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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_EFFECT_H
     19 #define ANDROID_AUDIO_EFFECT_H
     20 
     21 #include <errno.h>
     22 #include <stdint.h>
     23 #include <strings.h>
     24 #include <sys/cdefs.h>
     25 #include <sys/types.h>
     26 
     27 #include <cutils/bitops.h>
     28 
     29 #include <system/audio.h>
     30 
     31 
     32 __BEGIN_DECLS
     33 
     34 
     35 /////////////////////////////////////////////////
     36 //      Common Definitions
     37 /////////////////////////////////////////////////
     38 
     39 //
     40 //--- Effect descriptor structure effect_descriptor_t
     41 //
     42 
     43 // Unique effect ID (can be generated from the following site:
     44 //  http://www.itu.int/ITU-T/asn1/uuid.html)
     45 // This format is used for both "type" and "uuid" fields of the effect descriptor structure.
     46 // - When used for effect type and the engine is implementing and effect corresponding to a standard
     47 // OpenSL ES interface, this ID must be the one defined in OpenSLES_IID.h for that interface.
     48 // - When used as uuid, it should be a unique UUID for this particular implementation.
     49 typedef struct effect_uuid_s {
     50     uint32_t timeLow;
     51     uint16_t timeMid;
     52     uint16_t timeHiAndVersion;
     53     uint16_t clockSeq;
     54     uint8_t node[6];
     55 } effect_uuid_t;
     56 
     57 // Maximum length of character strings in structures defines by this API.
     58 #define EFFECT_STRING_LEN_MAX 64
     59 
     60 // NULL UUID definition (matches SL_IID_NULL_)
     61 #define EFFECT_UUID_INITIALIZER { 0xec7178ec, 0xe5e1, 0x4432, 0xa3f4, \
     62                                   { 0x46, 0x57, 0xe6, 0x79, 0x52, 0x10 } }
     63 static const effect_uuid_t EFFECT_UUID_NULL_ = EFFECT_UUID_INITIALIZER;
     64 static const effect_uuid_t * const EFFECT_UUID_NULL = &EFFECT_UUID_NULL_;
     65 static const char * const EFFECT_UUID_NULL_STR = "ec7178ec-e5e1-4432-a3f4-4657e6795210";
     66 
     67 
     68 // The effect descriptor contains necessary information to facilitate the enumeration of the effect
     69 // engines present in a library.
     70 typedef struct effect_descriptor_s {
     71     effect_uuid_t type;     // UUID of to the OpenSL ES interface implemented by this effect
     72     effect_uuid_t uuid;     // UUID for this particular implementation
     73     uint32_t apiVersion;    // Version of the effect control API implemented
     74     uint32_t flags;         // effect engine capabilities/requirements flags (see below)
     75     uint16_t cpuLoad;       // CPU load indication (see below)
     76     uint16_t memoryUsage;   // Data Memory usage (see below)
     77     char    name[EFFECT_STRING_LEN_MAX];   // human readable effect name
     78     char    implementor[EFFECT_STRING_LEN_MAX];    // human readable effect implementor name
     79 } effect_descriptor_t;
     80 
     81 // CPU load and memory usage indication: each effect implementation must provide an indication of
     82 // its CPU and memory usage for the audio effect framework to limit the number of effects
     83 // instantiated at a given time on a given platform.
     84 // The CPU load is expressed in 0.1 MIPS units as estimated on an ARM9E core (ARMv5TE) with 0 WS.
     85 // The memory usage is expressed in KB and includes only dynamically allocated memory
     86 
     87 // Definitions for flags field of effect descriptor.
     88 //  +---------------------------+-----------+-----------------------------------
     89 //  | description               | bits      | values
     90 //  +---------------------------+-----------+-----------------------------------
     91 //  | connection mode           | 0..2      | 0 insert: after track process
     92 //  |                           |           | 1 auxiliary: connect to track auxiliary
     93 //  |                           |           |  output and use send level
     94 //  |                           |           | 2 replace: replaces track process function;
     95 //  |                           |           |   must implement SRC, volume and mono to stereo.
     96 //  |                           |           | 3 pre processing: applied below audio HAL on input
     97 //  |                           |           | 4 post processing: applied below audio HAL on output
     98 //  |                           |           | 5 - 7 reserved
     99 //  +---------------------------+-----------+-----------------------------------
    100 //  | insertion preference      | 3..5      | 0 none
    101 //  |                           |           | 1 first of the chain
    102 //  |                           |           | 2 last of the chain
    103 //  |                           |           | 3 exclusive (only effect in the insert chain)
    104 //  |                           |           | 4..7 reserved
    105 //  +---------------------------+-----------+-----------------------------------
    106 //  | Volume management         | 6..8      | 0 none
    107 //  |                           |           | 1 implements volume control
    108 //  |                           |           | 2 requires volume indication
    109 //  |                           |           | 4 reserved
    110 //  +---------------------------+-----------+-----------------------------------
    111 //  | Device indication         | 9..11     | 0 none
    112 //  |                           |           | 1 requires device updates
    113 //  |                           |           | 2, 4 reserved
    114 //  +---------------------------+-----------+-----------------------------------
    115 //  | Sample input mode         | 12..13    | 1 direct: process() function or EFFECT_CMD_SET_CONFIG
    116 //  |                           |           |   command must specify a buffer descriptor
    117 //  |                           |           | 2 provider: process() function uses the
    118 //  |                           |           |   bufferProvider indicated by the
    119 //  |                           |           |   EFFECT_CMD_SET_CONFIG command to request input.
    120 //  |                           |           |   buffers.
    121 //  |                           |           | 3 both: both input modes are supported
    122 //  +---------------------------+-----------+-----------------------------------
    123 //  | Sample output mode        | 14..15    | 1 direct: process() function or EFFECT_CMD_SET_CONFIG
    124 //  |                           |           |   command must specify a buffer descriptor
    125 //  |                           |           | 2 provider: process() function uses the
    126 //  |                           |           |   bufferProvider indicated by the
    127 //  |                           |           |   EFFECT_CMD_SET_CONFIG command to request output
    128 //  |                           |           |   buffers.
    129 //  |                           |           | 3 both: both output modes are supported
    130 //  +---------------------------+-----------+-----------------------------------
    131 //  | Hardware acceleration     | 16..17    | 0 No hardware acceleration
    132 //  |                           |           | 1 non tunneled hw acceleration: the process() function
    133 //  |                           |           |   reads the samples, send them to HW accelerated
    134 //  |                           |           |   effect processor, reads back the processed samples
    135 //  |                           |           |   and returns them to the output buffer.
