[mythtv] Wrong time in Myth with PVR350 PAL output

[Torsten Schenkel]

Hallo,

there is some oddity with the pvr350's tv-out feature of mythtv.

When watching everything is fine, then I want to skip a commercial and
the video jumps back for some amount with the first skip forward. This
is with old and new versions of ivtv and mythtv, not a new problem.
Isaac says it's related to the pvr350's tv-out and yes, I didn't notice
it when using the vga.

ATM I have David Engel's patch running, and while this takes some pvr
problems outof the picture, this one still remains. David also said he
didn't see this.

So I understook some tests, and here are the results:

I watch about 50 minutes of recorded video (according to the osd), then
I escape out of the playback, saving the bookmark. When I reenter the
same show, it jumps to the bookmark (50:00 on OSD) but is not a the same
scene I was at. I then skip forward (it doesn't jump back immedeately
after a search) to the scene I left and it's 60mins on OSD.

So the whole thing seems to be a problem with the pvr giving back wrong
information about frames processed or mythtv doing wrong maths on the
information it gets from the pvr.

Summary: The OSD shows correct time when searching and myth doesn't skip
backwards directly after a search. The displayed time does lag behind
actual time by 1/6th. When doing a search it therefore skips back to the
location myth thinks it currently is.

The 1/6th is interesting, this hints towards a relation to PAL/NTSC
discrepancy. When myth (or the pvr) takes 30fps as standard, it will
count 1 second for every 30 frames, but will have displayed 1.2 seconds
of video. This amounts to the 50mins on the OSD while 60mins have been
watched. When I skip forward then it will search in the file to
50:30mins and starts the video there.

Might my assumptions be correct? Is this a PAL-only problem? Can it be
fixed?

Torsten