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• Optimizing Adaptive Streaming with FFMPEG

  25 octobre 2018, par Ramesh Navi

  I am working on a video on demand website, I am using laravel 5.7, FFMPEG and DASH player from (dashif.org). Got some questions.

  Extracting audio like :

  ffmpeg -i original.mp4 -vn -acodec libvorbis -ab 128k -dash 1 my_audio.webm

  Converting video like :

  ffmpeg -i original.mp4 -c:v libvpx-vp9 -keyint_min 150 \
  
  -g 150 -tile-columns 4 -frame-parallel 1  -f webm -dash 1 \
  
  -an -vf scale=160:190 -b:v 250k -dash 1 video_160x90_250k.webm \
  
  -an -vf scale=320:180 -b:v 500k -dash 1 video_320x180_500k.webm \
  
  -an -vf scale=640:360 -b:v 750k -dash 1 video_640x360_750k.webm \
  
  -an -vf scale=1280:720 -b:v 1500k -dash 1 video_1280x720_1500k.webm

  Creating manifest like :

  ffmpeg \
  
  -f webm_dash_manifest -i video_160x90_250k.webm \
  
  -f webm_dash_manifest -i video_320x180_500k.webm \
  
  -f webm_dash_manifest -i video_640x360_750k.webm \
  
  -f webm_dash_manifest -i video_1280x720_1500k.webm \
  
  -f webm_dash_manifest -i my_audio.webm \
  
  -c copy \
  
  -map 0 -map 1 -map 2 -map 3 -map 4 \
  
  -f webm_dash_manifest \
  
  -adaptation_sets "id=0,streams=0,1,2,3 id=1,streams=4" \
  
  my_video_manifest.mpd

  Now the problems :

  1. Video conversion takes a lot of time on the latest i5 8gb
     think-pad running Ubuntu 18. 4minute mp4 took more than 30minute. 10minute, 720p MP4 took forever, had to kill the process. Is
     that normal ? Any idea to optimize ?
  2. Need to find out original
     video’s dimension so that I can avoid dimension conversion more than
     the original. ffprob looks fine in command but produces too much of
     information than required, is there any simple function ?
  3. Converted webm file is bigger in size than original mp4, original
     mp4 of 720p was 33MB, but 640p webm is 76MB. Is that normal or
     something wrong ?

  Any suggestions to optimize the process are welcome.

• fluent-ffmpeg to extract audio for wavesurfer

  6 novembre 2018, par beek

  I’m trying to get a video audio file for wavesurfer so can show the wave. I’m using fluent-ffmpeg in an express app.

  I’ve kind of got it working with

  app.get('/audio/:file', (req, res) => ffmpeg.audio(req, res))
  
  
  
  const path = req.params.file
  
  const file = path.replace('MP4', 'wav')
  
  ffmpeg(path)
  
  .noVideo()
  
  .withAudioCodec('copy')
  
  .toFormat('wav')
  
  .on('progress', console.log)
  
  .on('error',  console.log)
  
  .on('end',()=> res.sendFile(file))
  
  .save(file)

  And then in wavesurfer

   this.wavesurfer.load(encodeURI(`${LOCAL_SERVER}/audio/${video.file}`))

  This seems to work with smaller files, but it’s not with bigger files. I’ve tried streaming the output but wavesurfer doesn’t seem to be able to work with that.

  Any idea the best way around this ?

• ffmpeg does not produce smooth videos from mkv h265 [migrated]

  13 décembre 2018, par user3776738

  It’s kind of subjective, but I’m not able to produce 100% smooth videos with ffmpeg.
  As input I use https://www.libde265.org/hevc-bitstreams/tos-1720x720-cfg01.mkv as a example.This is a h264 mkv video which is running really badly with my vlc player on my win7 laptop.Converting it to a h264 video let it play much better, but it still appears not to be 100% smooth. Especialy in Vegas 9 it even hangs like once a second.

  Other h264 videos even with 1080p or bigger run perfect with vlc and much better with Vegas, so it is not my laptop.

  its seems that there can be a lot of differences between h264 and h264 ??
  what could i try to make them more smooth ?

  I’m using following command to convert the video :

  ffmpeg.exe -i INPUT_FILE -ac 2 -vf scale=trunc\\(oh*a/2\\)*2:480 -c:v libx264 -sn -dn -map_metadata -1 -map_chapters -1 -profile:v high -level:v 4.0 -pix_fmt yuv420p OUTPUT_FILE