include/hardware/bt_av.h - platform/system/bt - Gitiles

 /*
  * Copyright (C) 2012 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_INCLUDE_BT_AV_H
 #define ANDROID_INCLUDE_BT_AV_H

 #include <vector>

 #include <hardware/bluetooth.h>

 __BEGIN_DECLS

 /* Bluetooth AV connection states */
 typedef enum {
   BTAV_CONNECTION_STATE_DISCONNECTED = 0,
   BTAV_CONNECTION_STATE_CONNECTING,
   BTAV_CONNECTION_STATE_CONNECTED,
   BTAV_CONNECTION_STATE_DISCONNECTING
 } btav_connection_state_t;

 /* Bluetooth AV datapath states */
 typedef enum {
   BTAV_AUDIO_STATE_REMOTE_SUSPEND = 0,
   BTAV_AUDIO_STATE_STOPPED,
   BTAV_AUDIO_STATE_STARTED,
 } btav_audio_state_t;

 /*
  * Enum values for each A2DP supported codec.
  * There should be a separate entry for each A2DP codec that is supported
  * for encoding (SRC), and for decoding purpose (SINK).
  */
 typedef enum {
   BTAV_A2DP_CODEC_INDEX_SOURCE_MIN = 0,

   // Add an entry for each source codec here.
   // NOTE: The values should be same as those listed in the following file:
   //   BluetoothCodecConfig.java
   BTAV_A2DP_CODEC_INDEX_SOURCE_SBC = 0,
   BTAV_A2DP_CODEC_INDEX_SOURCE_AAC,
   BTAV_A2DP_CODEC_INDEX_SOURCE_APTX,
   BTAV_A2DP_CODEC_INDEX_SOURCE_APTX_HD,
   BTAV_A2DP_CODEC_INDEX_SOURCE_LDAC,

   BTAV_A2DP_CODEC_INDEX_SOURCE_MAX,

   BTAV_A2DP_CODEC_INDEX_SINK_MIN = BTAV_A2DP_CODEC_INDEX_SOURCE_MAX,

   // Add an entry for each sink codec here
   BTAV_A2DP_CODEC_INDEX_SINK_SBC = BTAV_A2DP_CODEC_INDEX_SINK_MIN,
   BTAV_A2DP_CODEC_INDEX_SINK_AAC,

   BTAV_A2DP_CODEC_INDEX_SINK_MAX,

   BTAV_A2DP_CODEC_INDEX_MIN = BTAV_A2DP_CODEC_INDEX_SOURCE_MIN,
   BTAV_A2DP_CODEC_INDEX_MAX = BTAV_A2DP_CODEC_INDEX_SINK_MAX
 } btav_a2dp_codec_index_t;

 typedef enum {
   // Disable the codec.
   // NOTE: This value can be used only during initialization when
   // function btav_source_interface_t::init() is called.
   BTAV_A2DP_CODEC_PRIORITY_DISABLED = -1,

   // Reset the codec priority to its default value.
   BTAV_A2DP_CODEC_PRIORITY_DEFAULT = 0,

   // Highest codec priority.
   BTAV_A2DP_CODEC_PRIORITY_HIGHEST = 1000 * 1000
 } btav_a2dp_codec_priority_t;

 typedef enum {
   BTAV_A2DP_CODEC_SAMPLE_RATE_NONE = 0x0,
   BTAV_A2DP_CODEC_SAMPLE_RATE_44100 = 0x1 << 0,
   BTAV_A2DP_CODEC_SAMPLE_RATE_48000 = 0x1 << 1,
   BTAV_A2DP_CODEC_SAMPLE_RATE_88200 = 0x1 << 2,
   BTAV_A2DP_CODEC_SAMPLE_RATE_96000 = 0x1 << 3,
   BTAV_A2DP_CODEC_SAMPLE_RATE_176400 = 0x1 << 4,
   BTAV_A2DP_CODEC_SAMPLE_RATE_192000 = 0x1 << 5,
   BTAV_A2DP_CODEC_SAMPLE_RATE_16000 = 0x1 << 6,
   BTAV_A2DP_CODEC_SAMPLE_RATE_24000 = 0x1 << 7
 } btav_a2dp_codec_sample_rate_t;

