1 ALaw/uLaw sample formats
2 ------------------------
3
4 This driver does not support the ALaw/uLaw sample formats.
5 ALaw is the default mode when opening a sound device
6 using OSS/Free. The reason for the lack of support is
7 that the hardware does not support these formats, and adding
8 conversion routines to the kernel would lead to very ugly
9 code in the presence of the mmap interface to the driver.
10 And since xquake uses mmap, mmap is considered important :-)
11 and no sane application uses ALaw/uLaw these days anyway.
12 In short, playing a Sun .au file as follows:
13
14 cat my_file.au > /dev/dsp
15
16 does not work. Instead, you may use the play script from
17 Chris Bagwell's sox-12.14 package (available from the URL
18 below) to play many different audio file formats.
19 The script automatically determines the audio format
20 and does do audio conversions if necessary.
21 http://home.sprynet.com/sprynet/cbagwell/projects.html
22
23
24 Blocking vs. nonblocking IO
25 ---------------------------
26
27 Unlike OSS/Free this driver honours the O_NONBLOCK file flag
28 not only during open, but also during read and write.
29 This is an effort to make the sound driver interface more
30 regular. Timidity has problems with this; a patch
31 is available from http://www.ife.ee.ethz.ch/~sailer/linux/pciaudio.html.
32 (Timidity patched will also run on OSS/Free).
33
34
35 MIDI UART
36 ---------
37
38 The driver supports a simple MIDI UART interface, with
39 no ioctl's supported.
40
41
42 MIDI synthesizer
43 ----------------
44
45 This soundcard does not have any hardware MIDI synthesizer;
46 MIDI synthesis has to be done in software. To allow this
47 the driver/soundcard supports two PCM (/dev/dsp) interfaces.
48
49 There is a freely available software package that allows
50 MIDI file playback on this soundcard called Timidity.
51 See http://www.cgs.fi/~tt/timidity/.
52
53
54
55 Thomas Sailer
56 sailer@ife.ee.ethz.ch
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