1 /****************************************************************************** 2 * 3 * Copyright (C) 2009-2012 Broadcom Corporation 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at: 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 ******************************************************************************/ 18 19 /***************************************************************************** 20 * 21 * Filename: audio_a2dp_hw.h 22 * 23 * Description: 24 * 25 *****************************************************************************/ 26 27 #ifndef AUDIO_A2DP_HW_H 28 #define AUDIO_A2DP_HW_H 29 30 /***************************************************************************** 31 ** Constants & Macros 32 ******************************************************************************/ 33 34 #define A2DP_AUDIO_HARDWARE_INTERFACE "audio.a2dp" 35 #define A2DP_CTRL_PATH "/data/misc/bluedroid/.a2dp_ctrl" 36 #define A2DP_DATA_PATH "/data/misc/bluedroid/.a2dp_data" 37 38 #define AUDIO_STREAM_DEFAULT_RATE 44100 39 #define AUDIO_STREAM_DEFAULT_FORMAT AUDIO_FORMAT_PCM_16_BIT 40 #define AUDIO_STREAM_DEFAULT_CHANNEL_FLAG AUDIO_CHANNEL_OUT_STEREO 41 42 // AUDIO_STREAM_OUTPUT_BUFFER_SZ controls the size of the audio socket buffer. 43 // If one assumes the write buffer is always full during normal BT playback, 44 // then increasing this value increases our playback latency. 45 // 46 // FIXME: AUDIO_STREAM_OUTPUT_BUFFER_SZ should be controlled by the actual audio 47 // sample rate rather than being constant. 48 // 49 // FIXME: The BT HAL should consume data at a constant rate. 50 // AudioFlinger assumes that the HAL draws data at a constant rate, which is true 51 // for most audio devices; however, the BT engine reads data at a variable rate 52 // (over the short term), which confuses both AudioFlinger as well as applications 53 // which deliver data at a (generally) fixed rate. 54 // 55 // 20 * 512 is not sufficient size to smooth the variability for some BT devices, 56 // resulting in mixer sleep and throttling. We increase this to 28 * 512 to help 57 // reduce the effect of variable data consumption. 58 #define AUDIO_STREAM_OUTPUT_BUFFER_SZ (28*512) 59 60 // AUDIO_STREAM_OUTPUT_BUFFER_PERIODS controls how the socket buffer is divided 61 // for AudioFlinger data delivery. The AudioFlinger mixer delivers data in chunks 62 // of AUDIO_STREAM_OUTPUT_BUFFER_SZ / AUDIO_STREAM_OUTPUT_BUFFER_PERIODS. If 63 // the number of periods is 2, the socket buffer represents "double buffering" 64 // of the AudioFlinger mixer buffer. 65 // 66 // In general, AUDIO_STREAM_OUTPUT_BUFFER_PERIODS * 16 * 4 should be a divisor of 67 // AUDIO_STREAM_OUTPUT_BUFFER_SZ. 68 // 69 // These values should be chosen such that 70 // 71 // AUDIO_STREAM_BUFFER_SIZE * 1000 / (AUDIO_STREAM_OUTPUT_BUFFER_PERIODS 72 // * AUDIO_STREAM_DEFAULT_RATE * 4) > 20 (ms) 73 // 74 // to avoid introducing the FastMixer in AudioFlinger. Using the FastMixer results in 75 // unnecessary latency and CPU overhead for Bluetooth. 76 #define AUDIO_STREAM_OUTPUT_BUFFER_PERIODS 4 77 78 #define AUDIO_SKT_DISCONNECTED (-1) 79 80 typedef enum { 81 A2DP_CTRL_CMD_NONE, 82 A2DP_CTRL_CMD_CHECK_READY, 83 A2DP_CTRL_CMD_START, 84 A2DP_CTRL_CMD_STOP, 85 A2DP_CTRL_CMD_SUSPEND, 86 A2DP_CTRL_GET_AUDIO_CONFIG, 87 A2DP_CTRL_CMD_OFFLOAD_START, 88 } tA2DP_CTRL_CMD; 89 90 typedef enum { 91 A2DP_CTRL_ACK_SUCCESS, 92 A2DP_CTRL_ACK_FAILURE, 93 A2DP_CTRL_ACK_INCALL_FAILURE, /* Failure when in Call*/ 94 A2DP_CTRL_ACK_UNSUPPORTED 95 } tA2DP_CTRL_ACK; 96 97 98 /***************************************************************************** 99 ** Type definitions for callback functions 100 ******************************************************************************/ 101 102 /***************************************************************************** 103 ** Type definitions and return values 104 ******************************************************************************/ 105 106 /***************************************************************************** 107 ** Extern variables and functions 108 ******************************************************************************/ 109 110 /***************************************************************************** 111 ** Functions 112 ******************************************************************************/ 113 114 115 /***************************************************************************** 116 ** 117 ** Function 118 ** 119 ** Description 120 ** 121 ** Returns 122 ** 123 ******************************************************************************/ 124 125 #endif /* A2DP_AUDIO_HW_H */ 126 127
