[mythtv-users] Patches that improve mythcommflag accuracy

Mon Nov 24 05:16:23 UTC 2014

Hoi faginbagin,

Monday, November 24, 2014, 5:41:57 AM, you wrote:

> Hoi Hika,

> On 11/23/2014 6:28 PM, Hika van den Hoven wrote:
>> Hoi Doug,
>> 
>> Sunday, November 23, 2014, 11:29:25 PM, you wrote:
>> 
>>> faginbagin wrote:
>>>> Commercial flagging is a tricky business. It's relatively easy to tune it for a specific recording, but quite often what you do for one recording, seriously screws up the accuracy for another recording
>> 
>>> Too bad commercial flagging couldn't 'learn' from the end users.  For
>>> the initial training, it would identify the show/series/what have you
>>> and; we could go in and do corrections (training).
>> 
>>> Sort of like bayesian training for SPAM filters.
>> 
>>> Doug
>> 
>> I now have the patches for almost three weeks in place. Testing took
>> some time for most I watch is commercial free. It looks like it gets
>> all breaks, but all to short. So far I haven't noticed false catches.
>> Most breaks are 7 to 8 minutes long and it catches only just over 6
>> minutes. Since I have the skip set to manual I first thought that
>> somehow the max length was set to short, but on checking it is as I
>> thought set to 600 or 10 minutes. Skipping again doesn't work or skips
>> to the next break.

> There is a setting, CommDetectMaxCommBreakLength, that defaults to
> 395 seconds. It's possible that increasing it to 600 might help your
> situation. You would have to insert a record in the
> mythconverg.settings table to override the default.
Isn't that on page 8 in Configuration > Video > Playback "Max
commercial Skip" in the MythCentre-Wide theme?
Because that I have set to 600
Or do I have to go to the database?
I anyhow will set it to automatically skip since detection, except for
length, is now so accurate.

>> I don't know about the mechanisms involved, but most breaks start and
>> end with the show sponsor clip, so I would think that would make it
>> easier. Maybe this to short catching has to do with my problems with
>> the seektables as mentioned further on, but I always rebuild them
>> before checking.

> In older versions of mythtv, I had noticed the seek table for some
> recordings would be missing entries for the last several seconds,
> sometimes minutes. I haven't been aware of that issue in 0.27, but
> maybe it's still an issue with low bit rate recordings? I'll try to find time to look into that.

>> My settings are to use all methodes and no experimental speed-up or
>> strickt checking. I record SD with two PVR500's on a dedicated backend
>> with a AMD64 dualcore and 4Gb memory.

> Please enable the strict checking option and then compare results.
> I have found accuracy is much better with it set, both without and with my patches.
I will do.

>> I's difficult to compare with the past for I have trouble since
>> upgrading from 0.26 to 0.27 with my seektables (they make the show
>> much to short) and I had an error in my script to first rebuild before
>> comm checking. I only fixed it when I compiled with the fixes. So the
>> last half year I skipped by hand ( I have right set to skip forward 1
>> min. and left to skip back 10 sec. Very handy). In 0.26 I had regular
>> falses and misses and also had sometimes (after I set it to manual
>> skip) to skip twice. But that could be before I lengthened the max
>> skip. But also often the full length.
>> I live in the Netherlands so all shows are from the dutch commercial
>> channels. If you want I can get you some sample recordings. Just say
>> how to get them to you.

> I appreciate the offer, but it's a time consuming and messy
> business to download other people's recordings and then insert
> reasonable records for those recordings in the database. So I would
> first prefer help in the form of feedback from people testing on
> their own systems. But if you are sure your results are consistently
> worse for most recordings with the patches than without them, then
> it might be worth the hassle to get a representative sample recording.

I'm simply responding to your earlier talk about building a test
database. But it's simply up to you all. I guess there are not many
people flying around from our little piece of earth.

> Thanks,
> Helen

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Tot mails,
  Hika                            mailto:hikavdh at gmail.com

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