Keep audio device open during pause

Some receivers have a noticeable delay when starting to play sound, which is emphasized on XBMC since it closes the audio device during pause. This means when you resume a movie you can miss a line or two. This might of course be software/hardware related, and if so, I run Linux with an ASRock ION 330 w/ Ubuntu 9.10. As comparison, the PS3 and XBOX360 does not behave like this, they keep the device open. So my suggestion is to keep the audio device open during pause of media, both movies and music.

I have the exact same problem with XBMC on Windows so it seems that it is a common problem and not platform specific. I'm using a Logitech Z-5500 as my surround sound system and I don't have this problem with MPC or VLC.

Is it on the same machine (same hardware and OS etc) that you test XBMC and VLC on against your Z-5500?

apanloco Wrote:Is it on the same machine (same hardware and OS etc) that you test XBMC and VLC on against your Z-5500?

Yeah currently I only have my HTPC and a laptop (broke my dev machine) but I never watch movies on my laptop (or the dev machine) so it isn't even connected to the Z-5500.

I just did some more testing and I got some weird results:

Playing AVI files
- XBMC: Sound is perfect. It stops exactly when I press "Pause" and resumes exactly when I press "Play". No glitches in the image either.
- VLC: Image stops right away but the sound goes on for about half a second on "Pause". On "Play" the sound is missing for half a second while the image kind of catches up with the sound already played on "Pause".
- MPC: Same as XBMC, everything is perfect.
- WMP: Same as XBMC, everything is perfect.

Playing MKV files (1080p and 20p)
- XBMC: Sound and image stop exaclty on "Pause". Sound is delayed for about a second on "Play" but image plays normally.
- VLC: Exactly the same as when playing an AVI file.
- MPC: Almost the same as XBMC but in the first second after "Play" the image plays a lot faster until sound pops in.
- WMP: Can't play MKVs.

I haven't used VLC ever since I found out about XBMC (which was about 1.5 years ago) but I'm sure that I didn't have any sound problems with VLC and my Z-5500 back then. Maybe they messed something up in the meantime.
It looks like XBMC and MPC have the exact same behavior so it looks to me like the problem is not the player but the MKV container or maybe it's the size of the MKV files. But I also tried playing "small" MKVs (1GB) and it gives the same result as when playing a 20GB MKV. Playing a "big" AVI (1.5GB) did not change the playback's performance and everything was perfectly fine.

I get this as well, but it's the same with various programs on my Win7 box and does not seem limited to XBMC. That said, neither my 360 or PS3 does this with anything, so I'm thinking a combination of hardware and receiver is my issue. I have a Nvidia chipset, connected to my Onkyo 607 receiver via HDMI.

It doesn't matter what happens, after awhile the receiver thinks there's no audio being sent and clicks back to stereo, then takes a few seconds to click back into whatever mode the video is in when I resume playback.

(I know I posted a thread about this recently but I can't find it anymore)

Stupid me!!! Why didn't I test the kind of audio instead of the kind of video?
I can only guess right now (as I'm at university and not at home, so I can't test it right now) but it might actually be the type of audio (stereo mp3 vs dts or ac3) which causes the delay. As most of my MKVs have AC3 or DTS sound and all of my AVIs have MP3 stereo this might be a reasonable explanation as the receiver might need a few milliseconds before recognizing the audio stream as AC3/DTS compared to stereo.

I can't actually compare it to the way it works on my Xbox360 as it isn't connected over coax and can therefore only provide stereo sound to the receiver.

EDIT: OK I just tested an MKV file which has both an mp3 stereo and an AC3 track. Playing/Pausing with the mp3 track works perfectly fine but with the AC3 track I get the break in the sound after pressing "Play".Don't know if this a problem of my receiver or XBMC.

pretty sure this is your receiver. i have the asrock too, and a denon receiver. it reacts instantaneously and the display shows dd/dts when paused. maybe turning off the sound effects will help for you. that way it can 'stay open' as you say..

alot of recievers are slow to start playback again after receiving the first ac3/dts frame... Not much we can do about it.
Keep sending audio would just introduce a delay to resume playback as whatever null audio that has been buffered must first be played out by the receiver before one can start playback (not to mention it would be quite hard to implement in code)

Does your receiver still say it's receiving DTS/Dolby digital when you pause? It could be your soundcard that's the problem.

Has anyone been able to solve this? I used to have a Yamaha receiver where I didn't exhibit this, but have just switched to a Denon and it's quite annoying. I think I know why it happens: the audio mode on the Denon switches when I pause the video, and when I resume, it switches back, which takes a few seconds. Is there a fix/hack?