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• Problem with FFmpeg breaking when streaming the entire screen and switching tabs

  2 octobre 2024, par Ibad Ahmad

  I'm working on a screen recording and streaming setup where the user records their entire screen and streams it to Twitch. The setup works fine initially, but when I switch tabs during recording, the stream breaks on the backend, and I get the following FFmpeg errors :

  


  FFmpeg STDERR: [matroska,webm @ 0x7f9dcb904580] EBML header parsing failed
[in#0 @ 0x7f9dcb904380] Error opening input: Invalid data found when processing input
Error opening input file -.
Error opening input files: Invalid data found when processing input


  


  My frontend code captures the screen and microphone and streams it via a WebSocket to the backend, where FFmpeg processes the stream. Below is my relevant frontend code :

  


  const startRecording = async () => {
    try {
        const screenStream = await navigator.mediaDevices.getDisplayMedia({
            preferCurrentTab: true,
            systemAudio: 'include',
            surfaceSwitching: 'include',
            monitorTypeSurfaces: 'include',
            video: {
                displaySurface: 'browser',
                height: 720,
                width: 1280,
                frameRate: { ideal: 24, max: 30 },
            },
        });

        screenStream.getVideoTracks()[0].onended = () => {
            console.log('Screen sharing ended. Stopping the recorder.');
            stopRecording();
        };

        const micStream = await navigator.mediaDevices.getUserMedia({
            audio: true,
        });

        const combinedStream = new MediaStream([
            ...screenStream.getVideoTracks(),
            ...micStream.getAudioTracks(),
        ]);

        const recorder = new MediaRecorder(combinedStream, {
            mimeType: 'video/webm; codecs=vp8,opus',
            videoBitsPerSecond: 3 * 1024 * 1024,
        });

        const timeslice = 1000;

        recorder.ondataavailable = async (event) => {
            if (socket?.current?.connected && event.data.size > 0) {
                console.log('Sending chunk data:', socket.current.id);
                socket?.current.send(event.data);
                recordedChunks.current.push(event.data);
            } else if (!socket?.current?.connected) {
                handleSocketDisconnection();
            }
        };

        mediaRecorder.current = recorder;
        recorder.start(timeslice);
        setIsRecording(true);
    } catch (error) {
        console.log('Error starting screen recording:', error);
        toast.error('Failed to start screen recording: ' + error);
    }
};

const stopRecording = () => {
    if (socket?.current && mediaRecorder) {
        mediaRecorder?.current?.stop();
        socket.current.close();
        setIsRecording(false);
        downloadRecordedVideo();
    }
};



  


  And here’s my backend code with FFmpeg settings for Twitch streaming :

  


  const inputSettings = [
    '-f', 'webm', '-i', '-', '-v', 'error', '-analyzeduration', '1000000', '-probesize', '5000000',
];

const twitchSettings = (twitch) => {
    return [
        '-c:v', 'libx264', '-preset', 'veryfast', '-tune', 'zerolatency',
        '-g', '60', '-b:v', '2500k', '-maxrate', '3000k', '-bufsize', '8000k',
        '-r', '30', '-vf', 'tpad=stop_mode=clone:stop_duration=2',
        '-c:a', 'aac', '-ar', '44100', '-b:a', '96k',
        '-use_wallclock_as_timestamps', '1', '-async', '1',
        '-err_detect', 'ignore_err', '-reconnect', '1',
        '-reconnect_streamed', '1', '-reconnect_delay_max', '5',
        '-y', '-f', 'flv', twitch,
    ];
};



  


  Problem : When switching tabs during screen sharing, it seems like the frame rate drops or the stream gets interrupted, leading to FFmpeg errors like EBML header parsing failed and Invalid data found when processing input. I suspect this happens because the browser deprioritizes resources when the tab is not active, which might lead to corrupt chunks being sent to FFmpeg.

