ffmpeg解码出的pcm数据使用edit cool播放全是杂音，求大神看看。

[jenf]

 // Register all formats and codecs
    av_register_all();
    avcodec_register_all();

    //av_log_set_callback(log_callback);

    USES_CONVERSION;
    string strSrcFile = P2P_W2A(pFileData->strInputFile);

    pFormatCtxDec = avformat_alloc_context();
    if (NULL == pFormatCtxDec)
    {
        return;
    }

    // Open video file
#define av_open_input_file avformat_open_input
    if(av_open_input_file(&pFormatCtxDec, strSrcFile.c_str(), NULL, NULL)!=0)
        return ; // Couldn't open file
 
    // Retrieve stream information
    if(av_find_stream_info(pFormatCtxDec)<0)
        return ; // Couldn't find stream information
for(i=0; i<pFormatCtxDec->nb_streams; i++) 
    {
        if(pFormatCtxDec->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO)
        {
            videoStream=i;
        }
        else if(pFormatCtxDec->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO)
        {
            audioStream=i;
        }
    }
 if (audioStream != -1)
    {
        pACodecCtxDec = pFormatCtxDec->streams[audioStream]->codec;
    }
 if (pACodecCtxDec)
    {
        pACodecDec=avcodec_find_decoder(pACodecCtxDec->codec_id);
    }
// Open codec
    BOOL bOpenAudio = FALSE;
    if (pACodecCtxDec && pACodecDec)
    {
        if(avcodec_open2(pACodecCtxDec, pACodecDec, NULL)>=0)
        {
            bOpenAudio = TRUE;
        }
    }
 pAFrameDec = avcodec_alloc_frame();
 if (audioStream!=-1 && pAFrameDec == NULL)
    {
        return;
    }
 while(av_read_frame(pFormatCtxDec, &packet)>=0)
 {
if (packet.stream_index==audioStream)
 {
int ret = 0;
        while(packet.size > 0)
        {
            ret = avcodec_decode_audio4(pACodecCtxDec,pAFrameDec,&got_output,&packet);//若为音频包，解码该音频包
            if(got_output == 0)
            {
                continue;
            }

            int data_size = av_samples_get_buffer_size(pAFrameDec->linesize, pACodecCtxDec->channels,  
                pAFrameDec->nb_samples,  
                pACodecCtxDec->sample_fmt, 0); 

            int n = fwrite(pAFrameDec->data[0], 1, pAFrameDec->linesize[0], TmpAudio);
            fflush(TmpAudio);
            packet.size -= ret;
            packet.data += ret;
｝
｝

[jenf]

有ffmpeg大神么，求帮忙。。。

[jenf]

mp3，wma众多格式解码均有问题，求大神指导！！！

[SoftSoftSoft2008]

我感觉应该不是ffmpeg的问题，可能是别的原因吧。他们发布时候肯定都做了测试的，不会出现这种错误的。

[sxcong]

ffmpeg带的example你看了吗？直接用那个试试 /* * Audio decoding. */ static void audio_decode_example(const char *outfilename, const char *filename) { AVCodec *codec; AVCodecContext *c= NULL; int len; FILE *f, *outfile; uint8_t inbuf[AUDIO_INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE]; AVPacket avpkt; AVFrame *decoded_frame = NULL; av_init_packet(&avpkt); printf("Decode audio file %s to %s\n", filename, outfilename); /* find the mpeg audio decoder */ codec = avcodec_find_decoder(AV_CODEC_ID_MP2); if (!codec) { fprintf(stderr, "Codec not found\n"); exit(1); } c = avcodec_alloc_context3(codec); /* open it */ if (avcodec_open2(c, codec, NULL) < 0) { fprintf(stderr, "Could not open codec\n"); exit(1); } f = fopen(filename, "rb"); if (!f) { fprintf(stderr, "Could not open %s\n", filename); exit(1); } outfile = fopen(outfilename, "wb"); if (!outfile) { av_free(c); exit(1); } /* decode until eof */ avpkt.data = inbuf; avpkt.size = fread(inbuf, 1, AUDIO_INBUF_SIZE, f); while (avpkt.size > 0) { int got_frame = 0; if (!decoded_frame) { if (!(decoded_frame = avcodec_alloc_frame())) { fprintf(stderr, "Could not allocate audio frame\n"); exit(1); } } else avcodec_get_frame_defaults(decoded_frame); len = avcodec_decode_audio4(c, decoded_frame, &got_frame, &avpkt); if (len < 0) { fprintf(stderr, "Error while decoding\n"); exit(1); } if (got_frame) { /* if a frame has been decoded, output it */ int data_size = av_samples_get_buffer_size(NULL, c->channels, decoded_frame->nb_samples, c->sample_fmt, 1); fwrite(decoded_frame->data[0], 1, data_size, outfile); } avpkt.size -= len; avpkt.data += len; avpkt.dts = avpkt.pts = AV_NOPTS_VALUE; if (avpkt.size < AUDIO_REFILL_THRESH) { /* Refill the input buffer, to avoid trying to decode * incomplete frames. Instead of this, one could also use * a parser, or use a proper container format through * libavformat. */ memmove(inbuf, avpkt.data, avpkt.size); avpkt.data = inbuf; len = fread(avpkt.data + avpkt.size, 1, AUDIO_INBUF_SIZE - avpkt.size, f); if (len > 0) avpkt.size += len; } } fclose(outfile); fclose(f); avcodec_close(c); av_free(c); avcodec_free_frame(&decoded_frame); }

[jenf]

嗯，我也是想不是ffmpeg的问题，就想看看是不是哪里的参数设置不对造成的，看看还有没有遇到同样问题的人说说有没有啥解决方法。

[wangzongze1015]

我之前遇到这问题。有一部分原因是数据真的频率间隔可能造成的，你查查看

[wangsky2]

不知道楼主解码的是mp3文件还是amr文件，我之前也遇到这个问题，用下面的代码可以对mp3保存为pcm正常。但是对amr保存为pcm还是不正常 char *data = (char *)malloc(data_size); short *sample_buffer = (short *)frame->data[0];

	////mp3 to pcm
	for (int i = 0; i < data_size/2; i++)
	{
		data[i*2] = (char)(sample_buffer[i/2] & 0xFF);
		data[i*2+1] = (char)((sample_buffer[i/2] >>8) & 0xFF);		

	}
	fwrite(data, data_size, 1, pcm);
	fflush(pcm);