 typedef enum {
   BTAV_A2DP_CODEC_BITS_PER_SAMPLE_NONE = 0x0,
   BTAV_A2DP_CODEC_BITS_PER_SAMPLE_16 = 0x1 << 0,
   BTAV_A2DP_CODEC_BITS_PER_SAMPLE_24 = 0x1 << 1,
   BTAV_A2DP_CODEC_BITS_PER_SAMPLE_32 = 0x1 << 2
 } btav_a2dp_codec_bits_per_sample_t;

 typedef enum {
   BTAV_A2DP_CODEC_CHANNEL_MODE_NONE = 0x0,
   BTAV_A2DP_CODEC_CHANNEL_MODE_MONO = 0x1 << 0,
   BTAV_A2DP_CODEC_CHANNEL_MODE_STEREO = 0x1 << 1
 } btav_a2dp_codec_channel_mode_t;

 /*
  * Structure for representing codec capability or configuration.
  * It is used for configuring A2DP codec preference, and for reporting back
  * current configuration or codec capability.
  * For codec capability, fields "sample_rate", "bits_per_sample" and
  * "channel_mode" can contain bit-masks with all supported features.
  */
 typedef struct {
   btav_a2dp_codec_index_t codec_type;
   btav_a2dp_codec_priority_t
       codec_priority;  // Codec selection priority
                        // relative to other codecs: larger value
                        // means higher priority. If 0, reset to
                        // default.
   btav_a2dp_codec_sample_rate_t sample_rate;
   btav_a2dp_codec_bits_per_sample_t bits_per_sample;
   btav_a2dp_codec_channel_mode_t channel_mode;
   int64_t codec_specific_1;  // Codec-specific value 1
   int64_t codec_specific_2;  // Codec-specific value 2
   int64_t codec_specific_3;  // Codec-specific value 3
   int64_t codec_specific_4;  // Codec-specific value 4

   std::string ToString() const {
     std::string codec_name_str;

     switch (codec_type) {
       case BTAV_A2DP_CODEC_INDEX_SOURCE_SBC:
         codec_name_str = "SBC";
         break;
       case BTAV_A2DP_CODEC_INDEX_SOURCE_AAC:
         codec_name_str = "AAC";
         break;
       case BTAV_A2DP_CODEC_INDEX_SOURCE_APTX:
         codec_name_str = "aptX";
         break;
       case BTAV_A2DP_CODEC_INDEX_SOURCE_APTX_HD:
         codec_name_str = "aptX HD";
         break;
       case BTAV_A2DP_CODEC_INDEX_SOURCE_LDAC:
         codec_name_str = "LDAC";
         break;
       case BTAV_A2DP_CODEC_INDEX_SINK_SBC:
         codec_name_str = "SBC (Sink)";
         break;
       case BTAV_A2DP_CODEC_INDEX_SINK_AAC:
         codec_name_str = "AAC (Sink)";
         break;
       case BTAV_A2DP_CODEC_INDEX_MAX:
         codec_name_str = "Unknown(CODEC_INDEX_MAX)";
         break;
     }

     std::string sample_rate_str;
     AppendCapability(sample_rate_str,
                      (sample_rate == BTAV_A2DP_CODEC_SAMPLE_RATE_NONE), "NONE");
     AppendCapability(sample_rate_str,
                      (sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_44100),
                      "44100");
     AppendCapability(sample_rate_str,
                      (sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_48000),
                      "48000");
     AppendCapability(sample_rate_str,
                      (sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_88200),
                      "88200");
     AppendCapability(sample_rate_str,
                      (sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_96000),
                      "96000");
     AppendCapability(sample_rate_str,
                      (sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_176400),
                      "176400");
     AppendCapability(sample_rate_str,
                      (sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_192000),
                      "192000");
     AppendCapability(sample_rate_str,
                      (sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_16000),
                      "16000");
     AppendCapability(sample_rate_str,
                      (sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_24000),
                      "24000");

