[mythtv] commdetector2

Daniel Walton dwalton at cisco.com
Fri Aug 18 14:40:27 UTC 2006


I tried out the new commercial flagging code last night (svn 10820).  The first
time I ran mythcommflag I saw a "convert: command not found" error in the log
but the commercial flagger kept going.  I installed imagemagick in order to get
'convert'.  No biggie but it might be worth mentioning in the install docs that
you need imagemagick now.

I tested the flagger on a 60 minute episode of Mythbusters recorded on a
PVR-150.  I recorded at 720x480, bitrate 6000, max bitrate 8000.

- The "Discovery Channel" logo appears in the bottom right hand corner about 5
seconds after the commercial break and disappears about 5 seconds before a
commercial break.  The logo looks like the following except the "Discovery"
letters are gray instead of black and the globe is always spinning in the logo
on tv.

http://www.tvimedia.com/Gif/discoveryChannel_logo.jpg

This is the tf-edgecounts.jpg file generated by the flagger.  You have to zoom
way in but you can see a very rough outline of the logo

http://www.pbase.com/alli/image/65342426/original

- When the show fades in and out of a commercial break there are 10 to 15 blank
frames

- The new commercial flagger found 11 commercial segments but in reality there
were 5 commercial breaks

2006-08-18 00:17:09.495 TemplateMatcher::finished(107865)
2006-08-18 00:17:09.502 TM Break:      1-   161 (0:00:00-0:00:05, 0:00:05)
2006-08-18 00:17:09.507 TM Break:  16732- 17957 (0:09:18-0:09:59, 0:00:41)
2006-08-18 00:17:09.511 TM Break:  19511- 20307 (0:10:51-0:11:18, 0:00:27)
2006-08-18 00:17:09.515 TM Break:  38368- 39343 (0:21:20-0:21:53, 0:00:33)
2006-08-18 00:17:09.519 TM Break:  39398- 41651 (0:21:55-0:23:10, 0:01:15)
2006-08-18 00:17:09.523 TM Break:  54257- 56028 (0:30:10-0:31:09, 0:00:59)
2006-08-18 00:17:09.527 TM Break:  58095- 59468 (0:32:18-0:33:04, 0:00:46)
2006-08-18 00:17:09.531 TM Break:  71139- 71907 (0:39:34-0:39:59, 0:00:26)
2006-08-18 00:17:09.535 TM Break:  92895- 94311 (0:51:40-0:52:27, 0:00:47)
2006-08-18 00:17:09.539 TM Break:  94343- 98648 (0:52:28-0:54:52, 0:02:24)
2006-08-18 00:17:09.543 TM Break:  98650- 99995 (0:54:52-0:55:37, 0:00:45)
2006-08-18 00:17:09.547 TM Break: 107556-107865 (0:59:49-0:59:59, 0:00:10)
2006-08-18 00:17:09.551 NVP Time: GetRawVideoFrame=973.440878s
2006-08-18 00:17:09.555 PGM Time: convert=351.619730s
2006-08-18 00:17:09.559 BD Time: analyze=60.844311s
2006-08-18 00:17:09.563 HA Time: analyze=105.644530s
2006-08-18 00:17:09.567 TM Time: analyze=417.611191s
2006-08-18 00:17:09.571 TemplateMatcher has 15% breaks (wanted 20-44%)
2006-08-18 00:17:09.575 BlankFrameDetector adjusting for logo surplus
2006-08-18 00:17:09.755 BF coalescing overlapping/nearby breaks ...
2006-08-18 00:17:09.804 Break: frame      1-   161 (0:00:00-0:00:05, 0:00:05)
2006-08-18 00:17:09.811 Break: frame  16732- 17957 (0:09:18-0:09:59, 0:00:41)
2006-08-18 00:17:09.815 Break: frame  19511- 20307 (0:10:51-0:11:18, 0:00:27)
2006-08-18 00:17:09.819 Break: frame  38368- 39343 (0:21:20-0:21:53, 0:00:33)
2006-08-18 00:17:09.823 Break: frame  39398- 42385 (0:21:55-0:23:34, 0:01:40)
2006-08-18 00:17:09.827 Break: frame  54257- 56028 (0:30:10-0:31:09, 0:00:59)
2006-08-18 00:17:09.831 Break: frame  57452- 59468 (0:31:57-0:33:04, 0:01:07)
2006-08-18 00:17:09.835 Break: frame  71139- 71907 (0:39:34-0:39:59, 0:00:26)
2006-08-18 00:17:09.839 Break: frame  73598- 74355 (0:40:56-0:41:21, 0:00:25)
2006-08-18 00:17:09.843 Break: frame  92895- 94311 (0:51:40-0:52:27, 0:00:47)
2006-08-18 00:17:09.847 Break: frame  94343-100128 (0:52:28-0:55:41, 0:03:13)
2006-08-18 00:17:09.851 Flagged 107864 of 107865 frames (0:59:59 of 0:59:59), 17% commercials (0:10:23)

Actual commercial segments (by hand)
------------------------------------
0:00:00-0:00:14		14sec
0:08:09-0:11:45		3min 36sec
0:21:08-0:23:43		2min 35sec
0:29:36-0:32:58		3min 22sec
0:38:50-0:41:20		2min 30sec
0:51:10-0:55:40		4min 30sec
                  Total 16min 47sec

The BlankFrameDetector results are a little puzzling to me.  I looked at the
video and there wasn't a blank frame at all at 0:00:05 (incorrectly flagged as
blank) but there was an obvious blank frame at 0:00:14 (not flagged).

I need to flag this same show with the old commflagg engine to see how it
compares but I would say that the new engine didn't seem to flag as well.  It
seemed to find too many mini breaks within the commercial.  When I watched the
show and told it to jump to the next break I had to click to the right on my
remote multiple times to make it through one commercial.  I understand that this
is a work in progress though and I appreciate all of the development that has
gone into this new engine :)

I have the backend log, HistogramAnalyzer-pgm.txt, etc that I can zip and email
to anyone interested.

Thanks
Daniel



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