premiere proxies with multichannel audio - audio offline

[Peter Reef]

As Premiere or Media Encoder cannot create proxies with audio passthrough, I create them externally - mostly with apple compressor or EditReady from Hedge.

I am creating them for my Sony Fx3 with four audio channels 24bit audio. So originals and proxies have the exact same audio configuration. However if i take my originals offline some of the audio tracks go offline as well - the last time channel 3 and 4 went offline. There does not seem any reliable offline proxy workflow. Is it right that premiere doesnt know how to deal with multichanel audio proxies? If I just transcode the files with audio passthrough it works, but I cannot deal with the file size of UHD ProRes files for a documentary so I relly need a reliable offline proxy workflow.

[Kevin-Monahan]

Hi @Peter Reef,

Thanks for detailing your issue. Things can go wrong if files are not encoded by Media Encoder. I hope a community member can assist here. Perhaps @John V Knowles, @PaulMurphy, or another community member might want to chime in here. I hope we can help you with this shortly. Sorry for the problem.

Thanks,
Kevin

[PaulMurphy]

When creating proxies in Adobe Premiere Pro, the audio in the proxy files is set to passthrough by default. This means the original audio configuration is maintained in the proxies.

If your proxies go offline, relinking them with the Link Media window can occasionally cause issues with audio channels. In such cases, I recommend using the Attach Proxies option instead:

1. Right-click the media in the Project panel.
2. Select Proxy > Attach Proxies.

[Peter Reef]

Thanks for your help, I had lots of issues creating proxies from my Sony Fx3 files with four 24 Bit audio channels, as there is not true audio passthrough option. Or am I wrong? As far as I know all Media Encoder Ingest settings reencode audio to some 16 bit audio and try to keep audio channel configuration - but not always. This issue has been discussed earlier in this forum. Apple Compressor and Hedge Editready have this simple option: Just a checkbox "enable passthrough audio" so the audio is not altered at all and can be processed further. So usually I do it exactly as you descripe: I create proxies externally (adding _Proxy to the filename" and then chosse Proxy-> Attach to add them. But this does not seem to work reliably when originals go offline, then some audio tracks go offline as well.

The proxies are still attached, but just some of the audio channels are not found.

[John V Knowles]

Sorry to keep asking but it's not clear to me: are you making the proxies from within Premiere using Proxy > Create Proxies, or are you just dragging the clips directly into Media Encoder?

Also: do you have a small sample clip to share that we can test on our systems? Unfortunately I don't have access to one of those cameras.

[John V Knowles]

Hi Peter,

I'm a bit confused by your statement "Premiere or Media Encoder cannot create proxies with audio passthrough.." If you use the Create Proxy command in Premiere and choose the QuickTime/ProRes option it will create a ProRes Proxy file with matching audio channels. Are you using that workflow?

[Peter Reef]

I tried it again as you told me, its still the same:

Instead of passing four audio tracks with one 24 bit audio channel each it creates a single audio track with four audio channels in 16 bit. This can lead to issues later on and this was the reason I switches to another transcoding workflow with audio passthrough. Heres the screenshot of the comparison view in media info: An original file in the middle, on the left is the conversion by AME and on the right side the conversion by editready, in apple compressor for example its exactly the same as it offers passthrough audio as well. 

[PaulMurphy]

What ingest preset are you using to create these proxies that are converting 24-bit audio to 16-bit audio? I tested all the QuickTime ingest presets in the "Create Proxies" window (ProRes, H.264, Cineform), and in my tests, the audio stayed 24-bit.

Just to confirm, are you creating these proxies directly in Premiere Pro, or are you using Adobe Media Encoder on its own?

Also, can you share more details about the issues you’re running into when the proxies have one audio track with four channels instead of four audio tracks with one channel each? In Premiere Pro, it usually doesn’t matter whether the audio is grouped into one stream or split into multiple streams, as long as the total number of channels matches the original media.

