diff options
Diffstat (limited to 'audio/maplay/pkg-descr')
| -rw-r--r-- | audio/maplay/pkg-descr | 186 |
1 files changed, 0 insertions, 186 deletions
diff --git a/audio/maplay/pkg-descr b/audio/maplay/pkg-descr deleted file mode 100644 index 5eb691764c05..000000000000 --- a/audio/maplay/pkg-descr +++ /dev/null @@ -1,186 +0,0 @@ -/* - * @(#) MPEG Audio Player maplay 1.2, last edit of this file: 6/23/94 13:02:49 - * @(#) Copyright (C) 1993, 1994 Tobias Bading (bading@cs.tu-berlin.de) - * @(#) Berlin University of Technology - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - */ - - -This is the README file of the MPEG Audio Player maplay, Version 1.2. -Besides this file, you should now own a copy of the following files: - - ANNOUNCEMENT the announcement for this release - INSTALL infos about compiling and installing the program - COPYING the GNU General Public License - Makefile a makefile - configuration.sh a shell script used by the makefile - -and the source files - - all.h maplay.cc subband_layer_1.h - crc.cc obuffer.cc subband_layer_2.cc - crc.h obuffer.h subband_layer_2.h - header.cc scalefactors.cc synthesis_filter.cc - header.h scalefactors.h synthesis_filter.h - ibitstream.cc subband.h ulaw.cc - ibitstream.h subband_layer_1.cc ulaw.h - -------------------------------------------------------------------------------- - -0) Introduction - -MPEG is a standard created by the ISO (International Organization for -Standardization) and the IEC (International Electrotechnical Commission). -The full name of this standard is "ISO/IEC DIS 11172: Information -Technology - Coding of moving pictures and associated audio for digital -storage media ut to about 1.5 Mbit/s". As the name already states, -it deals with digital video and audio. The video part of this standard has -inspired many people to write decoders and a few encoders for it. -Best known should be the Berkeley player. Players for the audio part on -the other hand are very rare. The ones I know are the XING player for Windoze -and a sample implementation of the ISO, which also includes an encoder. - -The audio part of the MPEG standard specifies three layers, whereat each -layer specifies its own file format. All three layers are using similar -audio coding techniques, but they vary in efficiency and complexity. -Layer I needs the fewest calculation time for en-/decoding a stream, layer III -the most. But a layer I MPEG audio stream is bigger than a layer III stream -at the same quality. This program is able to decode and play only layer I -and II streams, layer III is not supported (yet?!?). - -Like the MPEG video standard, the audio part also uses a lossy compression -algorithm, which means that you can't get back 100% the original from a -MPEG audio stream. Layer II MPEG audio streams are compressed by ratios -from 1:3 up to 1:24 compared to raw PCM data, like on an audio CD. -But the quality is still very (very) near to the original at ratios between -1:5 and 1:12. You'll love it... :-) - -------------------------------------------------------------------------------- - -1) What does maplay? - -maplay version 1.2 is the second release of my MPEG audio player/decoder. -It decodes layer I and layer II MPEG audio streams and plays them -using a CD-quality audio device. Currently supported devices are the -dbri device of SPARC 10 computers and the audio ports of Silicon -Graphics Indigo machines. Thanks to Louis P. Kruger (lpkruger@phoenix. -Princeton.EDU), maplay 1.2 can also use the /dev/dsp device under Linux. -Louis has tested it with the Pro Audio Spectrum 16 soundcard. Sound Blaster 16 -and Gravis Ultrasound cards should also work, but a bug in the dsp driver -prevents stereo playback on Gravis Ultrasound cards. An amd device of a -SPARC 2/IPX/... machine can be used, too, but this device is only capable of -producing audio output at 8 kHz in u-law format, which sounds like transmitted -through a telephone. Other audio device are not supported directly, but can be -used with the "decode to stdout" option and an audio format converter. -Besides it shouldn't be a problem to adapt the program to other audio devices. - -The player supports all modes, which are single channel, stereo, -joint stereo and dual channel, and all bitrates except free mode. -The missing free mode support should not be a problem for now, -because I haven't seen such a stream yet. - -maplay needs approximately 46% CPU time on SPARC 10/40 machines and 50% -on