[mythtv-users] ffmpeg vs vdpau decode for h264

[Tom Dexter]

On 5/18/19, Paul Gardiner <lists at glidos.net> wrote:
>>> That is this file:
>>> https://drive.google.com/file/d/0BwxFVkl63-lEbVptTVZ2NENURHM/view?usp=sharing
>>>
>>> I'd be interested to see if others find the same behavior. Most
>>> importantly, I'd love to see if someone running 29.1 and using vdpau
>>> can play this in mythtv with vdpau decoding.
>
> Plays under 29.1 using vdpau for me. That's on an oldish ION-based ZBox.
> Strangely, although "Video" shows it to be 1920x1080p50, "FPS" shows
> 25.1. I have other p50 videos, albeit 720, that show "FPS" as 50 while
> playing.
>
> Cheers,
> 	Paul.

Very interesting...thanks for testing that! I just posted a link in
that bug to this, which is another better example that falls back to
software in mythtv:

http://jell.yfish.us/media/jellyfish-60-mbps-hd-h264.mkv

For me the videos like this that fall back to software are doing so
because of sequential errors on packets like this:

2019-05-16 11:21:01.481512 E [30407/30474] Decoder
avformatdecoder.cpp:3785 (ProcessVideoPacket) - AFD: video
avcodec_send_packet error: Invalid data found when processing input
(-1094995529) gotpicture:0

This is starting to look more and more like an ffmpeg bug of some sort
to me. I see that one major change in 30.0 was the removal of the
(apparently deprecated) ffmpeg avcodec_decode_video2 function in place
of two new calls. That of course means that mythtv is using a lot of
ffmpeg code that wasn't used in 29.1. Interesting.

Thanks again! If you get a chance to test the above video that'd be great.

Tom