patch for 24-bit soft volume and uaudio's tiny fix
Kazuhito HONDA
kazuhito at ph.noda.tus.ac.jp
Sat Feb 18 22:12:39 PST 2006
Hello,
From: Ariff Abdullah <ariff at FreeBSD.org>
Subject: Re: patch for 24-bit soft volume and uaudio's tiny fix
Date: Wed, 15 Feb 2006 16:30:02 +0800
> (Especially to Kazuhito-san), Latest patchsets (rev. 091) contain:
>
> 1) 16/24/32bit feeder_volume
> 2) 16/24/32bit vchan mixing (default to 16, use sysctl or vchanformat
> kernel hint to toggle it).
> 3) Smarter (I would say *perfect*) format scoring during format
> chaining.
> 4) Endian/sign-free format conversion
> 5) Various fixups, especially on hardware, DMA buffer alignment
> 6) Samples processing are moving towards endian-safe, we just need to
> enclose varios PCM_READ/WRITE/CLAMP (sound.h) within BYTE_ORDER
> ifdefs.
I tried to play and to record sound sources with converting between 16-bit
and 24-bit each other, endian, volume and sampling rate on my USB device.
It worked without a big problem.
But sampling rate converter may be able to convert sampling rate
for 16-bit sound stream only, so 24-bit sound stream is
always down-converted to 16-bit when its sampling rate is converted.
Because it is more than enough for 24-bit sound devices,
a sampling rate converter for 24-bit sound stream is necessary.
Sincerely yours,
Kazuhito HONDA
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