    136 //  |                           |           | 2 tunneled hw acceleration: the process() function is
    137 //  |                           |           |   transparent. The effect interface is only used to
    138 //  |                           |           |   control the effect engine. This mode is relevant for
    139 //  |                           |           |   global effects actually applied by the audio
    140 //  |                           |           |   hardware on the output stream.
    141 //  +---------------------------+-----------+-----------------------------------
    142 //  | Audio Mode indication     | 18..19    | 0 none
    143 //  |                           |           | 1 requires audio mode updates
    144 //  |                           |           | 2..3 reserved
    145 //  +---------------------------+-----------+-----------------------------------
    146 //  | Audio source indication   | 20..21    | 0 none
    147 //  |                           |           | 1 requires audio source updates
    148 //  |                           |           | 2..3 reserved
    149 //  +---------------------------+-----------+-----------------------------------
    150 //  | Effect offload supported  | 22        | 0 The effect cannot be offloaded to an audio DSP
    151 //  |                           |           | 1 The effect can be offloaded to an audio DSP
    152 //  +---------------------------+-----------+-----------------------------------
    153 
    154 // Insert mode
    155 #define EFFECT_FLAG_TYPE_SHIFT          0
    156 #define EFFECT_FLAG_TYPE_SIZE           3
    157 #define EFFECT_FLAG_TYPE_MASK           (((1 << EFFECT_FLAG_TYPE_SIZE) -1) \
    158                                             << EFFECT_FLAG_TYPE_SHIFT)
    159 #define EFFECT_FLAG_TYPE_INSERT         (0 << EFFECT_FLAG_TYPE_SHIFT)
    160 #define EFFECT_FLAG_TYPE_AUXILIARY      (1 << EFFECT_FLAG_TYPE_SHIFT)
    161 #define EFFECT_FLAG_TYPE_REPLACE        (2 << EFFECT_FLAG_TYPE_SHIFT)
    162 #define EFFECT_FLAG_TYPE_PRE_PROC       (3 << EFFECT_FLAG_TYPE_SHIFT)
    163 #define EFFECT_FLAG_TYPE_POST_PROC      (4 << EFFECT_FLAG_TYPE_SHIFT)
    164 
    165 // Insert preference
    166 #define EFFECT_FLAG_INSERT_SHIFT        (EFFECT_FLAG_TYPE_SHIFT + EFFECT_FLAG_TYPE_SIZE)
    167 #define EFFECT_FLAG_INSERT_SIZE         3
    168 #define EFFECT_FLAG_INSERT_MASK         (((1 << EFFECT_FLAG_INSERT_SIZE) -1) \
    169                                             << EFFECT_FLAG_INSERT_SHIFT)
    170 #define EFFECT_FLAG_INSERT_ANY          (0 << EFFECT_FLAG_INSERT_SHIFT)
    171 #define EFFECT_FLAG_INSERT_FIRST        (1 << EFFECT_FLAG_INSERT_SHIFT)
    172 #define EFFECT_FLAG_INSERT_LAST         (2 << EFFECT_FLAG_INSERT_SHIFT)
    173 #define EFFECT_FLAG_INSERT_EXCLUSIVE    (3 << EFFECT_FLAG_INSERT_SHIFT)
    174 
    175 
    176 // Volume control
    177 #define EFFECT_FLAG_VOLUME_SHIFT        (EFFECT_FLAG_INSERT_SHIFT + EFFECT_FLAG_INSERT_SIZE)
    178 #define EFFECT_FLAG_VOLUME_SIZE         3
    179 #define EFFECT_FLAG_VOLUME_MASK         (((1 << EFFECT_FLAG_VOLUME_SIZE) -1) \
    180                                             << EFFECT_FLAG_VOLUME_SHIFT)
    181 #define EFFECT_FLAG_VOLUME_CTRL         (1 << EFFECT_FLAG_VOLUME_SHIFT)
    182 #define EFFECT_FLAG_VOLUME_IND          (2 << EFFECT_FLAG_VOLUME_SHIFT)
    183 #define EFFECT_FLAG_VOLUME_NONE         (0 << EFFECT_FLAG_VOLUME_SHIFT)
    184 
    185 // Device indication
    186 #define EFFECT_FLAG_DEVICE_SHIFT        (EFFECT_FLAG_VOLUME_SHIFT + EFFECT_FLAG_VOLUME_SIZE)
    187 #define EFFECT_FLAG_DEVICE_SIZE         3
    188 #define EFFECT_FLAG_DEVICE_MASK         (((1 << EFFECT_FLAG_DEVICE_SIZE) -1) \
    189                                             << EFFECT_FLAG_DEVICE_SHIFT)
    190 #define EFFECT_FLAG_DEVICE_IND          (1 << EFFECT_FLAG_DEVICE_SHIFT)
    191 #define EFFECT_FLAG_DEVICE_NONE         (0 << EFFECT_FLAG_DEVICE_SHIFT)
    192 
    193 // Sample input modes
    194 #define EFFECT_FLAG_INPUT_SHIFT         (EFFECT_FLAG_DEVICE_SHIFT + EFFECT_FLAG_DEVICE_SIZE)
    195 #define EFFECT_FLAG_INPUT_SIZE          2
    196 #define EFFECT_FLAG_INPUT_MASK          (((1 << EFFECT_FLAG_INPUT_SIZE) -1) \
    197                                             << EFFECT_FLAG_INPUT_SHIFT)
    198 #define EFFECT_FLAG_INPUT_DIRECT        (1 << EFFECT_FLAG_INPUT_SHIFT)
    199 #define EFFECT_FLAG_INPUT_PROVIDER      (2 << EFFECT_FLAG_INPUT_SHIFT)
    200 #define EFFECT_FLAG_INPUT_BOTH          (3 << EFFECT_FLAG_INPUT_SHIFT)
    201 
    202 // Sample output modes
    203 #define EFFECT_FLAG_OUTPUT_SHIFT        (EFFECT_FLAG_INPUT_SHIFT + EFFECT_FLAG_INPUT_SIZE)
    204 #define EFFECT_FLAG_OUTPUT_SIZE         2
    205 #define EFFECT_FLAG_OUTPUT_MASK         (((1 << EFFECT_FLAG_OUTPUT_SIZE) -1) \
    206                                             << EFFECT_FLAG_OUTPUT_SHIFT)
    207 #define EFFECT_FLAG_OUTPUT_DIRECT       (1 << EFFECT_FLAG_OUTPUT_SHIFT)
    208 #define EFFECT_FLAG_OUTPUT_PROVIDER     (2 << EFFECT_FLAG_OUTPUT_SHIFT)
    209 #define EFFECT_FLAG_OUTPUT_BOTH         (3 << EFFECT_FLAG_OUTPUT_SHIFT)
    210 
    211 // Hardware acceleration mode
    212 #define EFFECT_FLAG_HW_ACC_SHIFT        (EFFECT_FLAG_OUTPUT_SHIFT + EFFECT_FLAG_OUTPUT_SIZE)
    213 #define EFFECT_FLAG_HW_ACC_SIZE         2
    214 #define EFFECT_FLAG_HW_ACC_MASK         (((1 << EFFECT_FLAG_HW_ACC_SIZE) -1) \
    215                                             << EFFECT_FLAG_HW_ACC_SHIFT)
    216 #define EFFECT_FLAG_HW_ACC_SIMPLE       (1 << EFFECT_FLAG_HW_ACC_SHIFT)
    217 #define EFFECT_FLAG_HW_ACC_TUNNEL       (2 << EFFECT_FLAG_HW_ACC_SHIFT)
