[mythtv] 2019-devel: lipsync drift

John Pilkington johnpilk222 at gmail.com
Sat Nov 23 12:31:58 UTC 2019


On 18/11/2019 11:58, Mark Kendall wrote:
> On Mon, 18 Nov 2019 at 11:47, John Pilkington <johnpilk222 at gmail.com> wrote:
>> I'm still getting loss of a/v sync in my el7 box, more noticeable in
>> some recordings than others, but the fedora 30 system built at the same
>> commit has not yet done the same, using either NVdec or ffmpeg decoding.
> 
> I'm assuming el7 is enterprise linux 7?
> 
> What decoder/playback settings is that box using?
> 
> Thanks, Mark

My original reply to this revealed many opportunities for system 
misalignments that might be causing this drift, and I won't repeat them.

But here are lines from frontend startup and closedown that look as if 
they are system specific and could perhaps underlie a slow drift if all 
the digits are significant and the usage isn't quite right.

{{{

2019-11-23 11:35:57.867339 I  DispResX: Created
2019-11-23 11:35:57.867956 N  DispRes: Desktop video mode: 1440x900 
74.984 Hz

2019-11-23 11:49:27.987070 I  DispRes: Changing to 1440x900 75.000 Hz
2019-11-23 11:49:28.013150 I  DispRes: SwitchToGUI: Switched to 1440x900 
75.000 Hz

}}}

xrandr offers 59.89 +  74.98* at that (full) resolution of the only 
attached screen; I'm using a 1024x576 window

The Std.Devs shown here look (unfeasibly?) large, and sync was very bad 
while getting them.  The CPUs look busy.  BBC Four SD.  Playback is fine 
apart from the sync issue, and via DLNA on the TV it's excellent.

{{{
2019-11-23 12:11:19.873565 I  Player(0): FPS:   25.88 Mean: 38642 
Std.Dev: 28904 CPUs: 101% 101%
2019-11-23 12:11:20.890110 I  Player(0): FPS:   24.60 Mean: 40647 
Std.Dev: 25888 CPUs: 98% 97%
2019-11-23 12:11:21.903609 I  Player(0): FPS:   24.67 Mean: 40528 
Std.Dev: 26322 CPUs: 104% 97%
2019-11-23 12:11:22.894285 I  Player(0): FPS:   25.24 Mean: 39615 
Std.Dev: 25965 CPUs: 103% 102%

}}}

Cheers,

John


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