Subject: Re: [ecasound] Re: [linux-audio-user] 24 bit replacement for SOX (fwd)
From: Aaron Heller (heller_AT_AI.SRI.COM)
Date: Wed Dec 22 2004 - 00:07:37 EET
Excellent. I'll give it a try tonight. Thanks... Aaron
--On Tuesday, December 21, 2004 4:20 +0200 Kai Vehmanen <kvehmanen_AT_eca.cx>
wrote:
> 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:
>
> --cut--
> - 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'
> --cut--
>
> ---------- 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>
> Cc: ecasound-list_AT_eca.cx,
> 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
>
> Hello all,
>
> 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:
> http://ecasound.seul.org/download/snapshots/ecasound-2.3.6-cvs-20041221.t
> ar.gz
>
># 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.
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