[mythtv] Mediacodec problem with avcodec_flush_buffers

Aman Gupta aman at tmm1.net
Tue Jul 31 16:06:01 UTC 2018


On Mon, Jul 30, 2018 at 8:05 PM David Engel <david at istwok.net> wrote:

> On Mon, Jul 30, 2018 at 09:57:40PM -0500, David Engel wrote:
> > On Mon, Jul 30, 2018 at 01:26:24PM -0700, Aman Gupta wrote:
> > > On Mon, Jul 30, 2018 at 1:22 PM David Engel <david at istwok.net> wrote:
> > >
> > > > On Mon, Jul 30, 2018 at 12:59:17PM -0400, Peter Bennett wrote:
> > > > > On 07/29/2018 11:12 PM, David Engel wrote:
> > > > > > On Sun, Jul 29, 2018 at 08:55:20PM -0500, David Engel wrote:
> > > > > > > On Fri, Jul 27, 2018 at 12:35:25PM -0400, Peter Bennett wrote:
> > > > > > > > On 07/27/2018 10:37 AM, David Engel wrote:
> > > > > > > > > On Fri, Jul 27, 2018 at 08:09:36AM -0400, Peter Bennett
> wrote:
> > > > > > > > > > I think it is only with deinterlace. It may also happen
> with
> > > > h264 interlaced
> > > > > > > > > > content. I do not have much h264 interlaced content to
> test
> > > > with.
> > > > > > > > > I have at least one, 1080i, h264 channel.  I can check it
> > > > tonight.
> > > > > > > > >
> > > > > > > > > David
> > > > > > > > I have one 2-minute h264 interlaced 1080 file. I tested with
> that
> > > > and I do
> > > > > > > > not see the corrupted frame there when skipping.
> > > > > > > > Attached is a patch to undo the non-functional workaround
> for the
> > > > corrupted
> > > > > > > > frame in case you want to try it.
> > > > > > > This is now commit 4287f45f, right?  I just now got a chance
> to try
> > > > it
> > > > > > > and also look into another bug I found.  Do you still want
> feedback
> > > > on
> > > > > > > it?
> > > > > > Okay, I have some feedback.  Maybe, just maybe, this might help
> with a
> > > > > > fix.
> > > > > >
> > > > > > The previous behavior I saw was this.  The corruption was very
> > > > > > prevalent in ff/rew.  It was not very prevalent at all when
> skipping
> > > > > > forward and backward.
> > > > > >
> > > > > > The new behavior I now see is this.  I never saw any corruption
> even
> > > > > > once in ff/rew of a 1-hour and a half-hour show.  The corruption
> is
> > > > > > very prevalent now in skipping forward and backward.
> > > > > >
> > > > > > In other words, ff/rew was bad before and is now good and
> skipping was
> > > > > > good before and is now bad.  Do ff/rew and normal playback still
> have
> > > > > > separate GetFrame() calls?  If so, maybe what is being done now
> for
> > > > > > one ff/rew frame can be done for skips too and fix the problem.
> > > > > >
> > > > > > David
> > > > > Hi David
> > > > >
> > > > > This was expected. I reverted to the original behavior by taking
> out my
> > > > > patch, which did not fix the issue and likely made it worse. Aman
> has
> > > > > acknowledged the bug and passed it on to NVidia so maybe we can
> get a
> > > > patch
> > > > > from them in due course.
> > > >
> > > > Aman, do you have a good connection at Nvidia?  My local ABC station
> > > > seems to have again started sending streams that show corruption when
> > > > decoded with MediaCodec (and VDPAU, for that matter), but not when
> > > > decoded with ffmpeg software.  I have a short sample that I can
> > > > provide.
> > > >
> > >
> > > Yes I can forward the bug report and sample if you email them to me.
> Please
> > > test the sample with the latest Exoplayer and make sure it reproduces
> there
> > > so they can investigate easily.
> >
> > I've confirmed the problem show with Exoplayer r2.8.2.  I can try with
> > the latest, unreleased version from git if need be.  I'll send you
> > them sample directly.  It's only 16 MB so should be okay by email.  If
> > you don't get it in the next 10 minutes or so, let me know and I'll
> > put on Google Drive and send you a link.
>

Got it and reported upstream.


>
> There is something else I just noticed using the sample and Exoplayer.
> After the sample starts playing, bring up the OSD and keep pressing
> the |< (go back to the beginnig) button every second or so.  The
> corrupted, 1080i, mpeg2 issue we've been discussing happens almost
> every time.  Please pass that on the Nvidia as well.  Thanks for your
> help.
>

That's precisely how I told them to reproduce when I reported the bug last
week :)

Aman


>
> David
> --
> David Engel
> david at istwok.net
>
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