[mythtv] Experimental pvr 350 output patch

[David Engel]

FYI, if you have not tried this patch yet, now might be a good
time. All known issues have been addressed and the improved
functionality is, IMHO, well worth the effort.

On Tue, Dec 09, 2003 at 10:45:45PM -0600, David Engel wrote:
> Another day, another version.  The major changes in this version are
> as follows.

After many trials and tribulations with the ivtv driver and trying to
understand the idiosyncracies of the itvc15 decoder with very little
documentation, here is the latest version of my pvr350 patch.  The
major changes from the previous version (as best I remember) are as
follows.

Moved some funtionality from the video thread to the decoder thread to
avoid race conditions while pausing and unpausing.  The video thread
now exclusively controls the OSD aspects of the pvr350 and the decoder
thread exclusively controls the decoding aspects.

Finished seeking to exact frames with video update.  It's kind of
klugy because I have to single step the decoder to the desired frame.
As a result, exact seeks other than one frame forward will look a
little funny, but at least it works.  Since I still have concerns
about the flakiness of the decoder, debug output is still enabled for
this code.  As far as I can tell, the only way to improve on this way
of doing exact seeks is to do a more complete parsing of the mpeg2
stream and only feeding the decoder exactly what is needed.

Some driver issues could not be worked around from user space, so the
pvr350 patch now requires an ivtv driver patch.  The ivtv patch is
also attached.  It fixes output polling and adds support for
non-blocking output flushing queued data.  Once I get some feedback
from others on how well this works, I will address the issues with the
ivtv developers.

Again, if you have a pvr350 and haven't tried this yet, please
consider doing so.  It seems to work pretty well for me.

David
-- 
David Engel
dlengel at attbi.com
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