The AHI-Handler is an I/O mechanism that is used to play and record
sounds. The AHI-Handler is normally mounted as AUDIO: at
startup time, or later by double-clicking on its icon or by giving the
following command in a Shell window: mount AUDIO: RET.
The DOSDriver entry is:
Handler = L:AHI-Handler Stacksize = 4096 Priority = 5 GlobVec = -1
When the device is mounted, you can read from the device to record and write to it to play. Options can be given like this:
"AUDIO:PRIORITY=1 VOLUME=50"
All slashes (`/') in the name will be translated to spaces. Thus, if you use slashes instead of spaces, you don't have to use quotes around the name:
AUDIO:PRIORITY/1/VOLUME/50
The full template for reading is:
B=BITS/K/N,C=CHANNELS/K/N,F=FREQUENCY/K/N,T=TYPE/K,L=LENGTH/K/N, S=SECONDS/K/N,BUF=BUFFER/K/N,UNIT/K/N
The full template for writing is:
B=BITS/K/N,C=CHANNELS/K/N,F=FREQUENCY/K/N,T=TYPE/K,V=VOLUME/K/N, P=POSITION/K/N,PRI=PRIORITY/K/N,L=LENGTH/K/N,S=SECONDS/K/N, BUF=BUFFER/K/N,UNIT/K/N
`BITS' can be one of 8, 16 or 32. `CHANNELS' can be either 1 for
mono or 2 for stereo. The `FREQUENCY' is in Hertz, `TYPE' is one of
`SIGNED', `AIFF' or `AIFC'.
`VOLUME' ranges from 0 (silence) to 100 (full volume), and
`POSITION' ranges from -100 (far left) via 0 (center) to 100
(far right). The `PRIORITY' can be from -128 to
127 (unstoppable). `LENGTH' is how many bytes you wish to read or
write, and `SECONDS' is the same, but in seconds instead of bytes.
The `BUFFER' size is specified in bytes. Note that two buffers are
always used, which means that the memory usage will be two times BUFFER.
`UNIT' selects which ahi.device unit to use.
The default options for reading are `BITS=8 CHANNELS=1 FREQUENCY=8000 TYPE=SIGNED LENGTH=very-very-much BUFFER=32768 UNIT=0'.
The default options for reading are `BITS=8 CHANNELS=1 FREQUENCY=8000 TYPE=<none> VOLUME=100 POSITION=0 PRIORITY=0 LENGTH=very-very-much BUFFER=32768 UNIT=0'.
If `TYPE' is not specified, the default behavior is to identify the data stream as IFF-AIFF or IFF-AIFC. If so, the default values of `BITS', `CHANNELS', `FREQUENCY' and `LENGTH' will taken from the file. You can still override them if you wish. If the stream could not be identified, the data format is assumed to be `SIGNED'.
Both when reading and writing the sample rate will be converted on the fly to what the underlying hardware is configured to. Normally this is not a big problem when writing, but the quality when reading leaves quite a lot to wish for, since no low-pass filters are used.
Example 1:
copy Louise.AIFF AUDIO:
plays the file `Louise.AIFF'.
Example 2:
copy AUDIO:SECONDS/10/TYPE/AIFC/B/16/F/44100/C/2 sample.AIFC
records 10 seconds of audio and stores it in the file `sample.AIFC' as uncompressed IFF-AIFC, 16 bit stereo at 44.1 kHz.
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