                         AUDIO_FORMAT_AAC_SUB_LC),
    276     AUDIO_FORMAT_AAC_SSR             = (AUDIO_FORMAT_AAC |
    277                                         AUDIO_FORMAT_AAC_SUB_SSR),
    278     AUDIO_FORMAT_AAC_LTP             = (AUDIO_FORMAT_AAC |
    279                                         AUDIO_FORMAT_AAC_SUB_LTP),
    280     AUDIO_FORMAT_AAC_HE_V1           = (AUDIO_FORMAT_AAC |
    281                                         AUDIO_FORMAT_AAC_SUB_HE_V1),
    282     AUDIO_FORMAT_AAC_SCALABLE        = (AUDIO_FORMAT_AAC |
    283                                         AUDIO_FORMAT_AAC_SUB_SCALABLE),
    284     AUDIO_FORMAT_AAC_ERLC            = (AUDIO_FORMAT_AAC |
    285                                         AUDIO_FORMAT_AAC_SUB_ERLC),
    286     AUDIO_FORMAT_AAC_LD              = (AUDIO_FORMAT_AAC |
    287                                         AUDIO_FORMAT_AAC_SUB_LD),
    288     AUDIO_FORMAT_AAC_HE_V2           = (AUDIO_FORMAT_AAC |
    289                                         AUDIO_FORMAT_AAC_SUB_HE_V2),
    290     AUDIO_FORMAT_AAC_ELD             = (AUDIO_FORMAT_AAC |
    291                                         AUDIO_FORMAT_AAC_SUB_ELD),
    292 } audio_format_t;
    293 
    294 /* For the channel mask for position assignment representation */
    295 enum {
    296 
    297 /* These can be a complete audio_channel_mask_t. */
    298 
    299     AUDIO_CHANNEL_NONE                      = 0x0,
    300     AUDIO_CHANNEL_INVALID                   = 0xC0000000,
    301 
    302 /* These can be the bits portion of an audio_channel_mask_t
    303  * with representation AUDIO_CHANNEL_REPRESENTATION_POSITION.
    304  * Using these bits as a complete audio_channel_mask_t is deprecated.
    305  */
    306 
    307     /* output channels */
    308     AUDIO_CHANNEL_OUT_FRONT_LEFT            = 0x1,
    309     AUDIO_CHANNEL_OUT_FRONT_RIGHT           = 0x2,
    310     AUDIO_CHANNEL_OUT_FRONT_CENTER          = 0x4,
    311     AUDIO_CHANNEL_OUT_LOW_FREQUENCY         = 0x8,
    312     AUDIO_CHANNEL_OUT_BACK_LEFT             = 0x10,
    313     AUDIO_CHANNEL_OUT_BACK_RIGHT            = 0x20,
    314     AUDIO_CHANNEL_OUT_FRONT_LEFT_OF_CENTER  = 0x40,
    315     AUDIO_CHANNEL_OUT_FRONT_RIGHT_OF_CENTER = 0x80,
    316     AUDIO_CHANNEL_OUT_BACK_CENTER           = 0x100,
    317     AUDIO_CHANNEL_OUT_SIDE_LEFT             = 0x200,
    318     AUDIO_CHANNEL_OUT_SIDE_RIGHT            = 0x400,
    319     AUDIO_CHANNEL_OUT_TOP_CENTER            = 0x800,
    320     AUDIO_CHANNEL_OUT_TOP_FRONT_LEFT        = 0x1000,
    321     AUDIO_CHANNEL_OUT_TOP_FRONT_CENTER      = 0x2000,
    322     AUDIO_CHANNEL_OUT_TOP_FRONT_RIGHT       = 0x4000,
    323     AUDIO_CHANNEL_OUT_TOP_BACK_LEFT         = 0x8000,
    324     AUDIO_CHANNEL_OUT_TOP_BACK_CENTER       = 0x10000,
    325     AUDIO_CHANNEL_OUT_TOP_BACK_RIGHT        = 0x20000,
    326 
    327 /* TODO: should these be considered complete channel masks, or only bits? */
    328 
    329     AUDIO_CHANNEL_OUT_MONO     = AUDIO_CHANNEL_OUT_FRONT_LEFT,
    330     AUDIO_CHANNEL_OUT_STEREO   = (AUDIO_CHANNEL_OUT_FRONT_LEFT |
    331                                   AUDIO_CHANNEL_OUT_FRONT_RIGHT),
    332     AUDIO_CHANNEL_OUT_QUAD     = (AUDIO_CHANNEL_OUT_FRONT_LEFT |
    333                                   AUDIO_CHANNEL_OUT_FRONT_RIGHT |
    334                                   AUDIO_CHANNEL_OUT_BACK_LEFT |
    335                                   AUDIO_CHANNEL_OUT_BACK_RIGHT),
    336     AUDIO_CHANNEL_OUT_QUAD_BACK = AUDIO_CHANNEL_OUT_QUAD,
    337     /* like AUDIO_CHANNEL_OUT_QUAD_BACK with *_SIDE_* instead of *_BACK_* */
    338     AUDIO_CHANNEL_OUT_QUAD_SIDE = (AUDIO_CHANNEL_OUT_FRONT_LEFT |
    339                                   AUDIO_CHANNEL_OUT_FRONT_RIGHT |
    340                                   AUDIO_CHANNEL_OUT_SIDE_LEFT |
    341                                   AUDIO_CHANNEL_OUT_SIDE_RIGHT),
    342     AUDIO_CHANNEL_OUT_5POINT1  = (AUDIO_CHANNEL_OUT_FRONT_LEFT |
    343                                   AUDIO_CHANNEL_OUT_FRONT_RIGHT |
    344                                   AUDIO_CHANNEL_OUT_FRONT_CENTER |
    345                                   AUDIO_CHANNEL_OUT_LOW_FREQUENCY |
    346                                   AUDIO_CHANNEL_OUT_BACK_LEFT |
    347                                   AUDIO_CHANNEL_OUT_BACK_RIGHT),
    348     AUDIO_CHANNEL_OUT_5POINT1_BACK = AUDIO_CHANNEL_OUT_5POINT1,
    349     /* like AUDIO_CHANNEL_OUT_5POINT1_BACK with *_SIDE_* instead of *_BACK_* */
    350     AUDIO_CHANNEL_OUT_5POINT1_SIDE = (AUDIO_CHANNEL_OUT_FRONT_LEFT |
    351                                   AUDIO_CHANNEL_OUT_FRONT_RIGHT |
    352                                   AUDIO_CHANNEL_OUT_FRONT_CENTER |
    353                                   AUDIO_CHANNEL_OUT_LOW_FREQUENCY |
    354                                   AUDIO_CHANNEL_OUT_SIDE_LEFT |
    355                                   AUDIO_CHANNEL_OUT_SIDE_RIGHT),
    356     // matches the correct AudioFormat.CHANNEL_OUT_7POINT1_SURROUND definition for 7.1
    357     AUDIO_CHANNEL_OUT_7POINT1  = (AUDIO_CHANNEL_OUT_FRONT_LEFT |
    358                                   AUDIO_CHANNEL_OUT_FRONT_RIGHT |
    359                                   AUDIO_CHANNEL_OUT_FRONT_CENTER |
    360                                   AUDIO_CHANNEL_OUT_LOW_FREQUENCY |
    361                                   AUDIO_CHANNEL_OUT_BACK_LEFT |
    362                                   AUDIO_CHANNEL_OUT_BACK_RIGHT |
    363                                   AUDIO_CHANNEL_OUT_SIDE_LEFT |
    364                                   AUDIO_CHANNEL_OUT_SIDE_RIGHT),
    365     AUDIO_CHANNEL_OUT_ALL      = (AUDIO_CHANNEL_OUT_FRONT_LEFT |
    366                                   AUDIO_CHANNEL_OUT_FRONT_RIGHT |
    367                                   AUDIO_CHANNEL_OUT_FRONT_CENTER |
    368                                   AUDIO_CHANNEL_OUT_LOW_FREQUENCY |
    369                                   AUDIO_CHANNEL_OUT_BACK_LEFT |
    370                                   AUDIO_CHANNEL_OUT_BACK_RIGHT |
    371                                   AUDIO_CHANNEL_OUT_FRONT_LEFT_OF_CENTER |
    372                                   AUDIO_CHANNEL_OUT_FRONT_RIGHT_OF_CENTER |
    373                                   AUDIO_CHANNEL_OUT_BACK_CENTER|