     std::string bits_per_sample_str;
     AppendCapability(bits_per_sample_str,
                      (bits_per_sample == BTAV_A2DP_CODEC_BITS_PER_SAMPLE_NONE),
                      "NONE");
     AppendCapability(bits_per_sample_str,
                      (bits_per_sample & BTAV_A2DP_CODEC_BITS_PER_SAMPLE_16),
                      "16");
     AppendCapability(bits_per_sample_str,
                      (bits_per_sample & BTAV_A2DP_CODEC_BITS_PER_SAMPLE_24),
                      "24");
     AppendCapability(bits_per_sample_str,
                      (bits_per_sample & BTAV_A2DP_CODEC_BITS_PER_SAMPLE_32),
                      "32");

     std::string channel_mode_str;
     AppendCapability(channel_mode_str,
                      (channel_mode == BTAV_A2DP_CODEC_CHANNEL_MODE_NONE),
                      "NONE");
     AppendCapability(channel_mode_str,
                      (channel_mode & BTAV_A2DP_CODEC_CHANNEL_MODE_MONO),
                      "MONO");
     AppendCapability(channel_mode_str,
                      (channel_mode & BTAV_A2DP_CODEC_CHANNEL_MODE_STEREO),
                      "STEREO");

     return "codec: " + codec_name_str +
            " priority: " + std::to_string(codec_priority) +
            " sample_rate: " + sample_rate_str +
            " bits_per_sample: " + bits_per_sample_str +
            " channel_mode: " + channel_mode_str +
            " codec_specific_1: " + std::to_string(codec_specific_1) +
            " codec_specific_2: " + std::to_string(codec_specific_2) +
            " codec_specific_3: " + std::to_string(codec_specific_3) +
            " codec_specific_4: " + std::to_string(codec_specific_4);
   }

  private:
   static std::string AppendCapability(std::string& result, bool append,
                                       const std::string& name) {
     if (!append) return result;
     if (!result.empty()) result += "|";
     result += name;
     return result;
   }
 } btav_a2dp_codec_config_t;

 /** Callback for connection state change.
  *  state will have one of the values from btav_connection_state_t
  */
 typedef void (*btav_connection_state_callback)(const RawAddress& bd_addr,
                                                btav_connection_state_t state);

 /** Callback for audiopath state change.
  *  state will have one of the values from btav_audio_state_t
  */
 typedef void (*btav_audio_state_callback)(const RawAddress& bd_addr,
                                           btav_audio_state_t state);

 /** Callback for audio configuration change.
  *  Used only for the A2DP Source interface.
  */
 typedef void (*btav_audio_source_config_callback)(
     const RawAddress& bd_addr, btav_a2dp_codec_config_t codec_config,
     std::vector<btav_a2dp_codec_config_t> codecs_local_capabilities,
     std::vector<btav_a2dp_codec_config_t> codecs_selectable_capabilities);

 /** Callback for audio configuration change.
  *  Used only for the A2DP Sink interface.
  *  sample_rate: sample rate in Hz
  *  channel_count: number of channels (1 for mono, 2 for stereo)
  */
 typedef void (*btav_audio_sink_config_callback)(const RawAddress& bd_addr,
                                                 uint32_t sample_rate,
                                                 uint8_t channel_count);

 /** BT-AV A2DP Source callback structure. */
 typedef struct {
   /** set to sizeof(btav_source_callbacks_t) */
   size_t size;
   btav_connection_state_callback connection_state_cb;
   btav_audio_state_callback audio_state_cb;
   btav_audio_source_config_callback audio_config_cb;
 } btav_source_callbacks_t;

 /** BT-AV A2DP Sink callback structure. */
 typedef struct {
   /** set to sizeof(btav_sink_callbacks_t) */
   size_t size;
   btav_connection_state_callback connection_state_cb;
   btav_audio_state_callback audio_state_cb;
   btav_audio_sink_config_callback audio_config_cb;
 } btav_sink_callbacks_t;

