Question

我一直在尝试使用ffmpeg C库将MP3文件解码为原始格式，但大多数文件都会返回以下错误：

[mp3 @ 0x7fb922008400] Header missing

代码从examples_decoding.c：

示例中获取

#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#define AUDIO_INBUF_SIZE 20480
#define AUDIO_REFILL_THRESH 4096

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 + AV_INPUT_BUFFER_PADDING_SIZE];
    AVPacket avpkt;
    AVFrame *decoded_frame = NULL;
    av_init_packet(&avpkt);

    /* find the mpeg audio decoder */
    codec = avcodec_find_decoder(AV_CODEC_ID_MP3);
    if (!codec) {
        fprintf(stderr, "Codec not found\n");
        exit(1);
    }
    c = avcodec_alloc_context3(codec);
    if (!c) {
        fprintf(stderr, "Could not allocate audio codec context\n");
        exit(1);
    }
    /* 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 i, ch;
        int got_frame = 0;
        if (!decoded_frame) {
            if (!(decoded_frame = av_frame_alloc())) {
                fprintf(stderr, "Could not allocate audio frame\n");
                exit(1);
            }
        }

        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_get_bytes_per_sample(c->sample_fmt);

            if (data_size < 0) {
                /* This should not occur, checking just for paranoia */
                fprintf(stderr, "Failed to calculate data size\n");
                exit(1);
            }
            for (i=0; i<decoded_frame->nb_samples; i++)
            {
                for (ch=0; ch<c->channels; ch++)
                    fwrite(decoded_frame->data[ch] + data_size*i, 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);
    av_frame_free(&decoded_frame);
}
int main(int argc, char **argv)
{
    /* register all the codecs */
    avcodec_register_all();
    char *src_filename = "adele.mp3";
    audio_decode_example("adele.pcm", src_filename);
    return 0;
}

我尝试了这个av_read_frame，但得到了同样的错误。关于如何从这里开始或者如果我犯了一个需要纠正的错误的任何提示？（使用ffmpeg命令行正确解码相同的文件）

MP3标头缺失 - ffmpeg（mp3到原始格式）

0 个答案: