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READCDA2.DOC
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This file (READCDA2.DOC) describes the READCDA utility (version 2).
Index:
- What is READCDA2 ?
- What CD-ROM drives can be used ?
- How to use READCDA
- READCDA and Windows 3.xx/Windows 95
- Timing data
- Revision history
- List of CD-ROM drive that do/do-not support reading digital audio
- Credits
What is READCDA ?
==========================================================================
The READCDA program enables you to use your CD-ROM drive to read Digital
Audio Data from a Compact Disc. It reads the data digitally, so there is
no loss in quality.
What CD-ROM drives can be used ?
==========================================================================
Unfortunately not all CD-ROM drives support the drive call that enables
READCDA to read the data. I wrote this program and made it to work on a
Panasonic double speed drive (CR-562B, Creative Labs 2x drive). It also
works on various Sony and Teac drives.
!!!!!! It does NOT work on Mitsumi drives !!!!!
Thats Mitsumi's fault. They think the copyright issues could cause them
problems ...
Since we are on that subject, i take no responsibility for the use of
this program !!!
There are many CD-ROM drives.
On the end of this file is a list of CD-ROM drives that can be used.
How to use READCDA:
==========================================================================
The READCDA program can be used in two different ways:
1) By starting it without parameters. It will prompt for them.
2) By starting it with parameters. It will start directly (providing you
specified all the required parameters).
The possible parameters are shown when you start the READCDA program
with an unknown option (like -help ;-)).
It will display the following usage screen:
Usage: readcda [options]
If no options are specified the user is asked for the required data
Options: -file <output-filename> [needed]
-track <tracknumber> which track to read
-from <location> from where to read
-length <length> how long to read
Note: -track or -from are needed, and -from must be combined with -length
where -track CAN be combined with -length
both -length and -from can be 'min:sec' or sector number
Extra options:
-debug <level> Display more output with higher level
-wav Write an WAV file (=default)
-cdda Write the RAW CDDA output
-nbuf <#buf> Use #buf buffers (default 20x18K), for better memory usage
-swapbytes Swap all bytes (MSB/LSB) in output
-swapwords Swap all words (channels) in output
-nosynch Skip the synchronization algorithm
-synch Keep using the synchronization algorithm
Normal usage with parameters would be (example):
readcda -track 4 -length 0:10 -file some.wav
or
readcda -from 05:23 -length 0:10 -file some.wav
The options change the way READCDA works:
-debug
Will add extra debug output
-wav (default)
Will write a WAV output file, playable in Windows
-cdda
Will write RAW digital output
-nbuf (default is determined automatically, 18K each)
Changes the number of buffers used for reading the data.
Those buffer are filled, and written to the output file.
Then the data in the last buffer is re-read plus the rest of the buffers
The larger the number of buffers the better performance, since 1 in
nbuf buffers will we read twice.
The READCDA program try and reserve as much buffers as possible.
If the program won't work properly you can try to run it with less
buffers.
-swapbytes
Swaps all the bytes read from the CD. One CD-ROM drive (a HP4020i)
has been reported to need this.
-swapwords
Somebody claimed that the Left and Right channel were swapped.
I do not beleive so, but this option will do the job.
-nosynch
READCDA will tell you if synchronization is not needed. You can
then speed up the program by adding the '-nosynch' switch.
You can also use this switch to measure what speed you drive is
capable of reading digital audio.
-synch
Causes READCDA to USE the synchronization algorithm.
READCDA and Windows 3.xx/Windows 95
==========================================================================
Since READCDA is a dos program, it will not use Windows when you run
it in Windows. But many people might run it in Windows anyway, since
that is their normal environment.
A few remarks concerning the use of READCDA from within Windows.
- If it fails to operate like it should (resulting in synchronization
errors) try disabling any SMARTDRV or other caching on your CD-ROM
drive. You can do this for smartdrv with 'SMARTDRV D-' or whatever
drive your CD-ROM is...
- Using READCDA from withing Windows 95 is NOT straightforward. Since
READCDA does work in Windows 3 you would expect it to work in
Windows 95. But is doesn't !!! You can solve the problem by
installing the old (16-bit) device driver and the MSCDEX (which IS
supplied with Windows 95) in CONFIG.SYS and AUTOEXEC.BAT. When you
do that READCDA works again. Somehow Microsoft did not make the
newer CDFS device driver compatible with Windows 3.xx plus the
CD-ROM device driver/MSCDEX.
Timing data:
==========================================================================
This feature is put in by Stewart Addison. His description:
The program measures the speed of the drive when reading DA. The final
output of the program will show the reading speed with a line such as:
Reading speed was somewhere between 0.94x and 1.23x
Two values are given for the reading speed. The lower value is
calculated by timing the overall execution time. This will include the
time taken to write the output to the hard drive, so unless your hard
drive is extremely fast, this will be lower than the actual CD-DA
reading speed.
