Hi, We would normally work with op-atom for large multicam jobs cutting at full resolution. This means we are not able to play back a 9way split (not enough bandwidth) but the group still exists to flip between cameras as you want. Footage for a new show came in over the weekend that is op1a and when grouped playback becomes impossible. It's as if it is trying to play a 9 way split. Currently we are transcoding everything to op-atom via Resolve but obviously that is not ideal. We are on 2022.12.9 but I tested it in 2024.10 and got the same results. Is this expected behavior or is it an oversight? Cheers, Rory

Rory

Let me check into this now and get back to you.....

What OS are you on please?????

Marianna

Hi Marianna,

This is happening on Windows 11.  When the op1a track lay is downw with 15 video/15 audio layers it's throughput is 3.5Gb/s but can get up to 4.5Gb/s.  When that is grouped it is 2.4Gb/s but can get up to 3Gb/s.  When the group happens with the op-atom it is about 220Mb

Thank you

Are you linking to the op1a media and attempting to do a 15 camera multicam edit with linked media? Or are you consolidating it to OPAtom? What codec is it? OP1a is a container or wrapper, what is the video essence within? What raster size? HD? UHD? What storage is it playing back from and how is that connected? What workstations are you running? HP? Dell? Do they have the CPU grunt to playback 15 streams of whatever it is you are trying to play back?

I've never tried running a multicam edit with linked media, that sounds like a terrible idea. If, as you say, the OPAtom media gives you a very managable 220Mb/s, then why aren't you always using this method? If the codec is native it can be consolidated, then it would just be a re-wrap to OP Atom which is basically just a copy. 

More info please!

Andi

Hi RVM,

We are not linking.  The op1a media can now be read nativley in avid in a UME folder, at least that is my understanding of it.  Normally the OB truck creates op-atom media but it was all corrupt.  The backups are op1a.  We transcoded to op-atom, so everything works as expected.  I was just wondering if this expected behavior from the op1a. 

Files are mxf DNxHD220X 2997 op1a

Rory

Interesting. I didn't realise op1a media can be read like that? How does that work? If it's using UME it can't be quite the same as OP Atom media I guess, I thought UME was essentially just an updated way to AMA link. What's the workflow for that? Do you need to bring in an AAF or something that links up to the op1a files? 

Andi

Ah, just found a good explainer on LinkedIn. Wasn't aware this was a thing. Good to know.

https://www.linkedin.com/pulse/praise-op1a-mxfs-editorial-use-avid-media-composer-isaac-t--fqtme

Andi

Hey Rory

I believe Philip responded to your case with the following:

Response - Hello Rory, Thank you for raising this with us.

As you may already know, operational pattern 1a encodes the video/audio streams into one muxed file. This means that during playback, Media Composer has the overhead of demuxing video/audio from the .MXF, as well as decoding it.

With OP-Atom media, every channel is split into it's own .MXF, meaning Media Composer doesn't need to think about demuxing audio and video when trying to playback just an audio clip for example.

Therefore, performance is superior when working with OP-Atom files. Building waveforms or scrubbing through a 9-way multicamera split becomes faster with OPatom media.

Which codec are you attempting to play back with UME? Is it intraframe, or long GOP?
I suspect the issue here is the workflow.

Kindest regards,
Philip Kapadia
Technical Expert | Media Composer

--------

Did you get a chance to respond back to him?   C heck your inbox, spam and junk folder for the case.

Marianna

Hi Marianna,

Where is my inbox?  There is nothing in my email or junk.  Files are DNxHD 220X in an mxf container.  We are not trying to scrub through or play a 9 way split.  We are looking at a single layer after the the layers have been grouped, but it's as if the op1a is trying to show all the layers. 

How do I tell if itis intraframe or long GOP?  I had a look at media info and the closest I can find is: Format settings, wrapping mode: Frame

Cheers,

Rory

@Andi: you found my piece – thanks for sharing it!

I publish these pieces on isaact.micro.blog as well, so if you don't use LinkedIn: 

In Praise of OP1a MXFs for Editorial Use in Avid Media Composer

 

Also see:

Some Gotchas on Using OP1a MXFs With Avid Media Composer

Actually, this makes sense I think. Even if we are only playing one layer of video, there is audio from multiple cameras in the groups. So avid would still have to decode them. 

Thanks Isaac! Useful info for those of us not up to date with the more recent versions. Will check out the blog!

Andi

Rory T:

Hi, We would normally work with op-atom for large multicam jobs cutting at full resolution. This means we are not able to play back a 9way split (not enough bandwidth) but the group still exists to flip between cameras as you want. Footage for a new show came in over the weekend that is op1a and when grouped playback becomes impossible. It's as if it is trying to play a 9 way split. Currently we are transcoding everything to op-atom via Resolve but obviously that is not ideal. We are on 2022.12.9 but I tested it in 2024.10 and got the same results. Is this expected behavior or is it an oversight? Cheers, Rory

Hi, Have you learned if your Group playback issue was limited to just the weekend batch of OP1a's that you had trouble with or does it happen on your system everytime when using UME / OP1a clips in groupclips?