[mythtv] Automatic frame-rate switching on Fire TV

John Pilkington johnpilk222 at gmail.com
Sat Nov 16 23:51:43 UTC 2019

On 16/11/2019 15:33, John Pilkington wrote:
> On 16/11/2019 14:44, Paul Gardiner wrote:
>> One thing I've always loved about MythTV on my nvidia ION based 
>> frontend and hated about using Netflix and Amazon Prime on my Fire TV 
>> is automatic frame rate matching (well that on my frontend, and the 
>> lack of it on Fire TV). However, I've recently read this: 
>> http://www.aftvnews.com/explanation-of-the-new-frame-rate-matching-feature-on-the-amazon-fire-tv/ 
>> and realised that I may be seeing the problem partly because my Fire 
>> TV box is very old. Can anyone tell me if the Mythfrontend app 
>> supports this when running on modern Fire TV sticks?
>> (I've lied a little: actually my nvidia ION based frontend has 
>> recently lost this feature. I'd also love to know how to correct that.)
>> Cheers,
>>      Paul.
> My FireTVstick 4k says it has the framerate adjustment enabled, but 
> using the 31Pre539 build I don't see the 'Separate video modes for GUI 
> and TV playback' option that is offered in the 31Pre1232 2019-render 
> branch.  It just says 'Use GUI size for TV playback'
> I haven't looked at the log with this question in mind.  Playing a 
> BBCFour HD recording with 6-channel sound and ffmpeg decoding, the 
> displayed A/V Sync value flickers around, usually in the +/- 20 ms 
> range.  The 4 CPUs are often at around 90%, and stuttering can occur.

I found the 'System X-Ray' display:  1080P 59.93, IIRC

MythTV OSD shows Video 1920x1089 at 25.00fps,  FPS reported around 25 but 
seems to be varying over a wider range now than when I started writing 
this, when it was usually between 24.9 and 25.1 +/- 0.1

The CPU overload stutter is the main problem here.  It's probably worse 
with an active playback data display.  DLNA still gives me the best 
linear playback experience, with less wobble in slow panning shots, then 
nVidia, then the Firestick stutter.  But see below:

> FWIW, the leanfront build won't play that recording at all, but I looked 
> at BBCOne HD's 'Earth from space' recordings last night and playback was 
> excellent.  Some h264 content plays, some not...
> John

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