Hallo, Stuart Pook hat gesagt: // Stuart Pook wrote: > on Sat, 7 Feb 2004 19:37:21 +0100, Frank Barknecht said > > > > > Did you buy a TASCAM US-122? How well does it work? I am > > > > interested in converting 44.1kHz (MP3) and 48kHz (DVD/divx) > > > > files to line out (RCA). > > > > If you mean, playing files in various samplerates: This will work with > > any supported device using for example the rate converter built into > > ALSA (like plughw:0). USB in general is happier when using "even" > > samplerated that divide by 1000. > > But if you have a 48kHz file and you play it on a device that only does > 44.1kHz, wont the rate converter have to resample in software? Doesn't > that use CPU (my machine is very limited especially when watching DVDs) > and lose quality?
Yes, it does use CPU and it looses quality, if the resampling algorithm isn't really good. A good algorithm as in libsamplerate will use more CPU, though. > Are you also saying that if I have a device that does both 48kHz and > 44.1kHz, and a 44.1kHz imput file, that it is better to resample (using > some plughw magic) so as to send 48kHz to the device (because 44.1kHz > is not divisible by 1000)? This is more a latency problem. If you don't use samplerates that are divisible by 1000 over USB, you will need to use larger buffers. So for Jack applications I would say: Yes, resampling is better, but for DVD or mp3-playing latency isn't that important, so it might work with 44.1 as well. > Can you give us more details on your USB audio device tests? I am > hoping to replace my Audiophile USB and would like to know if you have > any more information that you can give us on the Audiotrak Mayas and the > Terratec Aureon. They all work. Aureon and Maya 5.1 only have 48000 samplerate, I didn't have the Maya 44 to test. > What are the signal to noises ratio like (compared to something like > the Audiophile USB or the TASCAM US-122)? The Terratec Producer > Phase 26 USB is a bit expensive for me at 320 euros. But it's cool. ;) Midi doesn't work yet, though, and I had some disturbances occasionally (like AM radio) so this is more for experimental users currently. (Street prices are below 320, e.g. http://www.netzmarkt.de/thomann/artikel-162363.html but it is still expensive, yes.) > It's a pity that the EDIROL UA20 only does 44.1kHz. It should do 48 kHz as well. I didn't test a UA-20 now, too, but AFAIK the Advanced Mode, which allows 48 kHz is supported by ALSA. I didn't make any tests regarding signal quality, that was the job of other guys. I don't know their results. I was only doing the "does it work on Linux" tests. I will put some of my results (including failures) into the USB devices database at http://www.qbik.ch/usb/devices/ later. Some are there already, for example the Phase 26. Maybe some alsa-guru can take a look at the midi problem sometime, using the debug info on qbik.ch Another problem I faced is compatibility with USB controllers. E.g. The Edirol UA1 would not work on my stationary PC, but did work on my laptop. So if possible, make sure, that you can test a new device on your own hardware before buying (or make sure you can give it back.) Actually USB audio tests on Linux are easy, as they all use the same driver (except the TASCAMs). If you have a laptop, you might even be able to take it to your dealer and test functionality there, because you can do all setup in advance at home. ciao -- Frank Barknecht _ ______footils.org__ ------------------------------------------------------- The SF.Net email is sponsored by EclipseCon 2004 Premiere Conference on Open Tools Development and Integration See the breadth of Eclipse activity. February 3-5 in Anaheim, CA. http://www.eclipsecon.org/osdn _______________________________________________ Alsa-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-user
