MPEGAud - MPEG Audio Encoder/Decoder
Version 1.0a6
by George Warner
01/24/95
warnergt@aloft.att.com

REQUIREMENTS:
Mac with 68020 or greater (and possibly FPU depending on version).

1. WHAT IT IS: MPEGAud is a Macintosh program which can encode and decode 
MPEG audio to/from AIFF files.

2.  RELEASE INFORMATION: 
Release 1.0a6	01/24/95  Sixth alpha version.  Switched to Metrowerks 
CodeWarrior (from Symantec Think C).  Now able to create a native PPC 
version.  Yes, CodeWarrior is as great as everyone says (I was skeptical).
a. Now three flavors:
  MPEGAud PPC - Native PowerMac version.
  MPEGAud FPU - Version for 68020 (or greater) with FPU.
  MPEGAud NoFPU - Version for 68020 (or greater).
What?  You only have a 68000?  Don't even bother me for a 68000 version.
b. More accurately (i.e. correctly) tests for the presence of an FPU 
and for the presence of at least a 68020.
c. Current file name displayed.
d. More information available on files being decoded.  Hold down option 
key when selecting "Decode."  Input file information will be alternately 
displayed with the file name.
e. Drop-Launch Support does not work with PPC version.  This code is 
still under construction.  It will become available when I get 
AppleEvents fully working.
 
Release 1.0a5	01/15/95  Fifth alpha version.  Significant fixes.
a. Fixed memory initialization problems.  This was a result of the major 
memory management overhaul in the last release.  Problems occurred when 
more than one file was processed.
b. Some optimization.  Converted all floats to long doubles (which are supposed 
to be faster).  Using native floating point format.  Turned on optimizations.
c. More error checking.  Detects more bad ".MP2" files (and you thought my 
code had all the problems!).  Also added code to correctly save already 
decoded audio when corrupt data is detected.
d. Fixed AIFF icons to be more "grabbable."
e. Now tests for necessary Mac parameters (e.g. FPU).
f. Made default extension on encoded files ".MP2".
g. Fixed thermometer to work correctly on second and subsequent files.
h. Disabled Layer II bitrate and mode combinations that are not allowed.

Release 1.0a4	01/11/95  Fourth alpha version.  Many new changes.  

New features:
a. Drop-Launch Support!  -  Take your MPEG audio files and drag them onto the 
MPEGAud icon.  MPEGAud will launch, decode them into AIFF files, and quit.  
Drag a dozen MPEG audio files on MPEGAud and let them decode on you Mac 
overnight.  This is a nice compensating feature for the lack of speed.
Notes about the drop-launch support:
    It only supports decoding (launch app normal way for encoding).
    It will only decode files ending in ".MP2" or ".MPG" or files of types 'MPEG' or 'MPGA'
        (contact me if this list should include other file types).
    For a new filename, it will truncate the ".MP2" or ".MPG" extension, add the ".AIFF" 
        extension and overwrite any files in the folder with the new name.

Fixes since last release:
a. Overhauled memory management.
b. Fixed background processing.

New features that didn't quite make it:
a. AppleEvents: Almost all of the code is there, but it doesn't work.
b. MPEG audio layer 3 support.  This is another case where much of the code is 
written but it just isn't quite there.  This is not a rainy day project, but a 
rainy week project.  I don't expect to get it working soon.

Feature being phased out:
a. Support for PCM audio.  It really is easier supporting only one uncompressed 
data format, so AIFF will be the one.  Email me with any arguments for maintaining 
PCM support.

Release 1.0a3	04/19/94  Third alpha version.  Fixed a significant bug which 
caused it to hang with a Type 4 error (divide by zero).  Data in table 
resources was not totally correct.  Also, cleaned up the user interface a 
little and added a progress thermometer to the decode to complement 
the encode thermometer.
Release 1.0a2	04/17/94  Second alpha version.  Now allow it to decode 
types other than just 'MPEG' and 'MPGA'.
Release 1.0a1	04/16/94	First alpha version.  I wasn't going to make this 
generally available, but what the heck.  I know that there are some memory 
management issues but it seems pretty solid.


3.  PERFORMANCE: Yes, it's slow, but what do you want for nothing?  I already 
have plans for accelerating it with the DSP3210 in av Macs and I'm sure that 
there is plenty of room of optimization for regular Macs.  This will come 
in time.

4.  FUTURE CAPABILITIES:  Although it is not yet working, MPEGAud already 
contains some code for supporting Apple Events.

5.  WHAT YOU CAN DO:  Send me your constructive criticisms and new ideas.  
I'm currently juggling a number of projects right now so finding time for 
this one is not easy.  The level of interest in this program will certainly 
affect its priority in my schedule.