Recherche avancée

Sur d’autres sites (5414)

• Using ffmpeg to change video framerate without video quality loss and keep audio ?

  31 mai 2020, par Johnny

  I recorded some game videos with my Samsung Galaxy S7 device. When I now add these videos to blender 3d in video editing, I get different video and audio frames.

  



  I think, that this is an fps problem, because on every recorded video I get different fps :
59.01, 59.80 etc.

  



  Now I want to change frame rate on all videos to 60 fps without video quality loss and keeping audio.

  



  So I would not have any problems in video editing.

  



  Does somebody have any tips ?

  


• avformat/matroskaenc : Write level 1 elements in one go

  30 décembre 2019, par Andreas Rheinhardt

  avformat/matroskaenc : Write level 1 elements in one go
  Up until now, writing level 1 elements proceeded as follows : First, the
  
  element id was written to the ordinary output AVIOContext and a dynamic
  
  buffer was opened for the content of the level 1 element in
  
  start_ebml_master_crc32(). Then this buffer was actually used and after it
  
  was closed (in end_ebml_master_crc32()), the size field corresponding to
  
  the buffer's size was written, after which the actual data was written.
  This commit changes this : Nothing is written to the main AVIOContext any
  
  more in start_ebml_master_crc32(). end_ebml_master_crc32() now writes
  
  both the id, the length field as well as the data. This implies that
  
  one can start a level 1 element in memory without outputting anything.
  
  This is done to enable to test whether enough space has been reserved
  
  for the Cues (if space has been reserved for them) before writing them.
  
  A large duration between outputting the header and outputting the rest
  
  could also break certain streaming usecases like the one from #8578
  
  (which this commit fixes).
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/matroskaenc.c

• How to reduce the size of video file as a buffer or blob before writing it on Nodejs ?

  7 novembre 2022, par Hypothesis

  I send live feed from client to the server using websocket from the client side like this :

  


      recorder = new MediaRecorder(canvasStream, {
        mimeType: 'video/webm;codecs=vp9',
        videoBitsPerSecond: 3 * 1024 * 1024
    });
    recorder.ondataavailable = async (e) => {
        const arbuf = await e.data.arrayBuffer()
        ws.send(pack({ type: 'REC', data: arbuf })) //sends to server
    }


  


  and on the server side I get them like this :

  


   let blob = new Blob(chunks, { type: 'video/mp4' })
      const buffer = Buffer.from(await blob.arrayBuffer());
      fs.writeFile("foo.mp4", buffer, () => console.log('video saved!'));


  


  However foo.mp4 is really large. Please help me find a way to reduce the size of foo.mp4 as it is being written down to the disc. ( I can reduce it after it is written, however that won't do the trick for me. It has to be encoded and compressed before it is written )