Issue with stills in ATEM TV studio

In my environment I use the ATEM Television Studio as a live monitoring tool for episodic production. We shoot with 2 or more cameras and I live switch between them on my 24" monitor as needed. It's helpful for me to be able to use the wipe function to help match cameras.

I also grab still frames from the cameras and load them into the media player as a reference as we progress throughout a scene. It's important for these stills to match the incoming video as closely as possible. I've found that grabbing via Media Express and loading into the ATEM's media player changes the geometry of the still slightly (have never analyzed to determine what exactly is happening, I just know there is a visual shift in the aspect of the image). Instead, I use the Scopebox app to capture the frame grabs. These have the correct geometry but there is still a slight color shift.

Any thoughts on why this issue with Media Express?

you are converting colour space twice from native YcRcB to RGB and then back again.

you'd be better off with a switcher which can grab directly to its framestore such as the Panasonic AW HS50

Thanks for your response months ago, I didn't get notification of it so I missed it!

Can you clarify this double conversion further--I am capture the frame in Scopebox in YUV, at what point in the chain does it get converted to RGB (and then back)? Is the ATEM media pool doing a conversion when I load it?

Charles, when posting questions about video modes, it is best to explain with full details, otherwise it is very difficult to help you.

So you don't even mention "how you are capturing from your TVS". If you are plugged into the USB, you are not receiving pictures that are even possible to match up to the original feed.

Just think about that..... the TVS on the USB is outputting a H.264 video stream. This will (A) be compressed and hence your colours will change, and (B) depending on software can be a rendered back differently due to the encoded resolution of 1920x1088, because of the way the H.264/AVC algorithm works.

If you are plugged into an actual raw output of the TVS, you then go on to list software you are using, like we'd all know how and what that software is doing internally with the video data, without mentioning what file format you are using to store the data. Unless you are using a format that supports uncompresed (or loss-less compression) of 10bit data, you are probably applying a change there.

Yes the BMD software does apply a resize and colour space conversion, but only when you give it something that isn't either: "The correct size", or "The correct colour space".

Like Tom says if you need a "absolutely perfect" reproduction of a frame from within the switcher, other mixers often have a direct snapshot frame to media store to make this easy.

Otherwise you need to attach a Decklink type card to your capture machine and link to the SDI/HDMI out of the mixer, capture the raw 10bit frame data, and then load it back to the ATEM via the network. Never pass into any kind of compression or conversion.

You probably need a custom application writing, but it's a very simple one, so if you don't have the resource to do this, see if someone on the Developer forum will do it for you. The BMD Decklink SDK kit comes with the samples necessary to & cut-paste a projects together in a very short period of time.

I'll give as many specifics as I can think of and if anyone thinks they can help but needs more, I'll be happy to supply them.

I'm taking the SDI output of the ATEM into an Ultrastudio Mini Recorder, then Thunderbolt into a Macbook Air.

I use the Scopebox app from Divergent Media which captures the still as a TIFF. I then access the capture folder with the ATEM Media Pool and load the stills.

As noted, if I use the Media Express app instead (which saves it as a .tga), the physical geometry of the still changes. The Scopebox app does not do this but there is a slight color shift.

Thank you.

Can anyone follow up on this issue? Still not sure why since I'm using all BM products in a specified workflow why the Media Express stills don't reproduce accurately (in terms of size) in the ATEM Media Pool.