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Multicam stands for multicamera set-up. It is a set-up where many cameras are stationed at different positions to record the same action from different angles. It’s common for recording sport or other events for TV live broadcast. Big events can require as many cameras as 16. Fiction films productions can use multicamera too, but the need to hide the equipment on the set usually limits the number of cameras to 2-3.
Editing multicamera recordings requires a specific workflow. You need a video mixer, that is a console that allow the simultaneous preview of all the videocamera inputs so that the editor can select the best camera angle for every moment.
To know more consult Mighty Wikipedia
How to turn Cinelerra into a video mixer (well… kind of)
Cinelerra has not a video mixer function.
However Lorenzo Sutton had the brilliant idea of turning the compositor window into a kind of mixer using the Projector zoom. You won’t have the easy workflow of a real video mixer but you can edit selecting from simultaneous preview of all cameras.
This workflow is experimental and needs improving. Main issue is performance.
Here you can see my Compositor window ready to accept 12 small camera inputs (one for each of the 12 cameras) and a bigger output for my edited video.
Step 1: setting up the tracks
The idea behind the set up is to double every track and use an instance of it for monitoring (preview) and the other for editing.
The twelve small canvases you can see above, numbered from 1 to 12 are 12 monitoring video tracks, zoomed in (projector Z=0.2100) and positioned well apart in the free space of the compositor.
The bigger canvas you can see in the bottom-left part of the compositor is made of 12 editing video tracks one over the other, mixed as you desire to a single output. All 12 tracks are zoomed in (projector Z=0.500) and positioned all in the same bottom-left part of the compositor.
To ease the job of setting up the tracks I’ve prepared a couple of empty template projects you can download and fill with your files.
Download the multicam template projects with the following loooong terminal command:
wget http://www.g-raffa.eu/Cinelerra/HOWTO/Files/Multicam-8-12-720x576-anamorphic.tar.gz && tar xvf Multicam-8-12-720x576-anamorphic.tar.gz && rm Multicam-8-12-720x576-anamorphic.tar.gz
You’ll get a folder named Multicam-8(12)-720x576-anamorphic containing an empty project set up for 8 cameras and and empty project set up for 12 cameras. This template project is set for an anamorphic PAL signal but can be easily adapted to other resolutions and aspect ratios.
Step 2: loading the files
Repeat the procedure untill you’ve loaded all the files from the cameras.
Step 3: editing
For soft transitions use the Fade line. For straight cuts use the Mute line. To make the Mute line visible go to View→Mute. This will make a blue line visible on each track.
Make all the edit tracks black. Make visible only the portion of tracks you choose by selecting one of the monitored tracks.
Note that the playback of 24 zoomed tracks may need a lot of computing power, even with standard definition assets, surely more than my average computer can afford. You might end up with unacceptalby low framerate (e.g. 2fps). To speed up playback for general preview disable the playback of monitor tracks. For editing, scroll playback on the timeline moving the mouse cursor over the timebar.
Step 4: rendering
Once you are done with editing, disable playback of monitor track (to save computing power).