Real time a/v sync difference when bitstreaming
#1
I've noticed that when I play files with dts or dolby digital soundtracks that the real time a/v sync difference is very high at the start of playback, sometimes as far as 70ms. This causes xbmc to make corrections to get the sync closer to 0, causing what looks like repeated frames. However, if I disable bitstreaming the sync difference is much lower, around 20ms. xbmc still corrects the sync, but there is no noticeable effect. I've tried using the sync to display options and they don't seem to make a difference (with bitstreaming). I'm running my display at 59.94hz and playing back mkvs that run mostly at 23.976 fps. I know the recommended setup calls for adjust refresh rate to match video to be enabled, but I'm not comfortable with using a sync offset because it doesn't seem to be consistent across all of my files. So I have three questions. First, should the real time a/v sync counter always start as close to 0 as possible? Second, is there anything I can do other than disabling bitstreaming? Third, should sync to display options be used if the display refresh rate doesn't match the frame rate of the video file? Even though it doesn't fix the problem, it does seem to improve playback. I'm running a Haswell NUC with the latest nightly build of openelec, a Denon 4311CI, and a Samsung D8000 plasma. Thanks for your time, and thanks for all of your work on the software.

Logfile: http://www.xbmclogs.com/show.php?id=170630
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#2
23.976 fps at 59.94hz .... what do you expect?

Disable passthrough and set the audio to resample.
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#3
The odd thing is, this works fine with dts-hd. it's just the lossy streams that exhibit this behavior. Disabling dts pass through kills dts-hd. Is there a way to disable the pass though of dts and still allow dts-hd to be bitstreamed?
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#4
(2014-04-10, 12:41)fritsch Wrote: 23.976 fps at 59.94hz .... what do you expect?

This
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#5
(2014-04-10, 14:07)Piers Wrote:
(2014-04-10, 12:41)fritsch Wrote: 23.976 fps at 59.94hz .... what do you expect?

This

I guess I'm wrong for expecting my htpc to be able to do what a Roku running Plex can do.
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#6
(2014-04-10, 13:17)nelson01 Wrote: The odd thing is, this works fine with dts-hd. it's just the lossy streams that exhibit this behavior. Disabling dts pass through kills dts-hd. Is there a way to disable the pass though of dts and still allow dts-hd to be bitstreamed?

Bitstreaming sorta IS passthrough - passing through audio signal untouched. I can't see how you could have one without the other. Don't think XBMC can do DTS-HD SW decode to LPCM - licencing and all that.
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#7
(2014-04-10, 16:51)pr0xZen Wrote:
(2014-04-10, 13:17)nelson01 Wrote: The odd thing is, this works fine with dts-hd. it's just the lossy streams that exhibit this behavior. Disabling dts pass through kills dts-hd. Is there a way to disable the pass though of dts and still allow dts-hd to be bitstreamed?

Bitstreaming sorta IS passthrough - passing through audio signal untouched. I can't see how you could have one without the other. Don't think XBMC can do DTS-HD SW decode to LPCM - licencing and all that.

it doesn't, it only decodes the core.
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#8
Well there you go. If you have the option, and /need/ SW decoding - go with Dobly TrueHD.
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