• 音频之Android NDK读写声卡

    通过Android NDK读写声卡通过 AudioRecord和AudioTrack两个类实现。

    AudioTrack：负责声音数据的输出
    AudioRecord：负责声音数据的采集

    • 相关头文件位置

     system/media/audio/include/system
     ├── audio-base.h
    ├── audio-base-utils.h
    ├── audio_effect-base.h
    ├── audio_effect.h
    ├── audio_effects
    ├── audio.h
    ├── audio_policy.h
    └── sound_trigger.h

    音频源：
    typedef enum {
        AUDIO_SOURCE_DEFAULT = 0, //默认输入源
        AUDIO_SOURCE_MIC = 1, //Microphone audio source 麦克风输入源
        AUDIO_SOURCE_VOICE_UPLINK = 2, //Voice call uplink (Tx) audio source 语音呼叫上行(Tx)输入源
        AUDIO_SOURCE_VOICE_DOWNLINK = 3, //Voice call downlink (Rx) audio source 语音呼叫下行(Rx)输入源
        AUDIO_SOURCE_VOICE_CALL = 4,     //Voice call uplink + downlink audio source 语音呼叫上下行输入源
        AUDIO_SOURCE_CAMCORDER = 5,      //Microphone audio source tuned for video recording 视频录制的麦克风音频源
        AUDIO_SOURCE_VOICE_RECOGNITION = 6, //Microphone audio source tuned for voice recognition 针对语音唤醒的输入源
        AUDIO_SOURCE_VOICE_COMMUNICATION = 7, //Microphone audio source tuned for voice communications such as VoIP 针对VOIP语音的输入源
        AUDIO_SOURCE_REMOTE_SUBMIX = 8,
        AUDIO_SOURCE_UNPROCESSED = 9,
        AUDIO_SOURCE_VOICE_PERFORMANCE = 10,
        AUDIO_SOURCE_ECHO_REFERENCE = 1997,
        AUDIO_SOURCE_FM_TUNER = 1998,
    #ifndef AUDIO_NO_SYSTEM_DECLARATIONS
        /**
         * A low-priority, preemptible audio source for for background software
         * hotword detection. Same tuning as VOICE_RECOGNITION.
         * Used only internally by the framework.
         */
        AUDIO_SOURCE_HOTWORD = 1999,
    #endif // AUDIO_NO_SYSTEM_DECLARATIONS
    } audio_source_t;


    typedef enum {
        AUDIO_SESSION_OUTPUT_STAGE = -1, // (-1)
        AUDIO_SESSION_OUTPUT_MIX = 0,
        AUDIO_SESSION_ALLOCATE = 0,
        AUDIO_SESSION_NONE = 0,
    } audio_session_t;

    //音频格式
    typedef enum {//省略部分定义
        AUDIO_FORMAT_INVALID             = 0xFFFFFFFFu,
        AUDIO_FORMAT_DEFAULT             = 0,
        AUDIO_FORMAT_PCM                 = 0x00000000u,
        AUDIO_FORMAT_MP3                 = 0x01000000u,
        AUDIO_FORMAT_AMR_NB              = 0x02000000u,
        /* Subformats */
        AUDIO_FORMAT_PCM_SUB_16_BIT        = 0x1u, 
        AUDIO_FORMAT_PCM_SUB_8_BIT         = 0x2u,
        AUDIO_FORMAT_PCM_SUB_32_BIT        = 0x3u,
        AUDIO_FORMAT_PCM_SUB_8_24_BIT      = 0x4u,
        AUDIO_FORMAT_PCM_SUB_FLOAT         = 0x5u,
        AUDIO_FORMAT_PCM_SUB_24_BIT_PACKED = 0x6u,

