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• ffmpeg encoding a video with time_base Not equal to framerate does not work in HML5 video players

  1er juillet 2019, par Gilgamesh22

  I have a time_base of 90000 with a frame rate of 30. I can generate a h264 video and have it work in VLC but this video does not work in the browser player. If I change the time_base to 30 It works fine.

  Note : I am changing the frame->pts appropriately to match the time_base.
  Note : Video does not have audio stream

  //header.h
  
  AVCodecContext *cctx;
  
  AVStream* stream;

  Here is the non working example code

  //source.cpp
  
  stream->time_base = { 1, 90000 };
  
  stream->r_frame_rate = { fps, 1 };
  
  stream->avg_frame_rate = { fps, 1 };
  
  
  
  cctx->codec_id = codecId;
  
  cctx->time_base = { 1 ,  90000 };
  
  cctx->framerate = { fps, 1 };
  
  
  
  // ...... 
  
  // add frame code later on timestamp are in millisecond
  
  frame->pts = (timestamp - startTimeStamp)* 90;

  Here is the working example code

  //source.cpp
  
  stream->time_base = { 1, fps};
  
  stream->r_frame_rate = { fps, 1 };
  
  stream->avg_frame_rate = { fps, 1 };
  
  
  
  cctx->codec_id = codecId;
  
  cctx->time_base = { 1 ,  fps};
  
  cctx->framerate = { fps, 1 };
  
  
  
  // ...... 
  
  //  add frame code timestamp are in millisecond
  
  frame->pts = (timestamp - startTimeStamp)/(1000/fps);

  Any ideas on why the second example works and the first does not in the HTML5 video player.

• How to covert video and extract frame from video using FFMPEG in single command

  13 juillet 2013, par kheya

  I am trying to convert and extract image frame from a video file in single command
  I can do this in 2 steps but I want to use pipe like technique to do this

  This is what I have :
  for %%a in ("*.avi") do ffmpeg -i "%%a" -c:v libx264 -preset slow -crf 20 -c:a libvo_aacenc -b:a 128k "%%~na.mp4" <— converts correctly

  I need to incorporate this extract command :

  ffmpeg -i inputfile.avi  -r  1  -t  4  image-%d.jpeg

  Merging two commands giving error.

  How do I do it ?

  EDIT :
  This is what I have. But it just converts the video, no jpg image created as second output

  for %%a in ("*.avi") do ffmpeg -i "%%a" -c:v libx264 -preset slow -crf 20 -c:a libvo_aacenc -b:a 128k "%%~na.mp4" | ffmpeg -r 1 -s 4cif "%%~na.jpeg"

• ffmpeg video unable to play properly in most video players

  7 septembre 2022, par Lars

  I'm trying to set up a node.js app that allows me to download files from a web interface.&#xA;I'm using yt-dl to get the video and audio stream and ffmpeg to pipe those streams into an mp4. This works and returns a mp4 file.

  &#xA;

  Now the only issue I have is that when I play the file through most video players, the video player is unable to seek, or skip through the song. I found somewhere deep down on a forum that means that that means the mp4 headers are not working but that is all I could find.&#xA;Here is my code, almost unchanged from this response on another thread.

  &#xA;

  Can anyone provide a solution for this issue.

  &#xA;

  ytdl.getInfo(link, options).then(info => {
        audioStream = ytdl.downloadFromInfo(info, { ...options, quality: 'highestaudio' });
        videoStream = ytdl.downloadFromInfo(info, { ...options, quality: 'highestvideo' });
        // create the ffmpeg process for muxing
        ffmpegProcess = cp.spawn(ffmpegPath, [
            // supress non-crucial messages
            '-loglevel', '8', '-hide_banner',
            // input audio and video by pipe
            '-i', 'pipe:3', '-i', 'pipe:4',
            // map audio and video correspondingly
            '-map', '0:a', '-map', '1:v',
            // no need to change the codec
            '-c', 'copy',
            // output mp4 and pipe
            '-f', 'matroska', 'pipe:5'
        ], {
            // no popup window for Windows users
            windowsHide: true,
            stdio: [
                // silence stdin/out, forward stderr,
                'inherit', 'inherit', 'inherit',
                // and pipe audio, video, output
                'pipe', 'pipe', 'pipe'
            ]
        });
        audioStream.pipe(ffmpegProcess.stdio[3]);
        videoStream.pipe(ffmpegProcess.stdio[4]);
        ffmpegProcess.stdio[5].pipe(result);
    });


  &#xA;