| wav2cdr(1) | General Commands Manual | wav2cdr(1) |
wav2cdr - converts input in (or similar to) wav format to cdr format suitable for writing onto audio CDs.
wav2cdr [options ...] [infile [outfile]] [--cut cutnumber ...]
This man page describes wav2cdr version 2.3.4.
wav2cdr is a conversion program for audio data which adopts automatically to big and little endian machines. Its primary use was to convert wav to cdr, but it is a little more flexible now and can handle some file formats and perform some operations on the data. These formats are possible (reading and writing):
wav MS Windows sound
cdr audio CD
raw fixed sampling rate, channels, and bytes per sample
(= that of cdr); byte order must be specified
These operations can be performed on the data (combinations are possible as long as they are meaningful):
Scaling (volume change), integer arithmetic
Scaling (volume change), floating point arithmetic
Cutting of the input into pieces / tracks
Conversion to mono and back to stereo
Swapping of the 2 channels
Adding silence to (or removing from, see cutting) the
start and/or end
Generation of cut numbers along silent intervals, e.g.
to break up a record into tracks
Information about non-silent intervals
Fading in and out
Fading in is performed by increasing the amplitude for CD sectors by an amount derived from LEN over a duration of LEN. --fadein 3 would result in the amplitude of the first sector lowered to 1/4, of the second sector to 2/4, and the third sector to 3/4. The fourth sector is unchanged and has then reached full amplitude.
The computation is similar to --fadein. --fadein 3 would result in the last 3 CD sectors having their amplitudes lowered to 3/4, 2/4, and 1/4. The (non-existant) following sector is assumed to be silent.
To add silent sector(s) to the end of the audio file, use --endsilence.
Fading out can only be performed if the input size can be determined (i.e. the input must be seekable and cannot be a pipe). If cutting is active, the end of the cut is always known and the fade-out can be applied.
If the fade-out starts before the fade-in is finished, both will overlap, producing sensible results.
Together with --verbose, the silence value of each sector is printed as well (can't be fed back into --cut then). This most likely produces some VERY long lines.
Silence is detected by applying a threshold (--silencethresh) to a value computed for each CD sector; the value must be below the threshold for a minimum number of sectors (delay --silencedelay). Currently, the average is computed first (this is the DC component); then the average of the absolute of the difference between each sample and the DC component. The difference between these 2 averages is compared with the threshold. Check whether the cuts really fall into the silent intervals, and adjust threshold and duration if not (or edit the cut numbers manually).
The silence delay period is part of the signal interval, not the silence interval. This means that each non-silent period has --silencedelay silence at the start and at the end. If the silent interval between two signal intervals is less than (2 * silence delay), the silent part at the start of the second signal period will be shortened.
As a special case, if the threshold is set to 0 the usual numerical computation of the silence value is bypassed, and the sector is deemed to be silent if all samples are 0.
From left to right. Later settings may override previous ones. Beware to switch file formats before byte ordering, or a byte order might be rejected for the (then active) format. When not using cutting, remaining arguments are used to fill up input and output filenames. When using cutting, remaining arguments are assumed to be cut numbers. When using negative cut numbers, use -- to terminate option processing or the negative numbers can be mistaken as options (this is a must with GNU getopt()).
All options which take an argument denoting a time accept the following number format. The number may be in decimal, octal (leading 0), or hexadecimal (leading 0x or 0X). A one-letter unit may be following. If there is space between the number and the unit, both must be quoted, as in "55 C". These units are recognised: b (bytes), C (audio CD sectors), s (seconds). When no unit is given, C is assumed. The progress display might only show numbers in some of these units. Fractions for seconds are allowed.
Negative cut numbers are only allowed if the input size can be determined (which will not be possible if the input comes from a pipe), and are shown as the equivalent positive ones. If the last cut number is 0 it means the end of the file. If the input file size can not be determined the longest possible input (about 405 minutes) is substituted.
A filename of '-' is taken as stdin/stdout.
If wav2cdr was compiled to use GNU getopt(), argument scanning is more powerful and long options can be shortened to significance. Options are also re-ordered; this is nice but can be a trap. Use -- if in doubt, and don't mix options with filename or cut number arguments.
All data handling currently assumes signed 16-bit integers, interleaved for 2 channels, at a sampling rate of that of a CD. Only wav files with these parameters can be read correctly. cdr files are in that format, and only raw formats with these parameters can be processed. The only flexibility allowed for raw is the byte order, which can be specified for both reading and writing. The byte ordering for wav and cdr is fixed.