    374                                   AUDIO_CHANNEL_OUT_SIDE_LEFT|
    375                                   AUDIO_CHANNEL_OUT_SIDE_RIGHT|
    376                                   AUDIO_CHANNEL_OUT_TOP_CENTER|
    377                                   AUDIO_CHANNEL_OUT_TOP_FRONT_LEFT|
    378                                   AUDIO_CHANNEL_OUT_TOP_FRONT_CENTER|
    379                                   AUDIO_CHANNEL_OUT_TOP_FRONT_RIGHT|
    380                                   AUDIO_CHANNEL_OUT_TOP_BACK_LEFT|
    381                                   AUDIO_CHANNEL_OUT_TOP_BACK_CENTER|
    382                                   AUDIO_CHANNEL_OUT_TOP_BACK_RIGHT),
    383 
    384 /* These are bits only, not complete values */
    385 
    386     /* input channels */
    387     AUDIO_CHANNEL_IN_LEFT            = 0x4,
    388     AUDIO_CHANNEL_IN_RIGHT           = 0x8,
    389     AUDIO_CHANNEL_IN_FRONT           = 0x10,
    390     AUDIO_CHANNEL_IN_BACK            = 0x20,
    391     AUDIO_CHANNEL_IN_LEFT_PROCESSED  = 0x40,
    392     AUDIO_CHANNEL_IN_RIGHT_PROCESSED = 0x80,
    393     AUDIO_CHANNEL_IN_FRONT_PROCESSED = 0x100,
    394     AUDIO_CHANNEL_IN_BACK_PROCESSED  = 0x200,
    395     AUDIO_CHANNEL_IN_PRESSURE        = 0x400,
    396     AUDIO_CHANNEL_IN_X_AXIS          = 0x800,
    397     AUDIO_CHANNEL_IN_Y_AXIS          = 0x1000,
    398     AUDIO_CHANNEL_IN_Z_AXIS          = 0x2000,
    399     AUDIO_CHANNEL_IN_VOICE_UPLINK    = 0x4000,
    400     AUDIO_CHANNEL_IN_VOICE_DNLINK    = 0x8000,
    401 
    402 /* TODO: should these be considered complete channel masks, or only bits, or deprecated? */
    403 
    404     AUDIO_CHANNEL_IN_MONO   = AUDIO_CHANNEL_IN_FRONT,
    405     AUDIO_CHANNEL_IN_STEREO = (AUDIO_CHANNEL_IN_LEFT | AUDIO_CHANNEL_IN_RIGHT),
    406     AUDIO_CHANNEL_IN_FRONT_BACK = (AUDIO_CHANNEL_IN_FRONT | AUDIO_CHANNEL_IN_BACK),
    407     AUDIO_CHANNEL_IN_ALL    = (AUDIO_CHANNEL_IN_LEFT |
    408                                AUDIO_CHANNEL_IN_RIGHT |
    409                                AUDIO_CHANNEL_IN_FRONT |
    410                                AUDIO_CHANNEL_IN_BACK|
    411                                AUDIO_CHANNEL_IN_LEFT_PROCESSED |
    412                                AUDIO_CHANNEL_IN_RIGHT_PROCESSED |
    413                                AUDIO_CHANNEL_IN_FRONT_PROCESSED |
    414                                AUDIO_CHANNEL_IN_BACK_PROCESSED|
    415                                AUDIO_CHANNEL_IN_PRESSURE |
    416                                AUDIO_CHANNEL_IN_X_AXIS |
    417                                AUDIO_CHANNEL_IN_Y_AXIS |
    418                                AUDIO_CHANNEL_IN_Z_AXIS |
    419                                AUDIO_CHANNEL_IN_VOICE_UPLINK |
    420                                AUDIO_CHANNEL_IN_VOICE_DNLINK),
    421 };
    422 
    423 /* A channel mask per se only defines the presence or absence of a channel, not the order.
    424  * But see AUDIO_INTERLEAVE_* below for the platform convention of order.
    425  *
    426  * audio_channel_mask_t is an opaque type and its internal layout should not
    427  * be assumed as it may change in the future.
    428  * Instead, always use the functions declared in this header to examine.
    429  *
    430  * These are the current representations:
    431  *
    432  *   AUDIO_CHANNEL_REPRESENTATION_POSITION
    433  *     is a channel mask representation for position assignment.
    434  *     Each low-order bit corresponds to the spatial position of a transducer (output),
    435  *     or interpretation of channel (input).
    436  *     The user of a channel mask needs to know the context of whether it is for output or input.
    437  *     The constants AUDIO_CHANNEL_OUT_* or AUDIO_CHANNEL_IN_* apply to the bits portion.
    438  *     It is not permitted for no bits to be set.
    439  *
    440  *   AUDIO_CHANNEL_REPRESENTATION_INDEX
    441  *     is a channel mask representation for index assignment.
    442  *     Each low-order bit corresponds to a selected channel.
    443  *     There is no platform interpretation of the various bits.
    444  *     There is no concept of output or input.
    445  *     It is not permitted for no bits to be set.
    446  *
    447  * All other representations are reserved for future use.
    448  *
    449  * Warning: current representation distinguishes between input and output, but this will not the be
    450  * case in future revisions of the platform. Wherever there is an ambiguity between input and output
    451  * that is currently resolved by checking the channel mask, the implementer should look for ways to
    452  * fix it with additional information outside of the mask.
    453  */
    454 typedef uint32_t audio_channel_mask_t;
    455 
    456 /* Maximum number of channels for all representations */
    457 #define AUDIO_CHANNEL_COUNT_MAX             30
    458 
    459 /* log(2) of maximum number of representations, not part of public API */
    460 #define AUDIO_CHANNEL_REPRESENTATION_LOG2   2
    461 
    462 /* Representations */
    463 typedef enum {
    464     AUDIO_CHANNEL_REPRESENTATION_POSITION    = 0,    // must be zero for compatibility
    465     // 1 is reserved for future use
    466     AUDIO_CHANNEL_REPRESENTATION_INDEX       = 2,
    467     // 3 is reserved for future use
    468 } audio_channel_representation_t;
    469 
    470 /* The return value is undefined if the channel mask is invalid. */
    471 static inline uint32_t audio_channel_mask_get_bits(audio_channel_mask_t channel)
    472 {
    473     return channel & ((1 << AUDIO_CHANNEL_COUNT_MAX) - 1);
    474 }
    475 
    476 /* The return value is undefined if the channel mask is invalid. */
    477 static inline audio_channel_representation_t audio_channel_mask_get_representation(
    478         audio_channel_mask_t channel)
    479 {
    480     // The right shift should be sufficient, but also "and" for safety in case mask is not 32 bits
    481     return (audio_channel_representation_t)
    482             ((channel >> AUDIO_CHANNEL_COUNT_MAX) & ((1 << AUDIO_CHANNEL_REPRESENTATION_LOG2) - 1));
    483 }
    484 
    485 /* Returns true if the channel mask is valid,
    486  * or returns false for AUDIO_CHANNEL_NONE, AUDIO_CHANNEL_INVALID, and other invalid values.
