Modified audio effect API.

Moved and renamed media/EffectApi.h to hardware/audio_effect.h
Modified the effect library API to expose a library info structure
containing an interface functions table.
Also removed enums for audio channels, audio format and devices
from effect API and use values from system/audio.h instead.

Change-Id: I32fd752e449337410115121c1c60c699d95247c2

1 files changed, 797 insertions, 0 deletions

diff --git a/include/hardware/audio_effect.h b/include/hardware/audio_effect.h
new file mode 100644
index 0000000..ff35247
--- /dev/null
+++ b/include/hardware/audio_effect.h
@@ -0,0 +1,797 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#ifndef ANDROID_AUDIO_EFFECT_H
+#define ANDROID_AUDIO_EFFECT_H
+
+#include <errno.h>
+#include <stdint.h>
+#include <strings.h>
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+#include <cutils/bitops.h>
+
+#include <system/audio.h>
+
+
+__BEGIN_DECLS
+
+
+/////////////////////////////////////////////////
+//      Common Definitions
+/////////////////////////////////////////////////
+
+//
+//--- Effect descriptor structure effect_descriptor_t
+//
+
+// Unique effect ID (can be generated from the following site:
+//  http://www.itu.int/ITU-T/asn1/uuid.html)
+// This format is used for both "type" and "uuid" fields of the effect descriptor structure.
+// - When used for effect type and the engine is implementing and effect corresponding to a standard
+// OpenSL ES interface, this ID must be the one defined in OpenSLES_IID.h for that interface.
+// - When used as uuid, it should be a unique UUID for this particular implementation.
+typedef struct effect_uuid_s {
+    uint32_t timeLow;
+    uint16_t timeMid;
+    uint16_t timeHiAndVersion;
+    uint16_t clockSeq;
+    uint8_t node[6];
+} effect_uuid_t;
+
+// Maximum length of character strings in structures defines by this API.
+#define EFFECT_STRING_LEN_MAX 64
+
+// NULL UUID definition (matches SL_IID_NULL_)
+#define EFFECT_UUID_INITIALIZER { 0xec7178ec, 0xe5e1, 0x4432, 0xa3f4, \
+                                  { 0x46, 0x57, 0xe6, 0x79, 0x52, 0x10 } }
+static const effect_uuid_t EFFECT_UUID_NULL_ = EFFECT_UUID_INITIALIZER;
+const effect_uuid_t * const EFFECT_UUID_NULL = &EFFECT_UUID_NULL_;
+const char * const EFFECT_UUID_NULL_STR = "ec7178ec-e5e1-4432-a3f4-4657e6795210";
+
+// The effect descriptor contains necessary information to facilitate the enumeration of the effect
+// engines present in a library.
+typedef struct effect_descriptor_s {
+    effect_uuid_t type;     // UUID of to the OpenSL ES interface implemented by this effect
+    effect_uuid_t uuid;     // UUID for this particular implementation
+    uint32_t apiVersion;    // Version of the effect control API implemented
+    uint32_t flags;         // effect engine capabilities/requirements flags (see below)
+    uint16_t cpuLoad;       // CPU load indication (see below)
+    uint16_t memoryUsage;   // Data Memory usage (see below)
+    char    name[EFFECT_STRING_LEN_MAX];   // human readable effect name
+    char    implementor[EFFECT_STRING_LEN_MAX];    // human readable effect implementor name
+} effect_descriptor_t;
+
+// CPU load and memory usage indication: each effect implementation must provide an indication of
+// its CPU and memory usage for the audio effect framework to limit the number of effects
+// instantiated at a given time on a given platform.
+// The CPU load is expressed in 0.1 MIPS units as estimated on an ARM9E core (ARMv5TE) with 0 WS.
+// The memory usage is expressed in KB and includes only dynamically allocated memory
+
+// Definitions for flags field of effect descriptor.
+//  +---------------------------+-----------+-----------------------------------
+//  | description               | bits      | values
+//  +---------------------------+-----------+-----------------------------------
+//  | connection mode           | 0..1      | 0 insert: after track process
+//  |                           |           | 1 auxiliary: connect to track auxiliary
+//  |                           |           |  output and use send level
+//  |                           |           | 2 replace: replaces track process function;
+//  |                           |           |   must implement SRC, volume and mono to stereo.
