Format Sensor
Mode
Reso-
lution
Color
Coding
Data
Rate
2
64 GB
SxS
PRO
2
XR
Capture
Drive
2
120 GB
CFast
2.0
2
16:9 1920 x
1080
12 bit
RGB
280
Mbit/s
29 min 107 min 53 min
1
Without alpha channel (444 only)
2
Data rate/recording time@24 fps; Apple ProRes
TM
is a variable bit rate
codec, meaning that the available recording time is subject to the
image content. The number given in the table is the MINIMUM
available recording time. When image content is easily compressed
without loss of image quality, the available recording time may exceed
the number given in the table.
Also note that the available recording time is listed for 24 fps. A lower
sensor frame rate will increase the available recording time, while a
higher sensor frame rate will decrease it.
For a detailed table of available frame rates and possible codec/card
combinations, please refer to the Chapter FPS on page 70.
DNxHD
With the DNxHD license key installed, the ALEXA can record 1920 x
1080 (16:9) DNxHD encoded MXF files internally. MXF/DNxHD material
can be edited in Avid Media Composer Version 5.5 and later without
transcoding.
The Material eXchange Format (MFX) is a core media container
technology for nonlinear workflows. An MXF container file can "wrap"
different types of video and audio material along with associated
metadata. The internal structure of MXF files is defined by the so-called
Operational Patterns. ALEXA cameras record DNxHD encoded images
together with sound and embedded metadata in an MXF container file
using the Operational Pattern 1a (OP1a) file structure. An Avid Media
Composer does not need to transcode this material, as it already is
available in a native DNxHD codec. The OP1a MXF format packages
picture, sound and metadata in a single file. This is ideal for both
camera acquisition and archiving since audio and video is always kept
together and no data is lost if recording is interrupted for any reason.
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