        /* Aliases */
        AUDIO_FORMAT_PCM_16_BIT            = 0x1u,        // (PCM | PCM_SUB_16_BIT) //PCM16位
        AUDIO_FORMAT_PCM_8_BIT             = 0x2u,        // (PCM | PCM_SUB_8_BIT)  //PCM 8位
        AUDIO_FORMAT_PCM_32_BIT            = 0x3u,        // (PCM | PCM_SUB_32_BIT)
        AUDIO_FORMAT_PCM_8_24_BIT          = 0x4u,        // (PCM | PCM_SUB_8_24_BIT)
        AUDIO_FORMAT_PCM_FLOAT             = 0x5u,        // (PCM | PCM_SUB_FLOAT)
        AUDIO_FORMAT_PCM_24_BIT_PACKED     = 0x6u,        // (PCM | PCM_SUB_24_BIT_PACKED)
        AUDIO_FORMAT_AAC_MAIN              = 0x4000001u,  // (AAC | AAC_SUB_MAIN)
        AUDIO_FORMAT_AAC_LC                = 0x4000002u,  // (AAC | AAC_SUB_LC)
        AUDIO_FORMAT_AAC_SSR               = 0x4000004u,  // (AAC | AAC_SUB_SSR)
      
    } audio_format_t;


    enum {//省略部分定义
        AUDIO_CHANNEL_REPRESENTATION_POSITION   = 0x0u,
        AUDIO_CHANNEL_REPRESENTATION_INDEX      = 0x2u,
        AUDIO_CHANNEL_NONE                      = 0x0u,
        AUDIO_CHANNEL_INVALID                   = 0xC0000000u,

        AUDIO_CHANNEL_OUT_FRONT_LEFT            = 0x1u,
        AUDIO_CHANNEL_OUT_FRONT_RIGHT           = 0x2u,
        AUDIO_CHANNEL_IN_TOP_RIGHT              = 0x400000u,
        AUDIO_CHANNEL_IN_VOICE_UPLINK           = 0x4000u,
        AUDIO_CHANNEL_IN_VOICE_DNLINK           = 0x8000u,
        AUDIO_CHANNEL_IN_MONO                   = 0x10u,     // IN_FRONT         //单声道
        AUDIO_CHANNEL_IN_STEREO                 = 0xCu,      // IN_LEFT | IN_RIGHT   立体声
        AUDIO_CHANNEL_IN_FRONT_BACK             = 0x30u,     // IN_FRONT | IN_BACK
        AUDIO_CHANNEL_IN_6                      = 0xFCu,     // IN_LEFT | IN_RIGHT | IN_FRONT | IN_BACK | IN_LEFT_PROCESSED | IN_RIGHT_PROCESSED
        AUDIO_CHANNEL_IN_2POINT0POINT2          = 0x60000Cu, // IN_LEFT | IN_RIGHT | IN_TOP_LEFT | IN_TOP_RIGHT
        AUDIO_CHANNEL_IN_2POINT1POINT2          = 0x70000Cu, // IN_LEFT | IN_RIGHT | IN_TOP_LEFT | IN_TOP_RIGHT | IN_LOW_FREQUENCY
        AUDIO_CHANNEL_IN_3POINT0POINT2          = 0x64000Cu, // IN_LEFT | IN_CENTER | IN_RIGHT | IN_TOP_LEFT | IN_TOP_RIGHT
        AUDIO_CHANNEL_IN_3POINT1POINT2          = 0x74000Cu, // IN_LEFT | IN_CENTER | IN_RIGHT | IN_TOP_LEFT | IN_TOP_RIGHT | IN_LOW_FREQUENCY
        AUDIO_CHANNEL_IN_5POINT1                = 0x17000Cu, // IN_LEFT | IN_CENTER | IN_RIGHT | IN_BACK_LEFT | IN_BACK_RIGHT | IN_LOW_FREQUENCY
        AUDIO_CHANNEL_IN_VOICE_UPLINK_MONO      = 0x4010u,   // IN_VOICE_UPLINK | IN_MONO
        AUDIO_CHANNEL_IN_VOICE_DNLINK_MONO      = 0x8010u,   // IN_VOICE_DNLINK | IN_MONO
        AUDIO_CHANNEL_IN_VOICE_CALL_MONO        = 0xC010u,   // IN_VOICE_UPLINK_MONO | IN_VOICE_DNLINK_MONO
    };


