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• Why does HTML5 video with very large h.264 encoded mp4 (with +faststart, ie metadata at beginning), take ages to load ?

  15 septembre 2015, par Tom Jenkinson

  The video is rendered with ffmpeg with the "faststart" flag added meaning the metadata should be at the start of the file, and the server appears to be handling partial content requests correctly, so why does it need to have downloaded so much of the video before the player becomes enabled and can play the video ? I am testing it in Google Chrome.

  Once the player becomes enabled I can seek around to various points in the video pretty instantly and see the new partial content requests being made.

  Here is a link to the video : http://iptv.la1tv.co.uk/unibrass.mp4

  Here is a jsbin with the video tag : https://jsbin.com/rahewidoru . It takes a few minutes but does work after it loads.

  Any suggestions ?

  I realise there are other methods like HLS and dash which use chunks, but I would like to know why it isn’t working this way because I can’t find anywhere that provides a reason as to why it doesn’t work well.

• How to convert and merge a list of webm files into a single large mp4 file with Node.js ?

  17 janvier 2024, par Terry Windwalker

  I am using MediaRecorder in the browser to get a chunk of webm file each 5 seconds, so it would end up with a list of webm files stored in AWS S3.

  


  And then, I am currently trying to convert them into one single MP4 file within my Node.js application with the help of ffmpeg. My code looks like this :

  


  async function convertAndMergeWebmStreams(webmStreams, outputFilePath) {
    return new Promise((resolve, reject) => {
        const command = ffmpeg();
    
        // Create a PassThrough stream to combine multiple readable streams
        const combinedStream = new PassThrough();
        
        // Pipe each webmStream into the combinedStream
        webmStreams.forEach(webmStream => {
            webmStream.pipe(combinedStream, { end: false });
        });

        // Set the combinedStream as the input for ffmpeg
        command.input(combinedStream);
    
        // Set input options
        command.inputOptions('-f webm');
    
        // Set output options
        command.outputOptions([
            '-c:v copy',
            '-c:a aac',
        ]);
    
        // Set the output format
        command.toFormat('mp4');
    
        // Set the output file path
        command.output(outputFilePath);
    
        // Event handling
        command
            .on('start', commandLine => {
                console.log('Spawned Ffmpeg with command: ' + commandLine);
            })
            .on('codecData', data => {
                console.log('Input is ' + data.audio + ' audio ' +
                'with ' + data.video + ' video');
            })
            .on('progress', progress => {
                console.log('Processing: ' + progress.percent + '% done');
            })
            .on('stderr', stderrLine => {
                console.log('Stderr output: ' + stderrLine);
            })
            .on('error', (err, stdout, stderr) => {
                console.error('Error converting and merging streams:', err);
                console.error('ffmpeg stdout:', stdout);
                console.error('ffmpeg stderr:', stderr);
                reject(err);
            })
            .on('end', () => {
                console.log('Conversion and merging finished successfully.');
                resolve();
            });
    
        // Run the command
        command.run();
    });
}


  


  And now ffmpeg says that :

  


  [matroska,webm @ 0x3712a6f0] EBML header parsing failed
[in#0 @ 0x3712a5f0] Error opening input: Invalid data found when processing input
Error opening input file pipe:0.
Error opening input files: Invalid data found when processing input

convertAndMergeWebmStreams error:  Error: ffmpeg exited with code 183: Error opening input file pipe:0.
Error opening input files: Invalid data found when processing input


  


  Based on this link, it seems it is a known issue that it does not have a valid EBML header with MediaRecorder from browsers. Is there another way to merge them and get one single MP4 file ?

  


• avfilter/vf_dejudder : use the name ’s’ for the pointer to the private context

  20 août 2015, par Paul B Mahol

  avfilter/vf_dejudder : use the name ’s’ for the pointer to the private context
  This is shorter and consistent across filters.
  Signed-off-by : Paul B Mahol <onemda@gmail.com>
  

  • [DH] libavfilter/vf_dejudder.c