+//  |                           |           | 3 reserved
+//  +---------------------------+-----------+-----------------------------------
+//  | insertion preference      | 2..4      | 0 none
+//  |                           |           | 1 first of the chain
+//  |                           |           | 2 last of the chain
+//  |                           |           | 3 exclusive (only effect in the insert chain)
+//  |                           |           | 4..7 reserved
+//  +---------------------------+-----------+-----------------------------------
+//  | Volume management         | 5..6      | 0 none
+//  |                           |           | 1 implements volume control
+//  |                           |           | 2 requires volume indication
+//  |                           |           | 3 reserved
+//  +---------------------------+-----------+-----------------------------------
+//  | Device indication         | 7..8      | 0 none
+//  |                           |           | 1 requires device updates
+//  |                           |           | 2..3 reserved
+//  +---------------------------+-----------+-----------------------------------
+//  | Sample input mode         | 9..10     | 0 direct: process() function or EFFECT_CMD_CONFIGURE
+//  |                           |           |   command must specify a buffer descriptor
+//  |                           |           | 1 provider: process() function uses the
+//  |                           |           |   bufferProvider indicated by the
+//  |                           |           |   EFFECT_CMD_CONFIGURE command to request input.
+//  |                           |           |   buffers.
+//  |                           |           | 2 both: both input modes are supported
+//  |                           |           | 3 reserved
+//  +---------------------------+-----------+-----------------------------------
+//  | Sample output mode        | 11..12    | 0 direct: process() function or EFFECT_CMD_CONFIGURE
+//  |                           |           |   command must specify a buffer descriptor
+//  |                           |           | 1 provider: process() function uses the
+//  |                           |           |   bufferProvider indicated by the
+//  |                           |           |   EFFECT_CMD_CONFIGURE command to request output
+//  |                           |           |   buffers.
+//  |                           |           | 2 both: both output modes are supported
+//  |                           |           | 3 reserved
+//  +---------------------------+-----------+-----------------------------------
+//  | Hardware acceleration     | 13..15    | 0 No hardware acceleration
+//  |                           |           | 1 non tunneled hw acceleration: the process() function
+//  |                           |           |   reads the samples, send them to HW accelerated
+//  |                           |           |   effect processor, reads back the processed samples
+//  |                           |           |   and returns them to the output buffer.
+//  |                           |           | 2 tunneled hw acceleration: the process() function is
+//  |                           |           |   transparent. The effect interface is only used to
+//  |                           |           |   control the effect engine. This mode is relevant for
+//  |                           |           |   global effects actually applied by the audio
+//  |                           |           |   hardware on the output stream.
+//  +---------------------------+-----------+-----------------------------------
+//  | Audio Mode indication     | 16..17    | 0 none
+//  |                           |           | 1 requires audio mode updates
+//  |                           |           | 2..3 reserved
+//  +---------------------------+-----------+-----------------------------------
+
+// Insert mode
+#define EFFECT_FLAG_TYPE_MASK           0x00000003
+#define EFFECT_FLAG_TYPE_INSERT         0x00000000
+#define EFFECT_FLAG_TYPE_AUXILIARY      0x00000001
+#define EFFECT_FLAG_TYPE_REPLACE        0x00000002
+
+// Insert preference
+#define EFFECT_FLAG_INSERT_MASK         0x0000001C
+#define EFFECT_FLAG_INSERT_ANY          0x00000000
+#define EFFECT_FLAG_INSERT_FIRST        0x00000004
+#define EFFECT_FLAG_INSERT_LAST         0x00000008
+#define EFFECT_FLAG_INSERT_EXCLUSIVE    0x0000000C
+
+
+// Volume control
+#define EFFECT_FLAG_VOLUME_MASK         0x00000060
+#define EFFECT_FLAG_VOLUME_CTRL         0x00000020
+#define EFFECT_FLAG_VOLUME_IND          0x00000040
+#define EFFECT_FLAG_VOLUME_NONE         0x00000000
+
+// Device indication
+#define EFFECT_FLAG_DEVICE_MASK         0x00000180
+#define EFFECT_FLAG_DEVICE_IND          0x00000080
+#define EFFECT_FLAG_DEVICE_NONE         0x00000000
+
+// Sample input modes
+#define EFFECT_FLAG_INPUT_MASK          0x00000600
+#define EFFECT_FLAG_INPUT_DIRECT        0x00000000
+#define EFFECT_FLAG_INPUT_PROVIDER      0x00000200
+#define EFFECT_FLAG_INPUT_BOTH          0x00000400
+
+// Sample output modes
+#define EFFECT_FLAG_OUTPUT_MASK          0x00001800
+#define EFFECT_FLAG_OUTPUT_DIRECT        0x00000000
+#define EFFECT_FLAG_OUTPUT_PROVIDER      0x00000800
+#define EFFECT_FLAG_OUTPUT_BOTH          0x00001000
+
+// Hardware acceleration mode
+#define EFFECT_FLAG_HW_ACC_MASK          0x00006000
+#define EFFECT_FLAG_HW_ACC_SIMPLE        0x00002000
+#define EFFECT_FLAG_HW_ACC_TUNNEL        0x00004000
+
+// Audio mode indication
+#define EFFECT_FLAG_AUDIO_MODE_MASK      0x00018000
+#define EFFECT_FLAG_AUDIO_MODE_IND       0x00008000
+#define EFFECT_FLAG_AUDIO_MODE_NONE      0x00000000
+
+
+#define EFFECT_MAKE_API_VERSION(M, m)  (((M)<<16) | ((m) & 0xFFFF))
+#define EFFECT_API_VERSION_MAJOR(v)    ((v)>>16)
+#define EFFECT_API_VERSION_MINOR(v)    ((m) & 0xFFFF)
+
+
+
+/////////////////////////////////////////////////
+//      Effect control interface
+/////////////////////////////////////////////////
+
+// Effect control interface version 2.0
+#define EFFECT_CONTROL_API_VERSION EFFECT_MAKE_API_VERSION(2,0)
+
+// The effect control interface is exposed by each effect engine implementation. It consists of
+// a set of functions controlling the configuration, activation and process of the engine.
+// The functions are grouped in a structure of type effect_interface_s:
+//    struct effect_interface_s {
+//        effect_process_t process;
+//        effect_command_t command;
+//        effect_get_descriptor_t get_descriptor;
+//    };
+
+
+// effect_handle_t: Effect control interface handle.
+// The effect_handle_t serves two purposes regarding the implementation of the effect engine:
+// - 1 it is the address of a pointer to an effect_interface_s structure where the functions
+// of the effect control API for a particular effect are located.
+// - 2 it is the address of the context of a particular effect instance.
+// A typical implementation in the effect library would define a structure as follows:
+// struct effect_module_s {
+//        const struct effect_interface_s *itfe;
+//        effect_config_t config;
+//        effect_context_t context;
+// }
+// The implementation of EffectCreate() function would then allocate a structure of this
+// type and return its address as effect_handle_t
+typedef struct effect_interface_s **effect_handle_t;
+
+
+// Forward definition of type audio_buffer_t
+typedef struct audio_buffer_s audio_buffer_t;
+
+////////////////////////////////////////////////////////////////////////////////
+//
+//    Function:       process
+//
+//    Description:    Effect process function. Takes input samples as specified
+//          (count and location) in input buffer descriptor and output processed
+//          samples as specified in output buffer descriptor. If the buffer descriptor
+//          is not specified the function must use either the buffer or the
+//          buffer provider function installed by the EFFECT_CMD_CONFIGURE command.
+//          The effect framework will call the process() function after the EFFECT_CMD_ENABLE
+//          command is received and until the EFFECT_CMD_DISABLE is received. When the engine
+//          receives the EFFECT_CMD_DISABLE command it should turn off the effect gracefully
+//          and when done indicate that it is OK to stop calling the process() function by
+//          returning the -ENODATA status.
+//
+//    NOTE: the process() function implementation should be "real-time safe" that is
+//      it should not perform blocking calls: malloc/free, sleep, read/write/open/close,
+//      pthread_cond_wait/pthread_mutex_lock...
