Parallel Recording; High Speed Recording - ARRI ALEXA Series User Manual

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12.1.3 Parallel recording

12.1.4 High Speed recording

Recording both internally and to external recorders simultaneously
offers additional workflow options. For example, the internal recording
can be used for dailies and proxy editing, while the external recorder
captures the master data. On ALEXA XTs or ALEXA Classic cameras
with an XR Module upgrade, the XR Capture Drive can capture the
ARRIRAW camera master while the REC OUT can be used to feed a
video assist.
Remote controlling the external recorder
Whenever the camera switches between record and standby mode, it
triggers the SDI record flag on the REC OUT connectors, signaling an
attached recorder to start or stop recording. The SDI record flag is an
ancillary data packet in the blanking area of the HD-SDI signal that
contains information about active recording.
Note: There is no feedback channel providing information to the camera if the
external recording is active. Check the external recorder directly to determine
whether or not recording is active.
Timecode on external recorders
To keep timecode locked across internal recording and the external
recorder when recording in parallel, configure the external recorder so
that it uses the TC embedded in the HD-SDI stream from the camera.
When a valid High Speed license key is installed, frame rates of 60 to
120 fps are enabled in 16:9 High Speed mode, and from 48 to 90 fps in
4:3 High Speed mode. 4:3 High Speed mode is only available on ALEXA
XT cameras and ALEXA Classic cameras with an XR Module upgrade
and in ARRIRAW recording mode.
For a detailed table of available frame rates and possible codec/card
combinations, please refer to the Chapter FPS on page 70.
The REC OUT output carries the same signal as the MON OUT during
High Speed mode (called 'MON OUT clone').
Note: Camera boot-time is increased by approximately 40 seconds when High
Speed mode is active during a power-cycle.
Operation of the Camera