ref: 7a503757b1251c2746df7bdcd891814c1518cc28
dir: /sys/man/1/scream/
.TH SCREAM 1 .SH NAME screamsend, screamrecv, screamenc, screamdec \- multicast audio protocol .SH SYNOPSIS .B audio/screamsend [ .I interfaceip ]... .br .B audio/screamrecv [ .I interfaceip ]... .br .B audio/screamenc .br .B audio/screamdec .SH DESCRIPTION .PP 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 .B 239.255.77.77 on port .BR 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). .PP .I Screamsend reads PCM audio from .B /dev/audio and sends scream packets to the local network on the interface given by .IR interfaceip. When .I interfaceip is omitted, it uses first IPv4 interface ip address from .B /net/ipselftab as a default. .PP .I Screamrecv listens for packets from the local network on the interfaces selected by .IR interfaceip and writes PCM audio to .BR /dev/audio . When no .I interfaceip addresses where given, it will listen on all interfaces with an IPv4 address. .PP Both .I screamsend and .I screamrecv are usually run after .I audio/mixfs (see .IR audio (1)) to provide loopback audio source as well as mixing for multiple senders. .PP .I Screamenc reads PCM audio from standard-input and writes scream packets to standard-output. .PP .I Screamdec reads scream packets from standard-input, and writes PCM audio to standard-output. It spawns .I audio/pcmconv (see .IR 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. .SH SOURCE .B /sys/src/cmd/audio/scream .SH SEE ALSO .IR audio (1). .br .B https://github.com/duncanthrax/scream