精简aac相关代码

src/Extension/AAC.cpp

@@ -12,62 +12,55 @@
 
 namespace mediakit{
 
-void writeAdtsHeader(const AACFrame &hed, uint8_t *pcAdts) {
+class AdtsHeader{
-    pcAdts[0] = (hed.syncword >> 4 & 0xFF); //8bit
+public:
-    pcAdts[1] = (hed.syncword << 4 & 0xF0); //4 bit
+    unsigned int syncword = 0; //12 bslbf 同步字The bit string ‘1111 1111 1111’，说明一个ADTS帧的开始
-    pcAdts[1] |= (hed.id << 3 & 0x08); //1 bit
+    unsigned int id;        //1 bslbf   MPEG 标示符, 设置为1
-    pcAdts[1] |= (hed.layer << 1 & 0x06); //2bit
+    unsigned int layer;    //2 uimsbf Indicates which layer is used. Set to ‘00’
-    pcAdts[1] |= (hed.protection_absent & 0x01); //1 bit
+    unsigned int protection_absent;  //1 bslbf  表示是否误码校验
+    unsigned int profile; //2 uimsbf  表示使用哪个级别的AAC，如01 Low Complexity(LC)--- AACLC
+    unsigned int sf_index;           //4 uimsbf  表示使用的采样率下标
+    unsigned int private_bit;        //1 bslbf
+    unsigned int channel_configuration;  //3 uimsbf  表示声道数
+    unsigned int original;               //1 bslbf
+    unsigned int home;                   //1 bslbf
+    //下面的为改变的参数即每一帧都不同
+    unsigned int copyright_identification_bit;   //1 bslbf
+    unsigned int copyright_identification_start; //1 bslbf
+    unsigned int aac_frame_length; // 13 bslbf  一个ADTS帧的长度包括ADTS头和raw data block
+    unsigned int adts_buffer_fullness;           //11 bslbf     0x7FF 说明是码率可变的码流
+    //no_raw_data_blocks_in_frame 表示ADTS帧中有number_of_raw_data_blocks_in_frame + 1个AAC原始帧.
+    //所以说number_of_raw_data_blocks_in_frame == 0
+    //表示说ADTS帧中有一个AAC数据块并不是说没有。(一个AAC原始帧包含一段时间内1024个采样及相关数据)
+    unsigned int no_raw_data_blocks_in_frame;    //2 uimsfb
+};
 
-    pcAdts[2] = (hed.profile << 6 & 0xC0); // 2 bit
+static void dumpAdtsHeader(const AdtsHeader &hed, uint8_t *out) {
-    pcAdts[2] |= (hed.sf_index << 2 & 0x3C); //4bit
+    out[0] = (hed.syncword >> 4 & 0xFF); //8bit
-    pcAdts[2] |= (hed.private_bit << 1 & 0x02); //1 bit
+    out[1] = (hed.syncword << 4 & 0xF0); //4 bit
-    pcAdts[2] |= (hed.channel_configuration >> 2 & 0x03); //1 bit
+    out[1] |= (hed.id << 3 & 0x08); //1 bit
-
+    out[1] |= (hed.layer << 1 & 0x06); //2bit
-    pcAdts[3] = (hed.channel_configuration << 6 & 0xC0);  // 2 bit
+    out[1] |= (hed.protection_absent & 0x01); //1 bit
-    pcAdts[3] |= (hed.original << 5 & 0x20);				//1 bit
+    out[2] = (hed.profile << 6 & 0xC0); // 2 bit
-    pcAdts[3] |= (hed.home << 4 & 0x10);				//1 bit
+    out[2] |= (hed.sf_index << 2 & 0x3C); //4bit
-    pcAdts[3] |= (hed.copyright_identification_bit << 3 & 0x08);			//1 bit
+    out[2] |= (hed.private_bit << 1 & 0x02); //1 bit
-    pcAdts[3] |= (hed.copyright_identification_start << 2 & 0x04);		//1 bit
+    out[2] |= (hed.channel_configuration >> 2 & 0x03); //1 bit
-    pcAdts[3] |= (hed.aac_frame_length >> 11 & 0x03);				//2 bit
+    out[3] = (hed.channel_configuration << 6 & 0xC0);  // 2 bit
-
+    out[3] |= (hed.original << 5 & 0x20);				//1 bit
-    pcAdts[4] = (hed.aac_frame_length >> 3 & 0xFF);				//8 bit
+    out[3] |= (hed.home << 4 & 0x10);				//1 bit
-
+    out[3] |= (hed.copyright_identification_bit << 3 & 0x08);			//1 bit
-    pcAdts[5] = (hed.aac_frame_length << 5 & 0xE0);				//3 bit
+    out[3] |= (hed.copyright_identification_start << 2 & 0x04);		//1 bit
-    pcAdts[5] |= (hed.adts_buffer_fullness >> 6 & 0x1F);				//5 bit
+    out[3] |= (hed.aac_frame_length >> 11 & 0x03);				//2 bit
-
+    out[4] = (hed.aac_frame_length >> 3 & 0xFF);				//8 bit
-    pcAdts[6] = (hed.adts_buffer_fullness << 2 & 0xFC);				//6 bit
+    out[5] = (hed.aac_frame_length << 5 & 0xE0);				//3 bit
-    pcAdts[6] |= (hed.no_raw_data_blocks_in_frame & 0x03);				//2 bit
+    out[5] |= (hed.adts_buffer_fullness >> 6 & 0x1F);				//5 bit
-}
+    out[6] = (hed.adts_buffer_fullness << 2 & 0xFC);				//6 bit
-string 	makeAdtsConfig(const uint8_t *pcAdts){
+    out[6] |= (hed.no_raw_data_blocks_in_frame & 0x03);				//2 bit
-    if (!(pcAdts[0] == 0xFF && (pcAdts[1] & 0xF0) == 0xF0)) {
-        return "";
-    }
-    // Get and check the 'profile':
-    unsigned char profile = (pcAdts[2] & 0xC0) >> 6; // 2 bits
-    if (profile == 3) {
-        return "";
 }
 