    218 
    219 // Audio mode indication
    220 #define EFFECT_FLAG_AUDIO_MODE_SHIFT    (EFFECT_FLAG_HW_ACC_SHIFT + EFFECT_FLAG_HW_ACC_SIZE)
    221 #define EFFECT_FLAG_AUDIO_MODE_SIZE     2
    222 #define EFFECT_FLAG_AUDIO_MODE_MASK     (((1 << EFFECT_FLAG_AUDIO_MODE_SIZE) -1) \
    223                                             << EFFECT_FLAG_AUDIO_MODE_SHIFT)
    224 #define EFFECT_FLAG_AUDIO_MODE_IND      (1 << EFFECT_FLAG_AUDIO_MODE_SHIFT)
    225 #define EFFECT_FLAG_AUDIO_MODE_NONE     (0 << EFFECT_FLAG_AUDIO_MODE_SHIFT)
    226 
    227 // Audio source indication
    228 #define EFFECT_FLAG_AUDIO_SOURCE_SHIFT  (EFFECT_FLAG_AUDIO_MODE_SHIFT + EFFECT_FLAG_AUDIO_MODE_SIZE)
    229 #define EFFECT_FLAG_AUDIO_SOURCE_SIZE   2
    230 #define EFFECT_FLAG_AUDIO_SOURCE_MASK   (((1 << EFFECT_FLAG_AUDIO_SOURCE_SIZE) -1) \
    231                                           << EFFECT_FLAG_AUDIO_SOURCE_SHIFT)
    232 #define EFFECT_FLAG_AUDIO_SOURCE_IND    (1 << EFFECT_FLAG_AUDIO_SOURCE_SHIFT)
    233 #define EFFECT_FLAG_AUDIO_SOURCE_NONE   (0 << EFFECT_FLAG_AUDIO_SOURCE_SHIFT)
    234 
    235 // Effect offload indication
    236 #define EFFECT_FLAG_OFFLOAD_SHIFT       (EFFECT_FLAG_AUDIO_SOURCE_SHIFT + \
    237                                                     EFFECT_FLAG_AUDIO_SOURCE_SIZE)
    238 #define EFFECT_FLAG_OFFLOAD_SIZE        1
    239 #define EFFECT_FLAG_OFFLOAD_MASK        (((1 << EFFECT_FLAG_OFFLOAD_SIZE) -1) \
    240                                           << EFFECT_FLAG_OFFLOAD_SHIFT)
    241 #define EFFECT_FLAG_OFFLOAD_SUPPORTED   (1 << EFFECT_FLAG_OFFLOAD_SHIFT)
    242 
    243 #define EFFECT_MAKE_API_VERSION(M, m)  (((M)<<16) | ((m) & 0xFFFF))
    244 #define EFFECT_API_VERSION_MAJOR(v)    ((v)>>16)
    245 #define EFFECT_API_VERSION_MINOR(v)    ((m) & 0xFFFF)
    246 
    247 
    248 
    249 /////////////////////////////////////////////////
    250 //      Effect control interface
    251 /////////////////////////////////////////////////
    252 
    253 // Effect control interface version 2.0
    254 #define EFFECT_CONTROL_API_VERSION EFFECT_MAKE_API_VERSION(2,0)
    255 
    256 // Effect control interface structure: effect_interface_s
    257 // The effect control interface is exposed by each effect engine implementation. It consists of
    258 // a set of functions controlling the configuration, activation and process of the engine.
    259 // The functions are grouped in a structure of type effect_interface_s.
    260 //
    261 // Effect control interface handle: effect_handle_t
    262 // The effect_handle_t serves two purposes regarding the implementation of the effect engine:
    263 // - 1 it is the address of a pointer to an effect_interface_s structure where the functions
    264 // of the effect control API for a particular effect are located.
    265 // - 2 it is the address of the context of a particular effect instance.
    266 // A typical implementation in the effect library would define a structure as follows:
    267 // struct effect_module_s {
    268 //        const struct effect_interface_s *itfe;
    269 //        effect_config_t config;
    270 //        effect_context_t context;
    271 // }
    272 // The implementation of EffectCreate() function would then allocate a structure of this
    273 // type and return its address as effect_handle_t
    274 typedef struct effect_interface_s **effect_handle_t;
    275 
    276 
    277 // Forward definition of type audio_buffer_t
    278 typedef struct audio_buffer_s audio_buffer_t;
    279 
    280 
    281 
    282 
    283 
    284 
    285 // Effect control interface definition
    286 struct effect_interface_s {
    287     ////////////////////////////////////////////////////////////////////////////////
    288     //
    289     //    Function:       process
    290     //
    291     //    Description:    Effect process function. Takes input samples as specified
    292     //          (count and location) in input buffer descriptor and output processed
    293     //          samples as specified in output buffer descriptor. If the buffer descriptor
    294     //          is not specified the function must use either the buffer or the
    295     //          buffer provider function installed by the EFFECT_CMD_SET_CONFIG command.
    296     //          The effect framework will call the process() function after the EFFECT_CMD_ENABLE
    297     //          command is received and until the EFFECT_CMD_DISABLE is received. When the engine
    298     //          receives the EFFECT_CMD_DISABLE command it should turn off the effect gracefully
    299     //          and when done indicate that it is OK to stop calling the process() function by
    300     //          returning the -ENODATA status.
    301     //
    302     //    NOTE: the process() function implementation should be "real-time safe" that is
    303     //      it should not perform blocking calls: malloc/free, sleep, read/write/open/close,
    304     //      pthread_cond_wait/pthread_mutex_lock...
    305     //
    306     //    Input:
    307     //          self:       handle to the effect interface this function
    308     //              is called on.
    309     //          inBuffer:   buffer descriptor indicating where to read samples to process.
    310     //              If NULL, use the configuration passed by EFFECT_CMD_SET_CONFIG command.
    311     //
    312     //          outBuffer:   buffer descriptor indicating where to write processed samples.
    313     //              If NULL, use the configuration passed by EFFECT_CMD_SET_CONFIG command.
