This is a technical post that may help other creators tackling similar challenges.
So a few days ago I posted a GIF from a movie sequence I basically color-corrected in Adobe Photoshop. Why do that if all popular movie editors come with their own color-correction filters?
To get the same look I’d need to build and adjust a chain of about a dozen filters, including some Adobe secret sauce. I have a good idea what Photoshop does when I ask it to “soften structures” and “boost shadows”, but does it really make sense trying to reinvent the wheel in Vegas? It’s your choice as a creator.
After a lot of missteps I arrived at the batch file that is currently running in the background. I also attached it to this post in case you want to copy and paste a few things to your own project.
Here we go.
I start with a loop that counts from 13 to 44 and increases the counter by 1. This is because the files from the camera are named c0013.mp4 to c0044.mp4 and I can use the counting variable %I when telling the tools what to do.
First command, create a subfolder on my C drive where the temp files go. The C-drive is an SSD, a type of hard drive is built to work with a lot of smaller files.
Then I call FFMPEG, a command line tool that is the swiss army knife of video conversion.
Here it makes an image sequence out of the movie files because Photoshop can only work with single images. As file format I use BMP, which is usually very wasteful, because it is uncompressed. In theory PNG would a better choice, because it uses a lossless compression. But reading and writing PNG in Photoshop is really, really slow, so better not try it.
This is the piece of the puzzle I was missing until today.
There is no way you can call Photoshop from a batch file to do some automated processing. But with recent versions you can make what is called a Droplet. A droplet is a small executable file that performs a pre-recorded Action on whatever you feed it. Exactly what we need! I presume that you know your way around Photoshop already, so I just point you to the documentation. To not waste any extra space just let it overwrite the files in the image sequence. https://helpx.adobe.com/photoshop/using/processing-batch-files.html#create_a_droplet_from_an_action
So hello my dear droplet, please apply Adobe magic sauce to all files in that folder. This will take a while. Even longer if you didn’t listen and use PNG after all.
You know what else is slow? Editing a 4K image sequence in Vegas. They also take up a lot of space on my SSD. So I make two movie files out of each sequence with FFMPEG and clean up the SSD later.
Movie file number one uses ProRes, an intermediate codec used in broadcasting with a near-lossless compression.
Movie file number two is a downscaled SD-version which speeds up previewing my cut in Vegas. When I render the final version I replace those proxy files with the ProRes version.
Most important part, cleaning up so I don’t run of hard drive space. Also don’t forget to close the loop.
To give me a chance to review the process the pause command will ask me to press a key before closing the window.
In case all of this still sounds pretty insane to you, you have no idea how insane it was before. Terabytes of temp files, command lines writen in Excel, Windows folder compression crashing Photoshop in the middle of the night. It was wild.