-    // Get and check the 'sampling_frequency_index':
+static void parseAacConfig(const string &config, AdtsHeader &adts) {
-    unsigned char sampling_frequency_index = (pcAdts[2] & 0x3C) >> 2; // 4 bits
+    uint8_t cfg1 = config[0];
-    if (samplingFrequencyTable[sampling_frequency_index] == 0) {
+    uint8_t cfg2 = config[1];
-        return "";
-    }
-
-    // Get and check the 'channel_configuration':
-    unsigned char channel_configuration = ((pcAdts[2] & 0x01) << 2)
-                                          | ((pcAdts[3] & 0xC0) >> 6); // 3 bits
-
-    unsigned char audioSpecificConfig[2];
-    unsigned char const audioObjectType = profile + 1;
-    audioSpecificConfig[0] = (audioObjectType << 3) | (sampling_frequency_index >> 1);
-    audioSpecificConfig[1] = (sampling_frequency_index << 7) | (channel_configuration << 3);
-    return string((char *)audioSpecificConfig,2);
-}
-void makeAdtsHeader(const string &strAudioCfg,AACFrame &adts) {
-    uint8_t cfg1 = strAudioCfg[0];
-    uint8_t cfg2 = strAudioCfg[1];
 
     int audioObjectType;
     int sampling_frequency_index;
@@ -93,9 +86,44 @@ void makeAdtsHeader(const string &strAudioCfg,AACFrame &adts) {
     adts.adts_buffer_fullness = 2047;
     adts.no_raw_data_blocks_in_frame = 0;
 }
-void getAACInfo(const AACFrame &adts,int &iSampleRate,int &iChannel){
+
-    iSampleRate = samplingFrequencyTable[adts.sf_index];
+string 	makeAacConfig(const uint8_t *hex){
-    iChannel = adts.channel_configuration;
+    if (!(hex[0] == 0xFF && (hex[1] & 0xF0) == 0xF0)) {
+        return "";
+    }
+    // Get and check the 'profile':
+    unsigned char profile = (hex[2] & 0xC0) >> 6; // 2 bits
+    if (profile == 3) {
+        return "";
+    }
+
+    // Get and check the 'sampling_frequency_index':
+    unsigned char sampling_frequency_index = (hex[2] & 0x3C) >> 2; // 4 bits
+    if (samplingFrequencyTable[sampling_frequency_index] == 0) {
+        return "";
+    }
+
+    // Get and check the 'channel_configuration':
+    unsigned char channel_configuration = ((hex[2] & 0x01) << 2) | ((hex[3] & 0xC0) >> 6); // 3 bits
+    unsigned char audioSpecificConfig[2];
+    unsigned char const audioObjectType = profile + 1;
+    audioSpecificConfig[0] = (audioObjectType << 3) | (sampling_frequency_index >> 1);
+    audioSpecificConfig[1] = (sampling_frequency_index << 7) | (channel_configuration << 3);
+    return string((char *)audioSpecificConfig,2);
+}
+
+void dumpAacConfig(const string &config, int length, uint8_t *out){
+    AdtsHeader header;
+    parseAacConfig(config, header);
+    header.aac_frame_length = length;
+    dumpAdtsHeader(header, out);
+}
+
+void parseAacConfig(const string &config, int &samplerate, int &channels){
+    AdtsHeader header;
+    parseAacConfig(config, header);
+    samplerate = samplingFrequencyTable[header.sf_index];
+    channels = header.channel_configuration;
 }
 