    typedef enum {
        AUDIO_INPUT_FLAG_NONE       = 0x0,
        AUDIO_INPUT_FLAG_FAST       = 0x1,
        AUDIO_INPUT_FLAG_HW_HOTWORD = 0x2,
        AUDIO_INPUT_FLAG_RAW        = 0x4,
        AUDIO_INPUT_FLAG_SYNC       = 0x8,
        AUDIO_INPUT_FLAG_MMAP_NOIRQ = 0x10,
        AUDIO_INPUT_FLAG_VOIP_TX    = 0x20,
        AUDIO_INPUT_FLAG_HW_AV_SYNC = 0x40,
    #ifndef AUDIO_NO_SYSTEM_DECLARATIONS  // TODO: Expose at HAL interface, remove FRAMEWORK_FLAGS mask
        AUDIO_INPUT_FLAG_DIRECT     = 0x80,
        AUDIO_INPUT_FRAMEWORK_FLAGS = AUDIO_INPUT_FLAG_DIRECT,
    #endif
    } audio_input_flags_t;

        
    enum {
        AUDIO_IO_HANDLE_NONE = 0,
        AUDIO_MODULE_HANDLE_NONE = 0,
        AUDIO_PORT_HANDLE_NONE = 0,
        AUDIO_PATCH_HANDLE_NONE = 0,
    };


    TRANSFER_CALLBACK    通过回调函数传输数据
    TRANSFER_OBTAIN       
    TRANSFER_SYNC        
    TRANSFER_DEFAULT

    • demo源码：

    ├── Android.mk
    ├── include
    └── src
        └── audio_main.cpp

    audio_main.cpp:

