[mythtv-users] How to drop content between flagged commercials from video files?

Brian Wood beww at beww.org
Sun Sep 19 16:17:35 UTC 2010


On Sunday, September 19, 2010 09:51:08 am Raymond Wagner wrote:
>   On 9/19/2010 11:44, Dave Richardson wrote:
> > If a recorded program is comm-flagged correctly, is there another
> > job/option that would be able to "shrink" the media file itself by
> > dropping the content between the flags (leaving just the "show")?
> > 
> > I want to be able to save some NFL broadcasts from this season.  At 3+
> > hrs of HD content per game, those are large files.  It would be REALLY
> > nice to save ~30% of the disk space per game by physically discarding
> > the commercials from the video files.
> 
> See the following page on the wiki:
> 
> http://mythtv.org/wiki/Removing_Commercials
> 
> You want to go into 'edit' mode while watching the recording, load, and
> confirm or revise the automatic commercial detection.  Go into one of
> the transcoding profiles, and check off 'Lossless transcoding'.  Then
> use that profile to transcode the job.

If commercial detection has worked perfectly, it's a simple click-click process. Of course the problem is when detection 
has not worked perfectly, in which case you'll have to manually adjust the cutpoints.

I have found that how well detection works is very much dependent on the source or network, some are very predictable, 
always coming back from a break with the "CC" or the rating logo for example, while others are not as consistent, leading 
to unpredictable results.

Unfortunately, sporting events are among the "hard to predict" cases, primarily due to the live nature of the programming, 
and the inability to correct errors after the fact.

Networks like the History Channel, Discovery and the like tend to be more predictable and have generally good commflag 
results.

This applies to the US, users in other countries have generally reported poorer results than us Yanks. Civilized 
countries, without frequent short breaks, are of course a different matter. (of course "short" is approaching 4 minutes in 
some cases).

So be very careful, especially with live events that might not be easily re-recorded. You might want to make a backup copy 
of the unadulterated recording before any editing.



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