    314     //
    315     //    Output:
    316     //        returned value:    0 successful operation
    317     //                          -ENODATA the engine has finished the disable phase and the framework
    318     //                                  can stop calling process()
    319     //                          -EINVAL invalid interface handle or
    320     //                                  invalid input/output buffer description
    321     ////////////////////////////////////////////////////////////////////////////////
    322     int32_t (*process)(effect_handle_t self,
    323                        audio_buffer_t *inBuffer,
    324                        audio_buffer_t *outBuffer);
    325     ////////////////////////////////////////////////////////////////////////////////
    326     //
    327     //    Function:       command
    328     //
    329     //    Description:    Send a command and receive a response to/from effect engine.
    330     //
    331     //    Input:
    332     //          self:       handle to the effect interface this function
    333     //              is called on.
    334     //          cmdCode:    command code: the command can be a standardized command defined in
    335     //              effect_command_e (see below) or a proprietary command.
    336     //          cmdSize:    size of command in bytes
    337     //          pCmdData:   pointer to command data
    338     //          pReplyData: pointer to reply data
    339     //
    340     //    Input/Output:
    341     //          replySize: maximum size of reply data as input
    342     //                      actual size of reply data as output
    343     //
    344     //    Output:
    345     //          returned value: 0       successful operation
    346     //                          -EINVAL invalid interface handle or
    347     //                                  invalid command/reply size or format according to
    348     //                                  command code
    349     //              The return code should be restricted to indicate problems related to this API
    350     //              specification. Status related to the execution of a particular command should be
    351     //              indicated as part of the reply field.
    352     //
    353     //          *pReplyData updated with command response
    354     //
    355     ////////////////////////////////////////////////////////////////////////////////
    356     int32_t (*command)(effect_handle_t self,
    357                        uint32_t cmdCode,
    358                        uint32_t cmdSize,
    359                        void *pCmdData,
    360                        uint32_t *replySize,
    361                        void *pReplyData);
    362     ////////////////////////////////////////////////////////////////////////////////
    363     //
    364     //    Function:        get_descriptor
    365     //
    366     //    Description:    Returns the effect descriptor
    367     //
    368     //    Input:
    369     //          self:       handle to the effect interface this function
    370     //              is called on.
    371     //
    372     //    Input/Output:
    373     //          pDescriptor:    address where to return the effect descriptor.
    374     //
    375     //    Output:
    376     //        returned value:    0          successful operation.
    377     //                          -EINVAL     invalid interface handle or invalid pDescriptor
    378     //        *pDescriptor:     updated with the effect descriptor.
    379     //
    380     ////////////////////////////////////////////////////////////////////////////////
    381     int32_t (*get_descriptor)(effect_handle_t self,
    382                               effect_descriptor_t *pDescriptor);
    383     ////////////////////////////////////////////////////////////////////////////////
    384     //
    385     //    Function:       process_reverse
    386     //
    387     //    Description:    Process reverse stream function. This function is used to pass
    388     //          a reference stream to the effect engine. If the engine does not need a reference
    389     //          stream, this function pointer can be set to NULL.
    390     //          This function would typically implemented by an Echo Canceler.
    391     //
    392     //    Input:
    393     //          self:       handle to the effect interface this function
    394     //              is called on.
    395     //          inBuffer:   buffer descriptor indicating where to read samples to process.
    396     //              If NULL, use the configuration passed by EFFECT_CMD_SET_CONFIG_REVERSE command.
    397     //
    398     //          outBuffer:   buffer descriptor indicating where to write processed samples.
    399     //              If NULL, use the configuration passed by EFFECT_CMD_SET_CONFIG_REVERSE command.
    400     //              If the buffer and buffer provider in the configuration received by
    401     //              EFFECT_CMD_SET_CONFIG_REVERSE are also NULL, do not return modified reverse
    402     //              stream data
    403     //
    404     //    Output:
    405     //        returned value:    0 successful operation
    406     //                          -ENODATA the engine has finished the disable phase and the framework
    407     //                                  can stop calling process_reverse()
    408     //                          -EINVAL invalid interface handle or
    409     //                                  invalid input/output buffer description
    410     ////////////////////////////////////////////////////////////////////////////////
    411     int32_t (*process_reverse)(effect_handle_t self,
    412                                audio_buffer_t *inBuffer,
    413                                audio_buffer_t *outBuffer);
    414 };