Indigos for realtime stereo playback of a 44.1 kHz 128 kbit/s stream. -Single channel playback needs about the half CPU time. On a SPARCstation IPX, -maplay needs about 43% CPU time for realtime mono playback. Stereo playback -is not possible via an amd device. - -Besides realtime playing of audio streams, maplay can decode streams to -stdout for further conversions. The output consists of 16 bit signed PCM -values. For stereo streams, the values are interleaved, which means that -a value for the left channel is followed by a value for the right channel -and so on. If maplay has been compiled for u-law output, the output consists -of 8 bit u-law samples at a rate of 8 kHz, no matter what frequency the stream -uses. - -------------------------------------------------------------------------------- - -2) How to create a maplay binary? - -Please read the install file for this topic. - -------------------------------------------------------------------------------- - -3) How to start the program? - -For a quick mono test enter "./maplay -v -l filename", where filename is the -name of an audio stream, like "things.mp2". This stream has been posted along -with the sources and is the beginning of Roxette's song "Things Will Never Be -The Same". It is coded in joint stereo mode with 128 kbit/s, which is a -compression ratio of 1:11. If the output is ok, you can test stereo playback -by leaving out the -l option. If the stereo output stutters, the problem is -not enough free CPU time in most cases. Stereo output is not possible when -using an amd u-law device. If maplay shows error messages like -"ioctl AUDIO_GETDEV on /dev/audio: ..." -and maplay was compiled for u-law output, please try out the -amd option. -This option forces maplay to treat /dev/audio as an amd device and may be -required on SPARC clones. - -To convert a MPEG audio stream into other audio formats, you can use -"maplay -v -s filename | your_converter". Unfortunately, I can't be of much -help for you to find such a converter. The only good converter I know is the -"soundfiler" on Indigos. But if you would have an Indigo, you wouldn't need a -converter... - -------------------------------------------------------------------------------- - -4) Command line options - -maplay [-v] [-s] [-l] [-r] [-us] [-uh] [-ul] [-amd] [-c] [-f ushort] filename - -with these options: - filename filename of a MPEG audio stream or - for stdin - -h short help - -v verbose mode - You will get information about the stream, like mode, bitrate, - copyright etc., if you use this option. - -s stdout mode - This option tells the program to decode the stream to stdout. - The created output contains 16 bit signed PCM samples. If the - binary has been compiled for 8 kHz u-law format usage, the - output consists of 8 bit u-law samples at a 8 kHz rate. If the - stream is in stereo mode, the samples of both channels are - interleaved, the sample for the left channel first. - -l maplay decodes (and plays) the left channel of stereo streams - only. This option halves the required CPU time. - -r Same as above, but decodes the right channel only - -us, -uh These options are available on SPARCstations only. - They specify where the audio signal should be send to: - "-us" means speaker and "-uh" headphone jack. - -ul This option is available on machines with the dbri device - and sends the audio output to the line out jack. - -amd This option forces maplay to treat /dev/audio as an amd - device. Use it if your SPARC clone has an amd device, but - maplay doesn't recognize it. You may also use this option on a - machine with a dbri device, because the dbri device can also - produce u-law output. But I suggest to recompile the program - without the ULAW define in this case to get the CD-quality - output. - -c This option instructs the program to report filter range - violations to stderr. Sometimes PCM values calculated by - the synthesis filter exceede the 16 bit boundary and must - be mapped to these boundaries. If you can hear this, you - may use the next option. - -f ushort maplay uses this scalefactor instead of the default value 32768 - for the synthesis filter. You can reduce or eliminate range - violations with this option, but lower scalefactor values - reduce the signal-to-noise ratio, too. I can't remember when - I used this option the last time myself. - - -Ok, that's all for now and this release, -I hope you like it, - Tobias Bading (bading@cs.tu-berlin.de) |