Upsampling to 32bit

Discuss client development (or even MPD development if you feel so inclined), ask questions about the client libs, MPD feature requests from client developers, etc...
Post Reply
Ran
Posts: 144
Joined: February 25th, 2013, 3:47 am

Upsampling to 32bit

Post by Ran » December 11th, 2013, 5:19 am

When playing a 24Bit / 96Khz file, MPD identifies the file correctly but according to the logs, upsamples the file:

Dec 11 00:17 : alsa_output: opened hw:CARD=Interface,DEV=0 type=HW
Dec 11 00:17 : alsa_output: format=S32_LE (Signed 32 bit Little Endian)
Dec 11 00:17 : alsa_output: buffer: size=24..131072 time=250..1365334
Dec 11 00:17 : alsa_output: period: size=12..65536 time=125..682667
Dec 11 00:17 : alsa_output: default period_time = buffer_time/4 = 500000/4 = 125000
Dec 11 00:17 : alsa_output: buffer_size=48000 period_size=12000
Dec 11 00:17 : output: opened plugin=alsa name="Wyred4Sound" audio_format=96000:32:2
Dec 11 00:17 : output: converting from 96000:24:2

Why MPD converts the bit rate from 24 to 32?

Running Ubuntu 13.10 64bit / MPD - Latest GIT version.

scar
Posts: 6
Joined: May 3rd, 2014, 8:41 pm

Re: Upsampling to 32bit

Post by scar » May 3rd, 2014, 8:43 pm

would also like to know why this is happening. thanks

erre_erre
Posts: 10
Joined: February 15th, 2013, 5:57 pm

Re: Upsampling to 32bit

Post by erre_erre » May 4th, 2014, 7:33 am

Converting form 24 to 32 bits is not upsampling, but probably only zero padding (no new samples are generated, since the sampling rate is the same).

Probably your soundcard interface demands 32 bits samples, as do my M-Audio Delta 1010-LT. Try to see if it happens with other sample rates and bit depths (say, 44.1/16 bits)

Post Reply