Massive Magic Lantern Breakthrough. 1080p RAW video on Canon EOS DSLRs

It’s been a big day for the canon cameras with No Film School reporting this morning that magic lantern had achieved continuous 24p RAW recording (not just a few seconds) in a 2.40:1 aspect ratio which in itself was very big news as it makes the new RAW mode very usable; but now it looks like they have managed to get full 1920 x 1080 24fps continuous RAW recording working using “DMA cropping routines”.

A posting by a1ex on the Magic Lantern forum explains further:

Technical: we now know how to copy a cropped version of some image buffer at very high speeds (over 700MB/s), and with this trick we can save the video data the card at full speed, without being slowed down by image borders, for example.

1920x1080 RAW video now requires 83MB/s at 24fps, so it should work just fine on 1000x cards. I didn't try it.

So, I've lost my patience and rewritten the lv_rec module from scratch, to use these new routines and to experiment with different buffering algorithms. The new module is called raw_rec and outputs the same file format (RAW files).

Main changes:

- The ring buffer only uses 32MB memory blocks (maximum we can get). Reason: card benchmarks showed higher data rates for large buffers.
- Frame copying is done outside the LiveView task (not sure if it has any effect).
- When the buffer gets full, it skips some frames, rather than stopping.
- Fewer hardcoded things: should be easier to port.
- Resolution presets, from 640x320 to 3592x1320.

So it really looks like the magic lantern people have completely cracked it! Presently there’s no audio (time to bring back the slate) and slower cameras (like the 600d) might not be able to handle as much resolution, but certainly the 5D Mark III seems to be taking it all in it’s stride with the addition of these new DMA cropping routines.

Blown Away

I think everyone has been blown away by how fast developments have taken place since the discovery of a way to extract raw video on the cameras.  Just a couple of weeks ago Magic Lantern developer a1ex posted to say “Don’t hold your breath for raw video. 24fps at 1080p is unlikely IMO, even on 1000x cards.” Two weeks later it looks like we are already there!

Not only will this bring RAW video capability to many of the users of canon EOS series DSLR’s out there, but this is the first time that RAW video has been available from an off the shelf camera with a “full frame” sensor. Good news for fans of really shallow depth of field.

A fellow called lorenco on the Magic Lantern forums, has also made available some video of his dog, which gives you a nice comparison of the 5D Mark III video rendered from both RAW video and H.264 iframe (Technicolor CineStyle) video modes, so you can see the extra latitude the RAW video brings to the party. The RAW version is 1928x820 resolution to give something closer to a 2.40:1 aspect ratio. (These video’s were made before the 1080p breakthrough became available)

Update: first extended RAW video sample here

RAW video version:

H.264 iframes only version: