[mythtv-users] Digital Signal decoder

[Raymond Wagner]

On 3/9/2011 10:37, quecumber256 at comcast.net wrote:
> I assume the "other graphics" you are referring to are the several 
> second graphical ads that show up on the left hand side of the screen 
> that take up about a third of the screen. This is the noise I'm 
> referring too.

I'll see advertisements for upcoming shows or new pilots at the bottom 
of the screen, but as mentioned, they are cooked into the video, and not 
removable.  I've never seen anything as obtrusive as what you describe.  
Perhaps you could post a screen grab of what you're talking about?

> I may be taking too simplistic a view of the problem. I assume if it 
> is encoded into the data stream there must be some kind of tag to 
> indicate the beginning and end of the small video segment. If it is 
> inserted there must be a away of removing it.
>

Chances are it is compressed into the video itself, not as a separate 
data stream.  It is not overlayed on top of the original information, 
but rather it has displaced the original.  Assuming you could accurately 
analyze the video and find the offending chunks, removal of it would 
just result in a blank void, not the original video.  If instead it is 
something your cable company has instructed your cable box of 
displaying, MythTV would not even be capable of understanding it, much 
less displaying it.  There would be no need to do anything.

> With proper analysis one might be able to indicate the flags where a 
> commercial breaks start. If that can be detected one can instruct the 
> TIVO to stop recording the program and resume recording when the end 
> commercial tag is triggered.
>

MythTV already does commercial detection, but it is done after the 
fact.  The entire show is recorded, and then the predicted commercials 
are flagged, and automatically skipped by the software.  The analyzer 
can never be 100% accurate, and with disk space being as cheap as it is, 
it's simply not worth the 30% (1-2GB/hr) you would save by doing this in 
real time and discarding what could be false positives.