    415 
    416 
    417 //
    418 //--- Standardized command codes for command() function
    419 //
    420 enum effect_command_e {
    421    EFFECT_CMD_INIT,                 // initialize effect engine
    422    EFFECT_CMD_SET_CONFIG,           // configure effect engine (see effect_config_t)
    423    EFFECT_CMD_RESET,                // reset effect engine
    424    EFFECT_CMD_ENABLE,               // enable effect process
    425    EFFECT_CMD_DISABLE,              // disable effect process
    426    EFFECT_CMD_SET_PARAM,            // set parameter immediately (see effect_param_t)
    427    EFFECT_CMD_SET_PARAM_DEFERRED,   // set parameter deferred
    428    EFFECT_CMD_SET_PARAM_COMMIT,     // commit previous set parameter deferred
    429    EFFECT_CMD_GET_PARAM,            // get parameter
    430    EFFECT_CMD_SET_DEVICE,           // set audio device (see audio.h, audio_devices_t)
    431    EFFECT_CMD_SET_VOLUME,           // set volume
    432    EFFECT_CMD_SET_AUDIO_MODE,       // set the audio mode (normal, ring, ...)
    433    EFFECT_CMD_SET_CONFIG_REVERSE,   // configure effect engine reverse stream(see effect_config_t)
    434    EFFECT_CMD_SET_INPUT_DEVICE,     // set capture device (see audio.h, audio_devices_t)
    435    EFFECT_CMD_GET_CONFIG,           // read effect engine configuration
    436    EFFECT_CMD_GET_CONFIG_REVERSE,   // read configure effect engine reverse stream configuration
    437    EFFECT_CMD_GET_FEATURE_SUPPORTED_CONFIGS,// get all supported configurations for a feature.
    438    EFFECT_CMD_GET_FEATURE_CONFIG,   // get current feature configuration
    439    EFFECT_CMD_SET_FEATURE_CONFIG,   // set current feature configuration
    440    EFFECT_CMD_SET_AUDIO_SOURCE,     // set the audio source (see audio.h, audio_source_t)
    441    EFFECT_CMD_OFFLOAD,              // set if effect thread is an offload one,
    442                                     // send the ioHandle of the effect thread
    443    EFFECT_CMD_FIRST_PROPRIETARY = 0x10000 // first proprietary command code
    444 };
    445 
    446 //==================================================================================================
    447 // command: EFFECT_CMD_INIT
    448 //--------------------------------------------------------------------------------------------------
    449 // description:
    450 //  Initialize effect engine: All configurations return to default
    451 //--------------------------------------------------------------------------------------------------
    452 // command format:
    453 //  size: 0
    454 //  data: N/A
    455 //--------------------------------------------------------------------------------------------------
    456 // reply format:
    457 //  size: sizeof(int)
    458 //  data: status
    459 //==================================================================================================
    460 // command: EFFECT_CMD_SET_CONFIG
    461 //--------------------------------------------------------------------------------------------------
    462 // description:
    463 //  Apply new audio parameters configurations for input and output buffers
    464 //--------------------------------------------------------------------------------------------------
    465 // command format:
    466 //  size: sizeof(effect_config_t)
    467 //  data: effect_config_t
    468 //--------------------------------------------------------------------------------------------------
    469 // reply format:
    470 //  size: sizeof(int)
    471 //  data: status
    472 //==================================================================================================
    473 // command: EFFECT_CMD_RESET
    474 //--------------------------------------------------------------------------------------------------
    475 // description:
    476 //  Reset the effect engine. Keep configuration but resets state and buffer content
    477 //--------------------------------------------------------------------------------------------------
    478 // command format:
    479 //  size: 0
    480 //  data: N/A
    481 //--------------------------------------------------------------------------------------------------
    482 // reply format:
    483 //  size: 0
    484 //  data: N/A
    485 //==================================================================================================
    486 // command: EFFECT_CMD_ENABLE
    487 //--------------------------------------------------------------------------------------------------
    488 // description:
    489 //  Enable the process. Called by the framework before the first call to process()
    490 //--------------------------------------------------------------------------------------------------
    491 // command format:
    492 //  size: 0
    493 //  data: N/A
    494 //--------------------------------------------------------------------------------------------------
    495 // reply format:
    496 //  size: sizeof(int)
    497 //  data: status
    498 //==================================================================================================
    499 // command: EFFECT_CMD_DISABLE
    500 //--------------------------------------------------------------------------------------------------
    501 // description:
    502 //  Disable the process. Called by the framework after the last call to process()
    503 //--------------------------------------------------------------------------------------------------
    504 // command format:
    505 //  size: 0
    506 //  data: N/A
    507 //--------------------------------------------------------------------------------------------------
    508 // reply format:
    509 //  size: sizeof(int)
    510 //  data: status
    511 //==================================================================================================
    512 // command: EFFECT_CMD_SET_PARAM
    513 //--------------------------------------------------------------------------------------------------
    514 // description:
    515 //  Set a parameter and apply it immediately
    516 //--------------------------------------------------------------------------------------------------
    517 // command format:
    518 //  size: sizeof(effect_param_t) + size of param and value
    519 //  data: effect_param_t + param + value. See effect_param_t definition below for value offset
    520 //--------------------------------------------------------------------------------------------------
    521 // reply format:
    522 //  size: sizeof(int)
    523 //  data: status
    524 //==================================================================================================
    525 // command: EFFECT_CMD_SET_PARAM_DEFERRED
    526 //--------------------------------------------------------------------------------------------------
    527 // description:
    528 //  Set a parameter but apply it only when receiving EFFECT_CMD_SET_PARAM_COMMIT command
    529 //--------------------------------------------------------------------------------------------------
    530 // command format:
    531 //  size: sizeof(effect_param_t) + size of param and value
    532 //  data: effect_param_t + param + value. See effect_param_t definition below for value offset
    533 //--------------------------------------------------------------------------------------------------
    534 // reply format:
    535 //  size: 0
    536 //  data: N/A
    537 //==================================================================================================
    538 // command: EFFECT_CMD_SET_PARAM_COMMIT
    539 //--------------------------------------------------------------------------------------------------
    540 // description:
    541 //  Apply all previously received EFFECT_CMD_SET_PARAM_DEFERRED commands
    542 //--------------------------------------------------------------------------------------------------
    543 // command format:
    544 //  size: 0
    545 //  data: N/A
    546 //--------------------------------------------------------------------------------------------------
    547 // reply format:
    548 //  size: sizeof(int)
    549 //  data: status
    550 //==================================================================================================
    551 // command: EFFECT_CMD_GET_PARAM
    552 //--------------------------------------------------------------------------------------------------
    553 // description:
    554 //  Get a parameter value
    555 //--------------------------------------------------------------------------------------------------
    556 // command format:
    557 //  size: sizeof(effect_param_t) + size of param
    558 //  data: effect_param_t + param
    559 //--------------------------------------------------------------------------------------------------
    560 // reply format:
    561 //  size: sizeof(effect_param_t) + size of param and value
    562 //  data: effect_param_t + param + value. See effect_param_t definition below for value offset
    563 //==================================================================================================
    564 // command: EFFECT_CMD_SET_DEVICE
    565 //--------------------------------------------------------------------------------------------------
    566 // description:
    567 //  Set the rendering device the audio output path is connected to. See audio.h, audio_devices_t
    568 //  for device values.
    569 //  The effect implementation must set EFFECT_FLAG_DEVICE_IND flag in its descriptor to receive this
    570 //  command when the device changes
    571 //--------------------------------------------------------------------------------------------------
    572 // command format:
    573 //  size: sizeof(uint32_t)
    574 //  data: uint32_t
    575 //--------------------------------------------------------------------------------------------------
    576 // reply format:
    577 //  size: 0
    578 //  data: N/A
    579 //==================================================================================================
    580 // command: EFFECT_CMD_SET_VOLUME
    581 //--------------------------------------------------------------------------------------------------
    582 // description:
    583 //  Set and get volume. Used by audio framework to delegate volume control to effect engine.
    584 //  The effect implementation must set EFFECT_FLAG_VOLUME_IND or EFFECT_FLAG_VOLUME_CTRL flag in
    585 //  its descriptor to receive this command before every call to process() function
    586 //  If EFFECT_FLAG_VOLUME_CTRL flag is set in the effect descriptor, the effect engine must return
    587 //  the volume that should be applied before the effect is processed. The overall volume (the volume
    588 //  actually applied by the effect engine multiplied by the returned value) should match the value
    589 //  indicated in the command.
