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CiNcH · (This post was last modified: 2018-06-20, 16:32 by CiNcH.)

After seeking inside the timeshift buffer, audio and video are being played back totally out of sync.

I am attaching a log where I did the following:
- Pause live TV (DVBViewer Client add-on starts redirecting stream via file, see PauseStream)
- Waited 5 minutes to fill up timeshift buffer file a bit
- Skip ahead 10s

[LOG]

After skipping ahead, A/V is totally out of sync (by >2s). This only seems to be true for H.264 channels though (tried some 720p50 broadcast). MPEG-2 seems fine.

I also tried skipping ahead in some recordings and sync is fine.

I am not sure whether this is DVBViewer Client add-on related, as it only redirects the stream. I believe it to be a playback issue which is why I posted it here.

CiNcH · (This post was last modified: 2018-06-20, 08:19 by CiNcH.)

I was wrong about H.264 vs. MPEG-2. The problem is AC3 passthrough. So channels with AC3 are affected. After disabling passthrough, sync is fine after seek. So it might be Android related..

Still, playing back recordings with AC3 passthrough, sync is fine after seek which however does not use transcoding. Only timeshifted playback seems affected, which as far as I know also isn't being played back as real-time stream though (IsRealTimeStream should be returning false).

CiNcH · 2018-06-20, 16:03

Here is some further info on the issue...

Timeshifted playback indeed is not real-time. 'rr' stays 1.00000. So there is no resampling taking place. So it should actually be the same as seeking inside a recording no? Still A/V are totally out of sync when seeking inside the timeshift buffer while seeking inside a recording is fine. But only when AC3 passthrough is being used.

CiNcH · (This post was last modified: 2018-07-10, 15:30 by CiNcH.)

It looks like CTRL+SHIFT+O shows the async:

Player: a/v:-1.5

It looks like the player can't cope with the switch from live (realtime) to file (non-realtime) with Passthroug/transcoding enabled, especially after seeking in the timeshift buffer file, A/V are completely out of sync.

FernetMenta · 2018-07-12, 12:41

(2018-07-10, 15:20)CiNcH Wrote: It looks like CTRL+SHIFT+O shows the async:

Player: a/v:-1.5

It looks like the player can't cope with the switch from live (realtime) to file (non-realtime) with Passthroug/transcoding enabled, especially after seeking in the timeshift buffer file, A/V are completely out of sync.

Neither related to player nor realtime. Just a bug in AE: https://github.com/xbmc/xbmc/pull/14173

CiNcH · 2018-07-12, 12:50

Thanks. Will check it as soon as a build is available. Might this also fix this one? Another async problem related to transcoding...

FernetMenta · 2018-07-12, 12:55

likely

CiNcH · (This post was last modified: 2018-07-12, 13:42 by CiNcH.)

Just to get it right... when the DVBViewer Client add-on serves data from the file into which the stream is redirected in case of Timeshifting and returning false for IsRealTimeStream from then on, does Kodi still perform transcoding?

FernetMenta · 2018-07-12, 14:25

(2018-07-12, 13:27)CiNcH Wrote: Just to get it right... when the DVBViewer Client add-on serves data from the file into which the stream is redirected in case of Timeshifting and returning false for IsRealTimeStream from then on, does Kodi still perform transcoding?

There is no direct relationship between transcoding and realtime stream. We transcode if transcoding is enabled, audio device does not support multlichannel pcm, and source has more than 2 channels.

CiNcH · (This post was last modified: 2018-07-12, 15:21 by CiNcH.)

Quote:We transcode if transcoding is enabled, audio device does not support multlichannel pcm, and source has more than 2 channels.

And stream is live and therefore requires resampling, no? So if you have a channel with AC3 5.1, it will have to be transcoded to AC3 5.1 because of the necessary resampling, no? Question now is if you pause live stream, then resume and the PVR add-on now returns false for IsRealTimeStream because playback is now timeshifted from file? Do you still resample and transcode or do you on-the-fly switch to file mode without resampling/transcoding?

FernetMenta · 2018-07-12, 15:48

Once the stream signalled realtime, audio stays in resampling mode. You can' switch back and forth without losing audio.

CiNcH · 2018-07-13, 07:05

After a quick test, both async issues seem to be fixed. Thanks!

CiNcH · 2018-07-13, 14:14

Did some more testing with Wimbledon tennis now. You can really tell sync by the hitting of the ball. Both issues are indeed fixed now. Probably an important one. It at least has been bothering me for quite some time already...

richardc1983 · 2018-07-14, 12:29

Having same issues on windows and libreelec but issue isn't being addressed.

Turn off ac3 transcoding and it's back in sync. No issues like this on v17.

Also getting a horrible live TV and recordings flicker on all v18 clients. Rolled back one of them to v17 last night and all fine.

Nothing in the forum about it.

**jjd-uk** · 2018-07-15, 23:43

(2018-07-14, 12:29)richardc1983 Wrote: Having same issues on windows and libreelec but issue isn't being addressed.

Turn off ac3 transcoding and it's back in sync. No issues like this on v17.

Also getting a horrible live TV and recordings flicker on all v18 clients. Rolled back one of them to v17 last night and all fine.

Nothing in the forum about it.

Did you not read the above? the problem reported CiNcH was a bug and a fixed went in 3 days ago, so if you do indeed have a related issue then have you tried any new builds since the 12th?