Bluetooth + for Blackmagic app bug

Hi Everyone,
Shot my first project with BRAW at 5:1 ratio. I noticed some weird flickers on set, but I couldn't pinpoint any cause or reproduce - I chalked it up to an intermittent wireless video feed. Lo and behold, now in post I see that there are some intermittent frames that are darker - reminds me of a gamma shift issue? In the example below, the gamma shift looking artifact lasted for 5 frames, then returned to normal. This occured multiple times during the shoot.

Attached are four stills:
The first is the normal ungraded log still, the second is the glitchy frame.
The 3rd and 4th are the same shot with the on-set LUT applied.

What could have caused this? How can I prevent this in the future? I've not seen anyone else report this yet, so thought I should mention it.

Details:
Windows 10 Home, Release 1803
Resolve 15.1.0.025
Recorded to approved CFast

Best,
-Daniel

Log - Normal: https://drive.google.com/file/d/1rp5eY8 ... sp=sharing
Log - Shift: https://drive.google.com/file/d/1ExRo9h ... sp=sharing
Log + LUT Normal: https://drive.google.com/file/d/17jhksH ... sp=sharing
Log + LUT - Shift: https://drive.google.com/file/d/1tzUvEm ... sp=sharing

Hate to be "that guy" but you do realize it's a public beta ?

"Blackmagic Design today announced the public beta of Blackmagic RAW, a new and very modern codec that combines the quality and benefits of RAW with the ease of use, speed and file sizes of traditional video formats."

So they're looking for this exact kind of feedback to help them improve the implementation.

JB

Hi John!
Thanks for your reply - I love seeing your posts about all things BM, so it's nice to finally connect directly!
Yes, very much aware I'm working with a beta update. That's why I thought it might be important to report my results with it.

I have been thrilled with the color reproduction and apparently cleaner image.
Just trying to figure out what would cause this, or let the engineers work on it since I hadn't see any other reports as of yet.

Sorry if it came across differently than that!
Cheers!
-Daniel

EDIT: I've removed the reference to my specific camera, as I can see how that made it sound like I thought hardware, not software. Best!

It was said by BM that you should submit any feedback to the beta firmware here: 6.0beta@blackmagicdesign.com

Hi John!
Thanks for your reply - I love seeing your posts about all things BM, so it's nice to finally connect directly!
Yes, very much aware I'm working with a beta update. That's why I thought it might be important to report my results with it.

I have been thrilled with the color reproduction and apparently cleaner image.
Just trying to figure out what would cause this, or let the engineers work on it since I hadn't see any other reports as of yet.

Sorry if it came across differently than that!
Cheers!
-Daniel

EDIT: I've removed the reference to my specific camera, as I can see how that made it sound like I thought hardware, not software. Best!

I guess they're not THAT clear on how they want that feedback delivered.

I certainly haven't seen what you're seeing if that helps!

JB

Daniel, on the remote off chance this has something to do with noise removal (Sony users have been reporting stars flickering/going missing apparently from temporal noise removal) can you describe your lighting. It might be some odd interaction with lighting/image levels.

I've had a look. Surely it wouldn't be the reflection off that ring when using locked down exposure?

It was said by BM that you should submit any feedback to the beta firmware here: 6.0beta@blackmagicdesign.com

Thanks Robert, I hadn't seen that info!

Daniel, on the remote off chance this has something to do with noise removal (Sony users have been reporting stars flickering/going missing apparently from temporal noise removal) can you describe your lighting. It might be some odd interaction with lighting/image levels.

I've had a look. Surely it wouldn't be the reflection off that ring when using locked down exposure?

Hi Wayne!
Lighting was an Aputure 300d shooting through a silk pretty much straight down at the surface. Camera was mounted on an overhead bar rig. All of my settings should have been set to manual, so I'm not sure about exposure lock? Using false color, all the information appeared to be within safe range, but I didn't necessarily check it with the ring in frame.

Best,
-Daniel

[Tim Schumann]

The best way to diagnose this, as others have mentioned is to email 6.0beta@blackmagicdesign.com

If you are able to send us a .braw trim of the clip or clips in question then we can have a look directly at the source file. This is great because it works without any sort of additional steps of transcoding or rendering and it keeps all of the camera metadata.

Trimming the clip in Resolve is simple...

1. Drop it into a timeline and edit the clip down to the frames you are concerned about.

2. Go to File > Media Management.

3. Set it to Timelines, Copy using 'Copy and trim used media keeping 12 frame handles'.

If you can send us a link to those trims through to the email address above we can check it out.

Daniel. As Tim says. But you can test things out yourself. Does it change in response to the ring, trying a reflection with something else with similar scene/back ground and lighting offset, does it do it with different settings. Change the lighting and see. Camera use anti banding functions to match frames to lighting power frequency flicker. If there is a mismatch there can be issues.

However, it could just be a BRaw temporal interaction bug.

[Tim Schumann]

After looking at the source clips that were sent through we have been able to successfully recreate this bug. It is a bug in the third party 'Bluetooth + for Blackmagic' app for iPhone when used with URSA Mini Pro on Camera 6.0 Beta.

The app is changing the camera settings momentarily (the shutter value in this case) when it first connects to the camera. This happens whether you are shooting in CinemaDNG, ProRes or Blackmagic RAW and in this case it was happening whilst recording mid-clip changing the shutter from 1/48th of a second to 1/78th and back again, possibly due to the phone going in and out of bluetooth range. We will notify the app developer.

The bug is not present when using the 'Blackmagic Camera Control' app or using the camera on its own.

Thanks to the BM support team for looking into this for me!
They did find the problem even despite the fact that it had nothing to do with their firmware,
but the third party bluetooth app I used.

Again, such great work and support at every touch point with BM.
My favorite film tool company
-Daniel

Hi, Dean here, I'm the developer of Bluetooth+

Sorry for the hassle, I'll aim to have a fix out in a day or two, depending on app review times.

I'll also have my Pocket 4K tomorrow, and will do a thorough compatibility check with the app

Hi, Dean here, I'm the developer of Bluetooth+

Sorry for the hassle, I'll aim to have a fix out in a day or two, depending on app review times.

I'll also have my Pocket 4K tomorrow, and will do a thorough compatibility check with the app

Hi Dean!
Thanks so much for staying on the bugs!
Best,
-Daniel

Ok update is out and all should be well