Kemp Strings's video: Making a grid of any number of videos in REAPER automatic columns rows virtual band collaboration

The improved version of the code (with automatic cropping to the grid) is now built into Reaper under Public Domain license from the 16th of June 2020 with the release of REAPER 6.12c. It is to be found in the Video Processor as the "Combine: Grid of videos" preset! You won't need to copy and paste the code any more! The extra features are demostrated at: https://youtu.be/2sQKpDBHFk8 Cockos REAPER http://reaper.fm has spectacular possibilities for video considering it is a digital audio workstation (DAW). I have made this video to demonstrate how, at the time of making this video, you can make a grid of any number of video files in REAPER. This is particularly useful for doing remote collaboration videos (which are popular with the COVID-19 outbreak going on at the moment). The number of columns and rows automatically adjust to play all available video tracks below the top track (which is running the Video Processor effect). Videos are not cropped and are ordered left to right, top row first. I recommending getting people to record in landscape when using the code at the bottom of this description (and if you want a landscape video featuring a grid of small portrait videos for a "virtual choir" look then have a look at https://youtu.be/u1s4dCGEGv4 instead). If some tracks have videos that stop or start (causing videos to hop around) you can drag an image file into Reaper and drag the duration of the image item to fill in all the gaps in track. If all tracks are full of either video file items and/or image file items then the allocation of videos on the grid will be stable. Use the Video Processor effect and select the "Combine: Grid of videos" preset. You won't need to copy and paste the code any more! The exact code for pasting into the Video Processor effect for reproducing this video is: // grid of videos - automatically draws any number of videos from tracks x=0; count_tracks = input_track_count(); cols = ceil(sqrt(count_tracks)); rows = ceil(count_tracks/cols); loop(count_tracks, gfx_blit(input_track(x), 1 /* preserve aspect */, (x%cols)*project_w/cols, ((x - (x%cols))/cols)*project_h/rows, // position project_w/cols,project_h/rows // output width and height ); x += 1; ); //End of code