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• FFmpeg : higher bitrates increases output size when input bitrate is lower

  14 janvier 2017, par David

  I want to convert several video files (1000+) by FFmpeg with a single command.
  High quality videos convert as expected to a lower size.
  But low quality videos will get several times larger due to the custom bitrate which is specified in the command. (A 5 min - 10mb mp4 video will convert to 30mb !)

  The same scenario for audio too !

  How can I force FFmpeg to choose 24000/700k as audio/video bitrates for high quality video files, or use same is input for low quality video files (if input bitrate is lower than 24000/700k) ?

  Here is the command I’ve written and use :

  ffmpeg -i input.mp4 -c:a libfdk_aac -vbr 2 -ac 1 -ar 24000 -c:v libx264 -preset slow -profile:v baseline -level 3.0 -b:v 700k -minrate 1k -maxrate 800k -bufsize 1024k -threads 10 output.mp4

  Thanks.

• HLS-streaming on VLC - cookies alternative

  5 juillet 2018, par unicornslayer

  I’m trying to build a streaming web api which creates m3u8 playlists of .ts files in .net core.

  I’ve built the live streaming option and it works fine on vlc.

  For example, in VLC -> File -> Open Network put my link : http://localhost:39986/api/Stream/MyChannel/index.m3u8 and VLC gives me the live version of the channel.

  But I need to implement the option of starting a video from a fixed time : http://localhost:39986/api/Stream/MyChannel/index.m3u8?timeStr="2018-07-04T17:16:01". In this case, I would need to create a session to know from which point to create the playlist, right ?[1]

  If so, sessions require an ID stored as a Cookie (right ?[2]). But from what I’ve read and what I’ve tested, vlc doesn’t support cookies.

  So my question is : is there any workaround for this scenario ?[3]

  It’s an university project and I am very confused about this task.

• Smartly concatenating gopro mp4 files - file-001.mp4 + file-002.mp4

  12 décembre 2017, par molly78

  Hello much smarter than me people out there...

  I have a folder of GoPro files which I have already renamed using this awesome utility : https://github.com/kcha/gopro_renamer

  However, I now have a folder of 110 files which should make up about 50 continuous videos...

  Some of which have only filename-001.mp4 parts, some are filename-001.mp4 and filename-002.mp4 parts. It could go on an on to say 10 parts per video, for argument sake.

  I’d like to get a hand with a script that would scan the folder and then join all the parts together into a new file.

  In windows 10 I know I can do a simple

  copy /b "C:\Filename-001.mp4" + "C:\Filename-002.mp4" Filename.mp4

  Just a bit lost how to loop thru this scenario with a (python is fine) script. I do not wish to re-encode them, simply join the parts that correspond to the base filename.

  So go from files looking like

  filename1-001.mp4 - 87 MB
  
  filename2-001.mp4 - 100 MB
  
  filename2-002.mp4 - 100 MB
  
  filename2-003.mp4 - 22 MB
  
  filename3-001.mp4 - 100 MB
  
  filename3-002.mp4 - 34 MB

  after concatenating the parts it would look like :

  filename1.mp4 - 87 MB (nothing done other than rename)
  
  filename2.mp4 - 222 MB (all joined)
  
  filename3.mp4 - 134 MB (all joined)

  Your help is greatly appreciated.