    487  * This function is unable to determine whether a channel mask for position assignment
    488  * is invalid because an output mask has an invalid output bit set,
    489  * or because an input mask has an invalid input bit set.
    490  * All other APIs that take a channel mask assume that it is valid.
    491  */
    492 static inline bool audio_channel_mask_is_valid(audio_channel_mask_t channel)
    493 {
    494     uint32_t bits = audio_channel_mask_get_bits(channel);
    495     audio_channel_representation_t representation = audio_channel_mask_get_representation(channel);
    496     switch (representation) {
    497     case AUDIO_CHANNEL_REPRESENTATION_POSITION:
    498     case AUDIO_CHANNEL_REPRESENTATION_INDEX:
    499         break;
    500     default:
    501         bits = 0;
    502         break;
    503     }
    504     return bits != 0;
    505 }
    506 
    507 /* Not part of public API */
    508 static inline audio_channel_mask_t audio_channel_mask_from_representation_and_bits(
    509         audio_channel_representation_t representation, uint32_t bits)
    510 {
    511     return (audio_channel_mask_t) ((representation << AUDIO_CHANNEL_COUNT_MAX) | bits);
    512 }
    513 
    514 /* Expresses the convention when stereo audio samples are stored interleaved
    515  * in an array.  This should improve readability by allowing code to use
    516  * symbolic indices instead of hard-coded [0] and [1].
    517  *
    518  * For multi-channel beyond stereo, the platform convention is that channels
    519  * are interleaved in order from least significant channel mask bit
    520  * to most significant channel mask bit, with unused bits skipped.
    521  * Any exceptions to this convention will be noted at the appropriate API.
    522  */
    523 enum {
    524     AUDIO_INTERLEAVE_LEFT   = 0,
    525     AUDIO_INTERLEAVE_RIGHT  = 1,
    526 };
    527 
    528 typedef enum {
    529     AUDIO_MODE_INVALID          = -2,
    530     AUDIO_MODE_CURRENT          = -1,
    531     AUDIO_MODE_NORMAL           = 0,
    532     AUDIO_MODE_RINGTONE         = 1,
    533     AUDIO_MODE_IN_CALL          = 2,
    534     AUDIO_MODE_IN_COMMUNICATION = 3,
    535 
    536     AUDIO_MODE_CNT,
    537     AUDIO_MODE_MAX              = AUDIO_MODE_CNT - 1,
    538 } audio_mode_t;
    539 
    540 /* This enum is deprecated */
    541 typedef enum {
    542     AUDIO_IN_ACOUSTICS_NONE          = 0,
    543     AUDIO_IN_ACOUSTICS_AGC_ENABLE    = 0x0001,
    544     AUDIO_IN_ACOUSTICS_AGC_DISABLE   = 0,
    545     AUDIO_IN_ACOUSTICS_NS_ENABLE     = 0x0002,
    546     AUDIO_IN_ACOUSTICS_NS_DISABLE    = 0,
    547     AUDIO_IN_ACOUSTICS_TX_IIR_ENABLE = 0x0004,
    548     AUDIO_IN_ACOUSTICS_TX_DISABLE    = 0,
    549 } audio_in_acoustics_t;
    550 
    551 enum {
    552     AUDIO_DEVICE_NONE                          = 0x0,
    553     /* reserved bits */
    554     AUDIO_DEVICE_BIT_IN                        = 0x80000000,
    555     AUDIO_DEVICE_BIT_DEFAULT                   = 0x40000000,
    556     /* output devices */
    557     AUDIO_DEVICE_OUT_EARPIECE                  = 0x1,
    558     AUDIO_DEVICE_OUT_SPEAKER                   = 0x2,
    559     AUDIO_DEVICE_OUT_WIRED_HEADSET             = 0x4,
    560     AUDIO_DEVICE_OUT_WIRED_HEADPHONE           = 0x8,
    561     AUDIO_DEVICE_OUT_BLUETOOTH_SCO             = 0x10,
    562     AUDIO_DEVICE_OUT_BLUETOOTH_SCO_HEADSET     = 0x20,
    563     AUDIO_DEVICE_OUT_BLUETOOTH_SCO_CARKIT      = 0x40,
    564     AUDIO_DEVICE_OUT_BLUETOOTH_A2DP            = 0x80,
    565     AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES = 0x100,
    566     AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER    = 0x200,
    567     AUDIO_DEVICE_OUT_AUX_DIGITAL               = 0x400,
    568     AUDIO_DEVICE_OUT_HDMI                      = AUDIO_DEVICE_OUT_AUX_DIGITAL,
    569     /* uses an analog connection (multiplexed over the USB connector pins for instance) */
    570     AUDIO_DEVICE_OUT_ANLG_DOCK_HEADSET         = 0x800,
    571     AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET         = 0x1000,
    572     /* USB accessory mode: your Android device is a USB device and the dock is a USB host */
    573     AUDIO_DEVICE_OUT_USB_ACCESSORY             = 0x2000,
    574     /* USB host mode: your Android device is a USB host and the dock is a USB device */
    575     AUDIO_DEVICE_OUT_USB_DEVICE                = 0x4000,
    576     AUDIO_DEVICE_OUT_REMOTE_SUBMIX             = 0x8000,
    577     /* Telephony voice TX path */
    578     AUDIO_DEVICE_OUT_TELEPHONY_TX              = 0x10000,
    579     /* Analog jack with line impedance detected */
    580     AUDIO_DEVICE_OUT_LINE                      = 0x20000,
    581     /* HDMI Audio Return Channel */
    582     AUDIO_DEVICE_OUT_HDMI_ARC                  = 0x40000,
    583     /* S/PDIF out */
    584     AUDIO_DEVICE_OUT_SPDIF                     = 0x80000,
    585     /* FM transmitter out */
    586     AUDIO_DEVICE_OUT_FM                        = 0x100000,
    587     /* Line out for av devices */
    588     AUDIO_DEVICE_OUT_AUX_LINE                  = 0x200000,
    589     /* limited-output speaker device for acoustic safety */
    590     AUDIO_DEVICE_OUT_SPEAKER_SAFE              = 0x400000,
    591     AUDIO_DEVICE_OUT_DEFAULT                   = AUDIO_DEVICE_BIT_DEFAULT,
    592     AUDIO_DEVICE_OUT_ALL      = (AUDIO_DEVICE_OUT_EARPIECE |
    593                                  AUDIO_DEVICE_OUT_SPEAKER |
    594                                  AUDIO_DEVICE_OUT_WIRED_HEADSET |
    595                                  AUDIO_DEVICE_OUT_WIRED_HEADPHONE |
    596                                  AUDIO_DEVICE_OUT_BLUETOOTH_SCO |
    597                                  AUDIO_DEVICE_OUT_BLUETOOTH_SCO_HEADSET |
    598                                  AUDIO_DEVICE_OUT_BLUETOOTH_SCO_CARKIT |
    599                                  AUDIO_DEVICE_OUT_BLUETOOTH_A2DP |
    600                                  AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES |
    601                                  AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER |
    602                                  AUDIO_DEVICE_OUT_HDMI |
    603                                  AUDIO_DEVICE_OUT_ANLG_DOCK_HEADSET |
    604                                  AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET |
    605                                  AUDIO_DEVICE_OUT_USB_ACCESSORY |
    606                                  AUDIO_DEVICE_OUT_USB_DEVICE |
    607                                  AUDIO_DEVICE_OUT_REMOTE_SUBMIX |
    608                                  AUDIO_DEVICE_OUT_TELEPHONY_TX |
    609                                  AUDIO_DEVICE_OUT_LINE |