The second value is calculated from the time the program spends in the
ReadLong function, which is the function which actually performs the DA
extraction. In theory this only takes into account the speed of the
CD-ROM drive so this figure should be accurate. However, it can be
higher than the true value, since the CD-ROM drive may cache the reads
while the program is writing the output, so the subsequent ReadLong will
be faster.
The above output is from a drive which performs DA extraction at single
speed - the true value is 1.00x. Depending on your system, when writing
the output to a file and performing synchronization you may get results
lower than the true DA reading speed.
You can usually obtain an accurate speed measurement by sending the
output to the NUL device, and performing a read of at least one minute.
The command line:
readcda -file NUL -track 1 -length 01:00
Should give you an output with both speeds virtually identical.
If you also specify the -nosynch commandline option than the
theoretical maximum reading speed of the CD-ROM drive is measured.
I've tried it on four drives, and all give different results:
My own Pioneer DR-UA124X : Single speed with or without synchronization.
0% Synchronization errors
An NEC273 : Reads dual speed with -nosynch, a bit less (~1.6x) with
synchronization. Usually <10% sync. errors
A Goldstar GCD-R540B : Reads at single speed with -nosynch, slower with
sync. 100% synchronization errors (all the time)
3*Panasonic 563B : Like the NEC for speed, but usually gives 100%
errors - 2 were on 386/40s, the third on a DX/2-66
Revision history:
==========================================================================
READCDA was written in august 1994.
It was based upon a simple source by Yeng-Chee Su, found on the Net.
To that source I added a synchronization algorithm, that prevented
problems with not so fast drives and/or systems.
It did not contain major bugs, so it remained unchanged for a long
time. In the meantime Michiel Overtoom wrote a Windows program based
upon the source of READCDA, which has a much better user interface.
But a few people came with some wishes and there were a few small
bugs, so I decided to write a version 2.
It is now August 1996. Version 2 is here !
It contains:
- The buffers are only half of what they were resulting in 10-20%
better execution time, since there is less data read twice.
- Some bugfixes in the synchronization algorithm
- Commandline parameters
- Timing data is given after the reading process (Thanks Stewart!)
- Commandline parameters for controlling some (extra) features
Drives that do/do-not support reading digital audio:
==========================================================================
The list below contains some drives that do or do not support reading
digital audio. This list is far from complete however. For a better
list please look at the WEB pages about reading digital audio on:
http://www.tardis.ed.ac.uk/~psyche/pc/cdrom/CDDA.html
IDE-like CD-ROM drives that do support the reading of digital audio:
- Sony CDU31, CDU33, CDU55, CDU76 , others probably
- Panasonic/Creative Labs drives (I think all of them)
- Toshiba XM-5302B
- Teac 4x
- Hitachi
- Pioneer DR-UA124X
SCSI CD-ROM players that work (maybe not with DIDO or READCDA, but
some other programs do support SCSI CD-ROM drives, like DA2WAV and
CDINFO):
- Apple 300, 300i, 300e (Sony CDU-8003, CDU-8003A)
- Apple CD300+
- Chinon CDS-535
- NEC CDR 200, 300, 400, 500, 600, 900 series
- NEC CDR 84-1/74-1 (with special firmware) (yet to be verified)
- Plextor (formerly TEXEL) DM-3028, DM-5028
- Sony CDU-561
- Toshiba XM3301 (Silicon Graphics)
- Toshiba XM3401, XM4101, XM3501
Drives that do NOT support reading digital audio:
- Mitsumi
- Yamaha
- Aztech
- Goldstar (Some newer ones DO support it)
Credits:
==========================================================================
The first one to thank is Yeng-Chee Sy (yenchee@csie.nctu.edu.tw) for
his initial source. I found it somewhere in a newsgroup on usenet.
After making it this little program definitely proved the
possibilities of first usenet and later the internet.
I get about one e-mail every two weeks, and that about 2 years after
writing the first version of READCDA !!!
So thanks to everybody that came with suggestions.
Special thanks to:
- Michiel Overtoom <motoom@xs4all.nl> for writing the nice DIDO
program for Windows (See http://www.xs4all.nl/~motoom ).
- Bodo Wolf <Bodo@Wolf.Ping.de> for is input for commandline parameters.
- Stewart Addison <psyche@tardis.ed.ac.uk> for putting the timing
stuff in READCDA and for finding some obscure bugs.
Hopefully i did not forgot any of you ...
If you have any questions, don't hesitate to mail me.
Also checkout the WEB pages about CD-DA from Stewart Addison:
http://www.tardis.ed.ac.uk/~psyche/pc/cdrom/CDDA.html
Klaas Hemstra <hst@mh.nl>