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• Fragmented MP4 : TrackFragHeader TFHD must have TrackID, is this in the spec ?

  27 juillet 2021, par Penquin

  I'm building a fragmented mp4 muxer and noticed that the track id is repeated inside the TFHD.
If the video does not have this undocumented track id, it will simply not play.

  


  Here's an example of a muxer adding it :
https://github.com/edgeware/mp4ff/blob/bb9320744777dc97f18034c8aed45a9bcdbaa995/mp4/tfhd.go#L154

  


  I was relying on the open spec provided by Microsoft :
https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-sstr/513ea48c-9a57-4792-a32a-fb6202ce2a58

  


  Is this an addition to the spec ? Is the spec provided by Microsoft wrong ?

  


• Supported audio and video formats in Windows Store apps

  27 décembre 2013, par TheQuestioner

  I searched a lot on the internet and I know that this problem has been discussed on several forums, but because I am making a media player and I intend to sell it, I fell the need to ask for a more complete answer.
  As I understand, this is the list with the audio and video formats available in Windows Store Apps : http://msdn.microsoft.com/en-us/library/windows/apps/hh986969.aspx. This are indeed the most used formats for playing audio and video, but I truly fell the lack of support for the .MKV files. So my questions are :

  1. Will Microsoft include .MKV in that list ? When ?
  2. Can I somehow include the .MKV codec in my app ? (or other codecs, like .flv)
  3. If I can't add the MKV codec in my app and Microsoft doesn't intend to add it, is there a way that I can convert the .MKV in , let's say, a .MP4 so that my app can be able to play it ?

  I know that I'm not the first that asks this questions, but I didn't find anywhere a good/complete answer or solution to this problem.

  In my opinion .MKV in pretty popular already. Searching for media players in the Windows Store I found one which claims that it supports .MKV (but only if you buy it, so I didn't try it). So is this possible ? How ?

• Conversion of individual mp4 files to ts yields unexpected playback

  3 août 2021, par MorenoGentili

  I'm converting three mp4 files (h264, no audio, each with a duration of three seconds) to the mpeg-ts format like so.

  


  ffmpeg -i 1.mp4 -c copy 1.ts
ffmpeg -i 2.mp4 -c copy 2.ts
ffmpeg -i 3.mp4 -c copy 3.ts


  


  Please note : I can't combine the mp4 files beforehand. Each one has to be converted individually as shown above since they're being generated by a live recorder.

  


  Then, I manually created a .m3u8 manifest like this one, so I could play those 3 ts files in sequence :

  


  #EXTM3U
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-PLAYLIST-TYPE:VOD
#EXT-X-TARGETDURATION:3
#EXTINF:3,
1.ts
#EXTINF:3,
2.ts
#EXTINF:3,
3.ts
#EXT-X-ENDLIST


  


  When I run the ffplay index.m3u8 command :

  


  

  • 1.ts is played for three seconds as expected ;

  


  • 2.ts is played "for a split second" (maybe just a frame) ;

  


  • 3.ts is played for three seconds as expected.

  


  


  Can someone explain why 2.ts is shown for such a brief time ? When I run ffmpeg -i 2.ts, the output is correctly displaying a duration of three seconds.

  


  Input #0, mpegts, from '2.ts':
  Duration: 00:00:03.00, start: 1.480000, bitrate: 49 kb/s


  


  How can I change my mp4 -> ts conversion commands so that each file can play for their whole duration (i.e. three seconds each) ? I'd like to avoid reencoding if possible.

  


  Thank you, I'm adding a link to the three files and the manifest for completeness.