SCREAM(1)SCREAM(1)
NAME
screamsend, screamrecv, screamenc, screamdec – multicast audio protocol
SYNOPSIS
audio/screamsend
[
interfaceip
]...
audio/screamrecv
[
interfaceip
]...
audio/screamenc
audio/screamdec
DESCRIPTION
Scream is a simple network protocol for transmitting PCM audio on a local network.
It sends UDP packets at a constant rate to the multicast address
239.255.77.77
on port
4010.
Each packet starts with a small 5-byte header that contains information about the
sample-rate and data format followed raw PCM data payload (maximum 1157 bytes).
Screamsend
reads PCM audio from
/dev/audio
and sends scream packets to the local network on the interface given by
interfaceip.
When
interfaceip
is omitted, it uses first IPv4 interface ip address from
/net/ipselftab
as a default.
Screamrecv
listens for packets from the local network on the interfaces
selected by
interfaceip
and writes PCM audio to
/dev/audio.
When no
interfaceip
addresses where given, it will listen on all interfaces with an IPv4 address.
Both
screamsend
and
screamrecv
are usually run after
audio/mixfs
(see
audio(1))
to provide loopback audio source as well as mixing for multiple senders.
Screamenc
reads PCM audio from standard-input and writes scream packets to standard-output.
Screamdec
reads scream packets from standard-input, and writes PCM audio to standard-output.
It spawns
audio/pcmconv
(see
audio(1))
to convert the audio in case the scream packet format is not
the default of 16-bit little-endian stereo samples at 44100 Hz.
It exits when no packets have arrived for 500 milliseconds.
SOURCE
/sys/src/cmd/audio/scream
SEE
audio(1).
https://github.com/duncanthrax/scream