>>>> My Wavelength Proton USB DAC works with the "default" device and with >>>> "plughw:0,0", but it does not work with "hw:0,0". I get the following >>>> error: >>>> >>>> output: Failed to open "Wavelength Proton" [alsa]: ALSA device >>>> "hw:0,0" does not support format 16: Invalid argument >>>> >>>> When trying to play a 24-bit file instead of 16-bit, "16:" is replaced >>>> by "24:" in the error message. The DAC supports 16-bit and 24-bit >>>> audio, and the manufacturer has assured me that it enumerates with >>>> Windows and Mac without error. Does this look like an ALSA bug? >>> >>> The device likely only supports one specific sample format (maybe S32_LE >>> or >> >> I know it works with S24_3LE. >> >>> something). Whatever app you're using likely is using a different sample >>> format. Using the hw device you get no automatic conversion at all, if >>> the >>> sample format doesn't match what the device requires it will fail. >>> >>> This is why one usually wants to use plughw devices or the default device >>> in >>> applications, since they don't want to be bothered with the details of >>> what >>> sample formats the device supports and those devices will do automatic >>> conversion if needed. >> >> I'm trying to avoid having the computer make any changes to the >> digital audio signal whatsoever. I don't use a software mixer, >> replaygain, etc. It sounds like using plughw or the default device >> causes conversions to take place. How can I send unaltered digital >> audio to the DAC? > > Well, it's not possible to send those samples to the DAC in totally > "unaltered" form, as the device simply doesn't support that format. The > sample format conversion is needed in this case. If you use the hw device, > then you're basically talking to the bare hardware, and if the software > you're using can't handle the specific format the device wants, you're out > of luck. Can the conversion to S24_3LE be lossy? - Grant ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
