[mythtv-users] Anyone running MythTV 31 on 32-bit x86 with nVidia card?

John Pilkington johnpilk222 at gmail.com
Thu Feb 11 19:58:15 UTC 2021

On 11/02/2021 19:47, Tom Dexter wrote:
> On 2/11/21, Stephen Worthington <stephen_agent at jsw.gen.nz> wrote:
>> On Thu, 11 Feb 2021 09:49:59 -0500, you wrote:
>>> On 2/11/21, George Mari <george_mythusers at mari1938.org> wrote:
>>>> On 2/10/21 11:56 AM, Tom Dexter wrote:
>>>>> My trusty old frontend is a 32-bit x86 machine with a GT 430 nVidia
>>>>> card.
>>>>> Quite some time ago I upgraded to MythTV 30.0 but ended up reverting
>>>>> back to 29.1 because I had some issues with some (though not most)
>>>>> h264 videos. Specifically, some h264 videos would fail the VDPAU
>>>>> decode and fallback to software decoding. These were videos that used
>>>>> VDPAU with no issue in other players like xine, and also in MythTV
>>>>> 29.1. This was never resolved and was an issue that apparently
>>>>> couldn't be reproduced on 64 bit systems.
>>>>> My understanding is that the FFmpeg hardware acceleration code has
>>>>> been radically changed in version 31.
>>>>> As per the subject, if anyone is running MythTV 31 on 32-bit x86 and
>>>>> is using an nVidia GPU, it would help me enormously if they could test
>>>>> this example:
>>>>> http://jell.yfish.us/media/jellyfish-60-mbps-hd-h264.mkv
>>>>> ...and see if it uses VDPAU decoding, which can be determined during
>>>>> playback from the menu under Playback -> Playback Data.
>>>> I have a 64-bit Fedora installation with a GT 430 card - not exactly
>>>> what you are asking for, I know.
>>>> But for me, the video Playback Data shows h.264 ffmpeg
>>> Wow. So it's NOT using VDPAU, and that's with MythTV 31? That is
>>> really not good news at all. Do other h264 videos use VDPAU? That
>>> sounds like a significant bug to me. Even on my 32-bit system that
>>> video uses VDPAU without issues in xine, mpv, and in MythTV 29.1.
>>> When I was temporarily on 30.0 I posted comments about this on this
>>> (semi-related) bug, but at that time apparently nobody using 64-bit
>>> could duplicate this one:
>>> https://code.mythtv.org/trac/ticket/13223
>>> As noted there, the error that caused it to fallback to software
>>> decode was this:
>>> 2019-05-17 10:37:09.222935 E [14504/28060] Decoder
>>> avformatdecoder.cpp:3785 (ProcessVideoPacket?) - AFD: video
>>> avcodec_send_packet error: Invalid data found when processing input
>>> (-1094995529) gotpicture:0
>>> I'm hesitant to update, though I'm going to have to soon, as (for a
>>> number of reasons) I can no longer compile MythTV 29.1 on my Gentoo
>>> system. What's worse is that, since I'm running 29.1 I can't very well
>>> log a bug or test any of this.
>>> I'd be interested to see what others find testing this...with 32 or 64
>>> bit. Thanks for the reply! That's significant for sure.
>>> Tom
>> That file is encoded using the H.264 High at L5 profile.  I am not sure
>> if a GT430 can play that profile, so that may be why it is dropping
>> back to using ffmpeg.  You only need High at L4.1 for playing BluRay, so
>> a lot of earlier Nvidia cards did not support higher than that, IIRC.
>> In v31 (using the new rendering code), when I play that file using
>> mythavtest on my GT1030, it plays using VDPAU.
> Again though, that can't possibly be the issue because it can use
> VDPAU on that same system and GT430 in MythTV 29.1, xine, and mpv.
> Clearly has to be a software issue and not the card.
> Tom

But you may well have to tell it to use VDPAU or NVDEC in your playback 
options in the frontend.  Frontend setup > Video > Playback, iirc

John P

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