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