28 Jul
2011
28 Jul
'11
2:41 p.m.
For music playing back I use a player which uses gstreamer as an engine. The player uses
an appropriate gst API for setting (software) volume level. Almost all content in my music
collection is 16 bit depth. gst forwards a stream to hdsp alsa driver, and then card's
spdif out is used to transfer a stream to external DAC, which is set to accept 24 bit
stream in accordance with card's bit depth format. DAC chip itself has 20 bit word
length (PCM63).
The question is, does gst attenuate samples after converting them into format with more
rather 16 bit? The thing is, I'd be happy to know I have those 24 db (at least
theoretically, 20 bit DAC - 16 bit content = 4 bit = 24 db) at which I can reduce level in
a player without loosing bits.
a
28 Jul
28 Jul
3:45 p.m.
Date: Thu, 28 Jul 2011 18:42:14 +0400
From: a(a)gaydenko.com
To: linux-audio-user(a)lists.linuxaudio.org
Subject: [LAU] volume settings and keeping bits
For music playing back I use a player which uses gstreamer as an engine. The player uses
an appropriate gst API for setting (software) volume level. Almost all content in my music
collection is 16 bit depth. gst forwards a stream to hdsp alsa driver, and then card's
spdif out is used to transfer a stream to external DAC, which is set to accept 24 bit
stream in accordance with card's bit depth format. DAC chip itself has 20 bit word
length (PCM63).
The question is, does gst attenuate samples after converting them into format with more
rather 16 bit? The thing is, I'd be happy to know I have those 24 db (at least
theoretically, 20 bit DAC - 16 bit content = 4 bit = 24 db) at which I can reduce level in
a player without loosing bits.
a
_______________________________________________
Most significant bits are the same for both, you just have less on the least significant
side between 16bit and 20/24bit.
Dynamic range does not equate to volume! Don't get confused just because both are
measured in dB.
4:10 p.m.
On Thu, 28 Jul 2011 15:43:55 +0000
Dale Powell <dj_kaza(a)hotmail.com> wrote:
Most significant bits are the same for both, you just
have less on the least significant side between 16bit and 20/24bit.
Dynamic range does not equate to volume! Don't get confused just because both are
measured in dB.
Sorry, I don't understand your answer. Probably, you didn't read my question
carefully. Just compare two chains:
16bit - 24bit - (attenuate up to -24db) - (to 20 bit in DAC), and
16bit - (attenuate up to -24db) - 24bit - (to 20 bit in DAC)
I just want to know which chain is used in gst (and, of course, prefer first one), as far
as at first case we keep resolution 16bit, while at second case we get 12bit only. You
see?
6:03 p.m.
Hi Andrew,
On Thu, Jul 28, 2011 at 11:11 AM, Andrew Gaydenko <a(a)gaydenko.com> wrote:
On Thu, 28 Jul 2011 15:43:55 +0000
Dale Powell <dj_kaza(a)hotmail.com> wrote:
While you might get an answer on this list... you'll probably have
better luck on the gstreamer list. (...since you're asking about gst
internals.) Most of the folks on LAU are doing pro audio, and gst is
generally not well suited for pro audio.
-gabriel
Most significant bits are the same for both, you
just have less on the least significant side between 16bit and 20/24bit.
Dynamic range does not equate to volume! Don't get confused just because both are
measured in dB.
Sorry, I don't understand your answer. Probably, you didn't read my question
carefully. Just compare two chains:
16bit - 24bit - (attenuate up to -24db) - (to 20 bit in DAC), and
16bit - (attenuate up to -24db) - 24bit - (to 20 bit in DAC)
I just want to know which chain is used in gst (and, of course, prefer first one), as far
as at first case we keep resolution 16bit, while at second case we get 12bit only. You
see?
6:16 p.m.
On Thu, 28 Jul 2011 13:03:14 -0500
Gabriel Beddingfield <gabrbedd(a)gmail.com> wrote:
While you might get an answer on this list...
you'll probably have
better luck on the gstreamer list. (...since you're asking about gst
internals.) Most of the folks on LAU are doing pro audio, and gst is
generally not well suited for pro audio.
-gabriel
Already am trying, thanks.
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4 comments
3 participants
participants (3)
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Andrew Gaydenko -
Dale Powell -
Gabriel Beddingfield