 Sdp::Ptr AACTrack::getSdp() {
@@ -107,5 +135,3 @@ Sdp::Ptr AACTrack::getSdp() {
 }
 
 }//namespace mediakit
-
-

src/Extension/AAC.h

@@ -13,71 +13,26 @@
 
 #include "Frame.h"
 #include "Track.h"
+#define ADTS_HEADER_LEN 7
 
 namespace mediakit{
 
 class AACFrame;
 
 unsigned const samplingFrequencyTable[16] = { 96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, 16000, 12000, 11025, 8000, 7350, 0, 0, 0 };
-void makeAdtsHeader(const string &strAudioCfg,AACFrame &adts);
+string makeAacConfig(const uint8_t *hex);
-void writeAdtsHeader(const AACFrame &adts, uint8_t *pcAdts) ;
+void dumpAacConfig(const string &config, int length, uint8_t *out);
-string makeAdtsConfig(const uint8_t *pcAdts);
+void parseAacConfig(const string &config, int &samplerate, int &channels);
-void getAACInfo(const AACFrame &adts,int &iSampleRate,int &iChannel);
 
 /**
  * aac帧，包含adts头
  */
-class AACFrame : public Frame {
+class AACFrame : public FrameImp {
 public:
     typedef std::shared_ptr<AACFrame> Ptr;
-
+    AACFrame(){
-    char *data() const override{
+        _codecid = CodecAAC;
-        return (char *)buffer;
     }
-    uint32_t size() const override {
-        return aac_frame_length;
-    }
-    uint32_t dts() const override {
-        return _dts;
-    }
-    uint32_t prefixSize() const override{
-        return _prefix_size;
-    }
-
-    CodecId getCodecId() const override{
-        return CodecAAC;
-    }
-
-    bool keyFrame() const override {
-        return false;
-    }
-
-    bool configFrame() const override{
-        return false;
-    }
-public:
-    unsigned int syncword = 0; //12 bslbf 同步字The bit string ‘1111 1111 1111’，说明一个ADTS帧的开始
-    unsigned int id;        //1 bslbf   MPEG 标示符, 设置为1
-    unsigned int layer;    //2 uimsbf Indicates which layer is used. Set to ‘00’
-    unsigned int protection_absent;  //1 bslbf  表示是否误码校验
-    unsigned int profile; //2 uimsbf  表示使用哪个级别的AAC，如01 Low Complexity(LC)--- AACLC
-    unsigned int sf_index;           //4 uimsbf  表示使用的采样率下标
-    unsigned int private_bit;        //1 bslbf
-    unsigned int channel_configuration;  //3 uimsbf  表示声道数
-    unsigned int original;               //1 bslbf
-    unsigned int home;                   //1 bslbf
-    //下面的为改变的参数即每一帧都不同
-    unsigned int copyright_identification_bit;   //1 bslbf
-    unsigned int copyright_identification_start; //1 bslbf
-    unsigned int aac_frame_length; // 13 bslbf  一个ADTS帧的长度包括ADTS头和raw data block
-    unsigned int adts_buffer_fullness;           //11 bslbf     0x7FF 说明是码率可变的码流
-    //no_raw_data_blocks_in_frame 表示ADTS帧中有number_of_raw_data_blocks_in_frame + 1个AAC原始帧.
-    //所以说number_of_raw_data_blocks_in_frame == 0
-    //表示说ADTS帧中有一个AAC数据块并不是说没有。(一个AAC原始帧包含一段时间内1024个采样及相关数据)
-    unsigned int no_raw_data_blocks_in_frame;    //2 uimsfb
-    unsigned char buffer[2 * 1024 + 7];
-    uint32_t _dts;
-    uint32_t _prefix_size = 7;
 };
 
