Audio drop outs at start of Video
#1
Hi,
I can't find this elsewhere so apologise if my search missed it. I am getting the following on Raspbmc RC5 xbmc build as of 9th Oct and OpenElec build r12080 and using HDMI audio.

1. Audio drop outs (no sound) at the start of playing videos ~2 drop outs within a few seconds. Appears to happen on most videos with various codecs.
2. Audio drop outs after jumping to another section within the video, symptoms are the same as in 1.
3. Occasional audio drop outs whilst playing video without me doing anything.

1 & 2 are very similar to what used to be experienced when playing audio tracks back before that was fixed.
3. Gut feel - might be due to CPU or network load / poor network connection but doesn't buffer (I have a wireless bridge between my NAS and Pi so sometimes the signal degrades)

Anyone else got this?
Rob
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#2
My Onkyo receiver does this. It also does it from my Popcorn Hour C200. Connected direct to TV doesn't do it.
What is the audio connected to?
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#3
(2012-10-15, 17:47)popcornmix Wrote: My Onkyo receiver does this. It also does it from my Popcorn Hour C200. Connected direct to TV doesn't do it.
What is the audio connected to?

Its connected directly to my TV, Sony KDL40W5710

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#4
Does it stop if you disable "Adjust display refresh rate to match video"?
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#5
(2012-10-16, 00:59)popcornmix Wrote: Does it stop if you disable "Adjust display refresh rate to match video"?

I'll have a play when I get home.

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#6
(2012-10-16, 00:59)popcornmix Wrote: Does it stop if you disable "Adjust display refresh rate to match video"?

No didn't make a difference.

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#7
I'm experiencing this problem, the first symptom anyway, and I'd really like to get to the bottom of it as it is a deal-breaker for me as far as fully adopting RPi/XBMC.
Here's what I know.

The typical situation is playing a video file (.TS) via HDMI and my Onkyo 609 to my Panasonic 50V20. As described, there is an initial silence of a few hundred milliseconds, a fragment of sound, another silence, then all is good. During the periods of silence, the Onkyo stops displaying its audio processor mode (e.g. "T-D"), suggesting loss of the audio signal.

If I play directly to the TV using HDMI, the symptom is a little different in that there is an initial "warble", with the pitch changing.

The reason it is a deal-breaker is that this happens at the start of every audio track, including music, meaning that the first few notes of every song are lost.

Now, I've read similar reports in lots of places, and I was even hopeful that there was a fix in place as this bug ticket (http://trac.xbmc.org/ticket/13326) seems to relate to this problem, and it is classed as fixed. Using the latest RC5 Raspbmc build however, which I believe includes the latest version of XBMC Frodo, the situation is unchanged.

Using Openelec - same problem.

Using Eden on my iMac (totally standalone, so no HDMI or AVR involved), there is no problem.

From another forum I picked up that earlier versions of Openelec did not have this flaw, and it's true! Build 11392 works, but it's broken by build 11782. I can't just use 11392 and be happy however as it does not include support for MPEG-2 decode keys.

So - where to point the finger?
Not Raspbmc as the fault also occurs in Openelec. Probably not XBMC itself as Eden works on my iMac. I'm now suspecting OMXplayer, and I'm hoping that some knowledgeable person, ideally the illustrious 'gimli' can shed some light on what is going on. Has it really been fixed as bug report 13326 suggests, or was that a misfire or something else entirely. If it has, should I be expecting to see it fixed in the Frodo nightlies now, or will it not appear until the beta release?

Please don't get me wrong - it's a marvellous project, and I truly appreciate the efforts made, but the inability just to play a song in its entirety is for me a pretty major deficiency. I mean, Beethoven's 5th without the first "Da" doesn't quite cut it.
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#8
@xarqi
As I mentioned before I have an Onkyo 609 (and a Panasonic VT30). I get the same problem you desribe.
My Popcorn Hour C200 exhibits exactly the same problem.

The only fix I can think of is a couple of seconds silence before playing the music.

(try disabling sync display frame rate to video if enabled - although that will only affect videos, not music).
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#9
This Popcorn Hour C200, excuse my ignorance, but is it also running XBMC, or are you saying it is a totally different platform, so the problem must lie with Onkyo or just possibly Panasonic?

