Re: Chapter marks not where specified.

On Wed, 28 Mar 2012 14:56:31 +0100, Tom Brock wrote:

> Now it gets interesting...
> 
> The chapter mark placement errors are exactly the same as for
> 0.6.18. However, I was lying when I said *all* the marks were earlier
> than specified. Out of 33 marks, 5 are in the specified time, 29 are
> at the I-frame immediately preceding the specified time and one was
> at the I-frame immediately following the specified time.
> 
> It does, indeed, look a bit like a rounding error, but only a bit.
> I'd expect a more even split between positive and negative errors.

I thought of something else: chapter/program starts must coincide with
cell starts, and cell starts must coincide with VOBU boundaries. Each
VOBU must contain one or more entire GOPs, and each GOP starts with an
I-frame.

DVDAuthor doesn’t demarcate the VOBUs, that is done by whatever tool is
generating the MPEG video, or converting it into DVD-Video-compatible
form. So if a frame (whether I-frame or not) you’re trying to specify as
a chapter start does not in fact lie at the beginning of a VOBU, then
DVDAuthor has no choice but to move to the nearest VOBU start.

mpeg2desc can show you these VOBU boundaries: each VOBU starts with a
PCI and DSI packet.

------------------------------------------------------------------------------
This SF email is sponsosred by:
Try Windows Azure free for 90 days Click Here 
http://p.sf.net/sfu/sfd2d-msazure
_______________________________________________
Dvdauthor-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/dvdauthor-users