 /**
  * NOTE:
  *
  * 1. AVRCP 1.0 shall be supported initially. AVRCP passthrough commands
  *    shall be handled internally via uinput
  *
  * 2. A2DP data path shall be handled via a socket pipe between the AudioFlinger
  *    android_audio_hw library and the Bluetooth stack.
  *
  */

 /** Represents the standard BT-AV A2DP Source interface.
  */
 typedef struct {
   /** set to sizeof(btav_source_interface_t) */
   size_t size;
   /**
    * Register the BtAv callbacks.
    */
   bt_status_t (*init)(btav_source_callbacks_t* callbacks,
                       int max_connected_audio_devices,
                       std::vector<btav_a2dp_codec_config_t> codec_priorities);

   /** connect to headset */
   bt_status_t (*connect)(const RawAddress& bd_addr);

   /** dis-connect from headset */
   bt_status_t (*disconnect)(const RawAddress& bd_addr);

   /** sets the connected device as active */
   bt_status_t (*set_active_device)(const RawAddress& bd_addr);

   /** configure the codecs settings preferences */
   bt_status_t (*config_codec)(
       const RawAddress& bd_addr,
       std::vector<btav_a2dp_codec_config_t> codec_preferences);

   /** Closes the interface. */
   void (*cleanup)(void);

 } btav_source_interface_t;

 /** Represents the standard BT-AV A2DP Sink interface.
  */
 typedef struct {
   /** set to sizeof(btav_sink_interface_t) */
   size_t size;
   /**
    * Register the BtAv callbacks
    */
   bt_status_t (*init)(btav_sink_callbacks_t* callbacks);

   /** connect to headset */
   bt_status_t (*connect)(const RawAddress& bd_addr);

   /** dis-connect from headset */
   bt_status_t (*disconnect)(const RawAddress& bd_addr);

   /** Closes the interface. */
   void (*cleanup)(void);

   /** Sends Audio Focus State. */
   void (*set_audio_focus_state)(int focus_state);

   /** Sets the audio track gain. */
   void (*set_audio_track_gain)(float gain);
 } btav_sink_interface_t;

 __END_DECLS

 #endif /* ANDROID_INCLUDE_BT_AV_H */
	/*
	* Copyright (C) 2012 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_INCLUDE_BT_AV_H
	#define ANDROID_INCLUDE_BT_AV_H

	#include <vector>

	#include <hardware/bluetooth.h>

	__BEGIN_DECLS

	/* Bluetooth AV connection states */
	typedef enum {
	BTAV_CONNECTION_STATE_DISCONNECTED = 0,
	BTAV_CONNECTION_STATE_CONNECTING,
	BTAV_CONNECTION_STATE_CONNECTED,
	BTAV_CONNECTION_STATE_DISCONNECTING
	} btav_connection_state_t;

	/* Bluetooth AV datapath states */
	typedef enum {
	BTAV_AUDIO_STATE_REMOTE_SUSPEND = 0,
	BTAV_AUDIO_STATE_STOPPED,
	BTAV_AUDIO_STATE_STARTED,
	} btav_audio_state_t;

	/*
	* Enum values for each A2DP supported codec.
	* There should be a separate entry for each A2DP codec that is supported
	* for encoding (SRC), and for decoding purpose (SINK).
	*/
	typedef enum {
	BTAV_A2DP_CODEC_INDEX_SOURCE_MIN = 0,

	// Add an entry for each source codec here.
	// NOTE: The values should be same as those listed in the following file:
	// BluetoothCodecConfig.java
	BTAV_A2DP_CODEC_INDEX_SOURCE_SBC = 0,
	BTAV_A2DP_CODEC_INDEX_SOURCE_AAC,
	BTAV_A2DP_CODEC_INDEX_SOURCE_APTX,
	BTAV_A2DP_CODEC_INDEX_SOURCE_APTX_HD,
	BTAV_A2DP_CODEC_INDEX_SOURCE_LDAC,