 class AACFrameNoCacheAble : public FrameFromPtr {
@@ -138,7 +93,7 @@ public:
         if(adts_header_len < 7){
             throw std::invalid_argument("adts头必须不少于7个字节");
         }
-        _cfg = makeAdtsConfig((uint8_t*)adts_header);
+        _cfg = makeAacConfig((uint8_t *) adts_header);
         onReady();
     }
 
@@ -150,7 +105,7 @@ public:
         if(aac_frame_with_adts->getCodecId() != CodecAAC || aac_frame_with_adts->prefixSize() < 7){
             throw std::invalid_argument("必须输入带adts头的aac帧");
         }
-        _cfg = makeAdtsConfig((uint8_t*)aac_frame_with_adts->data());
+        _cfg = makeAacConfig((uint8_t *) aac_frame_with_adts->data());
         onReady();
     }
 
@@ -205,7 +160,7 @@ public:
             //未获取到aac_cfg信息
             if (frame->prefixSize() >= 7) {
                 //7个字节的adts头
-                _cfg = makeAdtsConfig((uint8_t *)(frame->data()));
+                _cfg = makeAacConfig((uint8_t *) (frame->data()));
                 onReady();
             } else {
                 WarnL << "无法获取adts头!";
@@ -221,9 +176,7 @@ private:
         if (_cfg.size() < 2) {
             return;
         }
-        AACFrame aacFrame;
+        parseAacConfig(_cfg, _sampleRate, _channel);
-        makeAdtsHeader(_cfg,aacFrame);
-        getAACInfo(aacFrame,_sampleRate,_channel);
     }
 
     Track::Ptr clone() override {

src/Extension/AACRtmp.cpp

@@ -20,8 +20,9 @@ AACRtmpDecoder::AACRtmpDecoder() {
 AACFrame::Ptr AACRtmpDecoder::obtainFrame() {
     //从缓存池重新申请对象，防止覆盖已经写入环形缓存的对象
     auto frame = ResourcePoolHelper<AACFrame>::obtainObj();
-    frame->aac_frame_length = 7;
+    frame->_prefix_size = ADTS_HEADER_LEN;
-    frame->_prefix_size = 7;
+    //预留7个字节的空位以便后续覆盖
+    frame->_buffer.assign(ADTS_HEADER_LEN,(char)0);
     return frame;
 }
 
@@ -41,7 +42,7 @@ static string getAacCfg(const RtmpPacket &thiz) {
     return ret;
 }
 
-bool AACRtmpDecoder::inputRtmp(const RtmpPacket::Ptr &pkt, bool key_pos) {
+bool AACRtmpDecoder::inputRtmp(const RtmpPacket::Ptr &pkt, bool) {
     if (pkt->isCfgFrame()) {
         _aac_cfg = getAacCfg(*pkt);
         return false;
@@ -52,26 +53,18 @@ bool AACRtmpDecoder::inputRtmp(const RtmpPacket::Ptr &pkt, bool key_pos) {
     return false;
 }
 
-void AACRtmpDecoder::onGetAAC(const char* pcData, int iLen, uint32_t ui32TimeStamp) {
+void AACRtmpDecoder::onGetAAC(const char* data, int len, uint32_t stamp) {
-    if(iLen + 7 > sizeof(_adts->buffer)){
+    _adts->_dts = stamp;
-        WarnL << "Illegal adts data, exceeding the length limit.";
+    //先追加数据
-        return;
+    _adts->_buffer.append(data, len);
-    }
+    //覆盖adts头
-    //写adts结构头
+    dumpAacConfig(_aac_cfg, _adts->size(), (uint8_t *) _adts->data());
-    makeAdtsHeader(_aac_cfg,*_adts);
-
-    //拷贝aac负载
-    memcpy(_adts->buffer + 7, pcData, iLen);
-    _adts->aac_frame_length = 7 + iLen;
-    _adts->_dts = ui32TimeStamp;
-
-    //adts结构头转成头7个字节
-    writeAdtsHeader(*_adts, _adts->buffer);
 
