Subject: RE: [linux-audio-user] Playback slow from burned CD's
From: Mark Knecht (mknecht_AT_controlnet.com)
Date: Wed Dec 04 2002 - 18:52:14 EET
Hi,
This problem can occur (a bit more in Linux than Windows since Linux
gives us more freedom but requires more study) if you actually recorded your
session at 48K, but are putting it on CD at 44.1K. If the notes are off by
about 1 whole note (a recorded C became a B flat on the CD) then this is
likely what you're hearing.
If your wave files are really 48K (no matter what they say they are) then
look into resampling them down to 44.1K before writing the CD. There is open
source software to do that, but I haven't used any yet.
I've been burned by this problem a couple of times. The most interesting
one was when I was doing a 48K Pro Tools session and sending an ADAT sync to
a GigaStudio box, but using 44.1K libraries. In that case I had to play a
whole note low because the libraries were getting played back too fast.
It happens...
Mark
-----Original Message-----
From: linux-audio-user-admin_AT_music.columbia.edu
[mailto:linux-audio-user-admin_AT_music.columbia.edu]On Behalf Of Speaker
to Vegetables
Sent: Wednesday, December 04, 2002 8:20 AM
To: linux-audio-user_AT_music.columbia.edu
Subject: Re: [linux-audio-user] Playback slow from burned CD's
The 44100 Hz sample rate is absolutely the only one ever used for CD's,
but high end audio cards like the Hammerfall tend to be more flexible.
So probably a bug or misconfiguration of the audio card or driver is
causing the wavs to be recorded (and played back) at a faster sample
rate. "arecord" thinks it is getting 44100 Hz data, so that's what it
puts in the header, but it is evidently mistaken. "cdrecord" only knows
what is in the header, so it doesn't realize the data is at the wrong
sample rate. Look for a way to tell the Hammerfall what sample rate to
use, either a module option, ALSA config file option, or a
Hammerfall-specific utility program. Sorry to be so vague, but I've
reached (if not passed) the limit of my knowledge.
On Tuesday 03 December 2002 03:17 pm, patrick reardon wrote:
> hello everyone,
>
> i don't know if this is the right forum for my question, but here
> goes.
>
> i'm running on Intel PIII with kernel 2.4.18, ALSA, and a Hammerfall
> 9632 card. CD quality WAV files recorded with ALSA from live
> performances play back with no problem via "aplay".
>
> a Yamaha CRW8424S scsi burner was recently installed and i burned the
> WAV files to CD with both "cdrecord" and "cdrdao". data is actually
> transferred but when i play the CD's with a CD player, the tunes are
> too slow and too low by about a minor third.
>
> i tried burning at various speeds from 1x to 8x, but always the same
> problem. have also tried a variety of other options to "cdrecord,"
> like using a really big buffer, etc. the commands "file" and "aplay"
> give the following information:
>
> --------snip-----------
> $ file blues1.wav
> blues1.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16
> bit, stereo 44100 Hz
>
> $ aplay blues1.wav
> Playing WAVE 'blues1.wav' : Signed 16 bit Little Endian, Rate 44100
> Hz, Stereo --------snip-----------
>
> i wrote to Jorg Schilling who developed "cdrecord", but he only said
> i need to use 44100 Hz data and that if ALSA wrote incorrect headers,
> i should write the ALSA group instead. i doubt it's a problem with
> ALSA.
>
> at any rate, i'm out of ideas. has anyone experienced a similar
> problem? any pointers would be greatly appreciated.
>
> tia,
> patrick
-- "Can you remember the future? Forget it!"
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