[ALSA - driver 0001651]: ac3 passthrough not really work with ac3dec

[bugtrack@alsa-project.org]

The following issue has been SUBMITTED.
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<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=1651> 
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Reported By:                tycordinal
Assigned To:                
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Project:                    ALSA - driver
Issue ID:                   1651
Category:                   PCI - emu10k1
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Distribution:               
Kernel Version:             2.4.31
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Date Submitted:             12-14-2005 09:44 CET
Last Modified:              12-14-2005 09:44 CET
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Summary:                    ac3 passthrough not really work with ac3dec
Description: 
using the following from alsa-tools to play ac3 as passthrough:
ac3dec -C oneac3file.ac3 


the ac3dec is able to "open" the spdif device "iec958:{AES...}" and did
not report any error and keep on running, but the ac3 decoder (creative
ddts-100), connected to the "spdif output" from the card, did not switch
to dolby mode, and no sound come out from speaker.

one interesting thing is, when I run this:
ac3dec -6 oneac3file.ac3 

As this is software decoding to PCM, I can hear the left/right channels
from the front stereo jacket, as they also output on the "spdif output".
Therefore, I believe the "spdif output" on the card is indeed working,
just that for this card we might need to write some different AES command
to open the spdif output?

I am not sure if the alsa config files in /usr/share/alsa have to change
or maybe some "switches" in emu10k1_main.c needs to apply for the "spdif
output" to  really behave as "iec958" device to passthough ac3 stream to
external decoder.

Thanks.





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Issue History
Date Modified  Username       Field                    Change              
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12-14-05 09:44 tycordinal     New Issue                                    
12-14-05 09:44 tycordinal     Kernel Version            => 2.4.31          
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