    1. #include 
    2. #include 
    3. #include 
    4. #include 
    5. #include 
    6. #include 
    7.  
    8. using namespace android;
    9.  
    10. sp mAudioRecord;
    11. sp mAudioTrack;
    12. FILE *g_read_pcm = NULL;
    13. FILE *g_write_pcm = NULL;
    14. audio_channel_mask_t channelmask = AUDIO_CHANNEL_IN_MONO;
    15. audio_format_t audio_format = AUDIO_FORMAT_PCM_16_BIT;
    16. int sample_rate = 16000;
    17. int min_buf_size = 0;
    18.  
    19. void read_audio_data(int event, void *user, void *info)
    20. {
    21.     if (event != AudioRecord::EVENT_MORE_DATA) {
    22.         printf("%s: event: %d\n", __FUNCTION__, event);
    23.         return;
    24.     }
    25.  
    26.     AudioRecord::Buffer *buffer = static_cast(info);
    27.     if (buffer->size == 0) {
    28.         return;
    29.     }
    30.  
    31.     //printf("%s: buf size: %d\n", __FUNCTION__, buffer->size);
    32.     fwrite(buffer->raw, buffer->size, 1, g_write_pcm);
    33. }
    34.  
    35. //read from soundcard and write into file
    36. int ndk_audio_read()
    37. {
    38.     int ret = 0;
    39.     char file[256] = {'\0'};
    40.     size_t frame_count = 0;
    41.     int frame_size = 0;
    42.     String16  strName = String16("reader");
    43.  
    44.     mAudioRecord = new AudioRecord(strName);
    45.  
    46.     mAudioRecord.get();
    47.  
    48.     status_t result = AudioRecord::getMinFrameCount(&frame_count, sample_rate,
    49.                     audio_format, channelmask);
    50.     if (result == NO_ERROR) {
    51.         int channel_count = popcount(channelmask);
    52.         min_buf_size = frame_count * channel_count * (audio_format == AUDIO_FORMAT_PCM_16_BIT ? 2 : 1);
    53.     } else if (result == BAD_VALUE) {
    54.         printf("Invalid param when get min frame count\n");
    55.         return -1;
    56.     } else {
    57.         printf("Faield to get min frame count\n");
    58.         return -1;
    59.     }
    60.  
    61.     min_buf_size *= 2;// To prevent "buffer overflow" issue
    62.  
    63.     if (min_buf_size > 0) {
    64.         printf("get min buf size[%d]\n", min_buf_size);
    65.     } else {
    66.         printf("get min buf size failed\n");
    67.         return -1;
    68.     }
    69.  
    70.     frame_size = popcount(channelmask) * (audio_format == AUDIO_FORMAT_PCM_16_BIT ? 2 : 1);
    71.     frame_count = min_buf_size / frame_size;
    72.  
    73.     ret = mAudioRecord->set(
    74.         AUDIO_SOURCE_MIC,
    75.         sample_rate,
    76.         audio_format,
    77.         channelmask,
    78.         frame_count,
    79.         read_audio_data,
    80.         NULL,
    81.         0,
    82.         false,
    83.         AUDIO_SESSION_ALLOCATE,
    84.         AudioRecord::TRANSFER_CALLBACK,
    85.         AUDIO_INPUT_FLAG_FAST,
    86.         getuid(),
    87.         getpid(),
    88.         NULL,
    89.         AUDIO_PORT_HANDLE_NONE);
    90.     if (ret != NO_ERROR) {
    91.         printf("AudioRecord set failure\n");
    92.         return -1;
    93.     }
    94.     else
    95.     {
    96.         printf("set success\n");
    97.     }
    98.  
    99.     if (mAudioRecord->initCheck() != NO_ERROR) {
    100.         printf("AudioRecord initialization failed!");
    101.         return -1;
    102.     }
    103.  
    104.     snprintf(file, 256, "/data/ndksound.pcm");
    105.     g_write_pcm = fopen(file, "wb");
    106.  
    107.     ret = mAudioRecord->start();
    108.     if (ret != NO_ERROR) {
    109.         printf("Audio Record start failure ret: [%d]", ret);
    110.     }
    111.  
    112.     return 0;
    113. }
    114.  
    115. void write_audio_data(int event, void *user, void *info)
    116. {
    117.     if (event != AudioTrack::EVENT_MORE_DATA) {
    118.         printf("soundcard writer event: %d\n", event);
    119.         return;
    120.     }
    121.  
    122.     AudioTrack::Buffer *buffer = static_cast(info);
    123.     if (buffer->size == 0) {
    124.         return;
    125.     }
    126.     memset(buffer->raw, 0, buffer->size);
    127.  
    128.     int ret = fread(buffer->raw, 1, buffer->size, g_read_pcm);
    129.     if (ret <= 0) {
    130.         printf("%s: no more data:%d\n", __FUNCTION__, ret);
    131.         exit(1);
    132.     }
    133. }
    134.  
    135. //read from file and write into soundcard
    136. int ndk_audio_write()
    137. {
    138.     int ret = 0;
    139.     char file[256] = {'\0'};
    140.     size_t frame_count = 0;
    141.     int frame_size = 0;
    142.  
    143.     mAudioTrack = new AudioTrack();
    144.     mAudioTrack.get();
    145.  
    146.     status_t result = AudioTrack::getMinFrameCount(&frame_count, AUDIO_STREAM_DEFAULT,
    147.                     sample_rate);
    148.     if (result == NO_ERROR) {
    149.         int channel_count = popcount(channelmask);
    150.         min_buf_size = frame_count * channel_count * (audio_format == AUDIO_FORMAT_PCM_16_BIT ? 2 : 1);
    151.     } else if (result == BAD_VALUE) {
    152.         printf("Invalid param when get min frame count\n");
    153.         return -1;
    154.     } else {
    155.         printf("Faield to get min frame count\n");
    156.         return -1;
    157.     }
    158.  
    159.     if (min_buf_size > 0) {
    160.         printf("get min buf size[%d]\n", min_buf_size);
    161.     } else {
    162.         printf("get min buf size failed\n");
    163.         return -1;
    164.     }
    165.  
    166.     channelmask = AUDIO_CHANNEL_OUT_MONO;
    167.     frame_size = popcount(channelmask) * (audio_format == AUDIO_FORMAT_PCM_16_BIT ? 2 : 1);
    168.     frame_count = min_buf_size / frame_size;
    169.  
    170.     ret = mAudioTrack->set(
    171.             AUDIO_STREAM_VOICE_CALL,
    172.             sample_rate,
    173.             audio_format,
    174.             channelmask,
    175.             frame_count,
    176.             AUDIO_OUTPUT_FLAG_FAST,
    177.             write_audio_data,
    178.             NULL,
    179.             0,
    180.             0,
    181.             false,
    182.             AUDIO_SESSION_ALLOCATE,
    183.             AudioTrack::TRANSFER_CALLBACK,
    184.             NULL,
    185.             -1
    186.         );
    187.     if (ret != NO_ERROR) {
    188.         printf("mAudioTrack set failure\n");
    189.         return -1;
    190.     }
    191.     else
    192.     {
    193.         printf("set success\n");
    194.     }
    195.  
    196.     if (mAudioTrack->initCheck() != NO_ERROR) {
    197.         printf("mAudioTrack initialization failed!");
    198.         return -1;
    199.     }
    200.  
    201.     snprintf(file, 256, "/data/ndksound.pcm");
    202.     g_read_pcm = fopen(file, "rb");
    203.     if (!g_read_pcm) {
    204.         printf("open file failed\n");
    205.         return -1;
    206.     }
    207.  
    208.     ret = mAudioTrack->start();
    209.     if (ret != NO_ERROR) {
    210.         printf("Audio Track start failure ret: [%d]", ret);
    211.         return -1;
    212.     }
    213.  
    214.     printf("start success\n");
    215.     return 0;
    216. }
    217.  
    218. int main(int argc, char *argv[])
    219. {
    220.     int ret = 0;
    221.  
    222.     if (argc < 2) {
    223.         printf("need 2 param\n");
    224.         return -1;
    225.     }
    226.     if (0 == strcmp(argv[1], "read")) {
    227.         printf("read soundcard\n");
    228.         ret = ndk_audio_read();
    229.         if (ret < 0) {
    230.             exit(1);
    231.         }
    232.     } else {
    233.         printf("write soundcard\n");
    234.         ret = ndk_audio_write();
    235.         if (ret < 0) {
    236.             exit(1);
    237.         }
    238.     }
    239.  
    240.     while (1) {
    241.         sleep(5);
    242.     }
    243.  
    244.     if (g_read_pcm) {
    245.         fclose(g_read_pcm);
    246.     }
    247.  
    248.     if (g_write_pcm) {
    249.         fclose(g_write_pcm);
    250.     }
    251.  
    252. 	return 0;
    253. }