	BTAV_A2DP_CODEC_INDEX_SOURCE_MAX,

	BTAV_A2DP_CODEC_INDEX_SINK_MIN = BTAV_A2DP_CODEC_INDEX_SOURCE_MAX,

	// Add an entry for each sink codec here
	BTAV_A2DP_CODEC_INDEX_SINK_SBC = BTAV_A2DP_CODEC_INDEX_SINK_MIN,
	BTAV_A2DP_CODEC_INDEX_SINK_AAC,

	BTAV_A2DP_CODEC_INDEX_SINK_MAX,

	BTAV_A2DP_CODEC_INDEX_MIN = BTAV_A2DP_CODEC_INDEX_SOURCE_MIN,
	BTAV_A2DP_CODEC_INDEX_MAX = BTAV_A2DP_CODEC_INDEX_SINK_MAX
	} btav_a2dp_codec_index_t;

	typedef enum {
	// Disable the codec.
	// NOTE: This value can be used only during initialization when
	// function btav_source_interface_t::init() is called.
	BTAV_A2DP_CODEC_PRIORITY_DISABLED = -1,

	// Reset the codec priority to its default value.
	BTAV_A2DP_CODEC_PRIORITY_DEFAULT = 0,

	// Highest codec priority.
	BTAV_A2DP_CODEC_PRIORITY_HIGHEST = 1000 * 1000
	} btav_a2dp_codec_priority_t;

	typedef enum {
	BTAV_A2DP_CODEC_SAMPLE_RATE_NONE = 0x0,
	BTAV_A2DP_CODEC_SAMPLE_RATE_44100 = 0x1 << 0,
	BTAV_A2DP_CODEC_SAMPLE_RATE_48000 = 0x1 << 1,
	BTAV_A2DP_CODEC_SAMPLE_RATE_88200 = 0x1 << 2,
	BTAV_A2DP_CODEC_SAMPLE_RATE_96000 = 0x1 << 3,
	BTAV_A2DP_CODEC_SAMPLE_RATE_176400 = 0x1 << 4,
	BTAV_A2DP_CODEC_SAMPLE_RATE_192000 = 0x1 << 5,
	BTAV_A2DP_CODEC_SAMPLE_RATE_16000 = 0x1 << 6,
	BTAV_A2DP_CODEC_SAMPLE_RATE_24000 = 0x1 << 7
	} btav_a2dp_codec_sample_rate_t;

	typedef enum {
	BTAV_A2DP_CODEC_BITS_PER_SAMPLE_NONE = 0x0,
	BTAV_A2DP_CODEC_BITS_PER_SAMPLE_16 = 0x1 << 0,
	BTAV_A2DP_CODEC_BITS_PER_SAMPLE_24 = 0x1 << 1,
	BTAV_A2DP_CODEC_BITS_PER_SAMPLE_32 = 0x1 << 2
	} btav_a2dp_codec_bits_per_sample_t;

	typedef enum {
	BTAV_A2DP_CODEC_CHANNEL_MODE_NONE = 0x0,
	BTAV_A2DP_CODEC_CHANNEL_MODE_MONO = 0x1 << 0,
	BTAV_A2DP_CODEC_CHANNEL_MODE_STEREO = 0x1 << 1
	} btav_a2dp_codec_channel_mode_t;

	/*
	* Structure for representing codec capability or configuration.
	* It is used for configuring A2DP codec preference, and for reporting back
	* current configuration or codec capability.
	* For codec capability, fields "sample_rate", "bits_per_sample" and
	* "channel_mode" can contain bit-masks with all supported features.
	*/
	typedef struct {
	btav_a2dp_codec_index_t codec_type;
	btav_a2dp_codec_priority_t
	codec_priority; // Codec selection priority
	// relative to other codecs: larger value
	// means higher priority. If 0, reset to
	// default.
	btav_a2dp_codec_sample_rate_t sample_rate;
	btav_a2dp_codec_bits_per_sample_t bits_per_sample;
	btav_a2dp_codec_channel_mode_t channel_mode;
	int64_t codec_specific_1; // Codec-specific value 1
	int64_t codec_specific_2; // Codec-specific value 2
	int64_t codec_specific_3; // Codec-specific value 3
	int64_t codec_specific_4; // Codec-specific value 4

