Sequence output issues (batch .cxr processing, cryptomatte implementation)

[marchik]

Recently I needed to render 90 frames for a video and output AOVs, including several Cryptomatte passes. My renders had an alpha channel, but I also needed to get the same sequence as 16-bit images without an alpha channel with tone mapping from Corona VFB.
I rendered in 4K and did not expect the pain in the ass that awaited me.
Firstly, due to the very unfinished implementation of cryptomatte, in order to transfer the finished files to the compositing artist, I had to send 200 GB of .cxr files over the Internet, although I could have gotten by with a couple of GBs if they were separate render elements. Of course, I will not mention the questionable compatibility of .cxr with AE and the need to explain how to import them.

Secondly, when I tried to save several .tif files for a preview sequence using CoronaImageBatch, I realized that no matter what format I output the images in, the alpha will always be there, and if I output a format without an alpha channel, I get 8 bit. I tried adding arguments to the .bat file, but none of them worked. I tried to find documentation for CoronaImageCmd.exe, but there simply isn't any, except for a couple of paragraphs in docs.chaos.com. Plus, it doesn't respond to the -- help command
As a result, I had to manually open each .cxr file and save it in the required format (maybe that's why my request sounds a little irritated).

I understand that Corona Renderer is not intended for serious production and that VRay fills this niche, but this upsets me, because the features themselves exist, they just all feel unfinished.

Yes, you can consider this request as a feature request, but please fix this :'(

[TomG]

On the first, the idea is already floated internally of having a checkbox for "include Corona data" for CXRs, on by default but can be turned off. This would leave the cxr comparable in size to an exr, by removing the extra data that Corona can use for denoising later, resuming renders, etc. And that goes along with the idea of allowing 16 bit rather than 32 bit as an output (except forcing 32 bit output for those elements that still need it, but letting all the other data be 16 bit - V-Ray does something similar, for example). Between those two, that should give full control over "cxr file size vs. cxr functionality" to our Coronauts :) Nothing set for development timeframe yet, just as a heads up.

On the second, I'd have thought batch processing via Photoshop or other image or video editor would have been the way to go there, to load and resave while stripping alpha from a non-Corona specific format like .tif. You can pop the idea on the Ideas Portal if you like, but this is just a pointer for what may save you doing this manually in the meantime. Quite a lot of powerful batch editing out there for generic image formats, so no need to wait for Corona to develop something that handles those.

[marchik]

On the first, the idea is already floated internally of having a checkbox for "include Corona data" for CXRs, on by default but can be turned off. This would leave the cxr comparable in size to an exr, by removing the extra data that Corona can use for denoising later, resuming renders, etc. And that goes along with the idea of allowing 16 bit rather than 32 bit as an output (except forcing 32 bit output for those elements that still need it, but letting all the other data be 16 bit - V-Ray does something similar, for example). Between those two, that should give full control over "cxr file size vs. cxr functionality" to our Coronauts :) Nothing set for development timeframe yet, just as a heads up.

On the second, I'd have thought batch processing via Photoshop or other image or video editor would have been the way to go there, to load and resave while stripping alpha from a non-Corona specific format like .tif. You can pop the idea on the Ideas Portal if you like, but this is just a pointer for what may save you doing this manually in the meantime. Quite a lot of powerful batch editing out there for generic image formats, so no need to wait for Corona to develop something that handles those.

Thanks for your reply, Tom. Nice to hear about the first point!

I would definitely gladly use batch processing in Photoshop or any other package if it made sense. Let me explain my second problem one more time. I needed to get 16 bit images from .cxr with specific tone mapping that I set up in Corona VFB and without alpha channel. The whole point of .cxr is that I can get anything from them" - after all, they contain "all" the data. The catch is that any format that supports 16 bit outputs an image with premultiplied alpha, and any format without premultiplied alpha outputs an image in 8 bits. Batch processing from Corona Image Editor is the only way to get an image from CXR with the tone mapping I need, and I do not have the ability to "uncheck" include alpha channel.

It would be great if batch processing was built right into the Corona Image Editor interface with all the options, I hope you will consider this for the new announced version of Corona Image Editor.