Setting up and Grading ARRI Cameras

Livegrade comes with support for remote look control of ARRI cameras. This includes the following ARRI Alexa camera types:

• ARRI Alexa SXT
• ARRI Alexa Mini
• ARRI Amira
• ARRI Alexa 65
• ARRI Alexa LF
• ARRI Alexa Mini LF
• ARRI Alexa 35

With this feature set you can send looks to be applied in an ARRI camera. This has two main benefits:

• Live-graded image output directly from the camera: Each output of the camera – including the viewfinder – can show the live-graded image.
• Look metadata stored together with OCF: Without any additional steps needed, the looks will be saved in the file header of each recorded clip. Anyone in the post production pipeline who gets in touch with the material has the opportunity to reveal the look which was set live on set.

Additionally, it’s possible to receive metadata and frame grabs from the current live image of the camera. This way you can include camera and lens metadata to your shots and include the graded frame grabs to the Look Reports.

Furthermore, you can use the camera’s image source as an image reference in the Image Viewer, allowing the fine tuning of the looks later – even if the camera is not available.

Preconditions

• Editable Look selected in the camera: Before grading an ARRI camera, make sure that you have selected an editable look (e.g. through duplicating the “Default” look) in your camera.
• Network connection: In order to exchange look information with Livegrade, the camera needs to have a working network connection with the computer where Livegrade is running.
• Enable CAP: To connect Livegrade to the camera you have to enable the Camera Access Protocol (CAP) in the ARRI camera’s menu at System -> Camera Access Protocol. You can also set a CAP Server password there to protect access to the camera.

Adding the ARRI Camera as a Device

Once the camera is in the same network as your computer, launch Livegrade and add the ARRI Camera as a device via Livegrade’s main menu:

Slots > Add Device > Add ARRI Camera…

Alternatively, you can add the device through the Device Manager.

After that, a wizard window opens:

Add ARRI Camera

• Choose your ARRI camera from the list of automatically discovered cameras by clicking on the entry in the Found Cameras box
• Alternatively, you can enter the IP address manually. To do so click the checkbox Use Custom IP Address and fill in the information in the text field that appears.
• Enter the password for that camera as defined in the camera as CAP Server password before.
• Enter a client name that should be shown in the camera menu (e.g. your computer’s name)
• Enable / disable receive frame grabs from this camera by checking the Enable Framegrab checkbox.
• Enable / disable Look sync if you want Livegrade to get updated when you changed a look in the camera.
  • Note: This functionality is not available for Alexa 35 cameras.
• Select the value within the Grading selection depending on your needs:
  • Interactive for grading the camera’s signal live
  • Manual to upload looks onto the camera manually
  • Disabled (Metadata Only) to add the camera as a metadata only device (also available in grading modes other than ARRI CAP Compatible)
• Enable / disable Advanced Color Pipeline (Alexa 35 only)
  • Note: These options are only available for Alexa 35 cameras
  • Look Control CDL+CMT
    • Look will be sent as CDL and CMT to the camera. DRTs will be set by the camera
  • Look Control DRT only
    • The look will be sent as DRT to the camera. CDL and CMT will be set to neutral.
    • Target Colorspace SDR
      • will make the look available for a chosen SDR colorspace in the camera
    • Target Colorspace HDR
      • will make the look available for a chosen HDR colorspace in the camera
    • Note: Only one colorspace (HDR or SDR) can be set. Currently, there is no possibility to send two color pipelines at once to the camera.
• Click on Add ARRI Camera

Note: If you have selected the read-only “Default” look in your camera before, delete the camera from the slot again, select a look that is editable in your camera (e.g. through duplicating the “Default” look), and add the camera to the slot again.

Since the underlying looks of the ARRI camera generations ALEV3 (e.g. Alexa Mini LF) and ALEV4 (e.g. Alexa 35) differ significantly, Livegrade also offers different possibilities to grade the looks of those cameras.

For this reason, we will now also differentiate between ALEV3 and Alexa 35 in-camera grading in this article.

Grading an ARRI ALEV3 Camera

After adding the ARRI ALEV3 camera (e.g. Alexa Mini) to your slot, Livegrade will

• change the grading mode to ARRI CAP Compatible

• load the current look from the camera

• and indicate a proper connection with a green light next to the camera’s icon
  • If you get a yellow or grey light, please check your network and reconnect to the camera by deleting the device from the slot and adding it again.

As soon as you successfully have added the ARRI camera to one of your slots and your look is in ARRI CAP Compatible mode, you can start live grading.

Livegrading an ARRI ALEV3 camera basically means altering an ALF2 look file remotely, which is currently loaded in the camera. So let’s take a look at ALF2 look files first before we move on with explaining what actually happens when grading the camera.

