They might be being written at different points than in the source footage, but trust me, the presentation timestamps should be there, or your ripping software ain’t worth squat.
Your “rip” software SHOULD take this into account when producing it’s output file, but even so, the output streams in the MKV or MP4 file should ALSO have presentation timestamps. Frequently the timestamps aren’t included with every packet of audio or video, but are interspersed within the streams, like every 2 seconds or so.
The computer reads and decompresses the source footage, sometimes well ahead of where it’s playing, and waits on each stream, video and audio, for the right time to play its’ decompressed footage. These presentation timestamps tell the computer exactly when to play the media, so the audio and video don’t get out of sync. **bleep**, I wrote a good chunk of the code.įolks, almost any media that you would rip from, in order to obtain an MP4, MKV, AVI file, etc, has what are called “presentation timestamps” in the source media (DVD, blu-ray). I work at Microsoft as a developer in the audio/video department, and I know exactly what it takes to make audio and video play back in sync. However, unlike most “laymen” on this site, I know a lot about file formats and how sync works.
I’ve got lots of MKV files, and on the majority of them, which play FINE in VLC media player on Windows, they play out of sync on the WD TV Live. Yet another post about audio sync being off.