Slight video length changes (& sync problems)

[mg262]

I've been having the same problems several people have reported on this forum, where the video length changes by a second or two when encoded in CCE (causing audio sync problems). In my case I've found the source of the problem (I think :D), so I thought I'd report it in case it proves useful to anyone else...

The frame rate of my source (captured from PAL VHS via iuVCR) is "autodetect"ed from the source as being 25.0058 (in this case). Running it through CCE silently alters the frame rate to 25 exactly, which results in the video that is (in this case) half a second longer. (TMPGEnc by contrast appears to retain the original frame rate.)

A corollary to that is that the stretching is even over time, so that stretching/squashing the audio to match the video length is the correct thing to do and will not result in them drifting in and out of sync.

Apologies if this answer has already been posted somewhere else...

Mohan

[RB]

25.0058 isn't a valid frame rate for any video standard I'm aware of, so CCE really isn't to blame.

[mg262]

No, I wasn't suggesting it was a bug in CCE at all - what it did was perfectly sensible. It seems that if the frame rate is sufficiently close to 25 (something like 25.01 is the threshold), it tacitly assumes that it is 25, whereas if it differs by more than that it complains.

I'm not really sure how the 25.0058 actually cropped up... iuVCR was set to cap at 25 exactly, but one of the settings must have caused it to try to autodetect the frame rate or something of the sort. You wouldn't believe how much time I wasted before I used info() on the source.