On Fri, 12 Dec 2008, Paulo Moura Guedes wrote: > On Thursday 11 December 2008 01:42:12 Bill Unruh wrote: >> On Wed, 10 Dec 2008, stan wrote: >>> Paulo Moura Guedes wrote: >>>> I'm trying to get bit perfect output out of my linux box, but I can't >> >> What is "bit perfect output"? Sound output is an analog process ( sound >> waves in the air are analog). You do know that you can just copy the sound >> file whereever you want. > > "bit perfect output" is to pass the digital signal as it is, i.e., without > transforming it. You know, I'm using an external DAC to decode the digital > signal into analog. You mean out of a SPDIF output? Or what is your soundcard? Why can you not simply transfer the digital file? > >>>> find much >>>> info on the web. I'm using ALSA. >>>> >>>> >>>> Some questions: >>>> >>>> >>>> - does Linux/ALSA features dynamic sample rates? >>> >>> yes. You can specify whatever rate you want and it will >>> happen. eg 57,325 frames/second. >> >> And that produces lots of distortion and noise. Resampling of any digital >> signal does that. There are some highly inefficient (ie, take lots of >> computer time) process which can minimize that. (see for example >> www.theory.physics.ubc.ca/soundcard/resample.html for a test of the various >> sox algorithms. the good ones are slow. ) > > That is what I want to avoid: resampling. > >> Not sure what you mean by "dynamic sample rates". > > By that I mean to respect the original sample-rate of the file being played, > and don't try to resample it to an hardcoded value. > >>>> - is it possible to set the bit-depth? (in my case to 24 bit) >>> >>> yes, but your card has to support it. Most new cards have >>> internal processing larger than 24 bits > > It does. What is your card? What do you want the output to be? > How can I set it? Depends on the software you use to play the file. > > Thanks, > Paulo > > -- William G. Unruh | Canadian Institute for| Tel: +1(604)822-3273 Physics&Astronomy | Advanced Research | Fax: +1(604)822-5324 UBC, Vancouver,BC | Program in Cosmology | unruh@xxxxxxxxxxxxxx Canada V6T 1Z1 | and Gravity | www.theory.physics.ubc.ca/ ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
