ffmpeg-android Extract Audio From Digital Container Format - audio

Question

I make program extracts audio from Digital Container Format (DCF).
I want to obtain an encoded audio file.
so, I think that I can write to file only audio stream packet.
Some DCF file work well, but some files does not work.
Please, can you help me to find a problem?
// src -- is DCF
// dest -- is going to write file
int ExtractAudio(const char src[], const char dest[]) {
av_register_all();
avcodec_register_all();
__android_log_print(ANDROID_LOG_DEBUG, "test", "dest : %s", dest);
__android_log_print(ANDROID_LOG_DEBUG, "test", "src : %s", src);
//파일을 열고 컨텍스트에 파일 형식을 불러온다.
AVFormatContext * pInputFormatContext = NULL;
int err = avformat_open_input(&pInputFormatContext, src, NULL, NULL);
if (err < 0) {
__android_log_print( ANDROID_LOG_DEBUG, "test",
"avformat_open_input Err! %d",err);
return 0;
}
FILE *destFile = fopen(dest, "wb");
FILE *srcFile = fopen(src, "rb");
if (destFile == NULL || srcFile == NULL) {
__android_log_print(ANDROID_LOG_DEBUG, "test", "fopen Err!");
__android_log_print(ANDROID_LOG_DEBUG, "test", "fopen Err!");
return 0;
}
fseek(srcFile, 0, SEEK_END);
DCFSize = ftell(srcFile);
fseek(srcFile, 0, SEEK_SET);
int nAudioStreamIdx = -1;
AVCodec *pAudioCodec = NULL;
err = av_find_stream_info(pInputFormatContext);
if (err < 0) {
__android_log_print(ANDROID_LOG_DEBUG, "test",
"av_find_stream_info Err!");
__android_log_print(ANDROID_LOG_DEBUG, "test",
"av_find_stream_info Err!");
return 0;
}
err = av_find_best_stream(pInputFormatContext, AVMEDIA_TYPE_AUDIO, -1, -1,
&pAudioCodec, NULL);
//에러처리 임시
if (err < 0) {
nAudioStreamIdx = 1;
if (err == AVERROR_STREAM_NOT_FOUND)
__android_log_print(ANDROID_LOG_DEBUG, "test",
"AVERROR_STREAM_NOT_FOUND");
if (err == AVERROR_DECODER_NOT_FOUND)
__android_log_print(ANDROID_LOG_DEBUG, "test",
"AVERROR_DECODER_NOT_FOUND ");
} else
nAudioStreamIdx = err;
AVPacket Packet;
av_init_packet(&Packet);
while (av_read_frame(pInputFormatContext, &Packet) >= 0) {
if (Packet.stream_index == nAudioStreamIdx)
{
fwrite(Packet.data, 1, Packet.size, destFile);
PaketPos = Packet.pos;
//__android_log_print(ANDROID_LOG_DEBUG, "test","Extract Progress : %d",getExtractProgress());
}
}
PaketPos = DCFSize;
return 1;
}