* [ALSA - lib 0000385]: Rate conversion plugin generates noise on frequency reduction
@ 2004-10-22 14:20 bugtrack
0 siblings, 0 replies; 4+ messages in thread
From: bugtrack @ 2004-10-22 14:20 UTC (permalink / raw)
To: alsa-devel
The following issue has been UPDATED.
======================================================================
<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=385>
======================================================================
Reported By: fmoraes
Assigned To: perex
======================================================================
Project: ALSA - lib
Issue ID: 385
Category: pcm - digital audio
Reproducibility: always
Severity: major
Priority: normal
Status: assigned
======================================================================
Date Submitted: 07-13-2004 19:46 CEST
Last Modified: 10-22-2004 16:20 CEST
======================================================================
Summary: Rate conversion plugin generates noise on frequency
reduction
Description:
When reducing the frequency, the pcm_rate plugin causes noise on the output
data. This has been tested with both the snd-cs46xx and snd-emu10k1x
drivers and the following .asoundrc can be used to recreate the output in
a file:
pcm.CS46xx {
type hw
card 0
}
pcm.filetest {
type file
slave {
pcm "CS46xx"
}
file "/home/fmoraes/test-out.raw"
format "raw"
}
pcm.test {
type rate
slave {
pcm "filetest"
format "S16_LE"
rate 8000
}
}
Playing a 48Khz file will cause noticeable noise on the output (noise is
more noticeable the lower the target frequency is).
======================================================================
----------------------------------------------------------------------
Tobias Diedrich - 10-21-04 17:01
----------------------------------------------------------------------
I second that. Downsampling even from 48000Hz to 44100Hz produces very
noticable artifacts, which sound very much like nearest neighbour
resampling artifacts and are especially evident in high pitched vocals.
It would also be nice to implement better resampling methods than just
linear resampling, AFAICS from the source polyphase and bandlimited
resampling are planned but not yet implemented.
Issue History
Date Modified Username Field Change
======================================================================
07-13-04 19:46 fmoraes New Issue
07-15-04 14:07 perex Status new => assigned
07-15-04 14:07 perex Assigned To => perex
10-21-04 16:57 Tobias DiedrichIssue Monitored: Tobias Diedrich
10-21-04 17:01 Tobias DiedrichNote Added: 0002223
10-22-04 16:19 perex Project ALSA - driver => ALSA -
lib
10-22-04 16:20 perex Category OTHERS => pcm - digital
audio
======================================================================
-------------------------------------------------------
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^ permalink raw reply [flat|nested] 4+ messages in thread
* [ALSA - lib 0000385]: Rate conversion plugin generates noise on frequency reduction
@ 2004-10-22 14:34 bugtrack
0 siblings, 0 replies; 4+ messages in thread
From: bugtrack @ 2004-10-22 14:34 UTC (permalink / raw)
To: alsa-devel
A NOTE has been added to this issue.
======================================================================
<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=385>
======================================================================
Reported By: fmoraes
Assigned To: perex
======================================================================
Project: ALSA - lib
Issue ID: 385
Category: pcm - digital audio
Reproducibility: always
Severity: major
Priority: normal
Status: assigned
======================================================================
Date Submitted: 07-13-2004 19:46 CEST
Last Modified: 10-22-2004 16:34 CEST
======================================================================
Summary: Rate conversion plugin generates noise on frequency
reduction
Description:
When reducing the frequency, the pcm_rate plugin causes noise on the output
data. This has been tested with both the snd-cs46xx and snd-emu10k1x
drivers and the following .asoundrc can be used to recreate the output in
a file:
pcm.CS46xx {
type hw
card 0
}
pcm.filetest {
type file
slave {
pcm "CS46xx"
}
file "/home/fmoraes/test-out.raw"
format "raw"
}
pcm.test {
type rate
slave {
pcm "filetest"
format "S16_LE"
rate 8000
}
}
Playing a 48Khz file will cause noticeable noise on the output (noise is
more noticeable the lower the target frequency is).
