PIX 240i with Arri Alexa

Jesse describes the simple process to set the PIX 240i to record and follow from the Arri Alexa. Start/Stop, time code, and file name metadata are carried across from camera to recorder.

Introduction

Sound Devices PIX 240i recorder is a powerful, flexible recording companion for the Arri ALEXA. ALEXA’s built-in recorder records to removable SxS cards. Recording to the PIX 240i provides a secondary recording destination for immediate back up, a different storage medium type, and a different codec. Because the PIX 240i records to either Apple ProRes or Avid DNxHD files, a connected PIX 240i can be set differently from the camera to provide files for different purposes. One common application for the PIX 240i files is as REC 709 proxy files for instant dailies along with LOG C files recorded to the SxS cards.

To get the most out of the PIX 240i, proper connection and setup are necessary. Various settings in both the ALEXA and PIX 240i are described in this note.

Interconnection

Connect the PIX 240i to either of camera’s REC OUT SDI connectors. Connect to SDI IN on the PIX 240i.

Alexa Menu Settings

Numerous menu setting on the ALEXA are necessary for proper interconnection with the PIX 240i including:

  • HD-SDI format type
  • Output frame rate
  • Scan format
  • Output range
  • SDI remote
  • Color gamma
  • Time code

Each step is described below.

ALEXA Menu

Access the “REC OUT” settings in the ALEXA’s menu by navigating to Menu > Recording > REC OUT.

Frame Rate – ALEXA Setting

This setting controls the frame rate being sent to the REC OUT SDI outputs used to send the digital video signal to the PIX 240i. The PIX 240i will accept any frame rate compatible with the PIX 240i.

HD-SDI Format – ALEXA Setting

When recording 4:2:2 on the PIX 240i, this should be set to 422 1.5G SL

Scan Format – ALEXA Setting

Available options include “psf” (progressive segmented frame), and “p” (progressive). Both options result in a usable signal being sent to the PIX. Progressive is recommended because no scan conversion takes place.

Output Range – ALEXA Setting

Set to Legal. An image encoded in 10-bit legal range has a code value range from 64 to 940 (876 code values), and a 10-bit extended range signal has a code value range from 4 to 1019 (1015 code values). Apple specifies that ProRes should use the legal range.

SDI Remote – ALEXA Setting

Set SDI Remote to “On”. Once set, the SDI start/stop trigger is sent to the SDI outputs of ALEXA. This tells the PIX 240i to start and stop recording along with the ALEXA. If off, the PIX 240i will not start and stop with the ALEXA.

Gamma – ALEXA Setting

ALEXA’s digital video output can be set to different colorspaces. From the home screen press the center circular button under the LCD labeled “COLOR”. Next, press the button labeled “GAMMA”. Set the SDI output to REC 709 for accurate color representation on the PIX 240i screen. If set to any other colorspace, color grading is required after recording.

Timecode – ALEXA Setting

This setup describes ALEXA as the master timecode source, with its timecode signal carried over SDI. Verify the timecode settings of the ALEXA. On the ALEXA, press the blue button labeled “TC” and the press the button labeled “OPTIONS” on the bottom left of the LCD. Set “Source” to “Int TC”. Set “Mode” to “Free Run”.

PIX 240i Settings

Once the Arri ALEXA has been properly configured, the PIX 240i must be set to accept start/stop flags and to read ALEXA filename metadata.

Press Menu and set the following:

  • Video > Video Input > SDI
  • Video > File Resolution/Rate > Same as Video Input
  • File Storage > File Name Format > Arri File Format
  • System > Rec Start/Stop > SDI Flag – Arri
  • Timecode Sync > Timecode Mode > Ext TC (SDI,HDMI)

Video Input – PIX 240i Setting

To set the PIX 240i to receive its video signal from the SDI input, press the Menu button and select Video. Set the Video Input option to SDI. The PIX 240i will begin using the SDI input.

File Resolution/Rate – PIX 240i Setting

When the PIX 240i is set to Same as Video Input, it records the files in the exact format as the input. If set to anything other than Same as Video Input, the onboard hardware scaler activates and converts the PIX 204i output and recording to the set rate. This setting controls both the SDI and HDMI outputs of the PIX 240i.

File Name Format – PIX 240i Setting

To set the PIX 240i to read the embedded SDI metadata from the ALEXA and write it to the recorded files, select File Storage. Set the File Name Format option to Arri File Format in the drop-down menu. The PIX 240i will extract the Unique Camera ID, Reel, and Clip Counter from the ALEXA and apply them to the file’s CamID, Reel number, and Clip number respectively. This is important when using PIX 240i files as off-line edits that will be replaced with the Arri files later in post.

ARRI File Name

The illustration below shows the file name syntax, carried over from the ALEXA, applied to recorded PIX 240i files.

REC Start/Stop – PIX 240i Setting

To set the PIX 240i to start and stop recording along with the ALEXA, enter the System menu. Set the Rec Start/Stop option to SDI-Flag Arri in the drop-down menu. The PIX 240i will now begin to record and stop with the ALEXA.

Timecode Mode – PIX 240i Setting

To set the PIX 240i to read the embedded timecode metadata within the SDI stream, enter the Timecode/Sync menu. Set Timecode Mode to Ext TC (SDI,HDMI). The PIX 240i will now receive its timecode from the embedded timecode metadata in the SDI input.

Because the ALEXA is the master timecode generator in this setup, make certain to verify the ALEXA timecode settings.

More

For more information on Sound Devices PIX 240i visit the web pages linked below: