Magic Lantern Forum

Developing Magic Lantern => General Development Discussion => Topic started by: theBilalFakhouri on March 31, 2019, 01:26:16 PM

Title: RAW Down sampling Engine
Post by: theBilalFakhouri on March 31, 2019, 01:26:16 PM
I don't know what it's called in Canon cameras but it's there (Still didn't search about it, but I am sharing what I was thinking yesterday maybe some of you would start to dig into it before me).

Okay so most of Canon cameras have mRAW and sRAW settings in still photos and after some reading about it it's down sampling full sensor RAW image data to lower RAW resolution which will perform lower noise and small sizes and since you can do e.g. in 5D3 22.3 MP at 6 FPS also mRAW and sRAW is the same so it's very fast as Lossless compression.

1-Using it for decreasing crop factor:

If 5D3 can do 3840x1616 crop factor of x1.5 no continuous recording at 140 MB/S down sampling it to 3072x1308 will be continuous with less noise too and more sharper image instead of straight 3072x1308 crop factor of 1.88 .

Or for Time-Lapses if you want only 3840x2160 with advanges of 5.7K sensor , instead of shooting at Full-Res LiveView then down sample it in the post , it takes more processing time and stoarge, the other way is to shoot 3840x2160 from the beginning, oh now we have a crop factor, The compromise is using Down sampling straight from the camera no crop factor less file sizes more sharpness less noise.

2-Using it for real-time MLV file playback if that possible:

I made an experiment in the past playing 2560x1440 vs 1736x976 , the higher resolution took more time to view it, but hey since we are only need to *preview* it, we don't have to process it in full MLV resolution for example we don't need to playback 1920x1080 which is will be slow , down sampling 1920x1080 to 1280x720 or 960x540 on the fly then playing it from the RAM in mlv_play is enough to preview the footage maybe if not in real-time. Is this possible in theory?

1.5- Related to 1:
Of course using it in 1x3 Binning mode for continuous recording, we will have our Footage straight out of the camera 1736x738 (No aliasing No moire and Less noise with Less size file) instead of 1736x2214. Cool Ha? It's x5 cooler than the original Cool , but still *not sure if that possible in Cameras like 700D.

*Not sure if 700D have this Engine , We don't have mRAW and sRAW in 700D.

Related:
Can we use MotionJPEG Engine to convert DNGs to JPEGs from the card? This also could be better real-time playback solution.