Re: [Musicpd-dev-team] 24-bit file plays on a 16-bit DAC?
I got it working with alsa by specifying plughw:0 instead of hw:0. plughw enables half of dmix - i.e. the part of libasound which does the resampling and sample format conversion. That means that ALSA will automatically convert 24-16 if the hardware isn't 24 bit capable. I do hear glitches with plughw:0 that I don't hear when using OSS. It sounds like distortion during the music's peaks. I guess this is due to libasound? Another option could be that your device doesn't support the 24-in-32 format, but only the packed 24 bit format. That's not supported by MPD (yet). There are so many different sample formats and packing standards... I checked with the manufacturer on this and they don't think a USB DAC can support 24-in-32 because the USB driver would chop off anything above 24. Do you think this explains why hw:0 doesn't work? The DAC supports up to 24/96. I believe that the ALSA-OSS emulation enables dmix, and therefore also plughw. I definitely hear glitches from plughw and none when OSS is defined. - Grant -- The NEW KODAK i700 Series Scanners deliver under ANY circumstances! Your production scanning environment may not be a perfect world - but thanks to Kodak, there's a perfect scanner to get the job done! With the NEW KODAK i700 Series Scanner you'll get full speed at 300 dpi even with all image processing features enabled. http://p.sf.net/sfu/kodak-com ___ Musicpd-dev-team mailing list Musicpd-dev-team@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/musicpd-dev-team
Re: [Musicpd-dev-team] 24-bit file plays on a 16-bit DAC?
I believe that the ALSA-OSS emulation enables dmix, and therefore also plughw. Max I really don't think mpd-oss-dmix because I tried specifying a format my DAC can't handle in /etc/asound.conf for dmix. aplay and all other ALSA apps won't work, but mpd still plays. - Grant -- The NEW KODAK i700 Series Scanners deliver under ANY circumstances! Your production scanning environment may not be a perfect world - but thanks to Kodak, there's a perfect scanner to get the job done! With the NEW KODAK i700 Series Scanner you'll get full speed at 300 dpi even with all image processing features enabled. http://p.sf.net/sfu/kodak-com ___ Musicpd-dev-team mailing list Musicpd-dev-team@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/musicpd-dev-team
Re: [Musicpd-dev-team] 24-bit file plays on a 16-bit DAC?
On 2009/05/12 21:18, Grant emailgr...@gmail.com wrote: I got it working with alsa by specifying plughw:0 instead of hw:0. plughw enables half of dmix - i.e. the part of libasound which does the resampling and sample format conversion. That means that ALSA will automatically convert 24-16 if the hardware isn't 24 bit capable. Another option could be that your device doesn't support the 24-in-32 format, but only the packed 24 bit format. That's not supported by MPD (yet). There are so many different sample formats and packing standards... I believe that the ALSA-OSS emulation enables dmix, and therefore also plughw. Max -- The NEW KODAK i700 Series Scanners deliver under ANY circumstances! Your production scanning environment may not be a perfect world - but thanks to Kodak, there's a perfect scanner to get the job done! With the NEW KODAK i700 Series Scanner you'll get full speed at 300 dpi even with all image processing features enabled. http://p.sf.net/sfu/kodak-com ___ Musicpd-dev-team mailing list Musicpd-dev-team@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/musicpd-dev-team
Re: [Musicpd-dev-team] 24-bit file plays on a 16-bit DAC?
My USB DAC is only capable of 16/44.1 16/48 and doesn't do any sort
of oversampling (non-OS). I tried playing a 24/96 file in gmpc and it
plays just fine. This is puzzling since I have:
audio_output {
type alsa
name USB Monica
device hw:0,0
}
Shouldn't audio be passed off directly to the DAC in this
configuration, without dmix resampling it?
Not exactly. MPD sees that your card cannot do 24 bit, so it converts
internally - and it logs that (--verbose). That's usually better than
letting dmix it do transparently.
Max
Hi Max,
I've finally got my hands on a 24-bit USB DAC and some 24/96 files,
and it works with mpd, but I'm seeing some strange behavior.
I couldn't get mpd to play with any specification of device such as
hw:0,0. It plays if I don't specify audio_output at all, but the DAC
LEDs indicate 16/48 so dmix must be at work.
It does play and LEDs do indicate 24/96 if I specify this:
audio_output {
type oss
name USB DAC
}
I'm not familiar with OSS at all. Does dmix get involved with OSS, or
does OSS have something similar that I might prefer to bypass? I'm
trying to send music from the filesystem to the DAC untouched. Any
other reason to prefer ALSA over OSS?
Do you have any idea why the DAC doesn't work when hw:0,0 is specified? I
get:
# aplay -L
null
Discard all samples (playback) or generate zero samples (capture)
# cat /proc/asound/devices
0: [ 0] : control
1: : sequencer
16: [ 0- 0]: digital audio playback
33: : timer
# cat /proc/asound/cards
0 [USBDAC ]: USB-Audio - USBDAC
Otherwise 24-bit support works great in mpd. Thanks for coding that up!
- Grant
I got it working with alsa by specifying plughw:0 instead of hw:0.
- Grant
--
The NEW KODAK i700 Series Scanners deliver under ANY circumstances! Your
production scanning environment may not be a perfect world - but thanks to
Kodak, there's a perfect scanner to get the job done! With the NEW KODAK i700
Series Scanner you'll get full speed at 300 dpi even with all image
processing features enabled. http://p.sf.net/sfu/kodak-com
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