	std::string ToString() const {
	std::string codec_name_str;

	switch (codec_type) {
	case BTAV_A2DP_CODEC_INDEX_SOURCE_SBC:
	codec_name_str = "SBC";
	break;
	case BTAV_A2DP_CODEC_INDEX_SOURCE_AAC:
	codec_name_str = "AAC";
	break;
	case BTAV_A2DP_CODEC_INDEX_SOURCE_APTX:
	codec_name_str = "aptX";
	break;
	case BTAV_A2DP_CODEC_INDEX_SOURCE_APTX_HD:
	codec_name_str = "aptX HD";
	break;
	case BTAV_A2DP_CODEC_INDEX_SOURCE_LDAC:
	codec_name_str = "LDAC";
	break;
	case BTAV_A2DP_CODEC_INDEX_SINK_SBC:
	codec_name_str = "SBC (Sink)";
	break;
	case BTAV_A2DP_CODEC_INDEX_SINK_AAC:
	codec_name_str = "AAC (Sink)";
	break;
	case BTAV_A2DP_CODEC_INDEX_MAX:
	codec_name_str = "Unknown(CODEC_INDEX_MAX)";
	break;
	}

	std::string sample_rate_str;
	AppendCapability(sample_rate_str,
	(sample_rate == BTAV_A2DP_CODEC_SAMPLE_RATE_NONE), "NONE");
	AppendCapability(sample_rate_str,
	(sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_44100),
	"44100");
	AppendCapability(sample_rate_str,
	(sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_48000),
	"48000");
	AppendCapability(sample_rate_str,
	(sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_88200),
	"88200");
	AppendCapability(sample_rate_str,
	(sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_96000),
	"96000");
	AppendCapability(sample_rate_str,
	(sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_176400),
	"176400");
	AppendCapability(sample_rate_str,
	(sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_192000),
	"192000");
	AppendCapability(sample_rate_str,
	(sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_16000),
	"16000");
	AppendCapability(sample_rate_str,
	(sample_rate & BTAV_A2DP_CODEC_SAMPLE_RATE_24000),
	"24000");

	std::string bits_per_sample_str;
	AppendCapability(bits_per_sample_str,
	(bits_per_sample == BTAV_A2DP_CODEC_BITS_PER_SAMPLE_NONE),
	"NONE");
	AppendCapability(bits_per_sample_str,
	(bits_per_sample & BTAV_A2DP_CODEC_BITS_PER_SAMPLE_16),
	"16");
	AppendCapability(bits_per_sample_str,
	(bits_per_sample & BTAV_A2DP_CODEC_BITS_PER_SAMPLE_24),
	"24");
	AppendCapability(bits_per_sample_str,
	(bits_per_sample & BTAV_A2DP_CODEC_BITS_PER_SAMPLE_32),
	"32");

	std::string channel_mode_str;
	AppendCapability(channel_mode_str,
	(channel_mode == BTAV_A2DP_CODEC_CHANNEL_MODE_NONE),
	"NONE");
	AppendCapability(channel_mode_str,
	(channel_mode & BTAV_A2DP_CODEC_CHANNEL_MODE_MONO),
	"MONO");
	AppendCapability(channel_mode_str,
	(channel_mode & BTAV_A2DP_CODEC_CHANNEL_MODE_STEREO),
	"STEREO");

	return "codec: " + codec_name_str +
	" priority: " + std::to_string(codec_priority) +
	" sample_rate: " + sample_rate_str +
	" bits_per_sample: " + bits_per_sample_str +
	" channel_mode: " + channel_mode_str +
	" codec_specific_1: " + std::to_string(codec_specific_1) +
	" codec_specific_2: " + std::to_string(codec_specific_2) +
	" codec_specific_3: " + std::to_string(codec_specific_3) +
	" codec_specific_4: " + std::to_string(codec_specific_4);
	}

	private:
	static std::string AppendCapability(std::string& result, bool append,
	const std::string& name) {
	if (!append) return result;
	if (!result.empty()) result += "\|";
	result += name;
	return result;
	}
	} btav_a2dp_codec_config_t;