    590 //--------------------------------------------------------------------------------------------------
    591 // command format:
    592 //  size: n * sizeof(uint32_t)
    593 //  data: volume for each channel defined in effect_config_t for output buffer expressed in
    594 //      8.24 fixed point format
    595 //--------------------------------------------------------------------------------------------------
    596 // reply format:
    597 //  size: n * sizeof(uint32_t) / 0
    598 //  data: - if EFFECT_FLAG_VOLUME_CTRL is set in effect descriptor:
    599 //              volume for each channel defined in effect_config_t for output buffer expressed in
    600 //              8.24 fixed point format
    601 //        - if EFFECT_FLAG_VOLUME_CTRL is not set in effect descriptor:
    602 //              N/A
    603 //  It is legal to receive a null pointer as pReplyData in which case the effect framework has
    604 //  delegated volume control to another effect
    605 //==================================================================================================
    606 // command: EFFECT_CMD_SET_AUDIO_MODE
    607 //--------------------------------------------------------------------------------------------------
    608 // description:
    609 //  Set the audio mode. The effect implementation must set EFFECT_FLAG_AUDIO_MODE_IND flag in its
    610 //  descriptor to receive this command when the audio mode changes.
    611 //--------------------------------------------------------------------------------------------------
    612 // command format:
    613 //  size: sizeof(uint32_t)
    614 //  data: audio_mode_t
    615 //--------------------------------------------------------------------------------------------------
    616 // reply format:
    617 //  size: 0
    618 //  data: N/A
    619 //==================================================================================================
    620 // command: EFFECT_CMD_SET_CONFIG_REVERSE
    621 //--------------------------------------------------------------------------------------------------
    622 // description:
    623 //  Apply new audio parameters configurations for input and output buffers of reverse stream.
    624 //  An example of reverse stream is the echo reference supplied to an Acoustic Echo Canceler.
    625 //--------------------------------------------------------------------------------------------------
    626 // command format:
    627 //  size: sizeof(effect_config_t)
    628 //  data: effect_config_t
    629 //--------------------------------------------------------------------------------------------------
    630 // reply format:
    631 //  size: sizeof(int)
    632 //  data: status
    633 //==================================================================================================
    634 // command: EFFECT_CMD_SET_INPUT_DEVICE
    635 //--------------------------------------------------------------------------------------------------
    636 // description:
    637 //  Set the capture device the audio input path is connected to. See audio.h, audio_devices_t
    638 //  for device values.
    639 //  The effect implementation must set EFFECT_FLAG_DEVICE_IND flag in its descriptor to receive this
    640 //  command when the device changes
    641 //--------------------------------------------------------------------------------------------------
    642 // command format:
    643 //  size: sizeof(uint32_t)
    644 //  data: uint32_t
    645 //--------------------------------------------------------------------------------------------------
    646 // reply format:
    647 //  size: 0
    648 //  data: N/A
    649 //==================================================================================================
    650 // command: EFFECT_CMD_GET_CONFIG
    651 //--------------------------------------------------------------------------------------------------
    652 // description:
    653 //  Read audio parameters configurations for input and output buffers
    654 //--------------------------------------------------------------------------------------------------
    655 // command format:
    656 //  size: 0
    657 //  data: N/A
    658 //--------------------------------------------------------------------------------------------------
    659 // reply format:
    660 //  size: sizeof(effect_config_t)
    661 //  data: effect_config_t
    662 //==================================================================================================
    663 // command: EFFECT_CMD_GET_CONFIG_REVERSE
    664 //--------------------------------------------------------------------------------------------------
    665 // description:
    666 //  Read audio parameters configurations for input and output buffers of reverse stream
    667 //--------------------------------------------------------------------------------------------------
    668 // command format:
    669 //  size: 0
    670 //  data: N/A
    671 //--------------------------------------------------------------------------------------------------
    672 // reply format:
    673 //  size: sizeof(effect_config_t)
    674 //  data: effect_config_t
    675 //==================================================================================================
    676 // command: EFFECT_CMD_GET_FEATURE_SUPPORTED_CONFIGS
    677 //--------------------------------------------------------------------------------------------------
    678 // description:
    679 //  Queries for supported configurations for a particular feature (e.g. get the supported
    680 // combinations of main and auxiliary channels for a noise suppressor).
    681 // The command parameter is the feature identifier (See effect_feature_e for a list of defined
    682 // features) followed by the maximum number of configuration descriptor to return.
    683 // The reply is composed of:
    684 //  - status (uint32_t):
    685 //          - 0 if feature is supported
    686 //          - -ENOSYS if the feature is not supported,
    687 //          - -ENOMEM if the feature is supported but the total number of supported configurations
    688 //          exceeds the maximum number indicated by the caller.
    689 //  - total number of supported configurations (uint32_t)
    690 //  - an array of configuration descriptors.
    691 // The actual number of descriptors returned must not exceed the maximum number indicated by
    692 // the caller.
    693 //--------------------------------------------------------------------------------------------------
    694 // command format:
    695 //  size: 2 x sizeof(uint32_t)
    696 //  data: effect_feature_e + maximum number of configurations to return
    697 //--------------------------------------------------------------------------------------------------
    698 // reply format:
    699 //  size: 2 x sizeof(uint32_t) + n x sizeof (<config descriptor>)
    700 //  data: status + total number of configurations supported + array of n config descriptors
    701 //==================================================================================================
    702 // command: EFFECT_CMD_GET_FEATURE_CONFIG
    703 //--------------------------------------------------------------------------------------------------
    704 // description:
    705 //  Retrieves current configuration for a given feature.
    706 // The reply status is:
    707 //      - 0 if feature is supported
    708 //      - -ENOSYS if the feature is not supported,
    709 //--------------------------------------------------------------------------------------------------
    710 // command format:
    711 //  size: sizeof(uint32_t)
    712 //  data: effect_feature_e
    713 //--------------------------------------------------------------------------------------------------
    714 // reply format:
    715 //  size: sizeof(uint32_t) + sizeof (<config descriptor>)
    716 //  data: status + config descriptor
    717 //==================================================================================================
    718 // command: EFFECT_CMD_SET_FEATURE_CONFIG
    719 //--------------------------------------------------------------------------------------------------
    720 // description:
    721 //  Sets current configuration for a given feature.
    722 // The reply status is:
    723 //      - 0 if feature is supported
    724 //      - -ENOSYS if the feature is not supported,
    725 //      - -EINVAL if the configuration is invalid
    726 //--------------------------------------------------------------------------------------------------
    727 // command format:
    728 //  size: sizeof(uint32_t) + sizeof (<config descriptor>)
    729 //  data: effect_feature_e + config descriptor
    730 //--------------------------------------------------------------------------------------------------
    731 // reply format:
    732 //  size: sizeof(uint32_t)
    733 //  data: status
    734 //==================================================================================================
    735 // command: EFFECT_CMD_SET_AUDIO_SOURCE
    736 //--------------------------------------------------------------------------------------------------
    737 // description:
    738 //  Set the audio source the capture path is configured for (Camcorder, voice recognition...).
    739 //  See audio.h, audio_source_t for values.