In any case, what's the best way to make sure the right people know that there is (still) an issue in order that a fix may be forthcoming?
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#10
(2012-11-06, 20:56)xarqi Wrote: This Popcorn Hour C200, excuse my ignorance, but is it also running XBMC, or are you saying it is a totally different platform, so the problem must lie with Onkyo or just possibly Panasonic?

In any case, what's the best way to make sure the right people know that there is (still) an issue in order that a fix may be forthcoming?
Popcorn Hour has completely different hardware and software compared to R-Pi and XBMC.

Now either Popcorn Hour and Raspberry Pi are both doing the same wrong thing, or the Onkyo is.

When audio is DTS/AC3 passthrough, I don't expeerience the dropout. I do for PCM.
It's not directly an XBMC problem, as HDMI is driven by GPU firmware.
I think it is Onkyo rather than Panasonic, as you see Onkyo's display blank when the dropout occurs. I imagine you would still hear the dropout with Panasonic unplugged.
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#11
It's a bit perplexing. It's usually the case that one error is more likely to occur than two separate yet identical ones, but in these days of common libraries it may not always be as it seems on the surface. We could start pointing the finger at Onkyo, except:
- old versions of Openelec don't show the problem with audio, even through the Onkyo;
- when I go directly from the Rpi to the TV via HDMI, omitting the Onkyo, the problem is still there, but the symptoms change to a "warble" at the start of a track.

Something changed about the way the RPi (or more specifically OMXPlayer, I think) initiates HDMI audio between the release of Openelec where it was working and the one where it stopped, and that issue persists to the present. Different 'receivers' respond differently: the Onkyo says "What?" and ignores it; the TV says "Nonsense" and tries to fill the gap by spreading out the data, affecting pitch.

I may have a fiddle with the various audio modes on both the Onkyo and the Rpi and see if I can elicit some more information.

Thanks for keeping the thread going.
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#12
As far as I can remember this has always happened for me.
If you can find the most recent good version of openELEC (i.e. to pin down the day it became bad) I can have a look at the changes which might give some clues.
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#13
(2012-11-07, 21:45)popcornmix Wrote: As far as I can remember this has always happened for me.
If you can find the most recent good version of openELEC (i.e. to pin down the day it became bad) I can have a look at the changes which might give some clues.

I did a binary search through the builds looking for one with support for MPEG-2 licence and no audio glitch. There isn't one.

Audio works with build 11392 (but no codec key support), but it's broken by build 11782 (also no codec key support).
Somewhere in between will be the transition that breaks the audio. I can't investigate exactly where right now, but maybe within 48 hours.

Thanks for offering to look. It's beyond my ability.
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#14
Well, no joy I'm afraid. I went back to the source of img files I was using (http://openelec.thestateofme.com/) and versions of openelec earlier than 15-sep-12 (r11930) have been purged. That version has the audio flaw. I can't narrow it down any further than to say that the flaw was introduced after r11392, which works, and with or before r11782 (9-aug-12), which doesn't.

One further symptom I forgot to mention is that when playback is started the elapsed track timer moves very quickly to about 5 seconds (with no sound being output), then continues normally. I suspect that the visualisation display is out of synch also.

Is there another repository of old img files?
I'm a bit limited in the means at my disposal to load SDHC cards as I'm using an old iMac and have to rely on unzipping img files and using dd "manually" as there are no installer scripts or programs.
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#15
(2012-11-07, 21:45)popcornmix Wrote: As far as I can remember this has always happened for me.
If you can find the most recent good version of openELEC (i.e. to pin down the day it became bad) I can have a look at the changes which might give some clues.

http://www.raspberrypi.org/phpBB3/viewto...00#p107241
Quote:added experimental ALSA support, Menusounds and Music is now done via ALSA, this *maybe* provides USB speaker/soundcard support
r11392 was containing a patch for xbmc make alsa to work with xbmc. this was the only build with alsa support, xbmc menusound, music over alsa (afaik video sound over omxplayer). this build was fixing some audio problems including some "pop" sounds at the beginning but rgarding gimli it introduces some other problems so he has not worked further on the alsa integration.
greetings, Stephan

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