Daxaif uses a new lossless method to compress sampled audio. It accepts 8 or 16 bit files of any length, any sampling frequency, having up to 255 channels, in uncompressed wave, aiff, or audio CD format. Compressed files have the extension ".dax" and are of type "daxA" on Macintosh computers. The program requires at least 900 KB of memory and should run on any Macintosh using System 7 or later.
Groups of files, folders, CD tracks or disks can be dropped onto the program icon or dragged into the compression window. Uncompressed files are "queued" for compression (first in, first out) and additional files can be added at any time. Compressed .dax files bypass the queue and are opened immediately. They will also play in alphabetical order if the "Monitor" button is selected.
The audio in .dax files can be indexed using a compression factor map, which shows the amount of compression for each 0.1 second chunk of audio. A region of audio can be hilighted for playback or expansion back to AIFF format. An audio selection can be conveniently cropped by zooming and shift-clicking near the cut points. During playback a bar moves along the map to indicate the current file position.
Compression speed for CD audio ranges from about 10x slower than realtime for 68030 machines, to about 5x faster than realtime for 233 MHz G3s (plus CD or disk I/O times). Decompression of CD stereo requires less than 2% of the CPU on PowerPC's, so the program can play background audio while you word process or surf the internet. However, the play routines are currently not interrupt-driven and only buffer 2 seconds ahead, so the audio may stop during long mousedowns or dialog boxes.
The amount of compression depends on the amplitude, noise, and complexity of the input audio. Consistently loud music with a high harmonic content (Saxaphones, Electric Guitars, Cymbals) will compress only 10-20%. Music with alternating dynamics and fewer overtones (Piano, Flute, Opera) averages around 50%. Voice compression can be much higher.
The program was written to demonstrate a patented general-purpose fast data compression method [US patent #5,825,830, issued October 20, 1998, other national patents pending]. It is being distributed as shareware to find out whether it can be self-supporting. If enough $20 payments are received, I'll continue to improve it. or hire someone else to work on it. (Cut-and-paste multitrack editing, variable-loss dax recompression, color coding, text annotation, and MP3 output would be the next additions). If not, I'll have to spend my time consulting and licensing to companies...and you may end up waiting to pay more to get the same capabilities!
More information, including the most up-to-date version of daxaif, can always be found on the official daxaif home page at:
http://www.dakx.com/daxaif/
Please report bugs or suggested improvements by email:
mailto:bugs@dakx.com
mailto:suggestions@dakx.com
Warnings
Alerts are dismissed after 30 seconds to prevent hangups while you're away. You may miss some errors since there is currently no log file.
Preferences set in the compression window extension are saved in the resource fork of the daxaif program itself. Changes cannot be saved if the program resides on a locked or read-only disk. This inconvenience is offset by the ability to make duplicate copies of the program with different color, playback, or compression settings.
You must use this program at your own risk. No warranty, either expressed or implied, is given. This software is not certified for use in aircraft, nuclear power plants, medical therapeutic devices, or other applications where failure could place life or property in jeopardy. There is no guarantee that the .dax file format will continue to be supported on Macintoshes or any other computers or operating system platforms.
Daxaif 1.0 can be freely distributed as long as it remains unaltered and kept together with this ReadMe file. Anyone who converts the text resources to another language should not call the result " daxaif " until you mail me (dak@dakx.com) a copy so I can test it (If you wish, credit yourself for the translation in the About box). If it's OK, I'll make it available for download on the daxaif home page.
Licensing of the dakx compression method is available through DAKX, LLC, a registered North Carolina corporation, on the internet at http://dakx.com. DAKX, daxaif, dot-dax, .dax, and the two-blue-note logo are trademarks of DAKX, LLC. Macintosh is a trademark of Apple Computer, Inc.
Poweruser Hints
Once you've used the program a while, here are a few hints you might find useful:
• To view the color settings, click on the black triangle in the lower right-hand corner of the compression window. If you want to make color changes and the compression window is not visible, close all windows, select "Open" from the file menu, then cancel the file selection dialog. Different copies of the program can have different color and compression settings.
• The "Save Preferences" button also remembers the current location of the compression window.
• Clicking near the start or end of a selection plays 1 second from the start or to the end of the selection. Shift-clicking extends the selection and plays 0.5 second from/to the new cut point.
• Double-click plays the selection, zoomed display region, or file.
• Option-click plays from the mouse location to the end of selection or file.
• The clover key is not required to use the menu key equivalents. o,w,u,d will open and close files, zoom up and down, etc.