ALF2 Look Files

ALF2 look files used in ALEV3 cameras (e.g. Alexa Mini, Alexa LF, Alexa Mini LF, Alexa 65, Alexa SXT, Amira) consist of

• CDL & Saturation

ASC-CDL and Saturation values

• Custom 3D-LUT

A single 3D-LUT file which contains creative look adjustments and a colorspace conversion, e.g. from LogC3 to Rec709

ALF2 Look File

Both parts of an ALF2 look can be adjusted by Livegrade as explained in the next chapter.

Look Control of ALEV3 Cameras

When grading a slot with an attached ARRI ALEV3 camera, Livegrade adjusts the ALF2 look in the camera as follows:

• All CDL and Saturation nodes of your grade will be merged into one single ASC-CDL file and will be sent as such to the camera

• All Curves and LUTs – including your last LUT node which will be an output transform in most cases – of your grade will be merged into one single 3D LUT and will be sent as such to the camera

Look Control of an ARRI Camera

Extracting the look from a clip that was recorded by an ALEV3 camera will then give you

• an ASC-CDL containing all CDL and Saturation adjustments in one set of values
• a 3D LUT containing all LUT and Curve adjustments combined in one single 3D LUT

Now you should know the most important details about the in-camera grading of an ARRI ALEV3 camera in Livegrade. If you want to learn more about topics that relate to all ARRI cameras, please find more sections after Grading an Alexa 35 starting with Updating Looks in ARRI Cameras.

In the following chapter, we will discuss in-camera grading of Alexa 35 cameras.

Grading an Alexa 35

When adding an ARRI Alexa 35 to one of your slots, you can choose between two ways to control the ALF4 look of the camera. This is done via the Advanced Color Pipeline options found in the Add ARRI Camera dialog:

• CDL + CMT (default): This is the default way of controlling your Alexa 35’s look via ARRI CAP Compatible grading mode. It sets the CDL and CMT part of the camera’s ALF4 look and leaves the DRTs untouched.
• DRT only: This advanced way of in-camera grading allows you to send your whole look (including input and output transforms) as 3D LUT to the camera.

Depending on which option you choose, Livegrade will interact differently with the attached camera.

Before we go into the differences between CDL + CMT and DRT only mode, we take a look at the structure of ALF4 looks first.

ALF4 Look Files

ALF4 look files used by Alexa 35 consist of

• CDL & Saturation: CDL and Saturation values

• CMT (Color Modification Transform): A 3D-LUT which contains creative LogC4 to LogC4 look adjustments

• DRT SDR: A 3D-LUT which contains the colorspace conversion to a certain target SDR colorspace (Rec.709 or Rec.2020)

• DRT HDR: A 3D-LUT which contains the colorspace conversion to a certain target JDR colorspace (Rec.2100 PQ or Rec.2100 HLG)

ALF4 Look Files

ALF4c files are looks which contain a custom color management with DRTs which were created by a user.

Depending on the Look Control mode you have chosen, Livegrade will adjust the individual parts of the ALF4  or ALF4c look differently.

CDL+CMT Look Control

You can use this way of controlling your look to

• control an ALF4 look where the standard ARRI Color Management LUTs are used for the display rendering transforms
• control an ALF4c look created in the ARRI Reference tool where custom 3D LUTs are used for the display rendering transforms

Adding an Alexa 35 in CDL+CMT Mode

CDL+CMT Look Control

After adding an ARRI Alexa 35 camera with look control set to CDL+CMT, Livegrade will

• change the grading mode to ARRI CAP Compatible

• load the current look’s name from the camera into your Livegrade look’s name

• indicate a proper connection with a green light next to the camera’s icon
  • If you get a yellow or grey light, please check your network and reconnect to the camera by deleting the device from the slot and adding it again.

As soon as you successfully added the Alexa 35 camera in CDL + CMT mode to one of your slots and your look is in ARRI CAP Compatible mode, you can start live grading.

Grading Alexa 35 with CDL+CMT Look Control

Let’s take a look at what actually happens when grading an attached Alexa 35 camera in CDL+CMT mode remotely:

• All CDL and Saturation nodes of your grade will be merged into one single ASC-CDL and will be sent as such to the camera

• All Curves and LUTs (except the last LUT node) of your grade will be merged into one single 3D LUT and will be sent as such to the camera

• The last LUT node which is named DRT per default won’t be sent to the camera. The camera will apply the display render transforms (DRT) according to the currently loaded ALF4 or ALF4c file in the camera.

Grading with CDL+CMT Look Control

If you are working with a LogC4-image source in Livegrade (e.g. through using a capture device or requesting a frame grab from the camera) and want to use your Livegrade looks to be applied on the original camera footage at a later point (e.g. look matching between Livegrade and Silverstack), you should set the last LUT node accordingly to your monitoring setup.

