This is a buffered audio player for Linux. POSIX-thread library is
used. This is still considered BETA software and may not work as
expected. Please mail me for bug reports, opinions or suggestions.

This is primarily made for use with MPEG-decoders. They typically
consume lots of CPU-time and some kind of audio buffer is needed to
reduce cutting while writing to audio device. You can also play any
audio files with tplay or use it with any program that writes audio 
data to standard out.

RIFF/WAVE (WAV) and Sun audio (AU) file headers are recognized by
now.

Binary:

In the source tree there is a readily compiled binary that is build
under Linux/ELF 2.0.30 with libc 5.4.20 and LinuxThreads 0.6 (the
thread library is statically linked).

Command line options:

  tplay [-hvVmuxrf] [-s Hz] [-b 8|16] [-B kilobytes] [filename]

	-h, --help		Print help, then exit
	-v, --version		Print version, then exit
	-V, --verbose		Print useful information about the sample
	-x, --swap		Swap endianness
	-r, --raw		Force raw audio format. Ignore headers.
	-f, --force		Force playing with any parameters
	-m, --mono		Mono sample
	-u, --usage		Print buffer usage while playing
	-s, --speed=SPEED	Sample speed (Hz)
	-b, --bytes=BYTES	Bytes in a sample
	-B, --buffer-size=SIZE	Buffer size in (kB)

Buffer size is defaulted to 512k. It is about 3 seconds CD audio
(44100Hz/sample, 16bytes, stereo). If filename is not given, standard
input is used. If -x (or --swap) flag is set, the byte order of
audio sample is swapped before playing. The default is Intel little-
endian which is mostly used in x86 machines. The world outside Intel
is big-endian.
Option -r (or --raw) forces tplay to handle the sample as an raw
PCM audio sample. Sun audio or WAV headers are ignored.

Requirements:

	- Linux 2.0 or newer with audio card support
	- POSIX thread library
	- Audio card

There are several POSIX thread libraries available. I used
LinuxThreads by Xavier Leroy (Xavier.Leroy@inria.fr). LinuxThreads
library use clone() that is provided by Linux 2.0 kernel. 

The code:

tplay starts one thread, named consumer, that reads circular audio
buffer and writes it to audio device. The producer is a function that
runs in parallel with the consumer and its task is to read the sample
file or standard input and write this data to audio buffer to meet
consumer's needs. Usually, the buffer is full but on the times when
CPU-time is suddenly needed for other processes (usually: disk
read/write), the producer can't write fast enough and consumer can use
the buffer to keep audio stream uninterrupted. If the buffer is used
and the producer is still unable to feed it fast enough, underflow
situation is met and consumer waits for awhile (typically: one second)
for the producer to fill the buffer again.

Building:

If you want to link tplay with static libpthread library, edit
Makefile and uncomment preferred LIBS-setting there.  Type:

	- make
	- make install
	- make install.man

Thanks:

Jerko Golubovic <jerko.golubovic@public.srce.hr>
Jukka Palviainen <oh3kjt@ele.tut.fi>

TODO:

Find out the best sizes for the audio buffer and one block.  
Better documentation.
Better RIFF/WAVE checking.

Ilkka Karvinen
ik@iki.fi