by Nicholas J Humfrey
<njh@ecs.soton.ac.uk>
For the latest information on pcm6cast, please see: http://www.ecs.soton.ac.uk/~njh/pcm6cast/
pcm6cast is an audio streaming broadcaster and client using RTP over IPv6 Multicast.
Unlike VAT and RAT, which are designed primerily for audio conferencing, pcm6cast is designed to be used for audio distribution and broadcast.
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NOTE: This version doesn't support RTCP so doesn't inter-operate well with RAT but it will do in a future release. |
0 8000Hz Mono u-law encoded 16-bit PCM 8 8000Hz Mono A-law encoded 16-bit PCM 10 44.1kHz Stereo Raw 16-bit Audio 11 44.1kHz Mono Raw 16-bit Audio
Details are here: http://www.iana.org/assignments/rtp-parameters
You can listen to a test stream coming from Unversity of Southampton:
[hwickabab:~] njh% pcm6client FF1E:2001:630:d0:201:83::80/5000 Connecting to FF1E:2001:630:d0:201:83::80/5000. Joined multicast group. Waiting for first packet... Src IP: 2001:630:d0:201::83 SSRC: 0x1630b576 Payload: 0 Sample Rate: 8000 Hz Channels: 1 Size of first packet: 332 bytes |
Please email me if you have any problems listening. Please note that you must be connected to m6bone. (http://www.m6bone.net/)
SDL's audio output settings can be configured by setting environment variables.
You can choose the audio driver and sound card in this way.
For details see: http://sdldoc.csn.ul.ie/sdlenvvars.php
pcm6cast -f audiofile.aiff FF03::123/5010
Broadcast a sound file out to multicast group FF02::123 and port 5010
pcm6client FF03::123/5010
Listen to a stream on multicast on multicast group FF02::123 and port 5010
pcm6client -f recording.wav FF03::123/5010
Record stream to raw audio file
pcm6cast -d /dev/dsp -p 8 FF03::123/5010
Broadcast audio from sound card using payload 8
pcm6archive FF03::123/5010 output.mp3
Record stream and archive to MP3 Requires lame (http://sf.net/projects/lame)
pcm6client -q -p 10 -o FF03::123/5010 | \
sox -r 44100 -c 2 -w -s -t raw - \
-r 8000 -c 1 -w -s -t raw - | \
pcm6cast -p 10 -i FF03::124/5008
Downsample from payload 10 to another multicast group using payload 8
PowerMac G4 - Mac OS X 10.2.8 and 10.3.2
AMD K6 - Debian Linux 2.4.22
i386 - FreeBSD 5.1-RELEASE
PCM - Pulse Code Modulation A method by which an audio signal is represented as digital data.
Virtually all digital audio systems use PCM, including, CD, DAT, F1 format, 1630 format, DASH, DCC, and MD. Many people get confused because "PCM" is also slang for Sony's F1 format which stores PCM digital audio on videotape.
Last updated 12-Mar-2005 19:33:53 BST