[Peter Reef]

Thanks for your help, so maybe you can help me find a way to convert with audio passthrough.

Did you convert video files with four 24bit lpcm audio tracks on macos? 

I had exactly the same issues when i tried to offline edit using proxies as I am having now:

Audio tracks becoming offline when I unplugged the drive with the original media while proxy media was connected. 

And I am using the exact same preset as you told me - > prores proxies. 

Right now I cannot even start premiere, the icon is jumping but nothing happens. I have had SO many crashes, even after a few minutes using it, and trashing preferences does not help unfortunately..

I am using the "create proxies" window on macos. 

[PaulMurphy]

Yes, my test was on video files with four 24-bit LPCM audio tracks on macOS.

If you’re losing audio channels when your original media goes offline, try re-attaching your proxies. To do this, select all your offline files in the Project panel, right-click, and choose Proxy > Attach Proxies. This should reconnect the proxies and ensure the audio channels stay intact when the original media is not connected.

[John V Knowles]

Also: are you indeed using the full Proxy workflow in Premiere, where they are attached and you use the switch to toggle them on and off? Sorry to keep asking questions like this but it's not clear from your responses and it sounds like you might be importing the proxies directly ("offline") which you don't have to do.

If you are using the full proxy workflow then I would also ask why the audio channels matter so much at the edit stage. If you use proxies to cut then you would be reverting back to full res media before finishing anyway for color and sound. Or is the issue that your raw media has isolated mics on certain channels and those are not passing through to the proxies so you can't cut with them properly?

[Peter Reef]

Hi @John V Knowles, thanks for your help and sorry for the late reply. I had a lot of work and not a lot of sleep lately. 

I tried both: working with proxies I created externally using editready while offloading media - because editready - like apple compressor - have the option to "passthrough audio" unaltered - plus the full proxy workflow from apple - which always alters lpcm audio (converts 24 bit lpcm to 16 bit and changes track/channel assignment).

As I am now having colour shifts with editready I will definitely stick to the full adobe proxy workflow.

Until now I didnt find out a good way to finish my projects: The whole project is whot in XAVCHS, which means H265 UHD 422 50p 10bit and I need to deliver 1080i 25i in the end. I need more quality for post production and be able to zoom in later.

Last time I transcoded everything to Prores HQ UHD 50p but it takes up LOTS of TB SSD space, so I was hoping I could work with proxies.

So this time I created Prorex proxy UHD in Adobe itself and it kind of works, at least as long as original media is connected as well - Iast time when original media went offline part of the audio could not be relinked - I will try when the project is finshed.

Now when the project is almost finished going back to originals is not an option - even on an apple M2 max with 32 gb of ram premiere is not able to playback prores proxy smoothly when downsampling from 50p uhd to 25i HD in the sequence. Thats an issue I havent had with any other editing application (avid, resolve, fcpx). Usually the m2 max has lots of performance to downsample prores even with a little lumetri colour correction applied. (no other effects, sometimes just a blur on faces or license plates)

But now I notice that evend the proxy workflow.

Now I tried "render and replace" which is kind of annoying when having a colour managed workflow and transcoding through the "media manager" shifts a lot of keyframes like added blur for some faces.
So I guess the only "robust" workflow is to work with proxies - and those sometimes cause audio issues.

I think it would be better to work with prores 422 HD instead of prores proxy UHD (prores proxy HD is definitely too low quality), but only prores proxy is available - so I need to create a custom ingest preset and then again premiere (or AME) wants me to define the audio channel configuration - it does not adapt dynamically to the audio  configuration of the source clips. 

So is there any way to create a custom ingest (proxy) preset that adapts to the audio configuration of the source files?

And is the issue known that even Prores UHD conversion to 25i HD has such a massive performance degradation?

BTW - I am working with a blackmagic ultrastudio mini monitor breakout box - but in 50p there are no issues.