    740 //--------------------------------------------------------------------------------------------------
    741 // command format:
    742 //  size: sizeof(uint32_t)
    743 //  data: uint32_t
    744 //--------------------------------------------------------------------------------------------------
    745 // reply format:
    746 //  size: 0
    747 //  data: N/A
    748 //==================================================================================================
    749 // command: EFFECT_CMD_OFFLOAD
    750 //--------------------------------------------------------------------------------------------------
    751 // description:
    752 //  1.indicate if the playback thread the effect is attached to is offloaded or not
    753 //  2.update the io handle of the playback thread the effect is attached to
    754 //--------------------------------------------------------------------------------------------------
    755 // command format:
    756 //  size: sizeof(effect_offload_param_t)
    757 //  data: effect_offload_param_t
    758 //--------------------------------------------------------------------------------------------------
    759 // reply format:
    760 //  size: sizeof(uint32_t)
    761 //  data: uint32_t
    762 //--------------------------------------------------------------------------------------------------
    763 // command: EFFECT_CMD_FIRST_PROPRIETARY
    764 //--------------------------------------------------------------------------------------------------
    765 // description:
    766 //  All proprietary effect commands must use command codes above this value. The size and format of
    767 //  command and response fields is free in this case
    768 //==================================================================================================
    769 
    770 
    771 // Audio buffer descriptor used by process(), bufferProvider() functions and buffer_config_t
    772 // structure. Multi-channel audio is always interleaved. The channel order is from LSB to MSB with
    773 // regard to the channel mask definition in audio.h, audio_channel_mask_t e.g :
    774 // Stereo: left, right
    775 // 5 point 1: front left, front right, front center, low frequency, back left, back right
    776 // The buffer size is expressed in frame count, a frame being composed of samples for all
    777 // channels at a given time. Frame size for unspecified format (AUDIO_FORMAT_OTHER) is 8 bit by
    778 // definition
    779 struct audio_buffer_s {
    780     size_t   frameCount;        // number of frames in buffer
    781     union {
    782         void*       raw;        // raw pointer to start of buffer
    783         int32_t*    s32;        // pointer to signed 32 bit data at start of buffer
    784         int16_t*    s16;        // pointer to signed 16 bit data at start of buffer
    785         uint8_t*    u8;         // pointer to unsigned 8 bit data at start of buffer
    786     };
    787 };
    788 
    789 // The buffer_provider_s structure contains functions that can be used
    790 // by the effect engine process() function to query and release input
    791 // or output audio buffer.
    792 // The getBuffer() function is called to retrieve a buffer where data
    793 // should read from or written to by process() function.
    794 // The releaseBuffer() function MUST be called when the buffer retrieved
    795 // with getBuffer() is not needed anymore.
    796 // The process function should use the buffer provider mechanism to retrieve
    797 // input or output buffer if the inBuffer or outBuffer passed as argument is NULL
    798 // and the buffer configuration (buffer_config_t) given by the EFFECT_CMD_SET_CONFIG
    799 // command did not specify an audio buffer.
    800 
    801 typedef int32_t (* buffer_function_t)(void *cookie, audio_buffer_t *buffer);
    802 
    803 typedef struct buffer_provider_s {
    804     buffer_function_t getBuffer;       // retrieve next buffer
    805     buffer_function_t releaseBuffer;   // release used buffer
    806     void       *cookie;                // for use by client of buffer provider functions
    807 } buffer_provider_t;
    808 
    809 
    810 // The buffer_config_s structure specifies the input or output audio format
    811 // to be used by the effect engine. It is part of the effect_config_t
    812 // structure that defines both input and output buffer configurations and is
    813 // passed by the EFFECT_CMD_SET_CONFIG or EFFECT_CMD_SET_CONFIG_REVERSE command.
    814 typedef struct buffer_config_s {
    815     audio_buffer_t  buffer;     // buffer for use by process() function if not passed explicitly
    816     uint32_t   samplingRate;    // sampling rate
    817     uint32_t   channels;        // channel mask (see audio_channel_mask_t in audio.h)
    818     buffer_provider_t bufferProvider;   // buffer provider
    819     uint8_t    format;          // Audio format (see audio_format_t in audio.h)
    820     uint8_t    accessMode;      // read/write or accumulate in buffer (effect_buffer_access_e)
    821     uint16_t   mask;            // indicates which of the above fields is valid
    822 } buffer_config_t;
    823 
    824 // Values for "accessMode" field of buffer_config_t:
    825 //   overwrite, read only, accumulate (read/modify/write)
    826 enum effect_buffer_access_e {
    827     EFFECT_BUFFER_ACCESS_WRITE,
    828     EFFECT_BUFFER_ACCESS_READ,
    829     EFFECT_BUFFER_ACCESS_ACCUMULATE
    830 
    831 };
    832 
    833 // feature identifiers for EFFECT_CMD_GET_FEATURE_SUPPORTED_CONFIGS command
    834 enum effect_feature_e {
    835     EFFECT_FEATURE_AUX_CHANNELS, // supports auxiliary channels (e.g. dual mic noise suppressor)
    836     EFFECT_FEATURE_CNT
    837 };
    838 
    839 // EFFECT_FEATURE_AUX_CHANNELS feature configuration descriptor. Describe a combination
    840 // of main and auxiliary channels supported
    841 typedef struct channel_config_s {
    842     audio_channel_mask_t main_channels; // channel mask for main channels
    843     audio_channel_mask_t aux_channels;  // channel mask for auxiliary channels
    844 } channel_config_t;
    845 
    846 
    847 // Values for bit field "mask" in buffer_config_t. If a bit is set, the corresponding field
    848 // in buffer_config_t must be taken into account when executing the EFFECT_CMD_SET_CONFIG command
    849 #define EFFECT_CONFIG_BUFFER    0x0001  // buffer field must be taken into account
    850 #define EFFECT_CONFIG_SMP_RATE  0x0002  // samplingRate field must be taken into account
    851 #define EFFECT_CONFIG_CHANNELS  0x0004  // channels field must be taken into account
    852 #define EFFECT_CONFIG_FORMAT    0x0008  // format field must be taken into account
    853 #define EFFECT_CONFIG_ACC_MODE  0x0010  // accessMode field must be taken into account
    854 #define EFFECT_CONFIG_PROVIDER  0x0020  // bufferProvider field must be taken into account
    855 #define EFFECT_CONFIG_ALL (EFFECT_CONFIG_BUFFER | EFFECT_CONFIG_SMP_RATE | \
    856                            EFFECT_CONFIG_CHANNELS | EFFECT_CONFIG_FORMAT | \
    857                            EFFECT_CONFIG_ACC_MODE | EFFECT_CONFIG_PROVIDER)
    858 
    859 
    860 // effect_config_s structure describes the format of the pCmdData argument of EFFECT_CMD_SET_CONFIG
    861 // command to configure audio parameters and buffers for effect engine input and output.
