Crop mode recording (crop_rec.mo) (1:1, RAW/H.264, 25/30/50/60 fps)

[hjfilmspeed]

Im sure I can mess something up ha ha. I'm good at crashing. But I need to do more research on tragic lantern. I've never messed with TL. I've been on Nightlys since RAW vid was announced.

[a1ex]

I've linked to one particular message that tells you how to test things, not to the entire topic

[domasa]

Greate feature!
Please add "3x" next to focal distance. Now you can not recognize the current mode. Thx.

[a1ex]

Done.

Funny thing - while attempting to fix the interference with still photos, I've got upside-down images. They looked pretty normal otherwise; they had OB pixels both at top and bottom though.

I also found the feature useful in photo mode (for example, as a mild zoom), so I've enabled it there as well.

[domasa]

Let's say you adjust this line skipping register to 1 (that is, read every two lines). Now you have a little problem: you only captured two Bayer colors

Is RAW file smaller when I record only two colors? It will be good for black and white recording..

[dmilligan]

Nope. Each raw pixel is 14 bits and only one color.

https://en.wikipedia.org/wiki/Color_filter_array

Though, a 1:2 line skipping would probably work if you only wanted black and white. Though you would probably need some custom debayer algorithm, or only use the green channel (which you would loose resolution). Or you could go hardcore and scrape the CFA off of your sensor (I've been wanting to do this to my 1100D, but the probability I would destroy the sensor is quite high).

[hjfilmspeed]

@

I've linked to one particular message that tells you how to test things, not to the entire topic

Got it!!! Thank you! Test for the sake of testing! That's very important.

[beauchampy]

A1ex, is it possible to use this feature to record an area of the sensor that is 1440x1080?

Could be a useful way to implement 4:3 recording for anamorphic lenses.

[a1ex]

If I'm not mistaken, you can just select that resolution in the raw recorder. Are you asking something different?

[axelcine]

Do anybody know where I can find the latest ML/crop3x? I am using the April 2 version (with great satisfaction) but I think, the crop module and a few other items have "developed" somewhat. I'm looking forward to try it out - and of course to see it come out in the nigthlies when you think it's ready, being one of the more important improvements - thanks again, A1ex.

[The Director]

if this crop mode could shot down more than 1080 - it's would be f*cking amazing...

[pyjamaproductions]

I'm on the current nightly build for 5DIII.113 but when i but the crop_rec module from april 2nd into my modules folder on my sd card i can't boot ml anymore. once i delete it everything boots up normal again. What am i doing wrong here?

[axelcine]

From A1ex, April 1 (first post in this thread): Current implementation only works on 5D3, and I've tested it only on 1.1.3. The module is not yet compatible with current nightlies, so you need a full package (not just the module).

The latest ML/Crop3X may be found here: http://www.magiclantern.fm/forum/index.php?topic=17021.msg165282#msg165282

[Walter Schulz]

What am i doing wrong here?

Not reading first post comes to mind ...

[Danne]

Not reading first post comes to mind ...

+1

[Hans_Punk]

Did a shoot yesterday on the awesome 5D3 build 1.2.3 crop mode update from A1ex . h264 was requested by client (they needed 'easy' footage to edit)  - For some shots I utilised the 1:1 crop mode from the most recent update and noticed vertical stripes in the footage. Camera was iso 400-800 1/50 shutter and only noticed stripes after downloading footage from card. I've not encountered this issue when shooting raw with the same settings and crop mode - I wondered if anyone else had this issue?

Is there such a thing as post vertical stripe correction for .h264 files that does not require a programmers brain to implement?

Here is am example of the vertical stripes I've encountered on .h264 footage, when using the crop mode:

[aschille84]

Had the same problem to when using 5D3 1.1.3 build in h264 crop mode. Vertical stripes just like in some raw footage, only much harder too remove I guess..

[a1ex]

Do these appear every time you record H.264 in crop mode?

Is this a full-sized image? In raw, the same pattern repeats every 8 columns and it's caused by nonuniform amplifier gains. Basically, divide the image in 8 sub-images (columns 1:8:end, 2:8:end and so on) and match their histograms. Looks like avisynth might be useful here:

http://avisynth.nl/index.php/SeparateFields
http://avisynth.nl/index.php/Select#SelectEvery

[aschille84]

I've only tried indoor shoots, but it seems to be present most of the time. It is full-sized as in 1080p 3x3 crop mode. Can upload som sample footage later.

[a1ex]

A few frames extracted with ffmpeg -vcodec copy would be best.

[Hans_Punk]

Do these appear every time you record H.264 in crop mode?

Is this a full-sized image? In raw, the same pattern repeats every 8 columns and it's caused by nonuniform amplifier gains. Basically, divide the image in 8 sub-images (columns 1:8:end, 2:8:end and so on) and match their histograms. Looks like avisynth might be useful here:

http://avisynth.nl/index.php/SeparateFields
http://avisynth.nl/index.php/Select#SelectEvery

Yes - to both questions.

I'll look into avisynth and extracting frames with ffmpeg - vcodec, but I'm a total idiot when it comes to what I'm doing, and how to correct with code.
Many thanks for reply A1ex

[Danne]

You could do something like this

open terminal

Code: [Select]

ffmpeg -i drag your file here -t 1 -vcodec copy -acodec copy outputfile.movEven shorter clip do

Code: [Select]

ffmpeg -i drag your file here -t 0.2 -vcodec copy -acodec copy outputfile.mov
vcodec=video(no compression)
acodec=audio(no compression)
-t 1(1 second)
outputfile=name your outputfile with correct extension. Will probably export to your home folder.

[a1ex]

Ah, it's a 720p image? In this case, the pattern repeats every 5.33 pixels, or 15 pixels.

Can you do the pixel peeping part for me to confirm these numbers?

edit: FFT says it repeats every 5.3782 pixels; maybe Canon doesn't resize the 1280 image from 1920, but from 1904.

[beauchampy]

Here's a thought.. How about incremental stepping crop?

Could you map it so we can choose 1.1x, 1.2x, 1.3x, 1.4x......... 2x.... 3x....

Effectively we could just bang on a wide-ish lens and have a multitude of different focal lengths to choose from?

This would be amazing, I'm shopping for Leica glass at the moment and effectively turning the 35mm into a 50mm too would save me a lot of ££

[Hans_Punk]

@Danne Many thanks...first time I've ever used ffmpeg (errr...or typed any command line!) 
Even I understood that - thank you for helping.

Here are two short clip extracts, first in context of footage...second clip is start of take (against warm white background of studio)

https://www.dropbox.com/s/60jxn7e9ehwejtc/1080p%20Stripes%201.mov?dl=0

https://www.dropbox.com/s/a9zz2y4gihm9vfo/1080p%20Stripes%202.mov?dl=0


@A1ex, sorry - my fault I added confusion with my previous low res jpg uploaded grab.
All footage is 1080p, 25fps. iso between 400-800, 1/50th shutter throughout.