    610                                  AUDIO_DEVICE_OUT_HDMI_ARC |
    611                                  AUDIO_DEVICE_OUT_SPDIF |
    612                                  AUDIO_DEVICE_OUT_FM |
    613                                  AUDIO_DEVICE_OUT_AUX_LINE |
    614                                  AUDIO_DEVICE_OUT_SPEAKER_SAFE |
    615                                  AUDIO_DEVICE_OUT_DEFAULT),
    616     AUDIO_DEVICE_OUT_ALL_A2DP = (AUDIO_DEVICE_OUT_BLUETOOTH_A2DP |
    617                                  AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES |
    618                                  AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER),
    619     AUDIO_DEVICE_OUT_ALL_SCO  = (AUDIO_DEVICE_OUT_BLUETOOTH_SCO |
    620                                  AUDIO_DEVICE_OUT_BLUETOOTH_SCO_HEADSET |
    621                                  AUDIO_DEVICE_OUT_BLUETOOTH_SCO_CARKIT),
    622     AUDIO_DEVICE_OUT_ALL_USB  = (AUDIO_DEVICE_OUT_USB_ACCESSORY |
    623                                  AUDIO_DEVICE_OUT_USB_DEVICE),
    624 
    625     /* input devices */
    626     AUDIO_DEVICE_IN_COMMUNICATION         = AUDIO_DEVICE_BIT_IN | 0x1,
    627     AUDIO_DEVICE_IN_AMBIENT               = AUDIO_DEVICE_BIT_IN | 0x2,
    628     AUDIO_DEVICE_IN_BUILTIN_MIC           = AUDIO_DEVICE_BIT_IN | 0x4,
    629     AUDIO_DEVICE_IN_BLUETOOTH_SCO_HEADSET = AUDIO_DEVICE_BIT_IN | 0x8,
    630     AUDIO_DEVICE_IN_WIRED_HEADSET         = AUDIO_DEVICE_BIT_IN | 0x10,
    631     AUDIO_DEVICE_IN_AUX_DIGITAL           = AUDIO_DEVICE_BIT_IN | 0x20,
    632     AUDIO_DEVICE_IN_HDMI                  = AUDIO_DEVICE_IN_AUX_DIGITAL,
    633     /* Telephony voice RX path */
    634     AUDIO_DEVICE_IN_VOICE_CALL            = AUDIO_DEVICE_BIT_IN | 0x40,
    635     AUDIO_DEVICE_IN_TELEPHONY_RX          = AUDIO_DEVICE_IN_VOICE_CALL,
    636     AUDIO_DEVICE_IN_BACK_MIC              = AUDIO_DEVICE_BIT_IN | 0x80,
    637     AUDIO_DEVICE_IN_REMOTE_SUBMIX         = AUDIO_DEVICE_BIT_IN | 0x100,
    638     AUDIO_DEVICE_IN_ANLG_DOCK_HEADSET     = AUDIO_DEVICE_BIT_IN | 0x200,
    639     AUDIO_DEVICE_IN_DGTL_DOCK_HEADSET     = AUDIO_DEVICE_BIT_IN | 0x400,
    640     AUDIO_DEVICE_IN_USB_ACCESSORY         = AUDIO_DEVICE_BIT_IN | 0x800,
    641     AUDIO_DEVICE_IN_USB_DEVICE            = AUDIO_DEVICE_BIT_IN | 0x1000,
    642     /* FM tuner input */
    643     AUDIO_DEVICE_IN_FM_TUNER              = AUDIO_DEVICE_BIT_IN | 0x2000,
    644     /* TV tuner input */
    645     AUDIO_DEVICE_IN_TV_TUNER              = AUDIO_DEVICE_BIT_IN | 0x4000,
    646     /* Analog jack with line impedance detected */
    647     AUDIO_DEVICE_IN_LINE                  = AUDIO_DEVICE_BIT_IN | 0x8000,
    648     /* S/PDIF in */
    649     AUDIO_DEVICE_IN_SPDIF                 = AUDIO_DEVICE_BIT_IN | 0x10000,
    650     AUDIO_DEVICE_IN_BLUETOOTH_A2DP        = AUDIO_DEVICE_BIT_IN | 0x20000,
    651     AUDIO_DEVICE_IN_LOOPBACK              = AUDIO_DEVICE_BIT_IN | 0x40000,
    652     AUDIO_DEVICE_IN_DEFAULT               = AUDIO_DEVICE_BIT_IN | AUDIO_DEVICE_BIT_DEFAULT,
    653 
    654     AUDIO_DEVICE_IN_ALL     = (AUDIO_DEVICE_IN_COMMUNICATION |
    655                                AUDIO_DEVICE_IN_AMBIENT |
    656                                AUDIO_DEVICE_IN_BUILTIN_MIC |
    657                                AUDIO_DEVICE_IN_BLUETOOTH_SCO_HEADSET |
    658                                AUDIO_DEVICE_IN_WIRED_HEADSET |
    659                                AUDIO_DEVICE_IN_HDMI |
    660                                AUDIO_DEVICE_IN_TELEPHONY_RX |
    661                                AUDIO_DEVICE_IN_BACK_MIC |
    662                                AUDIO_DEVICE_IN_REMOTE_SUBMIX |
    663                                AUDIO_DEVICE_IN_ANLG_DOCK_HEADSET |
    664                                AUDIO_DEVICE_IN_DGTL_DOCK_HEADSET |
    665                                AUDIO_DEVICE_IN_USB_ACCESSORY |
    666                                AUDIO_DEVICE_IN_USB_DEVICE |
    667                                AUDIO_DEVICE_IN_FM_TUNER |
    668                                AUDIO_DEVICE_IN_TV_TUNER |
    669                                AUDIO_DEVICE_IN_LINE |
    670                                AUDIO_DEVICE_IN_SPDIF |
    671                                AUDIO_DEVICE_IN_BLUETOOTH_A2DP |
    672                                AUDIO_DEVICE_IN_LOOPBACK |
    673                                AUDIO_DEVICE_IN_DEFAULT),
    674     AUDIO_DEVICE_IN_ALL_SCO = AUDIO_DEVICE_IN_BLUETOOTH_SCO_HEADSET,
    675     AUDIO_DEVICE_IN_ALL_USB  = (AUDIO_DEVICE_IN_USB_ACCESSORY |
    676                                 AUDIO_DEVICE_IN_USB_DEVICE),
    677 };
    678 
    679 typedef uint32_t audio_devices_t;
    680 
    681 /* the audio output flags serve two purposes:
    682  * - when an AudioTrack is created they indicate a "wish" to be connected to an
    683  * output stream with attributes corresponding to the specified flags
    684  * - when present in an output profile descriptor listed for a particular audio
    685  * hardware module, they indicate that an output stream can be opened that
    686  * supports the attributes indicated by the flags.
    687  * the audio policy manager will try to match the flags in the request
    688  * (when getOuput() is called) to an available output stream.
    689  */
    690 typedef enum {
    691     AUDIO_OUTPUT_FLAG_NONE = 0x0,       // no attributes
    692     AUDIO_OUTPUT_FLAG_DIRECT = 0x1,     // this output directly connects a track
    693                                         // to one output stream: no software mixer
    694     AUDIO_OUTPUT_FLAG_PRIMARY = 0x2,    // this output is the primary output of
    695                                         // the device. It is unique and must be
    696                                         // present. It is opened by default and
    697                                         // receives routing, audio mode and volume
    698                                         // controls related to voice calls.
    699     AUDIO_OUTPUT_FLAG_FAST = 0x4,       // output supports "fast tracks",
    700                                         // defined elsewhere
    701     AUDIO_OUTPUT_FLAG_DEEP_BUFFER = 0x8, // use deep audio buffers
    702     AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD = 0x10,  // offload playback of compressed
    703                                                 // streams to hardware codec
    704     AUDIO_OUTPUT_FLAG_NON_BLOCKING = 0x20, // use non-blocking write
    705     AUDIO_OUTPUT_FLAG_HW_AV_SYNC = 0x40 // output uses a hardware A/V synchronization source
    706 } audio_output_flags_t;
    707 
    708 /* The audio input flags are analogous to audio output flags.
