[mythtv-users] New Custom Record

Bruce Markey bjm at lvcm.com
Sun Dec 12 23:01:13 UTC 2004

Brad Templeton wrote:
> On Sun, Dec 12, 2004 at 11:57:25AM -0800, Bruce Markey wrote:
>>this is a bug (read over sight on my part) for this type of show
>>regardless of the record rule. The duplicate detection sees these
>>DD listings as unidentified episodes of a series so it wants to
>>record all of them. However, they are actually each individual
> In other areas, I have suggested the following duplication detection
> approach for programs that do not have detailed listing data (like The
> Daily Show and many others.)
> a) If the show has closed captioning, extract and record it in the database.
> (Try to record for the show only, not for commercials.)


> Then, when you start recording a new show that you are not sure is a duplicate,
> examine the captions.  If you get a large number of identical captions
> for several minutes (ie. not commercials nor any voice-over on the standard
> intro) you have a duplicate -- give up recording or delete it.

This implies that there would need to be a transcript file written
as it records. This may be a Good Thing anyway as the text files
would be minuscule compared to the video file and would only need
to write out the VBI text as it comes along. I remember seeing a
feature like this with ATI's Windows software and at one time I had
been writing out the captions to the console during playback for my
own purposes but never really considered making this a feature.

> b) With no closed captioning, instead record the time gap between scene
> transitions.  In mpeg a scene transition will generate various clues such
> as a complete new frame.   Don't know if you could do it in mjpeg.
> The sequence of time gaps between scene transitions will be precise and
> unique to every program out there, changing only due to the placement of
> commercials -- or the much-later re-editing of shows and movies to fit
> shorter timeslots.   Also, time compression done by some stations would add
> a small amount of slop.   But none of these things would stop you from
> detecting that the same program has been shown twice in the same day or week.

Sounds feasible but might need some gnarly fuzzy logic.

> Of course, these methods would not free up a tuner for you to record other
> shows, they would primarily let you save disk space and clean up your show

I wonder if at the point that the tuner was used (and possibly
forced out a lower priority conflict) that it wouldn't make
just as much sense to keep it and let the user decide if it
looks familiar. For this to work all the transcripts and/or
scene transition data for every previously recorded show would
need to be kept. For this to short circuit a duplicate in progress,
it would run part way through or periodically during each recording.
That may be more burden on the system resources but may not be
too big of a deal.

> list.  You could finally say "Record the Daily Show" and get it just once
> a day.

The Daily Show has always been a good example for the "generic"
episode problem. They always used to only list the generic "A
humorous slant on top news stories." with the generic programid.
Ever since John Edwards announced his candidacy, or was it when
Bill Clinton was a guest, they've been pretty good about always
having descriptions for new episodes but still use the generic
description when they show re-runs or if the guest hasn't been
determined yet.

As it stands now, myth's "Record new episodes only" generally
sees generic episodes as out of date and marks then as repeats.
Whether they should be assumed to be old or unknown and therefore
possibly new is debatable. However, recording new episodes for
TDS generally works except they sometimes don't have the guest
list for the week in by Monday and so Monday's show may still
be generic even though it is a new show.

Another approach to TDS, Tech TV's "The Screen Savers" or other
shows that have a regularly scheduled time, repeats throughout
the day and no descriptions would be to have something like a
daily FindOne. In other words, say I set TDS once a day at 11pm.
If it couldn't record at 11 then try 1am then 10am so that it
would record once per 24 hour period. The same would be useful
for weekly shows. Record "Discoveries This Week" (never a desc.)
once from Fri at 5pm until the next Fri at 5pm. Same for "Best
week Ever", "Topic A With Tina Brown" or any other such show for
current events where the description isn't available ahead of time.

--  bjm

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