[mythtv] Ticket #13334: Improved Video timing and Synchronization

John Pilkington johnpilk222 at gmail.com
Tue Oct 30 16:17:08 UTC 2018


On 30/10/18 14:16, Peter Bennett wrote:
> 
> 
> On 10/30/18 7:39 AM, MythTV wrote:
>> #13334: Improved Video timing and Synchronization
>> -------------------------------------+-------------------------------
>>   Reporter:  Peter Bennett            |          Owner:  Peter Bennett
>>       Type:  Patch - Feature          |         Status:  assigned
>>   Priority:  minor                    |      Milestone:  30.0
>> Component:  MythTV - Video Playback  |        Version:  Master Head
>>   Severity:  medium                   |     Resolution:
>>   Keywords:                           |  Ticket locked:  0
>> -------------------------------------+-------------------------------
>>
>> Comment (by jpilk):
>>
>>   Some of my comments above probably applied to earlier builds.  I don't
>>   usually run with -v playback.
>>
>>   Playback restart after a step within the editor has a larger 
>> negative AV
>>   Sync offset, sometimes more than 1 sec, when not using vdpau.  
>> Lipsync is
>>   clearly bad initially but is quickly recovered.
>>
> John
> 
> See comment 2 in the ticket. You can adjust this to be quicker but at 
> the possible expense of more jitter in playback. Play around with the 
> "AVsync2 audio correction" and see what setting works best for you.
> 
> Peter
>

Yes, thanks, I saw that.  TBH I'm not much concerned about playback 
quality within the editor; I just want to get the correct byte-offset 
when using the cutlist that I create, and the bad initial sync looked as 
if it might perhaps break that.  It doesn't seem to.

Editing DVB radio, with 1 sec steps or, with some hoop-jumping, 320 ms 
steps, now seems to place the first attempted editpoints further from 
where I intended than it used to, but once they sound right the output 
is ok too.

The 1-frame-backward-step-jitter in the editor seems to apply to vdpau 
(f28 box) but not to software decoding (el7).

John







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