[mythtv-users] ac3 passthrough problems

Thomas Börkel thomas at boerkel.de
Fri Sep 22 19:54:01 UTC 2006


Scott wrote:

>> It is funny, that this actually works, because with these setting,
>> MythTV uses the "Default" device for AC3, not the one with the hex  
>> codes.
> Yes. But, my understanding of the "Passthrough output device" is that  
> if it is set to "Default" (case sensitive) then it simply refers to  
> the device defined by "Audio output device". This can be confirmed by  

You're right. I had forgotten that.

> Audio output device:  ALSA:digital-dmix
> Passthrough output device:  
> ALSA:iec958:CARD=0,AES0=0x6,AES1=0x82,AES2=0x0,AES3=0x2
> Enable AC3 to SPDIF passthrough: [checked]
> Enable DTS to SPDIF passthrough: [checked]
> Aggressive Sound card Buffering: [not checked]
> Use internal volume controls: [not checked]
> This config would be useful if MythTV was able to detect and route  
> AC3/DTS sound through the "Passthrough output device" only as needed.  

It does that already. It only uses the passthrough device for AC3. For 
MP2, it uses the normal device.

What I would like is, that it only uses the passthrough device for AC3 5.1.

> For example, if in MythMusic sound would not be 48kHz AC3 format and  
> get routed via the "Audio output device". During OTA ATSC playback  
> where AC3 formats are present MythTV would route sound via the  
> "Passthrough output device" instead.

MythMusic can be configured to use another device, so no problem there.


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