ARRI ALEXA - Parallel Recording; Highspeed Recording

110 Operation of The Camera
12.1.3 Parallel recording
Recording to both SxS PRO cards and external devics at the same time
requires additional attention from the user. First, it has to be determined
what function the two sets of data have. For example, the internal recording
could be used for on-set review and proxy editing, while the external device
captures the master data. Or the internal recording is used for TV utilization
and the external recorder captures ARRIRAW for cinematic use.
Remote controlling the external recorder
By activating the "SDI remote" in the REC OUT menu screen, it is possible
to control external recorders if they support this feature. When "SxS
recording" is set to On, this is only possible while recording to an SxS PRO
card.
Note: There is no feedback channel providing information to the camera if the
external recording is active - make sure to check the external recorder directly!
Timecode on external recorders
To guarantee the same Timecode for images that are parallely record
internally and exterally, set the external recorder so that it uses the TC
embedded in the HD-SDI stream coming from the camera.
12.1.4 Highspeed recording
With a valid license for highspeed recording installed, the camera can be
switched into highspeed mode. In highspeed mode, the camera can be
operated at frame rates of 60-120 fps. Recording is only possible on Sony
SxS PRO cards with ProRes codecs up to ProRes 422 HQ. ProRes 4444 is
not available in highspeed mode.
It is highly recommended to use Sony SxS PRO 64 GB cards, as only this
card type achieves the required write speeds.
The following table shows the achievable frame rates with the different SxS
PRO card types.
Regular speed
mode
Highspeed
mode
Codec
SxS
PRO 8-
32 GB
SxS
PRO 64
GB
SxS
PRO
8-32
GB
SxS
PRO
64 GB
ProRes 422
Proxy
60 fps 60 fps 120
fps
120 fps
ProRes 422 LT 60 fps 60 fps 120
fps
120 fps
ProRes 422 60 fps 60 fps 60 fps 120 fps