+//
+//    Input:
+//          effect_handle_t: handle to the effect interface this function
+//              is called on.
+//          inBuffer:   buffer descriptor indicating where to read samples to process.
+//              If NULL, use the configuration passed by EFFECT_CMD_CONFIGURE command.
+//
+//          inBuffer:   buffer descriptor indicating where to write processed samples.
+//              If NULL, use the configuration passed by EFFECT_CMD_CONFIGURE command.
+//
+//    Output:
+//        returned value:    0 successful operation
+//                          -ENODATA the engine has finished the disable phase and the framework
+//                                  can stop calling process()
+//                          -EINVAL invalid interface handle or
+//                                  invalid input/output buffer description
+////////////////////////////////////////////////////////////////////////////////
+typedef int32_t (*effect_process_t)(effect_handle_t self,
+                                    audio_buffer_t *inBuffer,
+                                    audio_buffer_t *outBuffer);
+
+////////////////////////////////////////////////////////////////////////////////
+//
+//    Function:       command
+//
+//    Description:    Send a command and receive a response to/from effect engine.
+//
+//    Input:
+//          effect_handle_t: handle to the effect interface this function
+//              is called on.
+//          cmdCode:    command code: the command can be a standardized command defined in
+//              effect_command_e (see below) or a proprietary command.
+//          cmdSize:    size of command in bytes
+//          pCmdData:   pointer to command data
+//          pReplyData: pointer to reply data
+//
+//    Input/Output:
+//          replySize: maximum size of reply data as input
+//                      actual size of reply data as output
+//
+//    Output:
+//          returned value: 0       successful operation
+//                          -EINVAL invalid interface handle or
+//                                  invalid command/reply size or format according to command code
+//              The return code should be restricted to indicate problems related to the this
+//              API specification. Status related to the execution of a particular command should be
+//              indicated as part of the reply field.
+//
+//          *pReplyData updated with command response
+//
+////////////////////////////////////////////////////////////////////////////////
+typedef int32_t (*effect_command_t)(effect_handle_t self,
+                                    uint32_t cmdCode,
+                                    uint32_t cmdSize,
+                                    void *pCmdData,
+                                    uint32_t *replySize,
+                                    void *pReplyData);
+
+
+typedef int32_t (*effect_get_descriptor_t)(effect_handle_t self,
+                                           effect_descriptor_t *pDescriptor);
+
+// Effect control interface definition
+struct effect_interface_s {
+    effect_process_t process;
+    effect_command_t command;
+    effect_get_descriptor_t get_descriptor;
+};
+
+
+//
+//--- Standardized command codes for command() function
+//
+enum effect_command_e {
+   EFFECT_CMD_INIT,                 // initialize effect engine
+   EFFECT_CMD_CONFIGURE,            // configure effect engine (see effect_config_t)
+   EFFECT_CMD_RESET,                // reset effect engine
+   EFFECT_CMD_ENABLE,               // enable effect process
+   EFFECT_CMD_DISABLE,              // disable effect process
+   EFFECT_CMD_SET_PARAM,            // set parameter immediately (see effect_param_t)
+   EFFECT_CMD_SET_PARAM_DEFERRED,   // set parameter deferred
+   EFFECT_CMD_SET_PARAM_COMMIT,     // commit previous set parameter deferred
+   EFFECT_CMD_GET_PARAM,            // get parameter
+   EFFECT_CMD_SET_DEVICE,           // set audio device (see audio.h, audio_devices_t)
+   EFFECT_CMD_SET_VOLUME,           // set volume
+   EFFECT_CMD_SET_AUDIO_MODE,       // set the audio mode (normal, ring, ...)
