[OT] Determining Video Formats

[Patrick O'Callaghan]

On Thu, 2008-03-27 at 11:36 -0600, Robin Laing wrote:
> Paul Lemmons wrote:
> > I am looking for a way to look at an AVI file and see how it was encoded 
> > with enough detail that I could reproduce the process using transcode or 
> > mencoder. I have a media server (D-Link DSM520) that plays most videos 
> > absolutely perfectly. Some, though, it has trouble keeping audio sync. I 
> > would like to compare the videos that work without issue to those that 
> > have issues to see if I can identify what the differentiator might be. I 
> > should then be able to identify those with problems and re-transcode 
> > them to look like the files without the problem. That is the goal, anyway.
> > 
> > I suspect this is real easy but I am just not finding it and I am 
> > completely Googled out. Any pointers in the right direction would be 
> > much appreciated!
> > 
> 
> I had a weird situation on the weekend with a whole set of files that I 
> downloaded from usenet.  All the audio was up to 15 seconds in advance 
> of the action.  I found out it was related to the black before the video 
> started as the sound started as soon as I hit play on the DVD player.
> 
> What I found was if I fast forwarded and then reversed, the audio was 
> almost synced.
> 
> These were DVIX encoded files.  They worked okay on the computer though.
> 
> This points to an issue with the software on the player.
> 
> File a bug report with D-Link when you get more info.

Happens to me frequently on a standard DVD player using DVIX files (the
player's an LG, which I'm otherwise very happy with). The sync problem
seems to increase the further into the video you get. I suspect, off the
top of my head, that it has to do with imprecision in specifying the
frame rate at encoding time but I'm no expert.

poc