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• Node JS partial video streaming to safari

  12 juin 2021, par Thor Bilsby

  I'm trying to stream a video directly to a browser using node.js as the backend. I would like the video to be streamed from a specific time and would also like it to be partially streamed since it is a pretty large file. Right now I am doing this with fluent-ffmpeg, like this :

  


  const ffmpeg = require('fluent-ffmpeg');

app.get('/clock/', (req, res) => {
  const videoPath = 'video.mp4'; 
  const now = new Date();

  ffmpeg(videoPath)
    .videoCodec('libx264')
    .withAudioCodec('aac')
    .setStartTime(`${(now.getHours() - 10) % 24}:${now.getMinutes() - 1}:${now.getSeconds()}`)
    .format('mp4')
    .outputOptions(['-frag_duration 100','-movflags frag_keyframe+faststart','-pix_fmt yuv420p'])
    .on('end', () => {
      console.log("File has been converted succesfully");
    })
    .on('error', (err) => {
      if (err.message.toLowerCase().includes('output stream closed')) return;
      console.log('An error occoured', err);
    })
    .pipe(res, { end: true });
});


  


  This will work with Chrome, but Safari just doesn't want to stream it.
I know that the reason why it doesn't work on Safari is that Safari needs the range header. I've therefore tried to do that, but :

  


  

  1. I can't get it to work with fluent-ffmpeg.

  


  2. When I try to do it the "normal" way, without fluent-ffmpeg, it needs to load the whole video file before it plays.

  


  


  The video doesn't need to start at the specific timestamp. It would be nice tho, but I have a workaround for that if it's not possible :)

  


  So my question is : How can I get the code above to work with Safari. And if that is impossible : How can I code something that doesn't need to be loaded fully, before it can be played in Safari browsers, aka. partial video streaming.

  


• Is ffmpeg broken for h.264 RTP Output ?

  13 mars 2023, par GroovyDotCom

  I used wireshark to capture the RTP stream sent with :

  


  ffmpeg -f lavfi -i "testsrc=duration=5:size=cif:rate=25" -pix_fmt yuv420p -g 25 -bf 2 -an -c:v libx264 -f rtp rtp://127.0.0.1:1234 > play.sdp

  


  ffmpeg -version
ffmpeg version git-2020-03-15-c467328 Copyright (c) 2000-2020 the FFmpeg developers

  


  As can be seen in bold, RTP timestamps go forward and backward. I expect them to be the same for every packet in the frame and then only go forward by 40ms (+3600 at 90khz clock) as per the H.264/RTP spec.

  


  Also, according to that spec, the last packet in a frame should have its marker-bit set but here almost all the packets have this bit set.

  


  Am I doing something wrong ? Not understanding something ? Or is ffmpeg support for writing H.264 RTP simply broken ?

  


  SSRC=0xA49C3DC9, Seq=3595, Time=3153114809
  
SSRC=0xA49C3DC9, Seq=3596, Time=3153114809
  
SSRC=0xA49C3DC9, Seq=3597, Time=3153114809
  
SSRC=0xA49C3DC9, Seq=3598, Time=3153114809, Mark
  
SSRC=0xA49C3DC9, Seq=3599, Time=3153125609, Mark
  
SSRC=0xA49C3DC9, Seq=3600, Time=3153118409, Mark
  
SSRC=0xA49C3DC9, Seq=3601, Time=3153122009, Mark
  
SSRC=0xA49C3DC9, Seq=3602, Time=3153136409, Mark
  
SSRC=0xA49C3DC9, Seq=3603, Time=3153129209, Mark
  
SSRC=0xA49C3DC9, Seq=3604, Time=3153132809, Mark
  
SSRC=0xA49C3DC9, Seq=3605, Time=3153147209, Mark
  
SSRC=0xA49C3DC9, Seq=3606, Time=3153140009, Mark
  
SSRC=0xA49C3DC9, Seq=3607, Time=3153143609, Mark
  
SSRC=0xA49C3DC9, Seq=3608, Time=3153158009, Mark
  
SSRC=0xA49C3DC9, Seq=3609, Time=3153150809, Mark
  
SSRC=0xA49C3DC9, Seq=3610, Time=3153154409, Mark
  
SSRC=0xA49C3DC9, Seq=3611, Time=3153168809, Mark
  
SSRC=0xA49C3DC9, Seq=3612, Time=3153161609, Mark
  
SSRC=0xA49C3DC9, Seq=3613, Time=3153165209, Mark
  
SSRC=0xA49C3DC9, Seq=3614, Time=3153179609, Mark
  
SSRC=0xA49C3DC9, Seq=3615, Time=3153172409, Mark
  
SSRC=0xA49C3DC9, Seq=3616, Time=3153176009, Mark
  
SSRC=0xA49C3DC9, Seq=3617, Time=3153190409, Mark
  
SSRC=0xA49C3DC9, Seq=3618, Time=3153183209, Mark
  

  


  The RTP specification, defined in RFC 3550, states that "the timestamp reflects the sampling instant of the first octet in the RTP data packet. The sampling instant must be derived from a clock that increments monotonically and linearly in time to allow synchronization and jitter calculations" (Section 5.1).

  


• lavc/videotoolboxenc : Add support for HEVC with Alpha.

  23 février 2021, par Hironori Bono

  lavc/videotoolboxenc : Add support for HEVC with Alpha.
  This change supports the "HEVC Video with Alpha" profile introduced in WWDC 2019
  
  <https://developer.apple.com/videos/play/wwdc2019/506/>. (This change is a
  
  partial fix for Ticket #7965.)
  For example, the following command converts an animation PNG file to an HEVC
  
  with Alpha video :
  
  ./ffmpeg -i fate-suite/apng/clock.png -c:v hevc_videotoolbox -allow_sw 1 -alpha_quality 0.75 -vtag hvc1 clock.mov
  (This change uses the "HEVC Video with Alpha" profile only when the
  
  '-alpha_quality' value is not 0 for backward compatibility.)
  Signed-off-by : Hironori Bono <bouno@rouge.plala.or.jp>
  

  • [DH] configure
  • [DH] libavcodec/videotoolboxenc.c