Jason Gauthier wrote: > I can't find many cards except for the Creative Labs X-Fi that seems to > fit both.. and from what I read SPDIF passthrough doesn't work. I'm > not 100% sure what that means. (Pretty new to this level of audio)
SPDIF was designed to transport two channels of 16-bit uncompressed audio at 48 kHz (this is 192,000 bytes per second). If you want to transport more channels (4.0/5.1/7.1), the data has to be compressed with a codec like Dolby Digital (AC-3) or DTS, and a special control bit must be set in the SPDIF stream to indicated that the data is compressed. (Since nobody wants to pay for an encoder license, this is mostly interesting for DVDs, which the audio data already in compressed form.) A sound card that can do SPDIF passthrough (usually called DTS/AC3 passthrough) can two things: 1) it does not modify the audio data in any way (every bit is needed for decoding), and 2) it allows to set the "non-audio" control bit. You don't need this feature if all you want is stereo. > Does anyone have any recommended cards that fit both PCI Express, USB, > or firewire and SPDIF out? USB: There are many devices with SPDIF output, but there isn't any one that does support passthrough in Linux. PCI-E: The X-Fi has SPDIF, and it should not take more than another few years before Creative adds passthrough support to the driver. The Asus Xonar DX and D2X cards do support passthrough, but you need a recent enough kernel; see <http://www.alsa-project.org/main/index.php/Matrix:Vendor-Asus>. Firewire: don't know, there is probably nothing that would be cheaper than the Xonar DX. HTH Clemens ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