+   EFFECT_CMD_FIRST_PROPRIETARY = 0x10000 // first proprietary command code
+};
+
+//==================================================================================================
+// command: EFFECT_CMD_INIT
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Initialize effect engine: All configurations return to default
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: 0
+//  data: N/A
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: sizeof(int)
+//  data: status
+//==================================================================================================
+// command: EFFECT_CMD_CONFIGURE
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Apply new audio parameters configurations for input and output buffers
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: sizeof(effect_config_t)
+//  data: effect_config_t
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: sizeof(int)
+//  data: status
+//==================================================================================================
+// command: EFFECT_CMD_RESET
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Reset the effect engine. Keep configuration but resets state and buffer content
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: 0
+//  data: N/A
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: 0
+//  data: N/A
+//==================================================================================================
+// command: EFFECT_CMD_ENABLE
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Enable the process. Called by the framework before the first call to process()
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: 0
+//  data: N/A
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: sizeof(int)
+//  data: status
+//==================================================================================================
+// command: EFFECT_CMD_DISABLE
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Disable the process. Called by the framework after the last call to process()
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: 0
+//  data: N/A
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: sizeof(int)
+//  data: status
+//==================================================================================================
+// command: EFFECT_CMD_SET_PARAM
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Set a parameter and apply it immediately
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: sizeof(effect_param_t) + size of param and value
+//  data: effect_param_t + param + value. See effect_param_t definition below for value offset
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: sizeof(int)
+//  data: status
+//==================================================================================================
+// command: EFFECT_CMD_SET_PARAM_DEFERRED
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Set a parameter but apply it only when receiving EFFECT_CMD_SET_PARAM_COMMIT command
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: sizeof(effect_param_t) + size of param and value
+//  data: effect_param_t + param + value. See effect_param_t definition below for value offset
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: 0
+//  data: N/A
+//==================================================================================================
+// command: EFFECT_CMD_SET_PARAM_COMMIT
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Apply all previously received EFFECT_CMD_SET_PARAM_DEFERRED commands
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: 0
+//  data: N/A
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: sizeof(int)
+//  data: status
+//==================================================================================================
+// command: EFFECT_CMD_GET_PARAM
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Get a parameter value
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: sizeof(effect_param_t) + size of param
+//  data: effect_param_t + param
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: sizeof(effect_param_t) + size of param and value
+//  data: effect_param_t + param + value. See effect_param_t definition below for value offset
+//==================================================================================================
+// command: EFFECT_CMD_SET_DEVICE
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Set the rendering device the audio output path is connected to. See audio.h, audio_devices_t
+//  for device values.
+//  The effect implementation must set EFFECT_FLAG_DEVICE_IND flag in its descriptor to receive this
+//  command when the device changes
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: sizeof(uint32_t)
+//  data: uint32_t
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: 0
+//  data: N/A
+//==================================================================================================
+// command: EFFECT_CMD_SET_VOLUME
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Set and get volume. Used by audio framework to delegate volume control to effect engine.
+//  The effect implementation must set EFFECT_FLAG_VOLUME_IND or EFFECT_FLAG_VOLUME_CTRL flag in
+//  its descriptor to receive this command before every call to process() function
+//  If EFFECT_FLAG_VOLUME_CTRL flag is set in the effect descriptor, the effect engine must return
+//  the volume that should be applied before the effect is processed. The overall volume (the volume
+//  actually applied by the effect engine multiplied by the returned value) should match the value
+//  indicated in the command.
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: n * sizeof(uint32_t)
+//  data: volume for each channel defined in effect_config_t for output buffer expressed in
+//      8.24 fixed point format
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: n * sizeof(uint32_t) / 0
+//  data: - if EFFECT_FLAG_VOLUME_CTRL is set in effect descriptor:
+//              volume for each channel defined in effect_config_t for output buffer expressed in
+//              8.24 fixed point format
+//        - if EFFECT_FLAG_VOLUME_CTRL is not set in effect descriptor:
+//              N/A
+//  It is legal to receive a null pointer as pReplyData in which case the effect framework has
+//  delegated volume control to another effect
+//==================================================================================================
+// command: EFFECT_CMD_SET_AUDIO_MODE
+//--------------------------------------------------------------------------------------------------
+// description:
+//  Set the audio mode. The effect implementation must set EFFECT_FLAG_AUDIO_MODE_IND flag in its
+//  descriptor to receive this command when the audio mode changes.
