mirror of
https://github.com/ZLMediaKit/ZLMediaKit.git
synced 2026-06-13 19:51:49 +08:00
精简aac相关代码
This commit is contained in:
xiongziliang
@@ -12,62 +12,55 @@
|
||||
|
||||
namespace mediakit{
|
||||
|
||||
void writeAdtsHeader(const AACFrame &hed, uint8_t *pcAdts) {
|
||||
pcAdts[0] = (hed.syncword >> 4 & 0xFF); //8bit
|
||||
pcAdts[1] = (hed.syncword << 4 & 0xF0); //4 bit
|
||||
pcAdts[1] |= (hed.id << 3 & 0x08); //1 bit
|
||||
pcAdts[1] |= (hed.layer << 1 & 0x06); //2bit
|
||||
pcAdts[1] |= (hed.protection_absent & 0x01); //1 bit
|
||||
class AdtsHeader{
|
||||
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
|
||||
};
|
||||
|
||||
pcAdts[2] = (hed.profile << 6 & 0xC0); // 2 bit
|
||||
pcAdts[2] |= (hed.sf_index << 2 & 0x3C); //4bit
|
||||
pcAdts[2] |= (hed.private_bit << 1 & 0x02); //1 bit
|
||||
pcAdts[2] |= (hed.channel_configuration >> 2 & 0x03); //1 bit
|
||||
|
||||
pcAdts[3] = (hed.channel_configuration << 6 & 0xC0); // 2 bit
|
||||
pcAdts[3] |= (hed.original << 5 & 0x20); //1 bit
|
||||
pcAdts[3] |= (hed.home << 4 & 0x10); //1 bit
|
||||
pcAdts[3] |= (hed.copyright_identification_bit << 3 & 0x08); //1 bit
|
||||
pcAdts[3] |= (hed.copyright_identification_start << 2 & 0x04); //1 bit
|
||||
pcAdts[3] |= (hed.aac_frame_length >> 11 & 0x03); //2 bit
|
||||
|
||||
pcAdts[4] = (hed.aac_frame_length >> 3 & 0xFF); //8 bit
|
||||
|
||||
pcAdts[5] = (hed.aac_frame_length << 5 & 0xE0); //3 bit
|
||||
pcAdts[5] |= (hed.adts_buffer_fullness >> 6 & 0x1F); //5 bit
|
||||
|
||||
pcAdts[6] = (hed.adts_buffer_fullness << 2 & 0xFC); //6 bit
|
||||
pcAdts[6] |= (hed.no_raw_data_blocks_in_frame & 0x03); //2 bit
|
||||
static void dumpAdtsHeader(const AdtsHeader &hed, uint8_t *out) {
|
||||
out[0] = (hed.syncword >> 4 & 0xFF); //8bit
|
||||
out[1] = (hed.syncword << 4 & 0xF0); //4 bit
|
||||
out[1] |= (hed.id << 3 & 0x08); //1 bit
|
||||
out[1] |= (hed.layer << 1 & 0x06); //2bit
|
||||
out[1] |= (hed.protection_absent & 0x01); //1 bit
|
||||
out[2] = (hed.profile << 6 & 0xC0); // 2 bit
|
||||
out[2] |= (hed.sf_index << 2 & 0x3C); //4bit
|
||||
out[2] |= (hed.private_bit << 1 & 0x02); //1 bit
|
||||
out[2] |= (hed.channel_configuration >> 2 & 0x03); //1 bit
|
||||
out[3] = (hed.channel_configuration << 6 & 0xC0); // 2 bit
|
||||
out[3] |= (hed.original << 5 & 0x20); //1 bit
|
||||
out[3] |= (hed.home << 4 & 0x10); //1 bit
|
||||
out[3] |= (hed.copyright_identification_bit << 3 & 0x08); //1 bit
|
||||
out[3] |= (hed.copyright_identification_start << 2 & 0x04); //1 bit
|
||||
out[3] |= (hed.aac_frame_length >> 11 & 0x03); //2 bit
|
||||
out[4] = (hed.aac_frame_length >> 3 & 0xFF); //8 bit
|
||||
out[5] = (hed.aac_frame_length << 5 & 0xE0); //3 bit
|
||||
out[5] |= (hed.adts_buffer_fullness >> 6 & 0x1F); //5 bit
|
||||
out[6] = (hed.adts_buffer_fullness << 2 & 0xFC); //6 bit
|
||||
out[6] |= (hed.no_raw_data_blocks_in_frame & 0x03); //2 bit
|
||||
}
|
||||
string makeAdtsConfig(const uint8_t *pcAdts){
|
||||
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':
|
||||
unsigned char sampling_frequency_index = (pcAdts[2] & 0x3C) >> 2; // 4 bits
|
||||
if (samplingFrequencyTable[sampling_frequency_index] == 0) {
|
||||
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];
|
||||
static void parseAacConfig(const string &config, AdtsHeader &adts) {
|
||||
uint8_t cfg1 = config[0];
|
||||
uint8_t cfg2 = config[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];
|
||||
iChannel = adts.channel_configuration;
|
||||
|
||||
string makeAacConfig(const uint8_t *hex){
|
||||
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() {
|
||||
@@ -106,6 +134,4 @@ Sdp::Ptr AACTrack::getSdp() {
|
||||
return std::make_shared<AACSdp>(getAacCfg(),getAudioSampleRate(), getAudioChannel());
|
||||
}
|
||||
|
||||
}//namespace mediakit
|
||||
|
||||
|
||||
}//namespace mediakit
|
||||
Reference in New Issue
Block a user