Table of Contents
Formats used for audio storage are Broadcast Wave Format (BWF), as specified in EBU Tech Pub 3285 with annexes.
Commands to the Core Audio Engine are passed by means of a TCP SOCK_STREAM connection to TCP port 5005 on the host server.
Commands have the following general syntax:
cmd-code [arg] [...]!
cmd-code
A two letter command code, describing the generic action to be performed
arg
Zero or more arguments, delimited by spaces or, if the last argument, by ! (see below)
The ASCII character 33, indicating the end of the command sequence.
Unless otherwise specified, the engine will echo back the command with a + or - before the !, to indicate the success or failure of the command execution.
Pass a password to the server for authentication.
PW
password!
password
Returns: PW +! to indicate success,
PW -! to indicate failure
Prepare an audio interface to play an audio file, while also muting all stream-to-port mixer controls for the stream that is internally allocated by caed(8).
LP
serial
card-num
port-num
name!
serial
card-num
port-num
name
Returns: LP
serial
card-num
port-num
name!
Free an audio playback interface.
UP
serial!
serial
The serial value used in the
corresponding Load Playback command.
Position the playback pointer.
PP
serial
position!
serial
The serial value used in the
corresponding Load Playback command.
position
Position in file, in milliseconds.
Play the loaded file from the current position.
PY
serial
length
speed
pitch-flag!
serial
The serial value used in the
corresponding Load Playback command.
length
Playback length in milliseconds, relative to the current start position.
speed
Playback speed in thousandths of a percent. 100000 = normal speed.
pitch-flag
Controls whether audio pitch changes with speed or not. 0 = no, 1 = yes.
Stop playback of the specified playback interface.
SP
serial!
serial
The serial value used in the
corresponding Load Playback command.
Set the volume of an output playback.
OV
serial
level!
serial
The serial value used in the
corresponding Load Playback command.
level
The level, in hundreths of a dB.
Transition the volume of an output playback over time.
FV
serial
level
length!
serial
The serial value used in the
corresponding Load Playback command.
level
The level, in hundreths of a dB.
length
The length of the transition, in milliseconds.
Prepare an audio interface to capture an audio file.
LR
card-num
port-num
coding
channels
samp-rate
bit-rate
name!
card-num
The number of the audio adapter to use.
port-num
The input port number to use. This is relative to the audio adapter selected.
coding
0 = PCM16, 1 = MPEG Layer 1, 2 = MPEG Layer 2, 4 = PCM24
channels
1 = Mono, 2 = Stereo
samp-rate
Sample Rate in samples/sec. 32000, 44100 or 48000 supported.
bit-rate
MPEG Bit Rate. For PCM, this should be zero.
name
The base name of a file in the audio storage filesystem. If the file already exists, it will be overwritten, otherwise it will be created.
port-num corresponds to
the recording stream number used internally by
caed(8).
Free an audio capture interface.
UR
card-num
port-num!
card-num
The card-num value used in the
corresponding Load Recording command.
port-num
The port-num value used in the
corresponding Load Recording command.
Returns: UR
card-num
port-num
length!
length
Length of recording, in mS.
Record a loaded file.
RD
card-num
port-num
length
threshold!
card-num
The card-num value used in the
corresponding Load Recording command.
port-num
The port-num value used in the
corresponding Load Recording command.
length
Length of time to record in milliseconds. If zero, record until sent a Stop Recording command.
threshold
Threshold of audio detected at which to start recording, in 1/100 dBFs. If '0', start immediately.
Returns: When recording actually begins, a Record Start (RS) confirmation will be echoed back. If record time expires a Stop Record (SR) confirmation will be echoed back.
Stop recording of the specified record interface.
SR
card-num
port-num!
card-num
The card-num value used in the
corresponding Load Recording command.
port-num
The port-num value used in the
corresponding Load Recording command.
Receive-only signal to indicate recording has actually started (as with a VOX event, where actual recording may begin some time after the interface is placed into record).
RS
card-num
port-num!
card-num
The card-num value used in the
corresponding Load Recording command.
port-num
The port-num value used in the
corresponding Load Recording command.
Set the volume of an input stream.
IV
card-num
port-num
level!
card-num
The card-num value used in the
corresponding Load Recording command.
port-num
The port-num value used in the
corresponding Load Recording command.
level
The level, in hundreths of a dB.
These commands operate independently of any specific playback or recording operation.
Set the gain level of an output port.
OL
card-num
port-num
level!
card-num
The number of the audio adapter to use.
port-num
The port number to use. This is relative to the audio adapter selected.
level
The level, in hundreths of a dB.
Set the mode of an output port.
OM
card-num
port-num
mode!
card-num
The number of the audio adapter to use.
port-num
The output port number to use. This is relative to the audio adapter selected.
mode
The mode, as follows:
0
Normal
1
Swap left and right channels
2
Left audio on both channels
3
Right audio on both channels
Set the gain level of an input port.
IL
card-num
port-num
level!
card-num
The number of the audio adapter to use.
port-num
The input port number to use. This is relative to the audio adapter selected.
level
The level, in hundreths of a dB.
Set the mode of an input port.
IM
card-num
port-num
mode!
card-num
The number of the audio adapter to use.
port-num
The input port number to use. This is relative to the audio adapter selected.
mode
The mode, as follows:
0
Normal
1
Swap left and right channels
2
Left audio on both channels
3
Right audio on both channels
Set the signal type of an input port.
IT
card-num
port-num
type!
card-num
The number of the audio adapter to use.
port-num
The port number to use. This is relative to the audio adapter selected.
type
The mode, as follows:
0
Analog
1
AES3 Digital
Request the status of an input port.
IS
card-num
port-num!
card-num
The number of the audio adapter to use.
port-num
The port number to use. This is relative to the audio adapter selected.
Returns: IS
card-num
port-num
status!
status
The status, as follows:
0
OK
1
No Sync
Set the gain of an audio passthrough path.
AL
card-num
input-num
output-num
level!
card-num
The number of the audio adapter to use.
input-num
The input number to use. This is relative to the audio adapter selected.
output-num
The output number to use. This is relative to the audio adapter selected.
level
The level, in hundreths of a dB.
Set UDP port to which to send meter update messages for the specified card(s). If set to a non-zero UDP port, update messages (see below) from the specified cards will be sent to that port.
ME
udp-port
card0
..!
udp-port
UDP port number.
card0
Audio card number for which to send updates.
The following messages are sent by CAE to indicate audio levels and playout positions. They are sent to the UDP port requested by the Meter Enable ['ME'] command.
Current meter levels of an input or output port.
ML
type
card-num
port-num
left-lvl
right-lvl!
type
Type of meter.
I
Input
O
Output
card-num
The number of the audio adapter to use.
port-num
The port number on the audio adapter.
left-lvl
Left channel level, in 100ths of dBFS.
right-lvl
Right channel level, in 100ths of dBFS.
Send current meter level of the output stream.
MO
serial
left-lvl
right-lvl!
serial
The serial number of the playback event, from the Load Playback call.
left-lvl
Left channel level, in 100ths of dBFS.
right-lvl
Right channel level, in 100ths of dBFS.