    862 typedef struct effect_config_s {
    863     buffer_config_t   inputCfg;
    864     buffer_config_t   outputCfg;
    865 } effect_config_t;
    866 
    867 
    868 // effect_param_s structure describes the format of the pCmdData argument of EFFECT_CMD_SET_PARAM
    869 // command and pCmdData and pReplyData of EFFECT_CMD_GET_PARAM command.
    870 // psize and vsize represent the actual size of parameter and value.
    871 //
    872 // NOTE: the start of value field inside the data field is always on a 32 bit boundary:
    873 //
    874 //  +-----------+
    875 //  | status    | sizeof(int)
    876 //  +-----------+
    877 //  | psize     | sizeof(int)
    878 //  +-----------+
    879 //  | vsize     | sizeof(int)
    880 //  +-----------+
    881 //  |           |   |           |
    882 //  ~ parameter ~   > psize     |
    883 //  |           |   |           >  ((psize - 1)/sizeof(int) + 1) * sizeof(int)
    884 //  +-----------+               |
    885 //  | padding   |               |
    886 //  +-----------+
    887 //  |           |   |
    888 //  ~ value     ~   > vsize
    889 //  |           |   |
    890 //  +-----------+
    891 
    892 typedef struct effect_param_s {
    893     int32_t     status;     // Transaction status (unused for command, used for reply)
    894     uint32_t    psize;      // Parameter size
    895     uint32_t    vsize;      // Value size
    896     char        data[];     // Start of Parameter + Value data
    897 } effect_param_t;
    898 
    899 // structure used by EFFECT_CMD_OFFLOAD command
    900 typedef struct effect_offload_param_s {
    901     bool isOffload;         // true if the playback thread the effect is attached to is offloaded
    902     int ioHandle;           // io handle of the playback thread the effect is attached to
    903 } effect_offload_param_t;
    904 
    905 
    906 /////////////////////////////////////////////////
    907 //      Effect library interface
    908 /////////////////////////////////////////////////
    909 
    910 // Effect library interface version 3.0
    911 // Note that EffectsFactory.c only checks the major version component, so changes to the minor
    912 // number can only be used for fully backwards compatible changes
    913 #define EFFECT_LIBRARY_API_VERSION EFFECT_MAKE_API_VERSION(3,0)
    914 
    915 #define AUDIO_EFFECT_LIBRARY_TAG ((('A') << 24) | (('E') << 16) | (('L') << 8) | ('T'))
    916 
    917 // Every effect library must have a data structure named AUDIO_EFFECT_LIBRARY_INFO_SYM
    918 // and the fields of this data structure must begin with audio_effect_library_t
    919 
    920 typedef struct audio_effect_library_s {
    921     // tag must be initialized to AUDIO_EFFECT_LIBRARY_TAG
    922     uint32_t tag;
    923     // Version of the effect library API : 0xMMMMmmmm MMMM: Major, mmmm: minor
    924     uint32_t version;
    925     // Name of this library
    926     const char *name;
    927     // Author/owner/implementor of the library
    928     const char *implementor;
    929 
    930     ////////////////////////////////////////////////////////////////////////////////
    931     //
    932     //    Function:        create_effect
    933     //
    934     //    Description:    Creates an effect engine of the specified implementation uuid and
    935     //          returns an effect control interface on this engine. The function will allocate the
    936     //          resources for an instance of the requested effect engine and return
    937     //          a handle on the effect control interface.
    938     //
    939     //    Input:
    940     //          uuid:    pointer to the effect uuid.
    941     //          sessionId:  audio session to which this effect instance will be attached.
    942     //              All effects created with the same session ID are connected in series and process
    943     //              the same signal stream. Knowing that two effects are part of the same effect
    944     //              chain can help the library implement some kind of optimizations.
    945     //          ioId:   identifies the output or input stream this effect is directed to in
    946     //              audio HAL.
    947     //              For future use especially with tunneled HW accelerated effects
    948     //
    949     //    Input/Output:
    950     //          pHandle:        address where to return the effect interface handle.
    951     //
    952     //    Output:
    953     //        returned value:    0          successful operation.
    954     //                          -ENODEV     library failed to initialize
    955     //                          -EINVAL     invalid pEffectUuid or pHandle
    956     //                          -ENOENT     no effect with this uuid found
    957     //        *pHandle:         updated with the effect interface handle.
    958     //
    959     ////////////////////////////////////////////////////////////////////////////////
    960     int32_t (*create_effect)(const effect_uuid_t *uuid,
    961                              int32_t sessionId,
    962                              int32_t ioId,
    963                              effect_handle_t *pHandle);
    964 
    965     ////////////////////////////////////////////////////////////////////////////////
    966     //
    967     //    Function:        release_effect
    968     //
    969     //    Description:    Releases the effect engine whose handle is given as argument.
    970     //          All resources allocated to this particular instance of the effect are
    971     //          released.
    972     //
    973     //    Input:
    974     //          handle:         handle on the effect interface to be released.
    975     //
    976     //    Output:
    977     //        returned value:    0          successful operation.
    978     //                          -ENODEV     library failed to initialize
    979     //                          -EINVAL     invalid interface handle
    980     //
    981     ////////////////////////////////////////////////////////////////////////////////
    982     int32_t (*release_effect)(effect_handle_t handle);
    983 
    984     ////////////////////////////////////////////////////////////////////////////////
    985     //
    986     //    Function:        get_descriptor
    987     //
    988     //    Description:    Returns the descriptor of the effect engine which implementation UUID is
    989     //          given as argument.
    990     //
    991     //    Input/Output:
    992     //          uuid:           pointer to the effect uuid.
    993     //          pDescriptor:    address where to return the effect descriptor.
    994     //
    995     //    Output:
    996     //        returned value:    0          successful operation.
    997     //                          -ENODEV     library failed to initialize
    998     //                          -EINVAL     invalid pDescriptor or uuid
    999     //        *pDescriptor:     updated with the effect descriptor.
   1000     //
   1001     ////////////////////////////////////////////////////////////////////////////////
   1002     int32_t (*get_descriptor)(const effect_uuid_t *uuid,
   1003                               effect_descriptor_t *pDescriptor);
   1004 } audio_effect_library_t;
   1005 
   1006 // Name of the hal_module_info
   1007 #define AUDIO_EFFECT_LIBRARY_INFO_SYM         AELI
   1008 
   1009 // Name of the hal_module_info as a string
   1010 #define AUDIO_EFFECT_LIBRARY_INFO_SYM_AS_STR  "AELI"
   1011 
   1012 __END_DECLS
   1013 
   1014 #endif  // ANDROID_AUDIO_EFFECT_H
   1015