+//--------------------------------------------------------------------------------------------------
+// command format:
+//  size: sizeof(uint32_t)
+//  data: audio_mode_e
+//--------------------------------------------------------------------------------------------------
+// reply format:
+//  size: 0
+//  data: N/A
+//==================================================================================================
+// command: EFFECT_CMD_FIRST_PROPRIETARY
+//--------------------------------------------------------------------------------------------------
+// description:
+//  All proprietary effect commands must use command codes above this value. The size and format of
+//  command and response fields is free in this case
+//==================================================================================================
+
+
+// Audio buffer descriptor used by process(), bufferProvider() functions and buffer_config_t
+// structure. Multi-channel audio is always interleaved. The channel order is from LSB to MSB with
+// regard to the channel mask definition in audio.h, audio_channels_t e.g :
+// Stereo: left, right
+// 5 point 1: front left, front right, front center, low frequency, back left, back right
+// The buffer size is expressed in frame count, a frame being composed of samples for all
+// channels at a given time. Frame size for unspecified format (AUDIO_FORMAT_OTHER) is 8 bit by
+// definition
+struct audio_buffer_s {
+    size_t   frameCount;        // number of frames in buffer
+    union {
+        void*       raw;        // raw pointer to start of buffer
+        int32_t*    s32;        // pointer to signed 32 bit data at start of buffer
+        int16_t*    s16;        // pointer to signed 16 bit data at start of buffer
+        uint8_t*    u8;         // pointer to unsigned 8 bit data at start of buffer
+    };
+};
+
+// The buffer_provider_s structure contains functions that can be used
+// by the effect engine process() function to query and release input
+// or output audio buffer.
+// The getBuffer() function is called to retrieve a buffer where data
+// should read from or written to by process() function.
+// The releaseBuffer() function MUST be called when the buffer retrieved
+// with getBuffer() is not needed anymore.
+// The process function should use the buffer provider mechanism to retrieve
+// input or output buffer if the inBuffer or outBuffer passed as argument is NULL
+// and the buffer configuration (buffer_config_t) given by the EFFECT_CMD_CONFIGURE
+// command did not specify an audio buffer.
+
+typedef int32_t (* buffer_function_t)(void *cookie, audio_buffer_t *buffer);
+
+typedef struct buffer_provider_s {
+    buffer_function_t getBuffer;       // retrieve next buffer
+    buffer_function_t releaseBuffer;   // release used buffer
+    void       *cookie;                // for use by client of buffer provider functions
+} buffer_provider_t;
+
+
+// The buffer_config_s structure specifies the input or output audio format
+// to be used by the effect engine. It is part of the effect_config_t
+// structure that defines both input and output buffer configurations and is
+// passed by the EFFECT_CMD_CONFIGURE command.
+typedef struct buffer_config_s {
+    audio_buffer_t  buffer;     // buffer for use by process() function if not passed explicitly
+    uint32_t   samplingRate;    // sampling rate
+    uint32_t   channels;        // channel mask (see audio_channels_t in audio.h)
+    buffer_provider_t bufferProvider;   // buffer provider
+    uint8_t    format;          // Audio format  (see see audio_format_t in audio.h)
+    uint8_t    accessMode;      // read/write or accumulate in buffer (effect_buffer_access_e)
+    uint16_t   mask;            // indicates which of the above fields is valid
+} buffer_config_t;
+
+// Values for "accessMode" field of buffer_config_t:
+//   overwrite, read only, accumulate (read/modify/write)
+enum effect_buffer_access_e {
+    EFFECT_BUFFER_ACCESS_WRITE,
+    EFFECT_BUFFER_ACCESS_READ,
+    EFFECT_BUFFER_ACCESS_ACCUMULATE
+
+};
+
+// Values for bit field "mask" in buffer_config_t. If a bit is set, the corresponding field
+// in buffer_config_t must be taken into account when executing the EFFECT_CMD_CONFIGURE command
+#define EFFECT_CONFIG_BUFFER    0x0001  // buffer field must be taken into account
+#define EFFECT_CONFIG_SMP_RATE  0x0002  // samplingRate field must be taken into account
+#define EFFECT_CONFIG_CHANNELS  0x0004  // channels field must be taken into account
+#define EFFECT_CONFIG_FORMAT    0x0008  // format field must be taken into account
+#define EFFECT_CONFIG_ACC_MODE  0x0010  // accessMode field must be taken into account
+#define EFFECT_CONFIG_PROVIDER  0x0020  // bufferProvider field must be taken into account
+#define EFFECT_CONFIG_ALL (EFFECT_CONFIG_BUFFER | EFFECT_CONFIG_SMP_RATE | \
+                           EFFECT_CONFIG_CHANNELS | EFFECT_CONFIG_FORMAT | \
+                           EFFECT_CONFIG_ACC_MODE | EFFECT_CONFIG_PROVIDER)
+
+
+// effect_config_s structure describes the format of the pCmdData argument of EFFECT_CMD_CONFIGURE
+// command to configure audio parameters and buffers for effect engine input and output.
