[mythtv-users] FireTV 4K vs. Shield TV for mythtv frontend and Leanfront

George Seymour gmixbsn at yahoo.com
Fri Sep 18 10:05:01 UTC 2020


     On Thursday, September 17, 2020, 04:44:27 PM EDT, James Abernathy <jfabernathy at gmail.com> wrote:  

On Wed, Sep 16, 2020 at 1:37 PM David Engel <david at istwok.net> wrote:

On Wed, Sep 16, 2020 at 12:08:37PM -0400, Jim Abernathy wrote:
> On 9/16/20 9:46 AM, Peter Bennett wrote:
> > 
> > A big gripe I have with the shield is that it still has the MPEG2 bug
> > that has been around in nvidia devices for years. If you use hardware
> > (mediacodec) decoding on certain broadcast channels, there is frequent
> > pixellation, which nvidia have acknowledged is due to "longer than
> > expected motion vectors". This occurs on some channels that are sharing
> > frequencies. They have a highly optimized mpeg stream and manage to fit
> > good quality into a low bitrate.
> > 
> > Peter
> Forgot to ask, does the MPEG2 bug not exist on FireTV 4K or FireTV Cube? 
> FireTV products seem to have more compatibility with streaming services so
> I'm thinking about retiring the Nvidia Shield TV (2017 model) and moving to
> the Cube.

No, it's an Nvidia-only bug, reportedly in the hardware so it can't be
fixed.  If it bothers you that much, just create a hybrid, palyback
profile that does mpeg2 decoding in software and the rest with
mediacodec.  That's what I do.  The only thing you lose is Nvidia's
deinterlacing for mpeg2 which, in reality, isn't that much better than
what MythTV can do in OpenGL.  Also, if youc care about time
stretching, you can pretty much forget about the FireTV devices.  They
aren't powerful enough.

If you still want to get rid of your 2017 Shield, I'll take it off
your hands.  I know some people who would put it to good use.

David Engel
david at istwok.net

I had some time today to work on the Shield playback profile.  Turns out my default was for MPEG2 to use Standard software, 4 cpu for decode and deinterlace. I deleted that one and put in one that just had Mediacodec hardware decode and deinterlace.  Both look flawless to me on HD ATSC MPEG2 720p and 1080i programs.
I'll see if any of the side channels, low-resolution  content have problems, but I'll keep an eye out. At least I know that the OpenGL software only is just as good as the mediacodec hardware. I need to test H.264 as I use that on some content but not broadcast.

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