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Backlot Delivery Instructions for "native" IMF


Netflix has been accepting IMF packages as far back as 2014 for 4K material, however in our original implementation we could accept only packages with a single video track and two audio tracks. We also required the IMF to be zipped as an uncompressed archive prior to delivery. When we received the zipped package, we basically tossed away all metadata XML files, and used the video and audio essences for transcode.

This 2014 implementation was extremely limited. Each time a shot fix, credit fix, or audio dropout needed to be corrected, a whole new IMF needed to be created and delivered. This subsequently resulted in large files, long transfer times, assets having to be QCed again in their entirety.

Since 2014 a lot of progress has been made by SMPTE and technology vendors, so we are now able to take advantage of the flexibility that IMF has always promised to provide and as such, we’ve had to update our internal workflows to support IMF as it was intended to be utilized.

Migration to "native" IMF

Throughout 2017 we will continue to migrate all Partners from our legacy "zip archive" delivery for IMF to our new "native" IMF delivery methodogy, where the contents of the IMF package are transferred to Netflix in their native state and not in a zip archive. This minimizes delivery and processing times and provides greater flexibility when working on titles and versions.

Another benefit, since the zip archive is no longer encapsulating the IMF, we can now run extra inspections prior to delivery. Today when you attempt to upload an IMP natively, we will automatically run our Photon inspections from within the Backlot Delivery UI then additionally, once the files transfer, our Inspection as a Service (IaaS) validations.

The native IMF workflow, including the delivery of supplementals began early 2017. The shift to this new workflow is very different and as such, your facility must be tested and approved. 

If your facility has not been tested and onboarded yet, you can SUBMIT A REQUEST and we will start the testing process.

Preparing your Package for Delivery 

To start and before you create your primary IMF package, you should check the OPEN Source Request in Backlot and confirm the language of your IMP. 

You should also confirm the audio configuration you will be delivering with your primary IMF package. You will see how this impacts the delivery process in a little bit. 

NOTE: At this time, we do not accept either foreign dubbed audio or timed text assets within the IMP. You will still continue to deliver those assets as secondaries items to their own Source Requests. 

Currently, if you are delivering a ProRes asset or perhaps an MPG, you define the language of the primary video from a drop-down field within the UI. With native IMF, the language is defined inside your IMP – within the XML and the MXF metadata.

Thus, it becomes essential prior to creating your IMP, that you have correctly identified the language code.


Navigate to the backlot Source Request and lookup the Language value.

In the below image the Source Request has a Language defined by *, so in order to know what language should be defined in our IMF, we need to drill into the Source Request Details.  


In this instance, you can see that the LANGUAGE defined on the Source Request is indicated by an asterix and states “Original Language” (this is a title metadata value supplied to Netflix by the Content Partner). Therefore, we need to review the ORIGINAL LANGUAGE (OL) metadata field to determine the correct language to use in our IMP, in this case English (en).


A second example reveals the Language as asterix pointing to the OL, defined as French (fr), so our IMP would be French.


In the next example, the Language value IS DEFINED. When the language value is defined, you should proceed with that language code and ignore the Original Language value. You would typically see this when handling multiple versions of a title, for instance a Japanese censorship version.


Rules for determining the Language of your IMP:

If AV MUX “Language” = *, then resolve to “Original Language” value
If AV MUX “Language” = “xx”, then resolve to “Language” value 

  • Original Language is metadata defined by the Content Partner
  • IMF language mismatch will block delivery



When you are ready to enact your IMP delivery, select the corresponding AV MUX Source Request in Backlot and click "Deliver" to launch the Backlot Delivery UI. 


Once in the Backlot Delivery UI, the Source Request will be listed. From this point, simply click and drag the contents of your IMP. Important, do not click and drag the folder, but select the actual files themselves and drop them into the landing zone at the top of the UI.

In the example below, you can see the contents of our full IMP - a video essence and two audio essence files defined by .mxf, the the five XML files that make up our IMF package. 


Once the files are placed in the drop-zone, our Photon validation checks will run. If there are any errors, they will be presented to you here, otherwise when the Asset Map, Packing List (PKL) and Composition Playlist (CPL) are confirmed, you can click "continue" to proceed.  


Next, select the "File to deliver" drop-down menu and click "CHOOSE A CPL". The fly-out panel on the right will reveal the CPL(s) listed in your package. 


In the example below, we have one CPL in our IMP to choose from and it reveals the essence filenames, as well as the audio language and configuration. This provides an opportunity to check the contents of your IMP one more time before the files begin transferring. 


The AV MUX Source Request in the UI will now reflect the tracks to be delivered. Select the Source Request and click "deliver" to launch the Aspera transfer.



Note: At this time we do not accept secondary assets, either foreign dubbed audio or timed text assets, within the IMP. You will still continue to deliver those items as secondaries items to their own Source Requests in Backlot. 


When you navigate back to the Backlot Source Management dashboard, don’t be alarmed! Your single AV MUX Source Request has been replaced with three individual Source Requests labeled Video, Audio 2.0, Audio 5.1 respectively. 

By breaking up the Source Request into the IMP's respective tracks, we are able to leverage the all benefits of IMF to create different versions or different branding scenarios by simply utilizing our primary IMP as the base package, and creating supplemental packages that refer back to it.



Supplemental (or version IMPs) can be leveraged for fulfilling different cuts of a title, for example a Director’s Cut or Japanese Censorship version. Supplemental IMPs can also be used to fulfill Redelivery Requests where maybe just a few frames or a shot in the video essence needs correction or perhaps an audio error is flagged, but the video is approved. For these examples, you would make the necessary changes to your primary IMF package and generate a supplemental package.

The supplemental package would just contain those frames and/or audio files that were corrected and a new set of instructions that refer back to the primary IMP delivered at an earlier date. Upon delivery to Netflix, we will use the UUIDs in the primary and supplemental packages to pair up the fixed elements with the existing package.  

To deliver a supplemental package to against a Redelivery Request, simply select the specific Source Requests in Backlot.  In this example below, a correction needs to be delivered to a rejected Audio 5.1 Source Request, the Video and Audio 2.0 are not rejected.


Similar to before, select the single Source Request, launch the Backlot Delivery UI, then click and drag the entire contents of your supplemental package into the UI drop-zone. In the image below, the supplemental package contains only the new, fixed 5.1 MXF essence and a new set of metadata.



Continue to follow the same procedure, once the files are dropped, Photon will run, then select your CPL, confirm the package details in the UI. In the image below, the CPL fly-out panel confirms that we are only delivering a package with an Audio track. 



When you are ready, select the Source Request and click the deliver button. 



If you have any further questions, please SUBMIT A REQUEST.

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