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+---- Thread: Short Sound dropouts over HDMI (/showthread.php?tid=155877)
RE: Short Sound dropouts over HDMI - fnac - 2013-10-13
tried some more: when turning OFF passthrough everything works fine. I can pause and skip and the A/V sync is perfect.
Turning "AC3 capable reciever" ON again, makes audio terrible out of sync direct after any pause.
this is the version i tested:
OpenELEC-RPi.arm-Rbej-Version-Frodo-Branch(10.10.2013)
RE: Short Sound dropouts over HDMI - popcornmix - 2013-10-13
(2013-10-13, 13:33)fnac Wrote: tried some more: when turning OFF passthrough everything works fine. I can pause and skip and the A/V sync is perfect.
Turning "AC3 capable reciever" ON again, makes audio terrible out of sync direct after any pause.
It is weird. I've seen this reported on raspbmc forum, but it makes little sense.
The problem didn't exist in an old build (20130503 of raspbmc)
It feels like it must be a firware issue, but using the firmware from 20130503 doesn't fix it.
Apparently stereo ac3 passthrough doesn't suffer from this. Multichannel does (but what we do is identical in either case).
Most TV's/receivers don't suffer this problem.
I believe switching channel away from pi and back fixes sync (so it seems the Pi isn't sending data that is out of sync, but is somehow getting the receiver into an out of sync state).
Turning off ASC (auto sound calibration) on receiver may fix it.
I can't reproduce the problem (and have tried numerous TVs/receivers).
Ideally what we need is someone who has this problem who can compile their own xbmc and help track down where the problem first occurred.
If not I can try making some older test builds, that others can test, but that will be a slow process.
(And I tried this with raspbmc, but unfortunately old builds I made still exhibited the problem, but I could try again with openelec).
RE: Short Sound dropouts over HDMI - fnac - 2013-10-13
i'm afraid I don't know how to compile.. perhaps if given detailed instructions..
but I'd be willing to try test builds no problems.
RE: Short Sound dropouts over HDMI - popcornmix - 2013-10-13
(2013-10-13, 16:40)fnac Wrote: i'm afraid I don't know how to compile.. perhaps if given detailed instructions..
but I'd be willing to try test builds no problems.
Is there an older openelec build that doesn't suffer this problem?
RE: Short Sound dropouts over HDMI - mduran - 2013-10-14
@popcornmix,
I don't understand what you mean with "It feels like it must be a firware issue, but using the firmware from 20130503 doesn't fix it."
If I download the 20130503 xbmc version from RaspBMC the issue does not occur, Also the Backport2 release does not have this issue, But the Backport3 does. So it is in these timeframes. Maybe I helped to narrow down the timeframe.
Another thing is, if I poweroff the DTS Receiver, there is no stutter, so downmixing the DTS stream is also helping to prevent this issue.
The issue also occurs on the XBMC 13 nightly builds, so I will try to find the one that does and doesn't have this issue. Maybe this way you can figure out what changed between these two builds...
RE: Short Sound dropouts over HDMI - popcornmix - 2013-10-14
(2013-10-14, 07:57)mduran Wrote: I don't understand what you mean with "It feels like it must be a firware issue, but using the firmware from 20130503 doesn't fix it."
Most of the work in setting the clocks, the audio info frame configuration, and encapsulation of passthrough data is handled by the firmware (start.elf).
Therefore I'd expect audio stutter to be more likely to be caused by a change to start.elf than xbmc.
However taking a new xbmc with an old (from a working 20130503 image) firmware doesn't fix the problem.
That suggests it is in xbmc code. However I produced a clean Frodo raspbmc build (i.e. xbmc as it was on 02 May 2013, with no rbp backports) and that still had the issue.
As far as I'm aware there are no significant differences between this build and 20130503.
Finding an openelec build that doesn't suffer from this problem may be useful, as I could try making an openelec build from that point in time.
Do any official openelec builds work?
