MP4
const int sampling_frequencies[ ] = { 96000 ,88200 ,64000 ,48000 ,44100 ,32000 ,24000 ,22050 ,16000 ,12000 ,11025 ,8000
} ; int adts_header( char * const p_adts_header, const int data_length,const int profile, const int samplerate,const int channels)
{ int sampling_frequency_index = 3 ; int adtsLen = data_length + 7 ; int frequencies_size = sizeof( sampling_frequencies) / sizeof( sampling_frequencies[ 0 ] ) ; for( int i = 0 ; i < frequencies_size; i++) { if( sampling_frequencies[ i] == samplerate) { sampling_frequency_index = i; break ; } } p_adts_header[ 0 ] = 0xff; p_adts_header[ 1 ] = 0xf0; p_adts_header[ 1 ] | = ( 0 << 3 ) ; p_adts_header[ 1 ] | = ( 0 << 1 ) ; p_adts_header[ 1 ] | = 1 ; p_adts_header[ 2 ] = ( profile) << 6 ; p_adts_header[ 2 ] | = ( sampling_frequency_index & 0x0f) << 2 ; p_adts_header[ 2 ] | = ( 0 << 1 ) ; p_adts_header[ 2 ] | = ( channels & 0x04) >> 2 ; p_adts_header[ 3 ] = ( channels & 0x03) << 6 ; p_adts_header[ 3 ] | = ( 0 << 5 ) ; p_adts_header[ 3 ] | = ( 0 << 4 ) ; p_adts_header[ 3 ] | = ( 0 << 3 ) ; p_adts_header[ 3 ] | = ( 0 << 2 ) ; p_adts_header[ 3 ] | = (( adtsLen & 0x1800) >> 11 ) ; p_adts_header[ 4 ] = ( uint8_t) (( adtsLen & 0x7f8) >> 3 ) ; p_adts_header[ 5 ] = ( uint8_t) (( adtsLen & 0x7) << 5 ) ; p_adts_header[ 5 ] | = 0x1f; p_adts_header[ 6 ] = 0xfc; return 0 ;
} int main( int argc, char **argv)
{ char *in_filename = "/home/yx/media_file/believe.mp4" ; char *h264_filename = "/home/yx/media_file/believe.h264" ; char *aac_filename = "/home/yx/media_file/believe.aac" ; FILE *aac_fd = NULL; FILE *h264_fd = NULL; h264_fd = fopen( h264_filename, "wb" ) ; aac_fd = fopen( aac_filename, "wb" ) ; AVFormatContext *ifmt_ctx = NULL; int video_index = -1; int audio_index = -1; AVPacket *pkt = NULL; ifmt_ctx = avformat_alloc_context( ) ; avformat_open_input( & ifmt_ctx, in_filename, NULL, NULL) ; // 将媒体流与解复用器相关联video_index = av_find_best_stream( ifmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0 ) ; // 查找视频流标签audio_index = av_find_best_stream( ifmt_ctx, AVMEDIA_TYPE_AUDIO, -1, -1, NULL, 0 ) ; // 查找音频流标签const AVBitStreamFilter *bsfilter = av_bsf_get_by_name( "h264_mp4toannexb" ) ; // 查找H264过滤器AVBSFContext *bsf_ctx = NULL; av_bsf_alloc( bsfilter, & bsf_ctx) ; avcodec_parameters_copy( bsf_ctx-> par_in, ifmt_ctx-> streams[ video_index] -> codecpar) ; av_bsf_init( bsf_ctx) ; // 初始化过滤器pkt = av_packet_alloc( ) ; av_init_packet( pkt) ; while ( 1 ) { if( av_read_frame( ifmt_ctx, pkt) < 0 ) // 逐个包读取break ; if( pkt-> stream_index == video_index) { av_bsf_send_packet( bsf_ctx, pkt) ; // 视频包就将包发给过滤器while ( 1 ) { if( av_bsf_receive_packet( bsf_ctx, pkt) != 0 ) // 从过滤器接收包break ; size_t size = fwrite( pkt-> data, 1 , pkt-> size, h264_fd) ; // 将包写到输出文件av_packet_unref( pkt) ; } } else if( pkt-> stream_index == audio_index) { char adts_header_buf[ 7 ] = { 0 } ; adts_header( adts_header_buf, pkt-> size,ifmt_ctx-> streams[ audio_index] -> codecpar-> profile,ifmt_ctx-> streams[ audio_index] -> codecpar-> sample_rate,ifmt_ctx-> streams[ audio_index] -> codecpar-> channels) ; // 音频包构建ADTS帧头部fwrite( adts_header_buf, 1 , 7 , aac_fd) ; // 将头部写到输出文件size_t size = fwrite( pkt-> data, 1 , pkt-> size, aac_fd) ; // 将AAC包写到输出文件av_packet_unref( pkt) ; // 引用计数--} else { av_packet_unref( pkt) ; } } printf( "while finish\n " ) ; printf( "Hello World!\n " ) ; return 0 ;
} 
