Working with CODEX Media

CODEX Device Manager is a set of drivers and utilities required to support CODEX media stations on macOS.

The latest version is available to download from CODEX Software Downloads

Device Manager provides the following features:

• Control of CODEX reader hardware peripherals (e.g. Load, Eject).
• Ability to Format and Erase filesystems on CODEX media.
• Access to recorded data on Capture Drives (CODEX FS) via a Virtual File System
  
• High Density Encoding workflows for ARRIRAW on all CODEX media.

CODEX media can be formatted as UDF or CODEX FS depending on the camera/workflow being used, as summarised in Table 1.

Universal Disk Format (UDF)
UDF is used by ARRI ALEXA cameras on Compact Drive and Capture Drive:

• On ALEXA Mini LF with Compact Drive, UDF is used for both MXF/ARRIRAW and MXF/Apple ProRes recording.
• On ALEXA LF and ALEXA SXT with Capture Drive, UDF is used for Apple ProRes recording (in Quicktime MOV
  container).

CODEX FS (CFS)
ARRI ALEXA LF and SXT cameras support ARRIRAW recording to Captures Drives using the CODEX File System (CODEX FS). The same Capture Drives are also used for recording Canon Cinema RAW on the CODEX / Canon C700 Recorder, and Panasonic VRAW on the CODEX / Panasonic VRAW Recorder and VariCam Pure.

CODEX FS is a proprietary object store designed for high performance and reliability. When CODEX FS volumes are loaded on a macOS system, their content is presented via a software layer called the Virtual File System (VFS).

VFS volumes have some special features and properties that are detailed in the next section.

Identifying a VFS volume
VFS volumes appear with a black disk icon that is marked with the CODEX logo text.

X2XFUSE is the software component used to create each VFS volume. If the properties of a VFS volume are checked using Finder > File > Get Info (Cmd-I) the Format is listed as ‘x2xfuse’.

As VFS volumes are dynamic and virtual they have some other special properties - the Capacity will reflect the total size of all files presented on the VFS, and in the case of a HDE volume this may be very small.

The Available space is given as Zero bytes due to the volume being readonly.

A hidden JSON document named ‘.codexvfs’ can be found at the root of each VFS volume. It contains static information that may be useful to a file copier application, e.g.

• The Modification Time of the .codexvfs file is repeatedly updated while the file system is built (as new files are exposed via the VFS). For applications indexing a VFS volume it is recommended to compare the Modification Time pre and post index, to check whether the contents has changed during the indexing process. Checks separated by 2 seconds or more will detect any changes to the Modification Time. When the Modification Time stops updating, the file system has finished building. The command ‘stat -x .codexvfs’ can be used to check the Modification Time.
• The .codexvfs file contains the following useful information in JSON format:
  • Volume label and Media ID - can be used for tracking.
  • Log File - path to the log file that contains details of mount/unmount times and any checksum errors during
    the VFS session for this media.

When HDE mode is enabled:

• For ARRIRAW on Codex FS - the files shown are .arx instead of .ari.
• For MXF/ARRIRAW on UDF - a new volume with ‘_hde’ name suffix is shown that contains .arx files. The original volume containing the .mxf files will also remain mounted.

HDE (.arx) files have 2 extended attributes that can be used to calculate space requirements when performing a backup:

• codex.decodedSize: this attribute gives the full file size for a decoded .ari version of the file.
• codex.estimatedHDESize: this attribute gives a conservative estimate of the .arx file size, based on 75% of the original size.
  Note: HDE typically results in a file that is around 60% of the original size, but some headroom is given due to HDE being variable bit rate. For example, images with lots of high frequency detail (sharpness) will not reduce as much as images in soft focus, and could even exceed the 75% conservative estimate.

Volume names for Compact Drive and Capture Drive are set by the ALEXA camera when the media is formatted.  The volume name is built using these camera settings:

• Camera Id - e.g. A, B, C, etc.
• Reel Number - e.g. 001, 002, 003, etc.
• Camera Serial - e.g. R0Z3, U8W4.