RE: Short Sound dropouts over HDMI - fnac - 2013-10-14
i tried some more today with earlier openelec rbej frodo builds
OpenELEC-RPi.arm-Rbej-Version-Frodo-Branch(05.07.2013) was the earliest i could find and it had the same problem with the delay
The problem is when testing with multichannel AC3 sound. Stereo AAC sound works fine.
btw, on another topic, perhaps this should have an own thread "HDMI passthrough Delays" `since this thread is really about drop outs over hdmi..
RE: Short Sound dropouts over HDMI - mduran - 2013-10-14
Wel I need to go now, But I narrowed it down to Raspbmc:
XBMC-13-20130723 does not have the stutter issue
XBMC-13-20130728 does stutter.
Tonight I will try the releases in between these two dates.
RE: Short Sound dropouts over HDMI - fnac - 2013-10-14
OpenELEC-RPi.arm-3.0.6.img
that worked fine, no delays and good sync after paus/play.
just to clarify: my testing is to check out the audio delay problem you get when you hit pause and then play. I don't know if that's called stutter?
RE: Short Sound dropouts over HDMI - popcornmix - 2013-10-14
(2013-10-14, 18:18)fnac Wrote: OpenELEC-RPi.arm-3.0.6.img
that worked fine, no delays and good sync after paus/play.
just to clarify: my testing is to check out the audio delay problem you get when you hit pause and then play. I don't know if that's called stutter?
I'm aware of three issues:
Audio delay that increases with each pause.
Noise being output when paused
Audio stutter.
All occur only with passthough and only on some receivers. The problems seem to have appeared at a similar time (okay in original frodo release, appeared after a commit in frodo_rbp_backports).
Currently I'm assuming they are all related, but can't be sure until we get a fix. Narrowing down when any one of these issues first appeared is of interest.
RE: Short Sound dropouts over HDMI - mduran - 2013-10-14
20130723 no stutter
20130724 stutter (somehow these stutters are not as often as later builds)
It is the XBMC 13 Nightly build. I installed a clean RaspBMC without any addons or something.
Playing from NFS with a download speed of 9,8MB/s measured with dd. So it must be something that is changed in this timeframe.
RE: Short Sound dropouts over HDMI - popcornmix - 2013-10-14
(2013-10-14, 18:47)mduran Wrote: 20130723 no stutter
20130724 stutter (somehow these stutters are not as often as later builds)
It is the XBMC 13 Nightly build. I installed a clean RaspBMC without any addons or something.
Playing from NFS with a download speed of 9,8MB/s measured with dd. So it must be something that is changed in this timeframe.
Hmmm. No commit to omxplayer near there:
https://github.com/xbmc/xbmc/commits/master/xbmc/cores/omxplayer?page=2
and I can't see anything that looks relevent in all of xbmc:
https://github.com/xbmc/xbmc/commits/master?page=43
I don't believe raspbmc changes firmware version when you manually switch builds, so I guess it's not firmware.
Thanks for looking. I'm sure with some piece of information it will become clear, but I'm confused at the moment.
RE: Short Sound dropouts over HDMI - mduran - 2013-10-14
I did a test again, 2307 no stutter, 2407 stutters. That's all I can do for now. ;-)
Isn't Sam building nightlies of the day before. Lets say all commits of 23 gets build on the 24th and named xbmc-13-20130725
Can I perhaps do something to help you?
RE: Short Sound dropouts over HDMI - fnac - 2013-10-14
and on the HDMI AC3 Delay topic:
testing the official builds of openelec:
OpenELEC-RPi.arm-3.2.0.img = NOT OK. it gets out of sync after pause>play
and as reported before
OpenELEC-RPi.arm-3.0.6.img = OK!
RE: Short Sound dropouts over HDMI - Sam.Nazarko - 2013-10-15
Raspbmc does not change /boot on XBMC changes, however the Pi libs are included at build time and used by Pi from ld.so.conf -- but start/fixup.elf itself is not changed.
@mduran: are you saying that you can 'fix'/ or bring back symptoms of this behaviour just by switching the nightlies in Raspbmc Settings?