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NwProPr
Known Participant
February 14, 2023
Question

Proxy workflow within Premiere Productions (8 channel audio / 4K UHD)

  • February 14, 2023
  • 1 reply
  • 2181 views

Hello,

There's been a lot of discussion about proxy workflows while maintaining multichannel audio, even on this forum. However, I didn't really find a one-way solution to my specific question. It seems that Premiere treats a transcoded proxy, created from the internal ingest section, as a non multichannel audio track, regardless of the number of audio channels in the source file. (when dragging the 'proxy attached' media file from the Project bin into a sequence, it now only drags one audio track)

As an alternative, I've created proxy presets in Media Encoder that preserve all eight audio channels when imported back into Premiere. However, when using these presets to create ingest presets to build proxies within Premiere itself, the resulting proxies, after toggling the proxy button, don't have any multichannel audio tracks, making it difficult to edit each track on their own.

Question 1: Workflow creating multichannel proxies
My first question is whether creating all proxies at once in Media Encoder, importing them into Premiere, and then reconnecting them to the original source files is the optimal way to manage a proxy workflow for multichannel audio. I am concerned that this workflow may cause problems during the final export, as Premiere typically looks through a proxy conversion and only uses the high-resolution source material. I wonder if all 8 audio tracks from the proxy file will be read from the source file as well.


Question 2: Different resolution

My second question relates to footage shot at two different resolutions (4096x2160 and 3840x2160). I plan to create 1920x1080 proxies and import them into a 3840x2160 sequence, scaling the footage to fit the frame size. The idea is to crop the 4096x2160 footage to remove black borders. However, I am worried that exporting the final product may result in some clips looking distorted, such as the 4096x2160 footage being stretched vertically.

 

How does Premiere deal with all of this, knowing that I'm using a manual proxy workflow? Creating 1080p proxies from a 4096x2160 file means it will add black borders by itself that aren't there in the source file.

 

I hope this all makes sense and appreciate any advice or experience with these issues.

Thanks!

This topic has been closed for replies.

1 reply

R Neil Haugen
R Neil Haugen
Legend
March 2, 2023

I'm not the person to answer all of your questions. But I've got a couple.

 

Are you using proxies to create sequences and editing from them? Or creating the sequences from the original media, then toggling to view proxies while working?

 

As ... if the sequence has the original media as the start point, it should then have all the audio, right? And you'd be just toggling the view of the proxy for playback ... ?

 

Premiere's proxy process kinda assumes that the sequences are made from the original media. And proxies are used for playback purposes.

 

Now, if you're doing the "older" offline proxy process, where you work from the proxy files, and only relink to originals at the end for best Q of export, that's ... got some things to think about in setup. Certainly.

 

Neil

Everyone's mileage always varies ...
N
NwProPrAuthor
Known Participant
March 3, 2023

Thank you for your reply.

I tried several ways of creating proxies. Both inside and outside of Premiere. All having to do with maintaining 8 separate mono tracks.

Like you said, what you would like to do is create a project, using the source files. In my case MXF files coming from a Sony PXW-FX6 or FX9. Next, from the project bin, you would wanna create proxies which will automatically be converted using Media Encoder.

The outcome is basically that Premiere doesn't like MXF files with an AVC-I codec that much. Not in terms of playback, not in terms of creating proxies while maintaining the all audio tracks. Therefore, for our next project, we decided to transcode ALL MXF files to ProRes HQ (with 8 mono tracks). The MXF files will be completely ignored from there on.

 

The outcome is that while importing these ProRes HQ files and trying to creating proxies from those (within Premiere), it all works fine. The transcoding is happening in Media Encoder, and after that, the files are toggable within Premiere (maintaining all audio tracks).

When I try this with MXF files, all 8 separate tracks will be squeezed into one single 8 channel audio track (like what happens with 5.1 audio). From there it seems impossible to split them back into 8 separate mono tracks that are actually separate. There is one way (using Modify, Audio Channels), but what happens, is that Premiere only recognizes the first track. The result is that you end up with 8 separate mono tracks, but they're all duplicates of the first tracks (which you can't adjust through the Audio Channels setup menu).

Therefore, with our previous project (what this post was all about), we went the 'old way' (as you describe it). First create working proxies using Media Encoder, import those in Premiere and immediately reconnect them with the Full Resolution Media. From there these 'toggable' files in the Project bin are dragged onto fitting sequences and editing is done from there.