    709  * Currently they are used only when an AudioRecord is created,
    710  * to indicate a preference to be connected to an input stream with
    711  * attributes corresponding to the specified flags.
    712  */
    713 typedef enum {
    714     AUDIO_INPUT_FLAG_NONE       = 0x0,  // no attributes
    715     AUDIO_INPUT_FLAG_FAST       = 0x1,  // prefer an input that supports "fast tracks"
    716     AUDIO_INPUT_FLAG_HW_HOTWORD = 0x2,  // prefer an input that captures from hw hotword source
    717 } audio_input_flags_t;
    718 
    719 /* Additional information about compressed streams offloaded to
    720  * hardware playback
    721  * The version and size fields must be initialized by the caller by using
    722  * one of the constants defined here.
    723  */
    724 typedef struct {
    725     uint16_t version;                   // version of the info structure
    726     uint16_t size;                      // total size of the structure including version and size
    727     uint32_t sample_rate;               // sample rate in Hz
    728     audio_channel_mask_t channel_mask;  // channel mask
    729     audio_format_t format;              // audio format
    730     audio_stream_type_t stream_type;    // stream type
    731     uint32_t bit_rate;                  // bit rate in bits per second
    732     int64_t duration_us;                // duration in microseconds, -1 if unknown
    733     bool has_video;                     // true if stream is tied to a video stream
    734     bool is_streaming;                  // true if streaming, false if local playback
    735 } audio_offload_info_t;
    736 
    737 #define AUDIO_MAKE_OFFLOAD_INFO_VERSION(maj,min) \
    738             ((((maj) & 0xff) << 8) | ((min) & 0xff))
    739 
    740 #define AUDIO_OFFLOAD_INFO_VERSION_0_1 AUDIO_MAKE_OFFLOAD_INFO_VERSION(0, 1)
    741 #define AUDIO_OFFLOAD_INFO_VERSION_CURRENT AUDIO_OFFLOAD_INFO_VERSION_0_1
    742 
    743 static const audio_offload_info_t AUDIO_INFO_INITIALIZER = {
    744     version: AUDIO_OFFLOAD_INFO_VERSION_CURRENT,
    745     size: sizeof(audio_offload_info_t),
    746     sample_rate: 0,
    747     channel_mask: 0,
    748     format: AUDIO_FORMAT_DEFAULT,
    749     stream_type: AUDIO_STREAM_VOICE_CALL,
    750     bit_rate: 0,
    751     duration_us: 0,
    752     has_video: false,
    753     is_streaming: false
    754 };
    755 
    756 /* common audio stream configuration parameters
    757  * You should memset() the entire structure to zero before use to
    758  * ensure forward compatibility
    759  */
    760 struct audio_config {
    761     uint32_t sample_rate;
    762     audio_channel_mask_t channel_mask;
    763     audio_format_t  format;
    764     audio_offload_info_t offload_info;
    765     size_t frame_count;
    766 };
    767 typedef struct audio_config audio_config_t;
    768 
    769 static const audio_config_t AUDIO_CONFIG_INITIALIZER = {
    770     sample_rate: 0,
    771     channel_mask: AUDIO_CHANNEL_NONE,
    772     format: AUDIO_FORMAT_DEFAULT,
    773     offload_info: {
    774         version: AUDIO_OFFLOAD_INFO_VERSION_CURRENT,
    775         size: sizeof(audio_offload_info_t),
    776         sample_rate: 0,
    777         channel_mask: 0,
    778         format: AUDIO_FORMAT_DEFAULT,
    779         stream_type: AUDIO_STREAM_VOICE_CALL,
    780         bit_rate: 0,
    781         duration_us: 0,
    782         has_video: false,
    783         is_streaming: false
    784     },
    785     frame_count: 0,
    786 };
    787 
    788 
    789 /* audio hw module handle functions or structures referencing a module */
    790 typedef int audio_module_handle_t;
    791 
    792 /******************************
    793  *  Volume control
    794  *****************************/
    795 
    796 /* If the audio hardware supports gain control on some audio paths,
    797  * the platform can expose them in the audio_policy.conf file. The audio HAL
    798  * will then implement gain control functions that will use the following data
    799  * structures. */
    800 
    801 /* Type of gain control exposed by an audio port */
    802 #define AUDIO_GAIN_MODE_JOINT     0x1 /* supports joint channel gain control */
    803 #define AUDIO_GAIN_MODE_CHANNELS  0x2 /* supports separate channel gain control */
    804 #define AUDIO_GAIN_MODE_RAMP      0x4 /* supports gain ramps */
    805 
    806 typedef uint32_t audio_gain_mode_t;
    807 
    808 
    809 /* An audio_gain struct is a representation of a gain stage.
    810  * A gain stage is always attached to an audio port. */
    811 struct audio_gain  {
    812     audio_gain_mode_t    mode;          /* e.g. AUDIO_GAIN_MODE_JOINT */
    813     audio_channel_mask_t channel_mask;  /* channels which gain an be controlled.
    814                                            N/A if AUDIO_GAIN_MODE_CHANNELS is not supported */
    815     int                  min_value;     /* minimum gain value in millibels */
    816     int                  max_value;     /* maximum gain value in millibels */
    817     int                  default_value; /* default gain value in millibels */
    818     unsigned int         step_value;    /* gain step in millibels */
    819     unsigned int         min_ramp_ms;   /* minimum ramp duration in ms */
    820     unsigned int         max_ramp_ms;   /* maximum ramp duration in ms */
    821 };
    822 
    823 /* The gain configuration structure is used to get or set the gain values of a
    824  * given port */
    825 struct audio_gain_config  {
    826     int                  index;             /* index of the corresponding audio_gain in the
    827                                                audio_port gains[] table */
    828     audio_gain_mode_t    mode;              /* mode requested for this command */
    829     audio_channel_mask_t channel_mask;      /* channels which gain value follows.
    830                                                N/A in joint mode */
    831     int                  values[sizeof(audio_channel_mask_t) * 8]; /* gain values in millibels
    832                                                for each channel ordered from LSb to MSb in
    833                                                channel mask. The number of values is 1 in joint
    834                                                mode or popcount(channel_mask) */
    835     unsigned int         ramp_duration_ms; /* ramp duration in ms */
    836 };
    837 
    838 /******************************
    839  *  Routing control
    840  *****************************/
    841 
    842 /* Types defined here are used to describe an audio source or sink at internal
    843  * framework interfaces (audio policy, patch panel) or at the audio HAL.
