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/ On Sun, 8 Mar 2015, Daniel Smedegaard Buus wrote: > On Sun, Mar 8, 2015 at 8:59 PM, Clemens Ladisch <cladisch@xxxxxxxxxxxxxx> wrote: >> Daniel Smedegaard Buus wrote: >>> I'd like to add a small delay to the 44.1 kHz output, and I've seen >>> some examples of introducing delays to a virtual device by using >>> lsdspa. However, according to LSDSPA docs, all processing is done in >>> 32 bits, and I would really prefer to avoid any format conversion... >> >> Why? Conversion to 32 bits and back should be lossless. >> > > Is it though? I haven't yet found specific details on what > intermediate format is used ... All I know so far is "32 bit". Could > be floating-point, and I don't know if there's any sample rate > conversion going on. Although that would be odd. It is not rate conversion, just integer conversion, from 16 bit to 32 bit. Now, if the original is maximal (Ie goes from +2^15 to - 2^15) then conversion, and then any other filtering, could drive the system into clipping on back conversion. It can also introduce a bit more digitization noise (90dB down from the max), but neither is likely to anywhere near as severe as the noise introduced by rate conversion. You are probably using the fastest rate conversion which is horribly distorting. See www.theory.physics.ubc.ca/soundcard/resample.html for tests of the various conversion procedures contained in sox (and I think the alsa ones are closer to the fastest/worst, rather than the slowest/best) > ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
