Level changes XAVC-L Slog 3 in Premiere Pro

[Lee Berger]

This may be a Premiere Pro issue, but I thought I'd start here and see if anybody else is having this problem.
I shot some XAVC-L 1080 30p tests using SLog 3 gamma. In Premiere Pro CC (2015.1 rel) I see random changes in the levels when native files are played in either the source monitor or program monitor. Can see it on the scopes too. It happens during playback and scrubbing. I don't see these changes in VLC, nor when the MXF files are imported into DaVinci Resolve. Also the problem goes away when I transcode the original files to ProRes 422, and when recorded on my Atomos Ninja Blade. The problem does not seem to occur in footage shot in Slog 2 and standard Gamma (Rec 709).
Here are two samples:
1. XAVC L edited natively

YouTube (Short URL)

2. Transcoded to ProRes

YouTube (Short URL)

No problems.

Thanks,

Lee

[Zach Hunter]

Looks like an issue with Premiere's ability to handle the native XAVC-L codec...XAVC-L is VERY hardware intensive, as opposed to it's intra-frame counter part, XAVC-I on the FS7. Maybe your GPU is having an issue with all the number crunching? Try updating your graphics card drivers or maybe check for updates/reinstall Premiere? Have you tried seeing if the issue persists in 4K XAVC? Also, not sure if this makes much of a difference, but did you try shooting in both 10 bit 4:2:2 and 8 bit 4:2:0?

As you mentioned, it's probably an issue with Premiere. However it is strange that it only happens with SLog 3.

Best of luck,

-Zach

[Jack Zhang]

Sometimes weird H.264 decoder issues cause broken GOPs when Premiere reads files. The level changes are likely due to Premiere mis-reading an I, P, or B frame.

Looks like it will be a while before Premiere tunes it's H.264 decoder for newer formats. CS5 had issues with previewing AVCHD 2.0 too.

[Lee Berger]

Originally Posted by Zach Hunter

Looks like an issue with Premiere's ability to handle the native XAVC-L codec...XAVC-L is VERY hardware intensive, as opposed to it's intra-frame counter part, XAVC-I on the FS7. Maybe your GPU is having an issue with all the number crunching? Try updating your graphics card drivers or maybe check for updates/reinstall Premiere? Have you tried seeing if the issue persists in 4K XAVC? Also, not sure if this makes much of a difference, but did you try shooting in both 10 bit 4:2:2 and 8 bit 4:2:0?

As you mentioned, it's probably an issue with Premiere. However it is strange that it only happens with SLog 3.

Best of luck,

-Zach

Thanks Zach:
Drivers are all up to date and I did shoot both 10 bit 4:2:2 and 8 bit 4:2:0. Perhaps it's the combo of XAVC-L and Slog3. I'm going to shoot a test with an F55, XAVC Intra Slog 3 and see what happens. I'll report back.

[Lee Berger]

Originally Posted by Jack Zhang

Sometimes weird H.264 decoder issues cause broken GOPs when Premiere reads files. The level changes are likely due to Premiere mis-reading an I, P, or B frame.

Looks like it will be a while before Premiere tunes it's H.264 decoder for newer formats. CS5 had issues with previewing AVCHD 2.0 too.

Thanks Jack:
I also posted this on the Adobe Premiere Pro forum at Adobe.com.

[Jean-Philippe Archibald]

Any news on that? I have the exact same problem. Until last week I was on CC 2014.2 and everything was fine witn XAVC - L and Slog 3.

[Nigel Davey]

This has been discussed over in the other forum: FS5: FS5 flickering problem

[Lee Berger]

For me this looks like it's fixed in the 2015.3 version of Premiere Pro that has just been released.

[Alister Chapman]

Also make sure you have the original file structure intact including all the XML files etc as these contain information that tell the codec how to decode the footage correctly.

[Lee Berger]

Originally Posted by Alister Chapman

Also make sure you have the original file structure intact including all the XML files etc as these contain information that tell the codec how to decode the footage correctly.

Thanks Alister. I did/do maintain the original file structure copying the "private" folder and all it's contents. The issue only occurred with Slog 2 and 3 and not standard gammas. Adobe admitted on their forum that this was an issue, and I believe fixed it in the current version of PP. I'm guessing that not everybody has experienced this error, but I seen it on several machines with my footage. Some others complained as well. BTW, I didn't see it at all on Slog XAVC-Intra from the F55. Only on XAVC-L. Furthermore, the same footage imported into PP 2014 played just fine. Anyway it's all moot now and I'm relieved.