Recherche avancée

Sur d’autres sites (2048)

• Any equivalent to '-c:v copy' for changing container of webm to mp4 video client-side in JS ?

  15 mars 2020, par programmingisphun

  Exploring the Mediarecorder API and really hope to get an mp4 output instead of webm. Prefer to stay client-side to reduce server resources and ffmpeg.js at 17mb doesn’t seem viable for online use.

  Discovered that one can create (Chrome/Firefox) a webm/h.264, which converts without re-encoding to an mp4 using FFMPEG. The resulting file opens fine in Quicktime MacOS (snippet source) :
  ffmpeg -i _inputfile_.webm -c:v copy _outputfile_.mp4

  Whereas this clever hack works to display the video maybe as an mp4 in the browser, but the downloaded file won’t open in Quicktime (just VLC, same for webm) :

  new Blob(recordedBlobs, {type: 'video/mp4'});
  
  video.src = window.URL.createObjectURL(superBuffer);

  Therefore, wondering if there’s another JS hack to do what FFMPEG’s -c:v copy does, but to the blob bytes of the MediaRecorder’s recordedBlobs and give it the same mp4 container that’s accepted by Quicktime/etc ?

  Pastebin of current setup

• ffmpeg - How to change the filter-paramaters depending on time oder framenumber ?

  2 mars 2020, par LookAndSee

  Hallo to all userse and helpers here in this forum ! Thank you, i am new and i have found allready a lot of solutions.

  Now I want to ask, if someone can help me :

  I have a Movie about 30 seconds made of 1 image.
  Now I want to pixelate depending on time or framenumber - every time a litlle bit less.
  My code so far :

  ffmpeg -i in.mp4 -vf scale=iw/n:ih/n,scale=niw:nih:flags=neighbor out.mp4

  where n should be the framenumber 1 to 900.
  this scould also be t+1 for slower change.

  the stars are gone - so i mean n times iw:n times ih :

  error-massage :

  undefined constant or missing ’(’ in ’n’
  error when evaluating the expression ’ih/n’
  maybe the expression for out_w :’w/n’ or for out_h :’ih/n’ is self-referencing.
  failed to configure output pad on paresed_scale_0
  error reinitializing filters !
  failed to inject frame into filter network : invalid argument
  error while processing the decoded data for stream #0:0

  Do you have some suggestion plaese - Thank you in Advance

• Fragmented mp4 broadcast with avformat

  6 mars 2020, par Daniel

  I want to broadcast a live stream (h264 -> fragmented mp4) with avformatfunctions.

  Now basically I have a working example with this pseudo :

  avformat_write_header
  
  while (!end) {
  
    av_read_frame
  
    av_write_frame
  
  }
  
  avformat_write_tailer

  I have this as output flags : movflags +frag_keyframe+empty_moov+default_base_moof.

  I’m dispatching the output to a html5 video which plays fine and smooth.
  However I want to broadcast it, so whenever a new player comes into picture I want to stream the very same data to it :

  avformat_write_header
  
  while (!end) {
  
    av_read_frame
  
    av_write_frame (to multiple clients)
  
  }
  
  avformat_write_tailer

  However the first client can play the stream but the rest of them can not.

  This is because the fmp4’s structure : the first client receives the correct ftyp and moov atoms, whereas the rest of the clients are not.

  Now I can hack my code to provide the earlier ftype and moov atoms to the later clients but I think that is not wise - correct me if I’m wrong.

  My quesions :

  1. How can I ask avformat during the stream to (calculate) and include the ftyp and moov atoms ?
  2. Will including ftyp and moov during the stream ruin the first client ? (Is it valid in fmp4 to have ftype and moov not just once in the beginning ?)

  Thank you