Left and right channel are swapped, which is the same as swapping consecutive 16 bit values with each other. Also see 'CDR Format' below.
Scaling can be performed with either integer or floating point arithmetic. Integer arithmetic is faster but possibly not as precise. Values will saturate (i.e. be clipped), rather than be truncated. The speed of this operation depends on the endianness of the input data, output data, and host. It is slowest when bytes have to be swapped before scaling and swapped back after. Negative scale factors are allowed but might be of dubious value.
Input data can be converted to mono and then back to stereo. The result is 2 channels with the same data. This can be useful in some cases.
Unless output is to stdout, the resulting filename is the name given with --outfile. A period and a 2-digit track number are appended.
Input data can be split into pieces resp. tracks. Currently cuts can only be placed at multiples of audio CD sectors (at the sector boundaries), whether the input format is cdr or not.
The cuts are placed at the given positions, which must be in ascending order (or equal). Negative numbers are counted from the end of the input data. This only works if the input is seekable (Unix pipes are not). Sectors of the input are numbered from 0. Bytes of a header, which the input format might have, are not counted.
Any number of cuts can be made, but only 99 tracks can be put on a CD. All sectors before the first but not including the first sector number are discarded, as well as all sectors after and including the last sector number. At least 2 sector numbers (cut numbers) must be given, in which case one piece is cut out.
If there are only 2 cut numbers (1 track to cut out) data can be written to stdout or file. More than one track can only be written to file, the track number will be added as an extension to the filename. To avoid the track number to be appended to the filename when only one cut is made, don't use --outfile but write to stdout and use output redirection.
Example (assuming 50000 sectors in the input):
wav2cdr < INPUT --outfile NAME --cut 500 20000 40000
sectors 0- 499: discarded
500-19999: saved to NAME.01
20000-39999: saved to NAME.02
40000-49999: discarded
Assuming a digitised record is stored in record.wav, and is to be cut into tracks.
wav2cdr < record.wav > cuts --silencecuts --silencedelay 2s
wav2cdr < record.wav --of tracks --cut `cat cuts`
Will store the tracks of the record in track.01, track.02, ..., with the delay for cutting at a silent part set to 2 seconds. The threshold used is the default. Note the `` syntax works under Unix and in this case puts the contents of file "cuts" on the command line.
--silenceinfo can be used in the same way as --silencecuts. It produces output like
(stdin):
silnc 0 b, 0 C, 0 s, 00:00.00 min
DIFF 811440 b, 345 C, 4 s, 00:04.22 min
--> 811440 b, 345 C, 4 s, 00:04.22 min
AUDIO 811440 b, 345 C, 4 s, 00:04.22 min
DIFF 20603520 b, 8760 C, 116 s, 01:56.05 min
--> 21414960 b, 9105 C, 121 s, 02:01.02 min
showing the beginning, length ("DIFF"), and end ("-->") of both silent ("silnc") and and non-silent ("AUDIO") intervals. This is useful for examining existing tracks, but it can not be used with --cut.
Progress messages and statistics are written to stderr when writing to stdout, and to stdout when writing to file. It is currently not possible to suppress this, other than by redirection to the bit bucket.
Only wav files with 2 channels, 16 bits per sample, and audio CD sampling rate can be written. If the input data is different, the resulting wav file is incorrect. Scaling can be performed when writing wav. Cutting can only be performed in multiples of an audio CD sector size. When writing wav the output must be seekable (e.g. no pipes).
Raw sample data at a sampling rate of 44100 Hz. The channels are interleaved. The numbers are 16 bit signed integers with this byte order: MSByte Left, LSByte Left, MSByte Right, LSByte Right. The track size must be a multiple of the sector size of 2352 bytes. There are 75 sectors per second.
All operations can only be performed on a minimum of 1 CD block or a multiple thereof.
Copyright (C) Nov, Dec 1997, Jan, Mar, Apr, May 1998, Feb, May, Jun, Jul, Aug 1999, Oct 2000, Jan 2006 by Volker Kuhlmann <VolkerKuhlmann@gmx.de> formerly c/o EEE Dept, University of Canterbury Christchurch, New Zealand
Permission granted to use and distribute this software free of charge, provided any improvements are sent back to the author. Comments and bug reports welcome. All rights reserved. Standard disclaimer applies.
Volker Kuhlmann
| 18 Jan 2006 | wav2cdr |