[mythtv-users] Remain in MPEG-2 but remove commercials?

Preston Crow pc-mythtv05 at crowcastle.net
Fri May 27 16:58:20 UTC 2005


On Fri, 2005-05-27 at 12:45, Adam Egger wrote:
> Yes, that's what I'm looking for. I'd just like to cut out the
> commercials without changing anything else with the source file (like
> I've done with VirtualDub on windows years ago).
> Is it possible to remove unneeded parts of a recording in a few
> seconds/minutes without having to transcode the source file (what
> takes ages on my AMD64-3000+)?

Yes and no.

>From what I've read on this subject, there are three problems that make
this a complicated issue:

1) The audio packets aren't as closely connected to the video packets as
you would like, so it's tricky to figure out exactly what you want,
keeping the audio sync the same in the edited version.

2) MPEG compresses based on previous frames, though some frames aren't
relative, so you have to recompress the first few frames after your cut
or keep a few more than you asked for, unless you get lucky.

3) MPEG sometimes compresses based on future frames, so you may have to
recompress the frames immediately before the cut starts, or keep more
frames than you intended.

That being said, there are a number of tools that people have talked
about that will cut out chunks, but I don't think any perfectly deal
with the three issues.  Personally, I would love to have a solid
solution (even if it leaves a slight glitch at the cut) integrated with
Myth that works with PVR-x50 and ATSC recordings.

--PC



More information about the mythtv-users mailing list