Extracting the look from a clip that was recorded by an Alexa 35 camera will then give you

• an ASC-CDL containing all CDL and Saturation adjustments in one set of values
• a 3D LUT representing the CMT part which contains all LUT and Curve adjustments (except the last LUT node) combined in one single 3D LUT
• two 3D LUTs representing the DRT SDR and DRT HDR part, which contain the SDR and HDR colorspace conversions

DRT only Look Control

DRT only Look Control

This advanced mode of controlling an Alexa 35’s look allows you to send your whole look (including input and output transforms) as 3D LUT to the camera.

You can use this way of controlling your look to

• send a custom look containing the whole pipeline (e.g. ACES or CDL Advanced) for one target colorspace to the camera. The look will be saved as an ALF4c file in the camera.

The entire look (including input and output transforms) of a slot will then be stored in the DRT part of the look, while CDL & Saturation, and CMT will be set to neutral.

Due to the structure of ALF4 files which consist of two DRTs, the 3D LUT is sent as DRT SDR and DRT HDR. Both fields receive the exact same 3D LUT. Depending on the production, this means an HDR or SDR 3D look LUT with a baked-in display rendering transform.

Note: Dual monitoring via the Alexa 35 is not possible in DRT only mode. However, dual monitoring is possible via an additional LUT box controlled by Livegrade. You could then send the primary color pipeline (HDR in most cases) to the camera, and the LUT box would be used to monitor the secondary colorspace (SDR in most cases)

Target Colorspace

As the DRTs are responsible for the colorspace conversion, the target colorspace must be set when adding the camera in DRT only mode accordingly to the output transform of the look you are going to send to the camera.

Example:

• If you set up an ACES look where you use an Rec.709 ODT, select SDR, and choose Rec.709-D65 as the target colorspace.

Adding an Alexa 35 in DRT only Mode

After adding an ARRI Alexa 35 camera with look control set to DRT only, Livegrade will

• set CDL & Saturation and CMT of the currently loaded in-camera look to neutral

• set DRT HDR and DRT SDR of the currently loaded in-camera look to the current look of the slot as 3D LUT

• set DRT HDR or DRT SDR target colorspace according to the target colorspace chosen in the Add ARRI camera dialog.

• load the current look’s name from the camera into your Livegrade look’s name

• indicate a proper connection with a green light next to the camera’s icon
  • If you get a yellow or grey light, please check your network and reconnect to the camera by deleting the device from the slot and adding it again.

As soon as you successfully have added the Alexa 35 camera in DRT only mode to one of your slots, you can start live grading.

Grading an Alexa 35 with DRT only Look control

Let’s take a look at what actually happens when grading an attached Alexa 35 camera in DRT only mode remotely:

• All CDL, Saturation, Curves, LUTs, Input, and Output Transform nodes of your look will be merged into one single 3D LUT which will be sent as DRT HDR and DRT SDR to the camera.

• CDL and CMT of the currently loaded in-camera look will be left untouched during grading, as they were already set to neutral when adding the camera to the slot.

Grading an Alexa 35 in DRT only

Extracting the look from a clip that was recorded by an Alexa 35 camera will then give you

• an ASC-CDL containing a neutral CDL
• an identity 3D LUT representing the neutral CMT part
• two 3D LUTs representing the DRT HDR and DRT SDR part, which contain exactly the same LUT representing the whole look you have created in Livegrade

ARRI Cameras and Livegrade

The following table summarizes the different camera types and possibilities to grade them with Livegrade.

Updating Looks in ARRI Cameras

While there are differences in how the look can be graded in a certain Alexa 35 or ALEV3 camera, the way looks are updated in the camera is the same for all ARRI cameras:

• A change of the camera’s look is indicated by a * next to the look’s name in the camera.

• When the camera records a clip, your look will be saved in the clip’s file header. This makes it possible that everyone who has the original camera footage or a copy of it can extract and apply your look during post production.

• When creating new shots in Livegrade you can choose if they should be stored permanently on the camera as well. There are two main purposes for storing looks permanently in the camera:
  • to update the look’s name in the camera menu and in the metadata
  • to be able to retrieve certain looks, even if Livegrade is currently not connected to the camera

Note: If a look is not updating in the camera, the camera device needs to be deleted and added again to your slot in Livegrade.

Frame Grabs

In case you want to display an updated live image, make sure you check the Enable framegrab function when adding the camera to a slot.

If Enable framegrab is activated, you can perform a frame grab in Livegrade by clicking on the «Refresh Image» button. After that, you will have the latest frame of the live image.

You can generally check if the ARRI camera is properly connected by going to the Device Manager. A green indicator shows a positive connection status.

Note: Please be aware that due to the frame size (especially of the ARRI Alexa 65), taking frame grabs can take longer than maybe expected. Please grant the camera and application some time to process the frame grab.

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