SPDIF won't play PCM after playing AC3
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
alsa-driver (Ubuntu) |
Won't Fix
|
Undecided
|
Unassigned | ||
linux (Ubuntu) |
Invalid
|
Undecided
|
Unassigned | ||
Bug Description
If I use the 'AC3 passthrough' feature of a multimedia app (e.g. totem-xine),
the SPDIF output will stop working with PCM (forever) if the mixer attempts to
access SPDIF simultaneously. Once this happens, SPDIF can only be used with AC3,
and all PCM is only output by the analogue line-out. I did this using an SBLive!
Value card:
russell@neo:~$ lspci | grep audio
0000:00:0a.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 08)
Here's a test script:
1. Attach an amplifier through SPDIF, and attach something else (like
headphones) to the line-out of the sound card.
2. Play any PCM sound file. It will play through both outputs.
3. Open totem-xine, and enable the AC3 passthrough, then play a DVD with a Dolby
Digital or DTS soundtrack. The amplifier will indicate that an AC3 (Dolby
Digital or DTS) stream is being output by the SPDIF.
4. While the DVD is playing, open another application (such as XMMS) and play a
sound file. Seeing that it is techincally impossible to play a PCM sound file
through SPDIF while it's outputting in AC3, the mixer will fail to open the
SPDIF (expected) and just play the PCM through the analogue line-out while the
DVD continues to play through SPDIF.
-- up to this point, this is all expected output --
5. Stop the DVD. Close totem-xine, restart XMMS and try playing the PCM sound
again. The PCM will no longer play through SPDIF (only through analogue). <- NOT
GOOD!
It appears that if the mixer fails to open the SPDIF once, it will never try
again. Not after rebooting, not after reinstalling every audio package that
synaptic has to offer. The SPDIF will never play PCM again. It will continue to
work for AC3, but even then, if a DVD uses PCM it still won't work. The bug
occurs right across the board, whether you're using alsa, oss, esd or whatever.
Playing around with the mixer (volumes and switches) doesn't seem to help either.
I've been able to replicate this problem in both Breezy (5.10) and Hoary (5.04).
Could someone *please* look into this, as I find myself having to reinstall
Ubuntu each time I accidentally run into this scenario.
Changed in alsa-driver: | |
importance: | Medium → Undecided |
status: | Confirmed → New |
Changed in linux: | |
assignee: | nobody → ubuntu-audio |
status: | New → Confirmed |
Changed in alsa-driver: | |
status: | New → Won't Fix |
Changed in linux (Ubuntu): | |
assignee: | Ubuntu Audio Team (ubuntu-audio) → nobody |
affects: | hundredpapercuts → null |
no longer affects: | null |
I have exactly the same problem with my SB Live 5.1 (emu10k1) running Ubuntu Dapper.