[haiku-bugs] Re: [Haiku] #1351: aliasing is heared with playback 44.1kHz files on 48kHz system sample rate
- From: "pulkomandy" <trac@xxxxxxxxxxxx>
- Date: Fri, 20 Aug 2010 14:52:24 -0000
#1351: aliasing is heared with playback 44.1kHz files on 48kHz system sample
rate
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Reporter: nutela | Owner: pulkomandy
Type: bug | Status: assigned
Priority: normal | Milestone: R1
Component: Kits/Media Kit | Version: R1/pre-alpha1
Resolution: | Keywords:
Blocked By: | Has a Patch: 0
Platform: x86 | Blocking:
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Comment (by pulkomandy):
I did some tests, printing the buffer sizes in tne Resample function. No
matter what sample rate is selected, the resampler always is asked to fill
a 2048 frame buffer from a 2048 frame buffer. This leads to using the "no-
op" resampler optimization. I have no idea how it ends up converting from
44100 to 48000 Hz that way, but it's definitely not the resampler doing
its work.
Anyway, the resampler does not know about the actual framerate and try to
guess it from the size of the buffers given to it, which is approximate
and actually does not work at all, as both input and output buffers are
2048 samples long. You can see that in MixerCore.cpp MixerThread function
:
* The call to fResampler[i]->Resample use fMixBufferFrameCount as the
frame count for the source while it is calculated from the output
information, and is equal to the frames_per_buffer(...) used for the
destination
* Compiling the mixer add on with debug level 4 will make the PRINT call
just below that show the buffer sizes are identical
* The resampling ratio computed in Resample.cpp is the ratio between
these frame counts, and thus is always 1, which means no resampling is
ever done.
--
Ticket URL: <http://dev.haiku-os.org/ticket/1351#comment:5>
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