Subject: Re: [linux-audio-user] Wave file conversion (multi-mono->stereo, then downsample/downsize, then dither)
From: Mark Knecht (markknecht_AT_comcast.net)
Date: Fri Sep 10 2004 - 02:03:45 EEST
On Thu, 2004-09-09 at 15:13, Kai Vehmanen wrote:
> On Thu, 9 Sep 2004, Mark Knecht wrote:
>
> > How would I be sure that my emerge of ecasound uses libsamplerate
> > capabilities? Can this be observed at runtime? Or in the output files
> > somehow? Anywhere else?
>
> ldd `which ecasound` |grep libsamplerate
flash mark $ ldd `which ecasound` |grep libsamplerate
libsamplerate.so.0 => /usr/lib/libsamplerate.so.0 (0x40067000)
flash mark $
Oops - I did have white space in the command line:
<SNIP>
-i:resample-hq,auto, data/GTSB-96K...
<SNIP>
flash mark $ ecasound -f:16,2,44100
-i:resample-hq,auto,data/GTSB-96K-24bit-Audio/T01-Startdust.L.wav
-o:TEST1.wav
****************************************************************************
* ecasound v2.3.3 (C) 1997-2004 Kai
Vehmanen
****************************************************************************
- [ Session created ]
------------------------------------------------------
- [ Chainsetup created (cmdline) ]
-----------------------------------------
- [ Connecting chainsetup ]
------------------------------------------------
(eca-chainsetup) 'nonrt' buffering mode selected.
(eca-chainsetup) Audio object
"data/GTSB-96K-24bit-Audio/T01-Startdust.L.wav", mode "read".
(audio-io) Format: s24_le, channels 1, srate 44100, interleaved.
(eca-chainsetup) Audio object "TEST1.wav", mode "read/write".
(audio-io) Format: s16_le, channels 2, srate 44100, interleaved.
- [ Chainsetup connected ]
-------------------------------------------------
(eca-controller) Connected chainsetup: "command-line-setup".
- [ Controller/Starting batch processing ]
---------------------------------
- [ Engine init - Driver start ]
-------------------------------------------
Warning: DBC_CHECK failed - "impl_repp->rt_lock_rep != true",
samplebuffer.cpp, 850.
- [ Controller/Batch processing finished ]
---------------------------------
- [ Engine exiting ]
-------------------------------------------------------
(eca-controller) Disconnecting chainsetup: "command-line-setup".
- [ Chainsetup disconnected ]
----------------------------------------------
flash mark $
and the output is corretly 44.1K
flash mark $ sndfile-info TEST1.wav
Version : libsndfile-1.0.10
========================================
File : TEST1.wav
Length : 37533024
RIFF : 37533012
WAVE
fmt : 16
Format : 0x1 => WAVE_FORMAT_PCM
Channels : 2
Sample Rate : 44100
Block Align : 4
Bit Width : 16
Bytes/sec : 176400
data : 37532980
End
----------------------------------------
Sample Rate : 44100
Frames : 9383245
Channels : 2
Format : 0x00010002
Sections : 1
Seekable : TRUE
Duration : 00:03:32.771
Signal Max : 27180 (-1.62 dB)
flash mark $
>
> > Anyway, If I'm going to downsize from 24-bits to 16-bits then I want
> > to add dithering, but I see no mention of dithering in man ecasound. I
> > know jack has an option to dither it's outputs, but from some dark
> > remote part of my memory I seem to remember that this only effects the
> > output going to the sound card and not what's going to a file. Comments
> > anyone?
>
> Unfortunately no. Adding dithering has been on the todo-list for ages,
> but still not implemented. :(
I can understand having things like this on your todo list. I guess I'm
now wondering if anyone running Linux is dithering their files before
they make CDs? Possibly no one is doing this? I'm just very used to
doing it on the Pro Tools side, and I still can, but it would be nice to
set up a mastering environment under Alsa and just stay in Linux all the
way to burning the CD if possible. I'd hate to go back to Windows just
for the dithering step. (I might have to if Linux dithering isn't up to
the task, as well it might not be if no one is really using it. We'll
see. (Or hear...) ;-)
Anyway, it's a few days away and not a huge amount of work if I have to.
>
> Also, Ecasound's 24bit is really 24bit, not the 24-in-32bit. This is
> usually not a problem, just as long you are aware of it.
I don't think that's a problem for me as long as I can send it back to
Pro Tools for dithering. I'll test that tonight or tomorrow. Possibly
I'll have to run sndfile-convert on the output before I go back? We'll
see...
Thanks for your help!
- Mark
This archive was generated by hypermail 2b28 : Fri Sep 10 2004 - 02:10:23 EEST