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• FFmpeg makes multipile HTTP requests before starting conversion [closed]

  13 juillet 2024, par imanworstcoderanditisafact

  Is there a way to make FFmpeg send only one HTTP request ? My HTTP page is dynamic so FFmpeg just fails to load the video.

  


  I expected it to do a HTTP request once, and load the video normally. It just doesn't load the video, my page is dynamic.

  


• Node spawn child process doesn't execute the command after exec child process in aws node 10 lambda

  29 juillet 2020, par Danielkent

  I am attempting to run 2 child processes, but one seems to be blocked and eventually times out the node lambda.

  


  Environment :

  


  

  • AWS node 10 lambda running in a docker container.

  


  • Accesses ffmpeg and ffprobe via a lambda layer in the /opt/bin directory.

  


  


  child_process.exec
I am running ffprobe in a child_process.exec to get the file format of an audio file. I am using exec because the output is a small json response (which shouldn't consume much memory).

  


  child_process.spawn
Shortly after I run ffmpeg to convert the audio file to mp3 using child_process.spawn.

  


  The problem is the FFMPEG child_process.spawn command doesn't run after ffprobe (even though ffprobe successfully completes). If I don't run the ffprobe command the FFMPEG command runs perfectly.

  


  Which leads me to believing this is an issue with how I am dealing with child processes in node.

  


  Is it possible the child_process.exec ffprobe command is somehow still running/ blocking the new ffmpeg (child_process.spawn) command from running - if so how do I check this ?

  


  When I access the running processes in the docker container only the new ffmpeg command seems to be running, although it consumes no memory and just hangs - seemingly doing nothing. I even tried launching the ffmpeg command from the docker cli (avoiding using the node env) and this works fine and runs as expected.

  


• Exception thrown at 0x00007FFC0B57BCEF (swscale-6.dll) in App.exe : 0xC0000005 : Access violation reading location 0xFFFFFFFFFFFFFFFF

  9 novembre 2023, par JIUN-YU

  Trying to play a video using FFmpeg on visual studio 2022 on windows 10.
Exception is thrown at sws_scale in the code. Don't know why this is occurred.
It is worth noting that this error sometimes occurs when reading the camera and sometimes it does not.

  


  here is my code

  


  bool CalibrationPanel::video_reader_read_frame(VReaderState* state, cv::Mat cvimg)
{
    // Unpack members of state
    auto& width = state->width;
    auto& height = state->height;
    auto& av_format_ctx = state->av_format_ctx;
    auto& av_codec_ctx = state->av_codec_ctx;
    auto& video_stream_index = state->video_stream_index;
    auto& av_frame = state->av_frame;
    auto& av_packet = state->av_packet;
    auto& sws_scaler_ctx = state->sws_scaler_ctx;


    // Decode one frame
    int response;
    while (av_read_frame(av_format_ctx, av_packet) >= 0)
    {
        if (av_packet->stream_index != video_stream_index)
        {
            av_packet_unref(av_packet);
            continue;
        }

        response = avcodec_send_packet(av_codec_ctx, av_packet);
        if (response < 0)
        {
            char errStr[256] = {0};
            av_strerror(response, errStr, sizeof(errStr));
            printf("Failed to decode packet: %s\n", errStr);
            return false;
        }

        response = avcodec_receive_frame(av_codec_ctx, av_frame);
        if (response == AVERROR(EAGAIN) || response == AVERROR_EOF)
        {
            av_packet_unref(av_packet);
            continue;
        }
        else if (response < 0)
        {
            char errStr[256] = {0};
            av_strerror(response, errStr, sizeof(errStr));
            printf("Failed to decode packet: %s\n", errStr);
            return false;
        }

        av_packet_unref(av_packet);
        break;
    }
    int64_t* pts = &ppts;
    *pts = av_frame->pts;

    // Set up sws scaler
    if (!sws_scaler_ctx)
    {
        sws_scaler_ctx = sws_getContext(width, height, av_codec_ctx->pix_fmt,
                                        width, height, AV_PIX_FMT_BGR24,
                                        SWS_BILINEAR, NULL, NULL, NULL);
        if (!sws_scaler_ctx)
        {
            printf("Couldn't initialize sw scaler\n");
            return false;
        }
    }


    // Creating an image space to hold YUV images
    AVFrame* frameYUV = av_frame_alloc();
    auto* out_buffer = (unsigned char*)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_BGR24, width, height, 1));
    av_image_fill_arrays(frameYUV->data, frameYUV->linesize, (const uint8_t*)out_buffer, AV_PIX_FMT_BGR24, width, height, 1);

    uint8_t* dest[4] = {cvimg.data, NULL, NULL, NULL};
    sws_scale(sws_scaler_ctx, av_frame->data, av_frame->linesize, 0, av_frame->height, dest, frameYUV->linesize);

    return true;
}


  


  fixed this bug, so it's not luck that makes the camera turn on every time.