+typedef struct effect_config_s {
+    buffer_config_t   inputCfg;
+    buffer_config_t   outputCfg;;
+} effect_config_t;
+
+
+// effect_param_s structure describes the format of the pCmdData argument of EFFECT_CMD_SET_PARAM
+// command and pCmdData and pReplyData of EFFECT_CMD_GET_PARAM command.
+// psize and vsize represent the actual size of parameter and value.
+//
+// NOTE: the start of value field inside the data field is always on a 32 bit boundary:
+//
+//  +-----------+
+//  | status    | sizeof(int)
+//  +-----------+
+//  | psize     | sizeof(int)
+//  +-----------+
+//  | vsize     | sizeof(int)
+//  +-----------+
+//  |           |   |           |
+//  ~ parameter ~   > psize     |
+//  |           |   |           >  ((psize - 1)/sizeof(int) + 1) * sizeof(int)
+//  +-----------+               |
+//  | padding   |               |
+//  +-----------+
+//  |           |   |
+//  ~ value     ~   > vsize
+//  |           |   |
+//  +-----------+
+
+typedef struct effect_param_s {
+    int32_t     status;     // Transaction status (unused for command, used for reply)
+    uint32_t    psize;      // Parameter size
+    uint32_t    vsize;      // Value size
+    char        data[];     // Start of Parameter + Value data
+} effect_param_t;
+
+
+
+/////////////////////////////////////////////////
+//      Effect library interface
+/////////////////////////////////////////////////
+
+// Effect library interface version 2.0
+#define EFFECT_LIBRARY_API_VERSION EFFECT_MAKE_API_VERSION(2,0)
+
+#define AUDIO_EFFECT_LIBRARY_TAG ((('A') << 24) | (('E') << 16) | (('L') << 8) | ('T'))
+
+// Every effect library must have a data structure named AUDIO_EFFECT_LIBRARY_INFO_SYM
+// and the fields of this data structure must begin with audio_effect_library_t
+
+typedef struct audio_effect_library_s {
+    // tag must be initialized to AUDIO_EFFECT_LIBRARY_TAG
+    uint32_t tag;
+    // Version of the effect library API : 0xMMMMmmmm MMMM: Major, mmmm: minor
+    uint32_t version;
+    // Name of this library
+    const char *name;
+    // Author/owner/implementor of the library
+    const char *implementor;
+
+    ////////////////////////////////////////////////////////////////////////////////
+    //
+    //    Function:        query_num_effects
+    //
+    //    Description:    Returns the number of different effects exposed by the
+    //          library. Each effect must have a unique effect uuid (see
+    //          effect_descriptor_t). This function together with EffectQueryEffect()
+    //          is used to enumerate all effects present in the library.
+    //
+    //    Input/Output:
+    //          pNumEffects:    address where the number of effects should be returned.
+    //
+    //    Output:
+    //        returned value:    0          successful operation.
+    //                          -ENODEV     library failed to initialize
+    //                          -EINVAL     invalid pNumEffects
+    //        *pNumEffects:     updated with number of effects in library
+    //
+    ////////////////////////////////////////////////////////////////////////////////
+    int32_t (*query_num_effects)(uint32_t *pNumEffects);
+
+    ////////////////////////////////////////////////////////////////////////////////
+    //
+    //    Function:        query_effect
+    //
+    //    Description:    Returns the descriptor of the effect engine which index is
+    //          given as argument.
+    //          See effect_descriptor_t for details on effect descriptors.
