[RndTbl] Problem burning cd using cdrtoaster-1.12:

[Gilles Detillieux]

While cleaning up my mailbox, I came across this message from Jan 3,
which I don't think was ever answered.  My apologies if this isn't news
to anyone...

According to S/C Conway:
>  Using cdrtoaster-1.12 to burn an MP3 to an audio cd results in never
> recorded before "chipmunks" coaster. The audio sounds like a 33rpm
> record played at 45rpm. This may be a bad analogy for the CD exposed
> generation.
>  Analyzing the script from cdrtoaster the creation of a CD takes place
> in two steps. One step converts the mp3 to wav the next step burns the
> cd.
> 
> Audio convert:
> mpg123 -s sample1.mp3|sox -t raw -w -s -c 2 -r 44100 - -t wav
> sample1.wav
> 
> CD burn:
> cdrecord -v -eject dev=/dev/sg0 speed=4 -audio -pad
> /home/username/sample1.wav

It appears cdrtoaster assumes the MP3 file will be sampled at 44.1 KHz,
which is why it puts the -r 44100 before the input filename, "-".

>  I have tried doing the audio convert manually an it produces a
> chipmunks wav file. If I change the rate parameter to -r 22050 the wav
> file is produced correctly. The new file is not in the correct format
> for cdrecord to handle and produces an error message "Inappropiate audio
> coding". According to my reading a wav file must be created with 16bit
> 44100hz sample rate.

WAVE files can support a number of sampling rates, but for burning to
audio CDs they must be 16 bit stereo at 44.1 KHz.  If the WAVE file you
produce at 22.05k play correctly, this must be the sampling rate of your
MP3 (surely there must be an easy way to query the MP3 for this info).
If you want sox to resample to a different rate, you must specify -r
options on both the input and output sides of the command line (before
and after the input file name).  You may want to read up on polyphase,
rate and resample effects in sox(1) and experiment with what works best.
The default is "rate", which does quick linear interpolation, and isn't
usually ideal if sound quality matters.

>  I have also tried changing the mp3 player to the GPL version
> mpg321-0.1.5-1 with no success.
>  I have found no indication at the SOX site of any problems with the
> software.
> 
>  This is my first foray into CD burning using Linux. The burner works
> fine under windows95 and its software. I have made a decision to
> eliminate as many windows machines as I can. My project is the
> burner/scanner box.
> 
> Sean

Near as I can tell, it's not a problem with the burner or any of the
software components you're using.  Just a bad assumption by cdrtoaster's
handling of MP3s - it really should enquire about the actual sampling
rate used in the MP3, or even in WAVE files, and get sox to resample
accordingly.

-- 
Gilles R. Detillieux              E-mail: <grdetil at scrc.umanitoba.ca>
Spinal Cord Research Centre       WWW:    http://www.scrc.umanitoba.ca/
Dept. Physiology, U. of Manitoba  Winnipeg, MB  R3E 3J7  (Canada)