[mythtv] Ticket #4872: Detect if video is letterboxed and switch to corect fill mode

[Mårten Bohlin]

On Tue, Mar 18, 2008 at 8:53 PM, Kevin Kuphal <kkuphal at gmail.com> wrote:
>
>
> On Tue, Mar 18, 2008 at 5:45 AM, Mårten Bohlin <mabo at mochc.net> wrote:
>
> >
> >
> >
> > On Tue, Mar 18, 2008 at 3:20 AM, Kevin Kuphal <kkuphal at gmail.com> wrote:
> > >
> > >
> > > On Mon, Mar 17, 2008 at 7:21 AM, Mårten Bohlin <mabo at mochc.net> wrote:
> > >
> > > >
> > > > On Wed, Mar 5, 2008 at 8:42 PM, MythTV <mythtv at cvs.mythtv.org> wrote:
> > > > > #4872: Detect if video is letterboxed and switch to corect fill mode
> > > > >
> > >
> -------------------------------------+--------------------------------------
> > > > >   Reporter:  Mårten <mabo at mochc.net>  |       Owner:  ijr
> > > > >      Type:  enhancement              |      Status:  new
> > > > >   Priority:  minor                    |   Milestone:  unknown
> > > > >  Component:  mythtv                   |     Version:  0.21-fixes
> > > > >   Severity:  medium                   |     Mlocked:  0
> > > > >
> > >
> -------------------------------------+--------------------------------------
> > > >
> > > > Some comments about the new version of the patch (version 6).
> > > >
> > > > I now do the detection on the pre-buffered frames. And this give me
> > > > two advantages:
> > > >  * Switches that are very shorter than the amount of pre-buffered
> > > > frames are removed. This makes it smoother to watch. On my setup there
> > > > seems to be about one second of pre-buffered frames.
> > > >
> > > >  * The switch can be done almost at the exact frame where the switch
> > > > is detected. This also makes it look much better.
> > > >
> > > > The cons is that I have to write multi-threaded code. Something that I
> > > > have not done i C before. I do not know how expensive locking a QMutex
> > > > is considered to be. So I have tried to keep that to a minimum.
> > > >
> > > > So please try it out and let me know if it works.
> > >
> > >
> > > Marten,
> > >
> > > I tried this out on my SVN release (patches applied OK) but all I get in
> the
> > > logs is "Detect letterbox failed, source is not YUV12" or something
> similar
> > > to that and it doesn't detect anything.  My recordings are HD recordings
> > > from an AverMedia A180 played back with XvMC decoding using Nvidia
> drivers
> > > on an FX5200
> > >
> > > Kevin
> >
> > Silly of me to not log what it was instead of YV12. Could you try to
> > update the line 2669 of libs/libmythtv/NuppelVideoPlayer.cpp to:
> >
> >        VERBOSE(VB_PLAYBACK, QString("Detect Letterbox: The source is
> > not in YV12 (was %1)").arg(frame->codec));
> >
> > And tell me which codec that is actually used?
>
>
> It read:
>
> 2008-03-18 14:51:26.692 Detect Letterbox: The source is not in YV12 (was 2)
>
> I figure you know what "2" means :)
>
> Kevin

Yes "2" means "XVMC_IDCT_MPEG2". Unfortunately I do not know how all
that stuff works.

Could anybody tell me if it is possible to analyze a decoded frame
when you run XvMC? And if that is possible where should I look for the
decoded frame?

Mårten