Hemant Vishwakarma: Python Flask: Saving live stream video to a file periodically

I am creating a flask application with JavaScript to save the live video streams to a file.

What I am trying to achieve here is that, the video stream will be sent to flask application periodically (20 secs). The first time it will create a video and after that, the video needs to be merged to the existing file.

I am using SocketIO to transmit the video from JS.

`async function startCapture() {
  try {
    // Access the user's webcam
    stream = await navigator.mediaDevices.getUserMedia({ 
      video: true,
      audio: { echoCancellation: true, noiseSuppression: true },
    });

    // Attach the stream to the video element
    video.srcObject = stream;

    // Create a new MediaRecorder instance to capture video chunks
    recorder = new MediaRecorder(stream);

    // Event handler for each data chunk received from the recorder
    recorder.ondataavailable = (e) => {
      const videoBlob = e.data;
      transmitVideoChunk(videoBlob);
      chunks.push(e.data);
    };

    // Start recording the video stream
    recorder.start();

    // Enable/disable buttons
    startButton.disabled = true;
    stopButton.disabled = false;

    // Start transmitting video chunks at the desired fps
    startTransmitting();
  } catch (error) {
    console.error('Error accessing webcam:', error);
  }
}`

`
function transmitVideoBlob() {
    const videoBlob = new Blob(chunks, { type: 'video/webm' });
    socket.emit('video_data', videoBlob);
    // Clear the chunks array
    chunks = [];
}

// Start transmitting video chunks at the desired fps
function startTransmitting() {
    const videoInterval = 20000; // Interval between frames in milliseconds
    videoIntervalId = setInterval(() => {
        transmitVideoBlob();
    }, videoInterval);
}`

In flask, I have created a function, which will call create_videos. video_path: location to save the video filename: file name of video new_video_data_blob: binary data received from JS

def create_videos(video_path, filename, new_video_data_blob):
    chunk_filename = os.path.join(video_path, f"{str(uuid1())}_{filename}")
    final_filename = os.path.join(video_path, filename)
    out_final_filename = os.path.join(video_path, "out_" + filename)
    # Save the current video chunk to a file
    with open(chunk_filename, "wb") as f:
        print("create file chunk ", chunk_filename)
        f.write(new_video_data_blob)

    if not os.path.exists(final_filename):
        # If the final video file doesn't exist, rename the current chunk file
        os.rename(chunk_filename, final_filename)
    else:
        while not os.path.exists(chunk_filename):
            time.sleep(0.1)
        # If the final video file exists, use FFmpeg to concatenate the current chunk with the existing file
        try:
            subprocess.run(
                [
                    "ffmpeg",
                    "-i",
                    f"concat:{final_filename}|{chunk_filename}",
                    "-c",
                    "copy",
                    "-y",
                    out_final_filename,
                ]
            )
            while not os.path.exists(out_final_filename):
                time.sleep(0.1)
            os.remove(final_filename)
            os.rename(out_final_filename, final_filename)

        except Exception as e:
            print(e)
        # Remove the current chunk file
        os.remove(chunk_filename)
    return final_filename

When I record as well using below code in JS

audio: { echoCancellation: true, noiseSuppression: true },

I get the following error.

[NULL @ 0x55e697e8c900] Invalid profile 5.
[webm @ 0x55e697ec3180] Non-monotonous DTS in output stream 0:0; previous: 37075, current: 37020; changing to 37075. This may result in incorrect timestamps in the output file.
[NULL @ 0x55e697e8d8c0] Error parsing Opus packet header.
    Last message repeated 1 times
[NULL @ 0x55e697e8c900] Invalid profile 5.
[NULL @ 0x55e697e8d8c0] Error parsing Opus packet header.