diff options
| author | cinap_lenrek <cinap_lenrek@felloff.net> | 2022-12-05 15:46:27 +0000 |
|---|---|---|
| committer | cinap_lenrek <cinap_lenrek@felloff.net> | 2022-12-05 15:46:27 +0000 |
| commit | cff0ebade5fb37b3d5614ae9ff76513e4b0e4640 (patch) | |
| tree | dce5da7b316b7cf71b4001808cd276f20d26ef16 /sys/man/1 | |
| parent | 48f53e57be61f7cee021fdb21849d4759770f722 (diff) | |
audio/scream: multicast audio protocol
Diffstat (limited to 'sys/man/1')
| -rw-r--r-- | sys/man/1/scream | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/sys/man/1/scream b/sys/man/1/scream new file mode 100644 index 000000000..9d0d26be4 --- /dev/null +++ b/sys/man/1/scream @@ -0,0 +1,77 @@ +.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 + |