[mythtv] Bug? HD-3000 DVB driver timestamps
John Patrick Poet
john at BlueSkyTours.com
Tue Apr 19 15:43:41 UTC 2005
On Tue, 19 Apr 2005, William Uther wrote:
> On Mon, 18 Apr 2005 23:16:30 -0600, John Patrick Poet
> <john at BlueSkyTours.com> wrote:
> > I switching from the V4L2 HD-3000 drivers to the DVB HD-3000 drivers on
> > Wednesday, 13 Apr 05. While they seem to work fine, commercial
> > flagging
> > suddenly seemed broken.
> > To give you an example of what I am talking about, here is a list of
> > detected comercial markers compared to the actual position:
> > detected actual difference
> > 0:07:51.09 -- 0:08:20.09 0:29
> > 0:17:21.22 -- 0:18:25.22 1:04
> > 0:20:26.16 -- 0:21:42.16 1:16
> > 0:30:38.29 -- 0:32:32.29 1:54
> > 0:33:55.23 -- 0:36:01.23 2:06
> > 0:45:33.24 -- 0:48:03.24 2:30
> > 0:49:25.05 -- 0:52:27.05 3:02
> > 0:58:41.01 -- 1:02:01.01 3:20
> > It kinda looks to me like the commercial flagger is using the "real"
> > keyframe positions, but the seektable is off, so when played the wrong
> > part of the show is skipped.
> > Any ideas why the seektable slowly gets more and more off with the DVB
> > driver?
> This may be related to the recent fix for this:
> discussed here:
> Assuming I'm reading your 'actual' vs 'detected' the right way around,
> then if the system was detecting bogus picture start codes in
> DTVRecorder::FindKeyframes() then you'd see what you're seeing.
> There are a few ways to start debugging it:
> If you have a look at FindKeyframes() in libs/libmythtv/dtvrecorder.cpp
> you'll see a debug define:
> #define DEBUG_FIND_KEY_FRAMES 0 /* set to 1 to debug */
> Turn on that define and get a backend log as you record something.
> Apply the patch attached to the bug report above in reverse (patch
> --reverse) to current CVS. See if the problem with DVB recording goes
> Try re-building the seek table with `mythcommflag --rebuild`. While
> debugging bug #221, I found that mythcommflag did not fix the seek
> table correctly. I haven't looked into why yet.
> Be well,
> Will :-}
Since I actually want my machine to record shows, it will have to be some
weekend before I can debug this, and my weekends have been full.
Thanks for the info. I will try this as soon as I can.
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