+    //          This function together with EffectQueryNumberEffects() is used to enumerate all
+    //          effects present in the library. The enumeration sequence is:
+    //              EffectQueryNumberEffects(&num_effects);
+    //              for (i = 0; i < num_effects; i++)
+    //                  EffectQueryEffect(i,...);
+    //
+    //    Input/Output:
+    //          index:          index of the effect
+    //          pDescriptor:    address where to return the effect descriptor.
+    //
+    //    Output:
+    //        returned value:    0          successful operation.
+    //                          -ENODEV     library failed to initialize
+    //                          -EINVAL     invalid pDescriptor or index
+    //                          -ENOSYS     effect list has changed since last execution of
+    //                                      EffectQueryNumberEffects()
+    //                          -ENOENT     no more effect available
+    //        *pDescriptor:     updated with the effect descriptor.
+    //
+    ////////////////////////////////////////////////////////////////////////////////
+    int32_t (*query_effect)(uint32_t index,
+                            effect_descriptor_t *pDescriptor);
+
+    ////////////////////////////////////////////////////////////////////////////////
+    //
+    //    Function:        create_effect
+    //
+    //    Description:    Creates an effect engine of the specified implementation uuid and
+    //          returns an effect control interface on this engine. The function will allocate the
+    //          resources for an instance of the requested effect engine and return
+    //          a handle on the effect control interface.
+    //
+    //    Input:
+    //          uuid:    pointer to the effect uuid.
+    //          sessionId:  audio session to which this effect instance will be attached. All effects
+    //              created with the same session ID are connected in series and process the same signal
+    //              stream. Knowing that two effects are part of the same effect chain can help the
+    //              library implement some kind of optimizations.
+    //          ioId:   identifies the output or input stream this effect is directed to at audio HAL.
+    //              For future use especially with tunneled HW accelerated effects
+    //
+    //    Input/Output:
+    //          pHandle:        address where to return the effect interface handle.
+    //
+    //    Output:
+    //        returned value:    0          successful operation.
+    //                          -ENODEV     library failed to initialize
+    //                          -EINVAL     invalid pEffectUuid or pHandle
+    //                          -ENOENT     no effect with this uuid found
+    //        *pHandle:         updated with the effect interface handle.
+    //
+    ////////////////////////////////////////////////////////////////////////////////
+    int32_t (*create_effect)(effect_uuid_t *uuid,
+                             int32_t sessionId,
+                             int32_t ioId,
+                             effect_handle_t *pHandle);
+
+    ////////////////////////////////////////////////////////////////////////////////
+    //
+    //    Function:        release_effect
+    //
+    //    Description:    Releases the effect engine whose handle is given as argument.
+    //          All resources allocated to this particular instance of the effect are
+    //          released.
+    //
+    //    Input:
+    //          handle:         handle on the effect interface to be released.
+    //
+    //    Output:
+    //        returned value:    0          successful operation.
+    //                          -ENODEV     library failed to initialize
+    //                          -EINVAL     invalid interface handle
+    //
+    ////////////////////////////////////////////////////////////////////////////////
+    int32_t (*release_effect)(effect_handle_t handle);
+
+    ////////////////////////////////////////////////////////////////////////////////
+    //
+    //    Function:        get_descriptor
+    //
+    //    Description:    Returns the descriptor of the effect engine which implementation UUID is
+    //          given as argument.
+    //
+    //    Input/Output:
+    //          uuid:           pointer to the effect uuid.
+    //          pDescriptor:    address where to return the effect descriptor.
+    //
+    //    Output:
+    //        returned value:    0          successful operation.
+    //                          -ENODEV     library failed to initialize
+    //                          -EINVAL     invalid pDescriptor or uuid
+    //        *pDescriptor:     updated with the effect descriptor.
+    //
+    ////////////////////////////////////////////////////////////////////////////////
+    int32_t (*get_descriptor)(effect_uuid_t *uuid,
+                              effect_descriptor_t *pDescriptor);
+} audio_effect_library_t;
+
+// Name of the hal_module_info
+#define AUDIO_EFFECT_LIBRARY_INFO_SYM         AELI
+
+// Name of the hal_module_info as a string
+#define AUDIO_EFFECT_LIBRARY_INFO_SYM_AS_STR  "AELI"
+
+__END_DECLS
+
+#endif  // ANDROID_AUDIO_EFFECT_H