    844  * Sink and sources are grouped in a concept of audio port representing an
    845  * audio end point at the edge of the system managed by the module exposing
    846  * the interface. */
    847 
    848 /* Audio port role: either source or sink */
    849 typedef enum {
    850     AUDIO_PORT_ROLE_NONE,
    851     AUDIO_PORT_ROLE_SOURCE,
    852     AUDIO_PORT_ROLE_SINK,
    853 } audio_port_role_t;
    854 
    855 /* Audio port type indicates if it is a session (e.g AudioTrack),
    856  * a mix (e.g PlaybackThread output) or a physical device
    857  * (e.g AUDIO_DEVICE_OUT_SPEAKER) */
    858 typedef enum {
    859     AUDIO_PORT_TYPE_NONE,
    860     AUDIO_PORT_TYPE_DEVICE,
    861     AUDIO_PORT_TYPE_MIX,
    862     AUDIO_PORT_TYPE_SESSION,
    863 } audio_port_type_t;
    864 
    865 /* Each port has a unique ID or handle allocated by policy manager */
    866 typedef int audio_port_handle_t;
    867 #define AUDIO_PORT_HANDLE_NONE 0
    868 
    869 
    870 /* maximum audio device address length */
    871 #define AUDIO_DEVICE_MAX_ADDRESS_LEN 32
    872 
    873 /* extension for audio port configuration structure when the audio port is a
    874  * hardware device */
    875 struct audio_port_config_device_ext {
    876     audio_module_handle_t hw_module;                /* module the device is attached to */
    877     audio_devices_t       type;                     /* device type (e.g AUDIO_DEVICE_OUT_SPEAKER) */
    878     char                  address[AUDIO_DEVICE_MAX_ADDRESS_LEN]; /* device address. "" if N/A */
    879 };
    880 
    881 /* extension for audio port configuration structure when the audio port is a
    882  * sub mix */
    883 struct audio_port_config_mix_ext {
    884     audio_module_handle_t hw_module;    /* module the stream is attached to */
    885     audio_io_handle_t handle;           /* I/O handle of the input/output stream */
    886     union {
    887         //TODO: change use case for output streams: use strategy and mixer attributes
    888         audio_stream_type_t stream;
    889         audio_source_t      source;
    890     } usecase;
    891 };
    892 
    893 /* extension for audio port configuration structure when the audio port is an
    894  * audio session */
    895 struct audio_port_config_session_ext {
    896     audio_session_t   session; /* audio session */
    897 };
    898 
    899 /* Flags indicating which fields are to be considered in struct audio_port_config */
    900 #define AUDIO_PORT_CONFIG_SAMPLE_RATE  0x1
    901 #define AUDIO_PORT_CONFIG_CHANNEL_MASK 0x2
    902 #define AUDIO_PORT_CONFIG_FORMAT       0x4
    903 #define AUDIO_PORT_CONFIG_GAIN         0x8
    904 #define AUDIO_PORT_CONFIG_ALL (AUDIO_PORT_CONFIG_SAMPLE_RATE | \
    905                                AUDIO_PORT_CONFIG_CHANNEL_MASK | \
    906                                AUDIO_PORT_CONFIG_FORMAT | \
    907                                AUDIO_PORT_CONFIG_GAIN)
    908 
    909 /* audio port configuration structure used to specify a particular configuration of
    910  * an audio port */
    911 struct audio_port_config {
    912     audio_port_handle_t      id;           /* port unique ID */
    913     audio_port_role_t        role;         /* sink or source */
    914     audio_port_type_t        type;         /* device, mix ... */
    915     unsigned int             config_mask;  /* e.g AUDIO_PORT_CONFIG_ALL */
    916     unsigned int             sample_rate;  /* sampling rate in Hz */
    917     audio_channel_mask_t     channel_mask; /* channel mask if applicable */
    918     audio_format_t           format;       /* format if applicable */
    919     struct audio_gain_config gain;         /* gain to apply if applicable */
    920     union {
    921         struct audio_port_config_device_ext  device;  /* device specific info */
    922         struct audio_port_config_mix_ext     mix;     /* mix specific info */
    923         struct audio_port_config_session_ext session; /* session specific info */
    924     } ext;
    925 };
    926 
    927 
    928 /* max number of sampling rates in audio port */
    929 #define AUDIO_PORT_MAX_SAMPLING_RATES 16
    930 /* max number of channel masks in audio port */
    931 #define AUDIO_PORT_MAX_CHANNEL_MASKS 16
    932 /* max number of audio formats in audio port */
    933 #define AUDIO_PORT_MAX_FORMATS 16
    934 /* max number of gain controls in audio port */
    935 #define AUDIO_PORT_MAX_GAINS 16
    936 
    937 /* extension for audio port structure when the audio port is a hardware device */
    938 struct audio_port_device_ext {
    939     audio_module_handle_t hw_module;    /* module the device is attached to */
    940     audio_devices_t       type;         /* device type (e.g AUDIO_DEVICE_OUT_SPEAKER) */
    941     char                  address[AUDIO_DEVICE_MAX_ADDRESS_LEN];
    942 };
    943 
    944 /* Latency class of the audio mix */
    945 typedef enum {
    946     AUDIO_LATENCY_LOW,
    947     AUDIO_LATENCY_NORMAL,
    948 } audio_mix_latency_class_t;
    949 
    950 /* extension for audio port structure when the audio port is a sub mix */
    951 struct audio_port_mix_ext {
    952     audio_module_handle_t     hw_module;     /* module the stream is attached to */
    953     audio_io_handle_t         handle;        /* I/O handle of the input.output stream */
    954     audio_mix_latency_class_t latency_class; /* latency class */
    955     // other attributes: routing strategies
    956 };
    957 
    958 /* extension for audio port structure when the audio port is an audio session */
    959 struct audio_port_session_ext {
    960     audio_session_t   session; /* audio session */
    961 };
    962 
    963 
    964 struct audio_port {
    965     audio_port_handle_t      id;                /* port unique ID */
    966     audio_port_role_t        role;              /* sink or source */
    967     audio_port_type_t        type;              /* device, mix ... */
    968     unsigned int             num_sample_rates;  /* number of sampling rates in following array */
    969     unsigned int             sample_rates[AUDIO_PORT_MAX_SAMPLING_RATES];
    970     unsigned int             num_channel_masks; /* number of channel masks in following array */
    971     audio_channel_mask_t     channel_masks[AUDIO_PORT_MAX_CHANNEL_MASKS];
    972     unsigned int             num_formats;       /* number of formats in following array */
    973     audio_format_t           formats[AUDIO_PORT_MAX_FORMATS];
    974     unsigned int             num_gains;         /* number of gains in following array */
    975     struct audio_gain        gains[AUDIO_PORT_MAX_GAINS];
    976     struct audio_port_config active_config;     /* current audio port configuration */
    977     union {
    978         struct audio_port_device_ext  device;
    979         struct audio_port_mix_ext     mix;
    980         struct audio_port_session_ext session;
    981     } ext;
    982 };
    983 
    984 /* An audio patch represents a connection between one or more source ports and
    985  * one or more sink ports. Patches are connected and disconnected by audio policy manager or by
    986  * applications via framework APIs.
    987  * Each patch is identified by a handle at the interface used to create that patch. For instance,
    988  * when a patch is created by the audio HAL, the HAL allocates and returns a handle.
    989  * This handle is unique to a given audio HAL hardware module.
    990  * But the same patch receives another system wide unique handle allocated by the framework.
    991  * This unique handle is used for all transactions inside the framework.
