Subject: Re: [ecasound] Re: [linux-audio-user] 24 bit replacement for SOX (fwd)
From: Kai Vehmanen (kvehmanen_AT_eca.cx)
Date: Tue Dec 21 2004 - 04:20:14 EET
Aaron, Kamil and others,
you reported about resampling problems in July this year. I think the
below snapshot finally fixes the problems you described. Especially the
96kHz-->44.1kHz conversion was affected by this bug.
Btw; -ei:xxx also uses libsamplerate if available. You can test multiple
ratios in one go by issuing:
sh> ecasound -i foo.wav -o alsa -ei:100 -kos:1,50,250,0.05 -c
Quick list of all changes in this snapshot:
- added: resample-lq (low-quality) audio object to force using
the internal resampler even though support for
libsamplerate is enabled at build time
- changed: more helpful messages to explain why a chainsetup
cannot be connected to the engine
- fixed: serious bugs in resampling between 96000 and 44100/48000
rates when using libsamplerate; upgraded Ecasound to use
the libsamplerate 'full API'
---------- Forwarded message ----------
Date: Tue, 21 Dec 2004 04:12:48 +0200 (EET)
From: Kai Vehmanen <kvehmanen_AT_eca.cx>
To: Jesse Chappell <jesse_AT_essej.net>,
Erik de Castro Lopo <erikd-lad_AT_mega-nerd.com>
A list for linux audio users <linux-audio-user_AT_music.columbia.edu>
Subject: Re: [ecasound] Re: [linux-audio-user] 24 bit replacement for SOX
On Fri, 17 Dec 2004, Jesse Chappell wrote:
>> I've received some bug reports about
>> resampling with the ecasound+libsamplerate combo, and the 44.1<->48
> Kai, I did notice that the SRC code in ecasound uses the simple
> API of libsamplerate, but it expects to use it blockwise with
> a continuous audio stream. The more advanced APIs maintain state
> between calls that I think are necessary when using it with a stream.
thank you for pointing this out to me -- this was indeed causing problems.
If anyone wants to help in testing, please try the snapshot at:
# the basic syntax is:
ecasound -f:16,2,44100 -i resample,auto,foo96khz.wav -o alsa
# with samplerate's 'SRC_SINC_BEST_QUALITY' quality
ecasound -f:16,2,44100 -i resample-hq,auto,foo96khz.wav -o alsa
Where 16(bit), 2(ch) and 44100(Hz) are the target audio parameters. This
should work with any ALSA/OSS, JACK, wav/aiff, ogg/mp3/flac/etc output.
-- http://www.eca.cx Audio software for Linux!
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