	/** Callback for connection state change.
	* state will have one of the values from btav_connection_state_t
	*/
	typedef void (*btav_connection_state_callback)(const RawAddress& bd_addr,
	btav_connection_state_t state);

	/** Callback for audiopath state change.
	* state will have one of the values from btav_audio_state_t
	*/
	typedef void (*btav_audio_state_callback)(const RawAddress& bd_addr,
	btav_audio_state_t state);

	/** Callback for audio configuration change.
	* Used only for the A2DP Source interface.
	*/
	typedef void (*btav_audio_source_config_callback)(
	const RawAddress& bd_addr, btav_a2dp_codec_config_t codec_config,
	std::vector<btav_a2dp_codec_config_t> codecs_local_capabilities,
	std::vector<btav_a2dp_codec_config_t> codecs_selectable_capabilities);

	/** Callback for audio configuration change.
	* Used only for the A2DP Sink interface.
	* sample_rate: sample rate in Hz
	* channel_count: number of channels (1 for mono, 2 for stereo)
	*/
	typedef void (*btav_audio_sink_config_callback)(const RawAddress& bd_addr,
	uint32_t sample_rate,
	uint8_t channel_count);

	/** BT-AV A2DP Source callback structure. */
	typedef struct {
	/** set to sizeof(btav_source_callbacks_t) */
	size_t size;
	btav_connection_state_callback connection_state_cb;
	btav_audio_state_callback audio_state_cb;
	btav_audio_source_config_callback audio_config_cb;
	} btav_source_callbacks_t;

	/** BT-AV A2DP Sink callback structure. */
	typedef struct {
	/** set to sizeof(btav_sink_callbacks_t) */
	size_t size;
	btav_connection_state_callback connection_state_cb;
	btav_audio_state_callback audio_state_cb;
	btav_audio_sink_config_callback audio_config_cb;
	} btav_sink_callbacks_t;

	/**
	* NOTE:
	*
	* 1. AVRCP 1.0 shall be supported initially. AVRCP passthrough commands
	* shall be handled internally via uinput
	*
	* 2. A2DP data path shall be handled via a socket pipe between the AudioFlinger
	* android_audio_hw library and the Bluetooth stack.
	*
	*/

	/** Represents the standard BT-AV A2DP Source interface.
	*/
	typedef struct {
	/** set to sizeof(btav_source_interface_t) */
	size_t size;
	/**
	* Register the BtAv callbacks.
	*/
	bt_status_t (init)(btav_source_callbacks_t callbacks,
	int max_connected_audio_devices,
	std::vector<btav_a2dp_codec_config_t> codec_priorities);

	/** connect to headset */
	bt_status_t (*connect)(const RawAddress& bd_addr);

	/** dis-connect from headset */
	bt_status_t (*disconnect)(const RawAddress& bd_addr);

	/** sets the connected device as active */
	bt_status_t (*set_active_device)(const RawAddress& bd_addr);

	/** configure the codecs settings preferences */
	bt_status_t (*config_codec)(
	const RawAddress& bd_addr,
	std::vector<btav_a2dp_codec_config_t> codec_preferences);

	/** Closes the interface. */
	void (*cleanup)(void);

	} btav_source_interface_t;

	/** Represents the standard BT-AV A2DP Sink interface.
	*/
	typedef struct {
	/** set to sizeof(btav_sink_interface_t) */
	size_t size;
	/**
	* Register the BtAv callbacks
	*/
	bt_status_t (init)(btav_sink_callbacks_t callbacks);

	/** connect to headset */
	bt_status_t (*connect)(const RawAddress& bd_addr);

	/** dis-connect from headset */
	bt_status_t (*disconnect)(const RawAddress& bd_addr);

	/** Closes the interface. */
	void (*cleanup)(void);

	/** Sends Audio Focus State. */
	void (*set_audio_focus_state)(int focus_state);

	/** Sets the audio track gain. */
	void (*set_audio_track_gain)(float gain);
	} btav_sink_interface_t;

	__END_DECLS

	#endif /* ANDROID_INCLUDE_BT_AV_H */