    992  */
    993 typedef int audio_patch_handle_t;
    994 #define AUDIO_PATCH_HANDLE_NONE 0
    995 
    996 #define AUDIO_PATCH_PORTS_MAX   16
    997 
    998 struct audio_patch {
    999     audio_patch_handle_t id;            /* patch unique ID */
   1000     unsigned int      num_sources;      /* number of sources in following array */
   1001     struct audio_port_config sources[AUDIO_PATCH_PORTS_MAX];
   1002     unsigned int      num_sinks;        /* number of sinks in following array */
   1003     struct audio_port_config sinks[AUDIO_PATCH_PORTS_MAX];
   1004 };
   1005 
   1006 
   1007 
   1008 /* a HW synchronization source returned by the audio HAL */
   1009 typedef uint32_t audio_hw_sync_t;
   1010 
   1011 /* an invalid HW synchronization source indicating an error */
   1012 #define AUDIO_HW_SYNC_INVALID 0
   1013 
   1014 static inline bool audio_is_output_device(audio_devices_t device)
   1015 {
   1016     if (((device & AUDIO_DEVICE_BIT_IN) == 0) &&
   1017             (popcount(device) == 1) && ((device & ~AUDIO_DEVICE_OUT_ALL) == 0))
   1018         return true;
   1019     else
   1020         return false;
   1021 }
   1022 
   1023 static inline bool audio_is_input_device(audio_devices_t device)
   1024 {
   1025     if ((device & AUDIO_DEVICE_BIT_IN) != 0) {
   1026         device &= ~AUDIO_DEVICE_BIT_IN;
   1027         if ((popcount(device) == 1) && ((device & ~AUDIO_DEVICE_IN_ALL) == 0))
   1028             return true;
   1029     }
   1030     return false;
   1031 }
   1032 
   1033 static inline bool audio_is_output_devices(audio_devices_t device)
   1034 {
   1035     return (device & AUDIO_DEVICE_BIT_IN) == 0;
   1036 }
   1037 
   1038 static inline bool audio_is_a2dp_in_device(audio_devices_t device)
   1039 {
   1040     if ((device & AUDIO_DEVICE_BIT_IN) != 0) {
   1041         device &= ~AUDIO_DEVICE_BIT_IN;
   1042         if ((popcount(device) == 1) && (device & AUDIO_DEVICE_IN_BLUETOOTH_A2DP))
   1043             return true;
   1044     }
   1045     return false;
   1046 }
   1047 
   1048 static inline bool audio_is_a2dp_out_device(audio_devices_t device)
   1049 {
   1050     if ((popcount(device) == 1) && (device & AUDIO_DEVICE_OUT_ALL_A2DP))
   1051         return true;
   1052     else
   1053         return false;
   1054 }
   1055 
   1056 // Deprecated - use audio_is_a2dp_out_device() instead
   1057 static inline bool audio_is_a2dp_device(audio_devices_t device)
   1058 {
   1059     return audio_is_a2dp_out_device(device);
   1060 }
   1061 
   1062 static inline bool audio_is_bluetooth_sco_device(audio_devices_t device)
   1063 {
   1064     if ((device & AUDIO_DEVICE_BIT_IN) == 0) {
   1065         if ((popcount(device) == 1) && ((device & ~AUDIO_DEVICE_OUT_ALL_SCO) == 0))
   1066             return true;
   1067     } else {
   1068         device &= ~AUDIO_DEVICE_BIT_IN;
   1069         if ((popcount(device) == 1) && ((device & ~AUDIO_DEVICE_IN_BLUETOOTH_SCO_HEADSET) == 0))
   1070             return true;
   1071     }
   1072 
   1073     return false;
   1074 }
   1075 
   1076 static inline bool audio_is_usb_out_device(audio_devices_t device)
   1077 {
   1078     return ((popcount(device) == 1) && (device & AUDIO_DEVICE_OUT_ALL_USB));
   1079 }
   1080 
   1081 static inline bool audio_is_usb_in_device(audio_devices_t device)
   1082 {
   1083     if ((device & AUDIO_DEVICE_BIT_IN) != 0) {
   1084         device &= ~AUDIO_DEVICE_BIT_IN;
   1085         if (popcount(device) == 1 && (device & AUDIO_DEVICE_IN_ALL_USB) != 0)
   1086             return true;
   1087     }
   1088     return false;
   1089 }
   1090 
   1091 /* OBSOLETE - use audio_is_usb_out_device() instead. */
   1092 static inline bool audio_is_usb_device(audio_devices_t device)
   1093 {
   1094     return audio_is_usb_out_device(device);
   1095 }
   1096 
   1097 static inline bool audio_is_remote_submix_device(audio_devices_t device)
   1098 {
   1099     if ((device & AUDIO_DEVICE_OUT_REMOTE_SUBMIX) == AUDIO_DEVICE_OUT_REMOTE_SUBMIX
   1100             || (device & AUDIO_DEVICE_IN_REMOTE_SUBMIX) == AUDIO_DEVICE_IN_REMOTE_SUBMIX)
   1101         return true;
   1102     else
   1103         return false;
   1104 }
   1105 
   1106 /* Returns true if:
   1107  *  representation is valid, and
   1108  *  there is at least one channel bit set which _could_ correspond to an input channel, and
   1109  *  there are no channel bits set which could _not_ correspond to an input channel.
   1110  * Otherwise returns false.
   1111  */
   1112 static inline bool audio_is_input_channel(audio_channel_mask_t channel)
   1113 {
   1114     uint32_t bits = audio_channel_mask_get_bits(channel);
   1115     switch (audio_channel_mask_get_representation(channel)) {
   1116     case AUDIO_CHANNEL_REPRESENTATION_POSITION:
   1117         if (bits & ~AUDIO_CHANNEL_IN_ALL) {
   1118             bits = 0;
   1119         }
   1120         // fall through
   1121     case AUDIO_CHANNEL_REPRESENTATION_INDEX:
   1122         return bits != 0;
   1123     default:
   1124         return false;
   1125     }
   1126 }
   1127 
   1128 /* Returns true if:
   1129  *  representation is valid, and
   1130  *  there is at least one channel bit set which _could_ correspond to an output channel, and
   1131  *  there are no channel bits set which could _not_ correspond to an output channel.
   1132  * Otherwise returns false.
   1133  */
   1134 static inline bool audio_is_output_channel(audio_channel_mask_t channel)
   1135 {
   1136     uint32_t bits = audio_channel_mask_get_bits(channel);
   1137     switch (audio_channel_mask_get_representation(channel)) {
   1138     case AUDIO_CHANNEL_REPRESENTATION_POSITION:
   1139         if (bits & ~AUDIO_CHANNEL_OUT_ALL) {
   1140             bits = 0;
   1141         }
   1142         // fall through
   1143     case AUDIO_CHANNEL_REPRESENTATION_INDEX:
   1144         return bits != 0;
   1145     default:
   1146         return false;
   1147     }
   1148 }
   1149 
   1150 /* Returns the number of channels from an input channel mask,
   1151  * used in the context of audio input or recording.
   1152  * If a channel bit is set which could _not_ correspond to an input channel,
   1153  * it is excluded from the count.
   1154  * Returns zero if the representation is invalid.
   1155  */
   1156 static inline uint32_t audio_channel_count_from_in_mask(audio_channel_mask_t channel)
   1157 {
   1158     uint32_t bits = audio_channel_mask_get_bits(channel);
   1159     switch (audio_channel_mask_get_representation(channel)) {
   1160     case AUDIO_CHANNEL_REPRESENTATION_POSITION:
   1161         // TODO: We can now merge with from_out_mask and remove anding
   1162         bits &= AUDIO_CHANNEL_IN_ALL;
   1163         // fall through
   1164     case AUDIO_CHANNEL_REPRESENTATION_INDEX:
   1165         return popcount(bits);
   1166     default:
   1167         return 0;
   1168     }
   1169 }
   1170 
   1171 /* Returns the number of channels from an output channel mask,
   1172  * used in the context of audio output or playback.
   1173  * If a channel bit is set which could _not_ correspond to an output channel,
   1174  * it is excluded from the count.
   1175  * Returns zero if the representation is invalid.
   1176  */
   1177 static inline uint32_t audio_channel_count_from_out_mask(audio_channel_mask_t channel)
   1178 {
   1179     uint32_t bits = audio_channel_mask_get_bits(channel);
   1180     switch (audio_channel_mask_get_representation(channel)) {
   1181     case AUDIO_CHANNEL_REPRESENTATION_POSITION:
   1182         // TODO: We can now merge with from_in_mask and remove anding
   1183         bits &= AUDIO_CHANNEL_OUT_ALL;
   1184         // fall through
   1185     case AUDIO_CHANNEL_REPRESENTATION_INDEX:
   1186         return popcount(bits);
   1187     default:
   1188         return 0;
   1189     }
   1190 }
   1191 
   1192 /* Derive an output channel mask for position assignment from a channel count.
   1193  * This is to be used when the content channel mask is unknown. The 1, 2, 4, 5, 6, 7 and 8 channel
   1194  * cases are mapped to the standard game/home-theater layouts, but note that 4 is mapped to quad,
   1195  * and not stereo + FC + mono surround. A channel count of 3 is arbitrarily mapped to stereo + FC
   1196  * for continuity with stereo.
