Mailing List Archive

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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On 11/6/18 10:04 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):
>
> DVB Radio: I placed editpoints using the non-AVSync2 setting. They
> worked, as expected.
>
> With AVSync2, playback in EditMode from those points (with cutlist
> inverted when appropriate) starts immediately, but from a position several
> seconds later ( ~15 to ~30 s).
>
> The time-and-frame display at the editpoint shows the values as intended.
> After start and immediate stop the values shown are updated to those for
> the sound being played.
>
> For these recordings the seektable shows a frame duration of 40 ms and
> keyframes separated by 8 frames. TTBOMK mythcommflag --rebuild will not
> work with a copied file. I suppose the timecodes in use here are embedded
> in the data.
>
> Non-AVSync2 skipping is unreliable for skip durations of 1 frame, 1
> keyframe and 0.5 s, but otherwise it works.
>
> I don't understand the magic numbers (133466 etc) in
> MythPlayer::UpdateFFRewSkip(void)
>
John

Thanks for looking at this. I never use the editing features, so I had
not tried them. I will take a look at it and fix this.

Peter
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