Question

Windows 7 64位环境。 C＃Windows Forms应用程序通过C ++桥接DLL调用FFmpeg库，包括avcodec-57.dll，avformat-57.dll，avutil-55.dll，swresample-2.dll和swscale-4.dll，用H编写MPEG-4文件。 264 / MPEG-4 AVC编解码器。编写单个MP4文件时，从来没有问题。当同时写入多个MP4文件时，通过多个C＃线程，偶尔会得到av_interleaved_write_frame failure -22，这是一个或两个但从不是所有文件的无效参数。不用说，参数永远不会改变。 FFmpeg是否使用临时文件？当使用相同的DLL同时写入多个文件时，是否可能存在自相残杀效应？编辑：在入口/出口处放置互斥到我的写帧功能，请参阅下面的源代码，并且无法再重现该问题。看起来有关FFmpeg的东西不是线程安全的。

extern "C" __declspec(dllexport) int ffmpeg_write_video_frame(FFMPEG_CONTEXT *ffmpegContext, uint8_t *frameBuffer)
{
#ifdef SINGLE_THREAD
    WaitForSingleObject(hMutex, INFINITE);
#endif
    AVFrame *frame = ffmpeg_get_video_frame(&ffmpegContext->video, frameBuffer);
    if (frame == NULL)
    {
        MessageBox(GetActiveWindow(), "ffmpeg_get_video_frame returned NULL", "ffmpeg_write_video_frame", MB_OK);
#ifdef SINGLE_THREAD
        ReleaseMutex(hMutex);
#endif
        return(-1);
    }

    AVPacket pkt = { 0 };
    av_init_packet(&pkt);

    // encode the image
    int got_packet = 0;
    int result = avcodec_encode_video2(ffmpegContext->video.avCodecContext, &pkt, frame, &got_packet);
    if (result < 0)
    {
        char text[256];
        sprintf_s(text, sizeof(text), "avcodec_encode_videos failure=%d", result);
        MessageBox(GetActiveWindow(), text, "ffmpeg_write_video_frame", MB_OK);
#ifdef SINGLE_THREAD
        ReleaseMutex(hMutex);
#endif
        return(result);
    }

    // if the encoder has produced an output packet
    if (got_packet)
    {
        result = ffmpeg_write_frame(ffmpegContext->avFormatContext, &ffmpegContext->video.avCodecContext->time_base, ffmpegContext->video.avStream, &pkt);
        if (result < 0)
        {
            char text[256];
            sprintf_s(text, sizeof(text), "ffmpeg_write_frame failure=%d", result);
            MessageBox(GetActiveWindow(), text, "ffmpeg_write_video_frame", MB_OK);
#ifdef SINGLE_THREAD
            ReleaseMutex(hMutex);
#endif
            return(result);
        }
    }
#ifdef SINGLE_THREAD
    ReleaseMutex(hMutex);
#endif
    return (0);
}

extern "C" int ffmpeg_write_frame(AVFormatContext *fmt_ctx, const AVRational *time_base, AVStream *st, AVPacket *pkt)
{
    /* rescale output packet timestamp values from codec to stream timebase */
    av_packet_rescale_ts(pkt, *time_base, st->time_base);
    pkt->stream_index = st->index;

    /* Write the compressed frame to the media file. */
#if 0
    log_packet(fmt_ctx, pkt);
#endif
    int result = av_interleaved_write_frame(fmt_ctx, pkt);
    if (result < 0)
    {
        char text[256];
        sprintf_s(text, sizeof(text), "av_interleaved_write_frame failure=%d", result);
        MessageBox(GetActiveWindow(), text, "ffmpeg_write_frame", MB_OK);
    }
    return(result);
}

FFmpeg av_interleaved_write_frame无效参数-22

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