[PATCH] Re: [mythtv-users] How well does commercial detection
Risto Treksler
risto at elkhornbanff.ca
Wed Apr 13 07:56:23 UTC 2005
On Tuesday 12 April 2005 10:41 pm, Chris Pinkham wrote:
> > So I am resending
>
> Got both of these actually.
>
sorry about the logjam
Thank you for commiting the patch
> >
> > 1) in strict mode - treat frames as blank only if logo is absent
>
> I get this part of the patch and see why it may reduce false positives
> where we detect show as commercial,
> but also see where it may cause
> missing of the first and last commercials in a commercial break if the
> network displays their commercial through all blank frames before and
> after the commercial break. Did you experience any of this after
> applying this change?
at least for me, the positives far outweigh the negatives
happened in two shows out of fifty that i have on the drive right now
but over all, even these shows detect better now than before.
a) far fewer false positives
b) it's consistent, and thus predictable
c) it's a minor problem
- it only misses a few seconds at the end of the comm block
for only a couple of shows
>
> > 2) more fixes for the "long long" issue
>
> Thought these were OK since they were in a sprintf not an arg(). Were
> these generating warnings somewhere?
Remember this ?
2005-04-11 14:31:23.171 d : 102549 (00:04:00.56) (58)
2005-04-11 14:31:23.171 d : 107739 (00:05:00.59) (51)
---------------------------------^--------------^-------------------
for some reason, if it was "long long" it would display a "d" and insert a "0"
into the argument list, causing a frame shift - making all debug output
useless
basically this makes debug output "work" for me
> > 3) fix for "white frames" triggering commercials
>
> So strict means black, non-strict means blank, correct?
more or less
-strict means "blank that is also reasonably dim"
-non-strict means "any blank"
> > 4) do not detect commercials less than 60 sec long, in the middle of a
> > show
>
> I had a question about this part, but after looking over the code 4-5
> times, I see what you're doing. Seems to make sense.
I tested this quite a bit
- b4 this patch i was getting tons of 1 second breaks
- so this fixes this bug (of not honoring the min_comm_break_length)
- but still allows for short commercials in the beginning of the show
> I've seen commercial longer than the 00:05:35, but I think I may have
> calculated wrong when I set the max to 485, that's 00:08:05 which is a bit
> too long. :) Did you try any values in between 335 and 485 or did you pick
I have seen a few that are longer than 00:05:35 as well
heck i saw an 11 minute break the other day
It's just been my experience that
if a block of 6 minutes or longer was marked,
then quite often some of the actual show was being cut off.
> These look OK, I committed the patch to CVS,
Thanks again
> and changed
> MAX_COMM_BREAK_LENGTH down to 395 for now. That's 00:06:35 so we can see
> how that goes. I don't want to take it much lower before 0.18.
maybe make strict be 335 and non-strict be 395?
I'll try to test with 395 to see if it's better or worse
i was thinking about making this also an undocumented setting in the
database:
maxCommBreakLength= gContext->GetNumSetting("MaxCommBreakLength",
MAX_COMM_BREAK_LENGTH);
ttyl
--
Risto Treksler
Elkhorn Lodge
Banff, Alberta, Canada
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