[mythtv-users] DVD audio with M-audio sound card

[Joseph A. Caputo]

On Thursday 11 March 2004 11:09, Mike Jasper wrote:
> Hi,
>
> I'm putting together a new Myth box with an M-audio Audiophile sound
> card.  I'm using this card because I also plan to do a bunch of
> recording of analog sources using that box, and this is a good card
> for that.
>
> However, the card doesn't have a connector where I can attach the
> audio cable from the DVD-ROM drive.  If I attach the connector to the
> motherboard header (Asus P4P800 mobo), will Myth be able to grab
> sound from the on-board sound device when playing DVDs and route it
> through the M-audio card?  Or is there a better solution?
>
> I'd hate to give up on the M-audio card but the more I look at it the
> less it seems viable.

The audio cable from a CD/DVD drive is typically only useful for 'dumb' 
audio CD player software which simply instructs the CD/DVD drive to 
start playing a particular audio CD track, which bypasses the IDE/
ATAPI/SCSI interface and just outputs line-level audio.  This 
capability is typically only useful for direct playback of audio CDs, 
and some CD-based games that play CD audio from the game CD.

DVD drives typically cannot 'play' DVD content in that manner, as the 
content is not 'raw', like CD-audio, but encoded MPEG-2 content 
encapulated in a special DVD format (VOBs + special filesystem 
structure).  Both the audio & video portion of the DVD stream must be 
decoded (usually in software, but it can be done in hardware if you 
have a PVR-350, DXR3 or other hardware MPEG-decoder board and software 
that makes use of it).  The decoded audio + video streams are handled 
by your player software and passed to the appropriate audio & video 
output devices.

So, the short answer is you do not need to connect the audio cable from 
your DVD drive to get audio in your DVD playback.

-JAC