One would assume this workflow wouldn't give any problems, as this is a standard workflow for many fiction editors (movies and tv shows). In other words: basically setting up their projects, only using proxies, to reconnect everything back together afterwards in the end.

I might be wrong, but this current project hasn't gotten us in any trouble so far. I did some extended testing on the front to make sure all steps that we might be facing (moving sequences between Production projects, exporting in different ways etc.) would actually work.

Or is there anything specific that might scr*w things up using this workflow?

Thanks again! 🙂

    N
    NwProPrAuthor
    Known Participant
    March 4, 2023

    Let's see... starting with the XDCAM 422 HD Sequence preset should result in a Sequence with 8 Standard Audio Tracks and a Stereo Mix with 2 Channels.

     

    Is the server configured for video editing?  It's not enough to just have a shared volume mounted on the Desktop.

     

    The 2017 Mac Pro is a great machine.  I would have expected it to handle MXF with 8 channels of audio fin if it has 32GB or 64GB of RAM.

     

    If starting with an XDCAM HD 422 Sequence, you'll want to change the Editing Mode from "Sony XDCAM HD422 100 NTSC" to "Custom" (Custom is at the top of the Editing Mode list, so you may need to scroll up to see it) and change the Preview File Format from "I-Frame Only MPEG" to "QuickTime" and the Codec from "Animation" to "ProRes 422 HQ".

     

    With ProRes 422 HQ source in a ProRes 422 HQ Timeline, the thing you should notice right away is that the Yellow bar above the footage goes away - even when the footage is scaled 50%, or is 100% and cropped on the sides, or is playing in reverse.  When you do need to render in the Timeline, you should notice faster render times (ProRes rendering ProRes) and when exporting ProRes 422 HQ you should notice much faster export times.  Even exporting to ProRes 422 Proxy (let's say to upload a rough cut to FrameIO), you should notice fast exports.  


    You'll need to create a custom Ingest preset for ProRes 422 HQ.  Once that's set up and Ingest is enabled, import the MXF files as you would normally and monitor the Progress tab.  If you've done this before, you'll remember that the MXF files will be swapped out for MOV as they are completed.  Those are ready for editing while the progress is still going.  I'm guessing that an hour of the source is going to take about 42 minutes to transcode.

     

     


     

    We basically use the XDCAM HD422 1080p25 preset and only change the custom resolution at the top if needed, like in the image above. It automatically sets video previews to ProRes 422 LT.

    The iMac Pro has a 3 GHz 10-Core Intel Xeon W CPU, Radeon Pro Vegas 8 GB GPU and 64 GB 2666 MHz DDR RAM. At the moment it runs the latest MacOS and the latest version of Premiere.

    The project which holds MXF files, attached to ProRes low res proxies, give a yellow line above the clips in the sequence. No matter what side they're toggled to. When I import a transcoded ProRes HQ (from MXF) and drag it on a (new) sequence (like in the image above), the line also stays yellow. Probably a case of the system not being powerful enough? It most likely will turn green if I render the timeline to create video previews.

    We're using an Avid NEXIS Pro video storage server. In general, with 'casual' projects, there are no problems. The only content we have to 'ease' with proxies are UHD projects or projects containing tons of footage from multiple camera's. We're using Premiere Productions which usually runs fine. Last year we faced a problem where the entire project was just running slow. From what it seems it might've mostly been a project issue. The same issues kept happening at the same place, from multiple computers, even when extracting the sequence into a new (clean) 'normal' Premiere project. For example, taking up to 10 seconds after hitting space to start playback, taking ages to full load all media in a single project (the 'Progress' tab would be constantly loading, everytime the Production would be opened), but also the responsivness in general -- importing a simple mp3 would be a real issue at certain times. To prevent all of that, we went for the all-ProRes workflow. There's no reason to believe it was network/server related.

     

    From what I understand, your last bit about automatically ingesting doesn't apply to/work for Productions projects. Right now, we customized the QuickTime ProRes 422 HQ preset within Media Encoder (max render quality/depth, 16-bit for colorist, 24-bit audio, 8 mono channel audio). The proxy workflow will get a few ingest presets as well (horizontal/vertical footage in different resolutions). Also, from now on the idea is to leave the MXF files out of the workflow entirely. So not having them imported into the Production project, but making ProRes HQ 'Full Res' files first and have those imported in Premiere to create proxies using the Ingest presets.

    Thanks!

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