On Jan 19, 2012, at 16:59 34, James Harrison wrote: > If JACK or ALSA supports it, Rivendell supports it.
This used to be pretty much true. However, I've been seeing a rash of cheapie cards (including integrated 'cards' on mobos) in the last year or so that come with their internal sample clock locked to a single rate (48000 samples/secs seems to be typical). The assumption behind this sort of design is that a playout or capture with a different rate will be resampled in software in the driver. While this saves a buck or two in manufacturing and kinda/sorta works for single playout/capture situations (think gaming or running a playout from iTunes), these cards fall apart completely when you try to to use them in an application that generates multiple captures/playouts as a matter of course, such as Rivendell. A typical symptom that you have one of these beauties is a message from caed(8) in syslog stating that the card will not support such-and-such sample rate, accompanied by weird sounding or non-existent audio. As for cards that are known to work, you have, broadly speaking, two choices: AudioScience [http://www.audioscience.com] Yes, they are expensive, but worth every penny. They are specifically designed for broadcast applications, and as such can handle things like lightening surges and sitting four feet away from a 100 kW MW transmitter operating at full power without picking up noise or causing other mayhem. [Full disclosure: Paravel Systems is an authorized ASI dealer]. If your budget can't handle an ASI card (or at least not yet) then a card based upon the ICE1712 chipset will generally perform adequately. M-Audio's 'Delta' line of so-called 'pro-sumer' cards is one example of such. I've also heard good things about RME's line of cards, but haven't personally tested them myself. Remember, Rivendell is targeted for professional broadcast environments. As such, it expects hardware appropriate for such an environment. If you use gear intended for Aunt Millie's e-mail machine or your teenage son's gaming system, then you should expect commensurate results. Cheers! |-------------------------------------------------------------------------| | Frederick F. Gleason, Jr. | Chief Developer | | | Paravel Systems | |-------------------------------------------------------------------------| | Harrisberger's Fourth Law of the Lab: | | Experience is directly proportional to the amount of equipment | | ruined. | |-------------------------------------------------------------------------| _______________________________________________ Rivendell-dev mailing list [email protected] http://lists.rivendellaudio.org/mailman/listinfo/rivendell-dev
