0
目前，我嘗試使用avcodec_decode_audio4（），它總是返回錯誤的音頻解碼。音頻解碼錯誤使用libavcodec avcodec_decode_audio4
注意：我的總體目標是將多個AMR_NB編碼文件合併爲一個音頻文件，並最終將此最終音頻文件與另一個視頻文件複合到.mp4容器中。
下面的代碼：
if(avformat_open_input(&sound, "/tmp/aud0", NULL, NULL)!=0) {
printf("Error in opening input file aud0\n");
exit(1);
} else {
printf("Opened aud0 into FormatContext\n");
}
if(avformat_find_stream_info(sound, NULL)<0){
printf("Error in finding stream info\n");
avformat_close_input(&sound);
exit(1);
}
int aud_stream_idx=-1;
for(int count=0; count<sound->nb_streams; count++) {
if(sound->streams[count]->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
aud_stream_idx = count;
printf("Audio stream index %d found\n", count);
break;
}
}
if(aud_stream_idx==-1) {
printf("Audio stream not found in the aud0 file\n");
avformat_close_input(&sound);
exit(1);
}
AVCodecContext *audioCC = sound->streams[aud_stream_idx]->codec;
printf("Audio codec_id=%d, codec_name=%s\n", audioCC->codec_id, audioCC->codec_name);
AVCodec *audioC = avcodec_find_decoder(audioCC->codec_id);
if (audioC == NULL) { printf("Couldn't find decoder\n");
avformat_close_input(&sound);
exit(1);
} else {
printf("Found decoder name %s\n", audioCC->codec_name);
}
if(avcodec_open2(audioCC, audioC, NULL)<0) {
printf("Couldn't open decoder\n");
avformat_close_input(&sound);
exit(1);
} else {
printf("Found decoder name %s\n", audioCC->codec_name);
printf("Found bitrate %d\n", audioCC->bit_rate);
printf("Found sample_rate %d\n", audioCC->sample_rate);
printf("Found sample_fmt %d\n", audioCC->sample_fmt); }
/* decode until eof */
av_init_packet(&avpkt);
avpkt.data=NULL;
avpkt.size=0;
if(av_read_frame(sound, &avpkt)<0) {
printf("Couldn't read encoded audio packet\n");
av_free_packet(&avpkt);
avformat_close_input(&sound);
exit(1);
} else {
printf("Read encoded audio packet\n");
printf("avpkt.pts = %d\n", avpkt.pts);
printf("avpkt.dts = %d\n", avpkt.dts);
printf("avpkt.duration = %d\n", avpkt.duration);
printf("avpkt.stream_index = %d\n", avpkt.stream_index);
printf("avpkt.data = %x\n", avpkt.data);
printf("avpkt.data[0] = %02x\n", avpkt.data[0]);
printf("avpkt.data[0]>>>3&0x0f = %02x\n", avpkt.data[0]>>3 & 0x0f);
}
fprintf(stderr, "avpkt.size=%d\n", avpkt.size);
while (avpkt.size > 0) {
int got_frame = 0;
if (!decoded_frame) {
if (!(decoded_frame = avcodec_alloc_frame())) {
fprintf(stderr, "out of memory\n");
exit(1);
} } else
avcodec_get_frame_defaults(decoded_frame);
len = avcodec_decode_audio4(audioCC, decoded_frame, &got_frame, &avpkt);
if (len < 0) {
fprintf(stderr, "Error %d while decoding\n", len);
exit(1);
}
這裏是輸出我看到（我想多路分解工作正常）：
Opened aud0 into FormatContext
Audio stream index 0 found
Audio codec_id=73728, codec_name=
Found decoder name
Found decoder name
Found bitrate 5200
Found sample_rate 8000
Found sample_fmt 3
Read encoded audio packet
avpkt.pts = 0
avpkt.dts = 0
avpkt.duration = 160
avpkt.stream_index = 0
avpkt.data = 91e00680
avpkt.data[0] = 04
avpkt.data[0]>>>3&0x0f = 00
avpkt.size=13
[amrnb @ 0x7fce9300bc00] Corrupt bitstream
Error -1094995529 while decoding
這個音頻是通過在Android設備上錄製語音創建。
我也嘗試了由QuickTime生成的.m4a，但沒有運氣。
我覺得我錯過了一些關鍵的步驟（如不初始化一些CodecContext字段，或不正確讀入AVPacket）。無論如何，如果有人有任何意見或類似的例子，請讓我知道。