   1197  * Returns the matching channel mask,
   1198  * or AUDIO_CHANNEL_NONE if the channel count is zero,
   1199  * or AUDIO_CHANNEL_INVALID if the channel count exceeds that of the
   1200  * configurations for which a default output channel mask is defined.
   1201  */
   1202 static inline audio_channel_mask_t audio_channel_out_mask_from_count(uint32_t channel_count)
   1203 {
   1204     uint32_t bits;
   1205     switch (channel_count) {
   1206     case 0:
   1207         return AUDIO_CHANNEL_NONE;
   1208     case 1:
   1209         bits = AUDIO_CHANNEL_OUT_MONO;
   1210         break;
   1211     case 2:
   1212         bits = AUDIO_CHANNEL_OUT_STEREO;
   1213         break;
   1214     case 3:
   1215         bits = AUDIO_CHANNEL_OUT_STEREO | AUDIO_CHANNEL_OUT_FRONT_CENTER;
   1216         break;
   1217     case 4: // 4.0
   1218         bits = AUDIO_CHANNEL_OUT_QUAD;
   1219         break;
   1220     case 5: // 5.0
   1221         bits = AUDIO_CHANNEL_OUT_QUAD | AUDIO_CHANNEL_OUT_FRONT_CENTER;
   1222         break;
   1223     case 6: // 5.1
   1224         bits = AUDIO_CHANNEL_OUT_5POINT1;
   1225         break;
   1226     case 7: // 6.1
   1227         bits = AUDIO_CHANNEL_OUT_5POINT1 | AUDIO_CHANNEL_OUT_BACK_CENTER;
   1228         break;
   1229     case 8:
   1230         bits = AUDIO_CHANNEL_OUT_7POINT1;
   1231         break;
   1232     default:
   1233         return AUDIO_CHANNEL_INVALID;
   1234     }
   1235     return audio_channel_mask_from_representation_and_bits(
   1236             AUDIO_CHANNEL_REPRESENTATION_POSITION, bits);
   1237 }
   1238 
   1239 /* Derive an input channel mask for position assignment from a channel count.
   1240  * Currently handles only mono and stereo.
   1241  * Returns the matching channel mask,
   1242  * or AUDIO_CHANNEL_NONE if the channel count is zero,
   1243  * or AUDIO_CHANNEL_INVALID if the channel count exceeds that of the
   1244  * configurations for which a default input channel mask is defined.
   1245  */
   1246 static inline audio_channel_mask_t audio_channel_in_mask_from_count(uint32_t channel_count)
   1247 {
   1248     uint32_t bits;
   1249     switch (channel_count) {
   1250     case 0:
   1251         return AUDIO_CHANNEL_NONE;
   1252     case 1:
   1253         bits = AUDIO_CHANNEL_IN_MONO;
   1254         break;
   1255     case 2:
   1256         bits = AUDIO_CHANNEL_IN_STEREO;
   1257         break;
   1258     default:
   1259         return AUDIO_CHANNEL_INVALID;
   1260     }
   1261     return audio_channel_mask_from_representation_and_bits(
   1262             AUDIO_CHANNEL_REPRESENTATION_POSITION, bits);
   1263 }
   1264 
   1265 /* Derive a channel mask for index assignment from a channel count.
   1266  * Returns the matching channel mask,
   1267  * or AUDIO_CHANNEL_NONE if the channel count is zero,
   1268  * or AUDIO_CHANNEL_INVALID if the channel count exceeds AUDIO_CHANNEL_COUNT_MAX.
   1269  */
   1270 static inline audio_channel_mask_t audio_channel_mask_for_index_assignment_from_count(
   1271         uint32_t channel_count)
   1272 {
   1273     if (channel_count == 0) {
   1274         return AUDIO_CHANNEL_NONE;
   1275     }
   1276     if (channel_count > AUDIO_CHANNEL_COUNT_MAX) {
   1277         return AUDIO_CHANNEL_INVALID;
   1278     }
   1279     uint32_t bits = (1 << channel_count) - 1;
   1280     return audio_channel_mask_from_representation_and_bits(
   1281             AUDIO_CHANNEL_REPRESENTATION_INDEX, bits);
   1282 }
   1283 
   1284 static inline bool audio_is_valid_format(audio_format_t format)
   1285 {
   1286     switch (format & AUDIO_FORMAT_MAIN_MASK) {
   1287     case AUDIO_FORMAT_PCM:
   1288         switch (format) {
   1289         case AUDIO_FORMAT_PCM_16_BIT:
   1290         case AUDIO_FORMAT_PCM_8_BIT:
   1291         case AUDIO_FORMAT_PCM_32_BIT:
   1292         case AUDIO_FORMAT_PCM_8_24_BIT:
   1293         case AUDIO_FORMAT_PCM_FLOAT:
   1294         case AUDIO_FORMAT_PCM_24_BIT_PACKED:
   1295             return true;
   1296         default:
   1297             return false;
   1298         }
   1299         /* not reached */
   1300     case AUDIO_FORMAT_MP3:
   1301     case AUDIO_FORMAT_AMR_NB:
   1302     case AUDIO_FORMAT_AMR_WB:
   1303     case AUDIO_FORMAT_AAC:
   1304     case AUDIO_FORMAT_HE_AAC_V1:
   1305     case AUDIO_FORMAT_HE_AAC_V2:
   1306     case AUDIO_FORMAT_VORBIS:
   1307     case AUDIO_FORMAT_OPUS:
   1308     case AUDIO_FORMAT_AC3:
   1309     case AUDIO_FORMAT_E_AC3:
   1310         return true;
   1311     default:
   1312         return false;
   1313     }
   1314 }
   1315 
   1316 static inline bool audio_is_linear_pcm(audio_format_t format)
   1317 {
   1318     return ((format & AUDIO_FORMAT_MAIN_MASK) == AUDIO_FORMAT_PCM);
   1319 }
   1320 
   1321 static inline size_t audio_bytes_per_sample(audio_format_t format)
   1322 {
   1323     size_t size = 0;
   1324 
   1325     switch (format) {
   1326     case AUDIO_FORMAT_PCM_32_BIT:
   1327     case AUDIO_FORMAT_PCM_8_24_BIT:
   1328         size = sizeof(int32_t);
   1329         break;
   1330     case AUDIO_FORMAT_PCM_24_BIT_PACKED:
   1331         size = sizeof(uint8_t) * 3;
   1332         break;
   1333     case AUDIO_FORMAT_PCM_16_BIT:
   1334         size = sizeof(int16_t);
   1335         break;
   1336     case AUDIO_FORMAT_PCM_8_BIT:
   1337         size = sizeof(uint8_t);
   1338         break;
   1339     case AUDIO_FORMAT_PCM_FLOAT:
   1340         size = sizeof(float);
   1341         break;
   1342     default:
   1343         break;
   1344     }
   1345     return size;
   1346 }
   1347 
   1348 /* converts device address to string sent to audio HAL via set_parameters */
   1349 static char *audio_device_address_to_parameter(audio_devices_t device, const char *address)
   1350 {
   1351     const size_t kSize = AUDIO_DEVICE_MAX_ADDRESS_LEN + sizeof("a2dp_sink_address=");
   1352     char param[kSize];
   1353 
   1354     if (device & AUDIO_DEVICE_OUT_ALL_A2DP)
   1355         snprintf(param, kSize, "%s=%s", "a2dp_sink_address", address);
   1356     else if (device & AUDIO_DEVICE_OUT_REMOTE_SUBMIX)
   1357         snprintf(param, kSize, "%s=%s", "mix", address);
   1358     else
   1359         snprintf(param, kSize, "%s", address);
   1360 
   1361     return strdup(param);
   1362 }
   1363 
   1364 
   1365 __END_DECLS
   1366 
   1367 #endif  // ANDROID_AUDIO_CORE_H
   1368