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• How to use ffmpeg.exe to produce a video with exact length for time from image sequence in C# ?

  28 avril 2016, par user2186102

  We try to use ffmpeg.exe to make a video from image sequence in C#. However, we can’t produce a video which has a predict length for time. For example, we want to produce a video whose length of time is one hour ; actually, the length of time is only 47 miniutes.

  According our understanding, the function, WriteVideoFrame(Bitmap frame, TimeSpan timestamp) of AForge.Video.FFMPEG, can solve this problem. It is because each input frame is associated with a timestamp.

  In ffmpeg.exe, however, we now can only use frame to as input of ffmpeg.exe.

  Who can show me how to write the command or parameters to input each image and the associated timestamp, the same to WriteVideoFrame(Bitmap frame, TimeSpan timestamp).

• Mapping audio to video with ffmpeg with metadata length

  20 juin 2023, par Tomáš Kordoš

  I'm using node.js ffmpeg-static to map a video and an audio together.

  


  var VideoStream = ytdl(video, { filter: 'videoonly', quality: 'highestvideo' });
var AduioStream = ytdl(video, { filter: "audioonly", quality: 'highestaudio' });

const ffmpegProcess = cp.spawn(ffmpeg, [
  '-i', `pipe:3`,
  '-i', `pipe:4`,
  '-map', '0:v',
  '-map', '1:a',
  '-c:v', 'copy',
  '-c:a', 'aac',
  '-movflags', 'frag_keyframe',
  '-f', 'mp4',
  '-'
 ], {
  stdio: [
    'pipe', 'pipe', 'pipe', 'pipe', 'pipe',
  ],
});

VideoStream.pipe(ffmpegProcess.stdio[3]);
AduioStream.pipe(ffmpegProcess.stdio[4]);
ffmpegProcess.stdio[1].pipe(fs.createWriteStream('./out.mp4'));


  


  The saved file contains both audio and video as expected, But the length of the file is only 4 seconds when using -movflags frag_keyframe. Although the video continues after that (00:10 / 00:04)

  


  -movflags faststart Never works

  


  How do I automatically or manualy (Ytdl allows me to download the video length)set the length ?

  


  Thank you

  


• Video length missing in FLV converted by ffmpeg-php

  19 janvier 2013, par Andrew

  I'm converting MP4 videos to FLV using ffmpeg-php on my CentOS server (without intervention from flvtool2 because it's not installed).

  The FLV videos are created, but no player is capable of retrieving the video duration, this creates serious issues when trying to seek the video. I'm using the player created by Moyea's Flash Video MX Pro, but the problem also happens with other FLV players as well, so I'm sure that ffmpeg-php is not createing the FLV with the proper length data.

  My MP4 videos are compatible because ffmpeg-php CAN get the video length properly from then, yet it does not apply that length information into the FLV file. I assume flvtool2 is ONLY to retrieve meta-data and has nothing to do with the output FLV video length, let me know if this is correct.

  This command I use for conversion :

  $command = "ffmpeg -i myvideo.mp4 -ar 22050 -ab 64k -f flv -s 320x240 -y myvideo.flv";
  
  $result = @shell_exec($command);

  This is my ffmpeg-php version :

  FFmpeg version 0.5, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  
    configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --mandir=/usr/share/man --incdir=/usr/include --extra-cflags=-fPIC --enable-libamr-nb --enable-libamr-wb --enable-libdirac --enable-libfaac --enable-libfaad --enable-libmp3lame --enable-libtheora --enable-libx264 --enable-gpl --enable-nonfree --enable-postproc --enable-pthreads --enable-shared --enable-swscale --enable-x11grab
  
    libavutil     49.15. 0 / 49.15. 0
  
    libavcodec    52.20. 0 / 52.20. 0
  
    libavformat   52.31. 0 / 52.31. 0
  
    libavdevice   52. 1. 0 / 52. 1. 0
  
    libswscale     0. 7. 1 /  0. 7. 1
  
    libpostproc   51. 2. 0 / 51. 2. 0
  
    built on Jul 24 2009 01:40:27, gcc: 4.1.2 20080704 (Red Hat 4.1.2-44)

  Any help on this issue will be greatly appreciated.