• If the cursor is in a .dax window, u,d will zoom up and down around the cursor position in that window, even if another window is selected.
• u,d can be used while making or extending a selection to get pinpoint accuracy.
• A zoomed window can be scrolled using the option key during mousedown.
• If the "Monitor" button is enabled at the time .dax files are opened, they will begin to play immediately. Groups of files or folders can be dragged onto the program icon to play sequentially. However this currently doesn't work using drags to the compression window since it would cause your computer to ignore mousedowns until all files are done playing.
• The space bar will toggle the "Monitor" button in the compression box.
• During compression, Caps-Lock will scroll the map in from the right.
• There is a grow region at the lower right corner of .dax windows. Change the window height to get better vertical resolution. There is also an invisible zoom box in the upper right corner which will zoom the window to fill the main screen.
• While listening to a .dax window, or monitoring an AIFF save:
Shift Fast-forwards the audio (no effect on contents of AIFF file)
+Control Even faster
+option Faster still
• While listening to a .dax window, or monitoring an AIFF save, z will zoom to display the next 30 seconds of audio. The map will shift as needed to keep the playbar in view. Additional u,z's will expand the window further.
• Suggestion for background playback:
Drop a folder containing .dax files onto the daxaif icon (having its preferences saved with the "Monitor" button hilighted), zoom the first window to fill the screen, and press z to start the automatic scrolling. This will make an interesting audiovisual desktop behind non-CPU-intensive programs (As I type this I'm listening to Bizet's "Carmen"). A future daxaif version or system extension might provide continuous background music regardless what other programs are running.
About CD importing
Audio CD's can have scratches and smudges which produce audio read errors. These are rarely noticed and CD playing programs usually ignore them. However, a program expected to provide lossless compression can't just sweep them under the rug.
A professional CD import program would read everything at least twice and give a warning if the copies were not identical. Unfortunately, this is all too likely to happen with your favorite, well-used CDs! Such a verification would also take too long for most consumer purposes.
The program compromises by reading slightly overlapped audio and verifying 800 bytes out of every 16484. If all goes well, the program will not complain. If verification fails, a warning alert will appear. After the first warning, you have the option of ignoring such errors for the rest of the tracks in the queue.
Short 0.12 second asynchronous reads are used to minimize memory usage, which is perhaps not the best way to read streaming CD audio reliably. Oddly enough, the newer fast CD drives seem to give more audio read errors than the old 1x or 2x drives. I do not pretend to be an expert in CD-reading technology. These routines were developed through experimentation on particular machines, and may not provide the best possible audio data. You always have the option of importing CD tracks into AIFF files using another and possibly better program, and then using daxaif to compress the result.
I apologize to those with non-Apple CD drives. I currently don't have the time or information to write general import routines. When a CD track is opened or dropped into the program, it will look for a CD in the default Apple drive only. If you have two CD's mounted, it may use the wrong one.
When the "Monitor" button is enabled, .dax files dragged onto the program icon will play in alphabetical order. To keep the original CD track ordering insert a zero or space before single-digit track numbers:
01 Cameo
02 Brazilian Breeze
...
10 Acrobop
11 Ellingtone Poem
...
On multivolume CD's, use file names like 1.01,1.02, 2.01, 2.02, etc. Or try:
Carmen 1/ 1 Overture
Carmen 1/ 2 Sur la place
...
Carmen 2/11 Enfin c'est toi!
...
During CD imports the program will keep everything before "/" for each output file, adding the track number. (You will be prompted to confirm this name if the "Save dialog: Every file" is checked in the compression window extension.)
Known Bugs
• File paths (including all subfolders) must be shorter than 255 characters.
• Sound files longer than 3276.7 seconds will have strange zoom and scroll characteristics. Files longer than 6553.5 seconds will not display properly. This is due to the size limitation of off-screen bitmaps.
• AIFF chunks in the original file other than the sampled sound will not be preserved across compression/decompression cycles.
• Files with more than two audio channels will not play properly. Output AIFF files are unaffected.
• Nested folder aliases are not resolved during drag-and-drop operations.
Version History
• daxaif 1.0b January 23, 1999
Black-and-white, AIFF files only
• daxaif 1.0b1 January 26, 1999
Fixed INST chunk skipping bug, freeze on error alerts during drag-and-drop
• daxaif 1.0 Feb 23, 1999
Color, WAVE files, CD import, full nested folder scans
D. A. Kopf /DAKX, LLC P. O. Box 1758, Pittsboro, NC, 27312, USA February 23, 1999
