29 Jul
2005
29 Jul
'05
6:32 p.m.
Hi folks,
I'm batch-ripping and encoding a lot of my CD collection to
put on my mp3 player. I've noticed that a number of CDs contain
an apparently spurious first track that's apparently very short
(about a tenth of a second) and contains no audible signal.
What the heck is the point of this track?
e.g.
$ sndfile-info track00.cdda.wav
Version : libsndfile-1.0.11
========================================
File : track00.cdda.wav
Length : 23564
RIFF : 23556
WAVE
fmt : 16
Format : 0x1 => WAVE_FORMAT_PCM
Channels : 2
Sample Rate : 44100
Block Align : 4
Bit Width : 16
Bytes/sec : 176400
data : 23520
End
----------------------------------------
Sample Rate : 44100
Frames : 5880
Channels : 2
Format : 0x00010002
Sections : 1
Seekable : TRUE
Duration : 00:00:00.133
Signal Max : 0 (-inf dB)
--
Paul Winkler
http://www.slinkp.com
29 Jul
29 Jul
8:38 p.m.
Paul Winkler wrote:
Hi folks,
I'm batch-ripping and encoding a lot of my CD collection to
put on my mp3 player. I've noticed that a number of CDs contain
an apparently spurious first track that's apparently very short
(about a tenth of a second) and contains no audible signal.
What the heck is the point of this track?
e.g.
$ sndfile-info track00.cdda.wav
Version : libsndfile-1.0.11
========================================
File : track00.cdda.wav
Length : 23564
RIFF : 23556
WAVE
fmt : 16
Format : 0x1 => WAVE_FORMAT_PCM
Channels : 2
Sample Rate : 44100
Block Align : 4
Bit Width : 16
Bytes/sec : 176400
data : 23520
End
----------------------------------------
Sample Rate : 44100
Frames : 5880
Channels : 2
Format : 0x00010002
Sections : 1
Seekable : TRUE
Duration : 00:00:00.133
Signal Max : 0 (-inf dB)
is that the extra, hidden file that the record labels put on some cd's,
in an effort to stop digital extraction of the disc? i can't remember
too much about it, and i don't think they use this method much anymore.
shayne
10:23 p.m.
On Sat, Jul 30, 2005 at 08:38:00AM +1000, Shayne O'Connor wrote:
is that the extra, hidden file that the record labels
put on some cd's,
in an effort to stop digital extraction of the disc? i can't remember
too much about it, and i don't think they use this method much anymore.
Maybe, I dunno. The one I saw today is on a disc from 1993.
--
Paul Winkler
http://www.slinkp.com
1 Aug
1 Aug
9:33 a.m.
Paul Winkler wrote:
I've noticed that a number of CDs contain an
apparently spurious
first track that's apparently very short (about a tenth of a
second) and contains no audible signal. What the heck is the
point of this track?
None.
Most positions on an audio CD are specified as sector numbers. The
Red Book says that the start of the first track is at sector 0; the
table of contents is placed in the lead-in area in sectors -32 to -1.
Some CDs (and/or some CD drives) get something wrong so that the first
track is reported to start at sector 32.
One sector is 1/75th of a second (588 frames), so usually nobody
notices this.
File : track00.cdda.wav
Data before the first track is grabbed as "track 0" which doesn't
ordinarily exist on audio CDs.
Frames : 5880
This is 10 sectors, not 32, so the explanation above doesn't apply.
;-)
HTH
Clemens
7055
days inactive
7058
days old
linux-audio-user@lists.linuxaudio.org
3 comments
3 participants
participants (3)
-
Clemens Ladisch -
Paul Winkler -
Shayne O'Connor