     //写入环形缓存
     RtmpCodec::inputFrame(_adts);
     _adts = obtainFrame();
 }
+
 /////////////////////////////////////////////////////////////////////////////////////
 
 AACRtmpEncoder::AACRtmpEncoder(const Track::Ptr &track) {
@@ -93,7 +86,7 @@ void AACRtmpEncoder::inputFrame(const Frame::Ptr &frame) {
     if (_aac_cfg.empty()) {
         if (frame->prefixSize() >= 7) {
             //包含adts头,从adts头获取aac配置信息
-            _aac_cfg = makeAdtsConfig((uint8_t *)(frame->data()));
+            _aac_cfg = makeAacConfig((uint8_t *) (frame->data()));
         }
         makeConfigPacket();
     }

src/Extension/AACRtmp.h

@@ -38,7 +38,7 @@ public:
     }
 
 protected:
-    void onGetAAC(const char* pcData, int iLen, uint32_t ui32TimeStamp);
+    void onGetAAC(const char* data, int len, uint32_t stamp);
     AACFrame::Ptr obtainFrame();
 protected:
     AACFrame::Ptr _adts;

src/Extension/AACRtp.cpp

@@ -9,7 +9,7 @@
  */
 
 #include "AACRtp.h"
-#define ADTS_HEADER_LEN 7
+#define AAC_MAX_FRAME_SIZE (2 * 1024)
 
 namespace mediakit{
 
@@ -77,11 +77,9 @@ AACRtpDecoder::AACRtpDecoder() {
 AACFrame::Ptr AACRtpDecoder::obtainFrame() {
     //从缓存池重新申请对象，防止覆盖已经写入环形缓存的对象
     auto frame = ResourcePoolHelper<AACFrame>::obtainObj();
-    frame->aac_frame_length = ADTS_HEADER_LEN;
     frame->_prefix_size = ADTS_HEADER_LEN;
-    if(frame->syncword == 0 && !_aac_cfg.empty()) {
+    //预留7个字节的空位以便后续覆盖
-        makeAdtsHeader(_aac_cfg,*frame);
+    frame->_buffer.assign(ADTS_HEADER_LEN,(char)0);
-    }
     return frame;
 }
 
@@ -96,19 +94,18 @@ bool AACRtpDecoder::inputRtp(const RtpPacket::Ptr &rtppack, bool key_pos) {
     //忽略Au-Header区
     ptr += 2 + au_header_count * 2;
 
-    static const uint32_t max_size = sizeof(AACFrame::buffer) - ADTS_HEADER_LEN;
+    static const uint32_t max_size = AAC_MAX_FRAME_SIZE - ADTS_HEADER_LEN;
     while (ptr < end) {
         auto size = (uint32_t) (end - ptr);
         if(size > max_size){
             size = max_size;
         }
-        if (_adts->aac_frame_length + size > sizeof(AACFrame::buffer)) {
+        if (_adts->size() + size > AAC_MAX_FRAME_SIZE) {
             //数据太多了，先清空
             flushData();
         }
         //追加aac数据
-        memcpy(_adts->buffer + _adts->aac_frame_length, ptr, size);
+        _adts->_buffer.append((char *)ptr, size);
-        _adts->aac_frame_length += size;
         _adts->_dts = rtppack->timeStamp;
         ptr += size;
     }
@@ -120,13 +117,14 @@ bool AACRtpDecoder::inputRtp(const RtpPacket::Ptr &rtppack, bool key_pos) {
     return false;
 }
 
-
 void AACRtpDecoder::flushData() {
-    if(_adts->aac_frame_length == ADTS_HEADER_LEN){
+    if (_adts->size() == ADTS_HEADER_LEN) {
         //没有有效数据
         return;
     }
-    writeAdtsHeader(*_adts, _adts->buffer);
+
+    //覆盖adts头
+    dumpAacConfig(_aac_cfg, _adts->size(), (uint8_t *) _adts->data());
     RtpCodec::inputFrame(_adts);
     _adts = obtainFrame();
 }