======================================================================
----------------------------------------------------------------------
Tobias Diedrich - 10-21-04 17:01
----------------------------------------------------------------------
I second that. Downsampling even from 48000Hz to 44100Hz produces very
noticable artifacts, which sound very much like nearest neighbour
resampling artifacts and are especially evident in high pitched vocals.
It would also be nice to implement better resampling methods than just
linear resampling, AFAICS from the source polyphase and bandlimited
resampling are planned but not yet implemented.
----------------------------------------------------------------------
perex - 10-22-04 16:34
----------------------------------------------------------------------
The reported problem should be solved in 1.0.7rc releases.
At the time, we don't have free resources to write code for another
resampling method. Also, there are several problems to use methods based
on sample history.
Issue History
Date Modified Username Field Change
======================================================================
07-13-04 19:46 fmoraes New Issue
07-15-04 14:07 perex Status new => assigned
07-15-04 14:07 perex Assigned To => perex
10-21-04 16:57 Tobias DiedrichIssue Monitored: Tobias Diedrich
10-21-04 17:01 Tobias DiedrichNote Added: 0002223
10-22-04 16:19 perex Project ALSA - driver => ALSA -
lib
10-22-04 16:20 perex Category OTHERS => pcm - digital
audio
10-22-04 16:34 perex Note Added: 0002244
======================================================================
-------------------------------------------------------
This SF.net email is sponsored by: IT Product Guide on ITManagersJournal
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Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more
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^ permalink raw reply [flat|nested] 4+ messages in thread
* [ALSA - lib 0000385]: Rate conversion plugin generates noise on frequency reduction
@ 2004-10-22 14:35 bugtrack
0 siblings, 0 replies; 4+ messages in thread
From: bugtrack @ 2004-10-22 14:35 UTC (permalink / raw)
To: alsa-devel
The following issue has been RESOLVED.
======================================================================
<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=385>
======================================================================
Reported By: fmoraes
Assigned To: perex
======================================================================
Project: ALSA - lib
Issue ID: 385
Category: pcm - digital audio
Reproducibility: always
Severity: major
Priority: normal
Status: resolved
Resolution: open
Fixed in Version:
======================================================================
Date Submitted: 07-13-2004 19:46 CEST
Last Modified: 10-22-2004 16:35 CEST
======================================================================
Summary: Rate conversion plugin generates noise on frequency
reduction
Description:
When reducing the frequency, the pcm_rate plugin causes noise on the output
data. This has been tested with both the snd-cs46xx and snd-emu10k1x
drivers and the following .asoundrc can be used to recreate the output in
a file:
pcm.CS46xx {
type hw
card 0
}
pcm.filetest {
type file
slave {
pcm "CS46xx"
}
file "/home/fmoraes/test-out.raw"
format "raw"
}
pcm.test {
type rate
slave {
pcm "filetest"
format "S16_LE"
rate 8000
}
}
Playing a 48Khz file will cause noticeable noise on the output (noise is
more noticeable the lower the target frequency is).
======================================================================
----------------------------------------------------------------------
Tobias Diedrich - 10-21-04 17:01
----------------------------------------------------------------------
I second that. Downsampling even from 48000Hz to 44100Hz produces very
noticable artifacts, which sound very much like nearest neighbour
resampling artifacts and are especially evident in high pitched vocals.
It would also be nice to implement better resampling methods than just
linear resampling, AFAICS from the source polyphase and bandlimited
resampling are planned but not yet implemented.
----------------------------------------------------------------------
perex - 10-22-04 16:34
----------------------------------------------------------------------
The reported problem should be solved in 1.0.7rc releases.
At the time, we don't have free resources to write code for another
resampling method. Also, there are several problems to use methods based
on sample history.