    Android.mk

    1. LOCAL_PATH := $(call my-dir)
    2. include $(CLEAR_VARS)
    3.  
    4. LOCAL_SRC_FILES += \
    5.     src/audio_main.cpp
    6.  
    7. LOCAL_C_INCLUDES += \
    8.     bionic \
    9.     external/stlport/stlport \
    10.     external/libcxx/include \
    11.     frameworks/av/include \
    12.     frameworks/av/media/libaudioclient/include \
    13.     frameworks/native/libs/nativebase/include \
    14.     frameworks/native/libs/math/include \
    15.     frameworks/av/media/ndk/include \
    16.     system/core/include \
    17.     system/core/libprocessgroup/include \
    18.     system/core/base/include \
    19.     system/core/libutils/include \
    20.  
    21. LOCAL_CFLAGS := -DANDROID -Wall -Wno-implicit-function-declaration  -Wl,--unresolved-symbols=ignore-all
    22.  
    23.  
    24. LOCAL_MODULE := ndk_audio
    25. LOCAL_LDLIBS := -lm -lmediandk -landroid -laudioclient -lstdc++ -lutils
    26.  
    27. include $(BUILD_EXECUTABLE)
    • demo运行

    从声卡读声音数据写到文件： ./ndk_audio  read

    从文件读声音数据写到声卡： ./ndk_audio write

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  • 原文地址：https://blog.csdn.net/szkbsgy/article/details/126555114