  


  Questions :

  


  

  1. Could switching tabs during screen capture be causing the issue by disrupting the frame rate or dropping frames ?

  


  2. Is there a way to ensure FFmpeg doesn’t break due to these interruptions ?

  


  3. Any suggestions on handling the stream more reliably when switching tabs or optimizing the FFmpeg setup for this scenario ?

  


  


  I tried adjusting the bitrate, frame rate, and buffer size but still experienced the same issue. I'm trying to figure out if the issue is related to how browsers handle screen capture when tab switching or something specific with FFmpeg handling the video stream.

  


  Any insights would be greatly appreciated.
Thanks in advance !

  


• Configuration error when configuring the FFMPEG compilation with NVCC/CUDA [closed]

  3 février, par Lerenn

  I'm trying to compile the last FFMPEG version (49726a922fd2b358feb7753488d415180da5121c) on Fedora 41 with some libraries, including the CUDA libraries.

  


  Everything works well when compiling without CUDA, but I have 2 cryptic errors when trying to run the configure command with the NVCC :

  


    nvcc -gencode arch=compute_60,code=sm_60 -O2 -std=c&#x2B;&#x2B;11 -m64 -ptx -c -o /tmp/ffconf.q0uMcStN/test.o /tmp/ffconf.q0uMcStN/test.cu&#xA;  nvcc warning : Support for offline compilation for architectures prior to &#x27;<compute></compute>sm/lto>_75&#x27; will be removed in a future release (Use -Wno-deprecated-gpu-targets to suppress warning).&#xA;  /usr/include/c&#x2B;&#x2B;/14/type_traits(1610): error: "__is_nothrow_new_constructible" is not a function or static data member&#xA;        constexpr bool __is_nothrow_new_constructible&#xA;                    ^&#xA;&#xA;  /usr/include/c&#x2B;&#x2B;/14/type_traits(1610): error: "constexpr" is not valid here&#xA;        constexpr bool __is_nothrow_new_constructible&#xA;        ^&#xA;&#xA;  2 errors detected in the compilation of "/tmp/ffconf.q0uMcStN/test.cu".&#xA;  ERROR: failed checking for nvcc.&#xA;

  


  I tried compiling it with default gcc (gcc (GCC) 14.2.1 20250110 (Red Hat 14.2.1-7)) but my NVCC version (Build cuda_12.8.r12.8/compiler.35404655_0) seems to support only the GCC version 13.2 : https://docs.nvidia.com/cuda/cuda-toolkit-release-notes/index.html.

  


  I have compiled it and ran the configure command again but it seems that I have the same errors.

  


  Here is the configure command :

  


    PKG_CONFIG_PATH="/usr/local/lib/pkgconfig" \
        ./configure \
        --cc=gcc-13.2 \
        --extra-libs=-lpthread --prefix="/usr/local" \
        --extra-cflags="-I/usr/local/include -I/usr/local/cuda/include" \
        --extra-ldflags="-L/usr/local/lib -L/usr/local/cuda/lib64" \
        --pkg-config-flags="--static" --enable-gpl --enable-nonfree \
        --enable-libfdk-aac --enable-libmp3lame --enable-libopus \
        --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 \
        --enable-libvidstab --enable-libaom \
        --enable-cuda-nvcc --enable-libnpp \
        --disable-static --enable-shared


  


  If you have any idea or lead on the matter, I would be really grateful.

  


• lavc/vvc : Fix derivation of inverse LMCS idx

  2 février, par Frank Plowman

  lavc/vvc : Fix derivation of inverse LMCS idx
  The clamping of idxYInv from H.266(V3) section 8.8.2.3 was missing.
  
  This could lead to OOB reads from lmcs->pivot or input_pivot.
  I also changed the derivation of the forward LMCS idx to use a shift
  
  rather than a division for speed and as this is actually how the
  
  variable is declared in the specification (8.7.5.2).
  Signed-off-by : Frank Plowman <post@frankplowman.com>
  

  • [DH] libavcodec/vvc/ps.c