Issue History
Date Modified Username Field Change
======================================================================
07-13-04 19:46 fmoraes New Issue
07-15-04 14:07 perex Status new => assigned
07-15-04 14:07 perex Assigned To => perex
10-21-04 16:57 Tobias DiedrichIssue Monitored: Tobias Diedrich
10-21-04 17:01 Tobias DiedrichNote Added: 0002223
10-22-04 16:19 perex Project ALSA - driver => ALSA -
lib
10-22-04 16:20 perex Category OTHERS => pcm - digital
audio
10-22-04 16:34 perex Note Added: 0002244
10-22-04 16:35 perex Status assigned => resolved
======================================================================
-------------------------------------------------------
This SF.net email is sponsored by: IT Product Guide on ITManagersJournal
Use IT products in your business? Tell us what you think of them. Give us
Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more
http://productguide.itmanagersjournal.com/guidepromo.tmpl
^ permalink raw reply [flat|nested] 4+ messages in thread
* [ALSA - lib 0000385]: Rate conversion plugin generates noise on frequency reduction
@ 2004-11-22 13:44 bugtrack
0 siblings, 0 replies; 4+ messages in thread
From: bugtrack @ 2004-11-22 13:44 UTC (permalink / raw)
To: alsa-devel
The following issue has been CLOSED
======================================================================
<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=385>
======================================================================
Reported By: fmoraes
Assigned To: perex
======================================================================
Project: ALSA - lib
Issue ID: 385
Category: pcm - digital audio
Reproducibility: always
Severity: major
Priority: normal
Status: closed
Resolution: open
Fixed in Version:
======================================================================
Date Submitted: 07-13-2004 19:46 CEST
Last Modified: 11-22-2004 14:44 CET
======================================================================
Summary: Rate conversion plugin generates noise on frequency
reduction
Description:
When reducing the frequency, the pcm_rate plugin causes noise on the output
data. This has been tested with both the snd-cs46xx and snd-emu10k1x
drivers and the following .asoundrc can be used to recreate the output in
a file:
pcm.CS46xx {
type hw
card 0
}
pcm.filetest {
type file
slave {
pcm "CS46xx"
}
file "/home/fmoraes/test-out.raw"
format "raw"
}
pcm.test {
type rate
slave {
pcm "filetest"
format "S16_LE"
rate 8000
}
}
Playing a 48Khz file will cause noticeable noise on the output (noise is
more noticeable the lower the target frequency is).
======================================================================
----------------------------------------------------------------------
Tobias Diedrich - 10-21-04 17:01
----------------------------------------------------------------------
I second that. Downsampling even from 48000Hz to 44100Hz produces very
noticable artifacts, which sound very much like nearest neighbour
resampling artifacts and are especially evident in high pitched vocals.
It would also be nice to implement better resampling methods than just
linear resampling, AFAICS from the source polyphase and bandlimited
resampling are planned but not yet implemented.
----------------------------------------------------------------------
perex - 10-22-04 16:34
----------------------------------------------------------------------
The reported problem should be solved in 1.0.7rc releases.
At the time, we don't have free resources to write code for another
resampling method. Also, there are several problems to use methods based
on sample history.
Issue History
Date Modified Username Field Change
======================================================================
07-13-04 19:46 fmoraes New Issue
07-15-04 14:07 perex Status new => assigned
07-15-04 14:07 perex Assigned To => perex
10-21-04 16:57 Tobias DiedrichIssue Monitored: Tobias Diedrich
10-21-04 17:01 Tobias DiedrichNote Added: 0002223
10-22-04 16:19 perex Project ALSA - driver => ALSA -
lib
10-22-04 16:20 perex Category OTHERS => pcm - digital
audio
10-22-04 16:34 perex Note Added: 0002244
10-22-04 16:35 perex Status assigned => resolved
11-22-04 14:44 tiwai Status resolved => closed
======================================================================
-------------------------------------------------------
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^ permalink raw reply [flat|nested] 4+ messages in thread
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