Question about 3x movie crop mode on EOS-M

Started by Janke, January 19, 2014, 10:59:16 AM

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Janke

It appears (but I'm not sure) that the video produced in crop mode is scaled up from 1728 pixels wide to 1920 pixels wide, i.e. the end result isn't a pixel-by-pixel image.

Can anybody confirm this?


(I'm not talking RAW here, just ordinary, compressed .MOV video...)

Janke

In any case, the moires are gone!

Thanks to the whole team for a fantastic piece of software!


Here's a picture of before/after; to get the same image area, I have to be either 3x further back, or use a 3x wider lens. In this case, the former. Contrast and saturation upped to clearly show the improvement (100% crops of actual frames) :


dfort

There are several test videos out there that confirm your findings. I did some quick calculations and the 22.3 wide APS-C sensor in 3x crop comes out to 7.4mm which is exactly the width of Super-16mm. Please correct me if I'm wrong. The EOS-M sensor is listed at 5,184 pixels wide. At 16:9 it should be using 2,916 vertical pixels. Scaling this down to 1280x720 to avoid "line skipping" I came up with a 4.05 crop factor so that means that there still must be some scaling/line skipping going on in 3x crop. However, the videos I've seen done at 3x and 1280x720 on Canon APS-C sensor cameras don't exhibit any aliasing or moire pattern issues. Can anyone explain why?

1%

Crop doesn't mean it doesn't upscale at all...

1x - Full sensor read with line skipping, entire FOV
Crop - Section of the sensor read with less line skipping
5x - pretty much 1:1 but small YUV buffer you can't record

Now after the fact, the HW encoder still upscales the YUV size to 1920x1080 h264.

You can see the YUV buffer size in the debug menu.

dfort

Got it. I was confusing crop with image size in pixels.

2blackbar

I posted this in another thread but it fits better here, does anyone have the same black bar on right side of the video in 3x crop recordings? Is this normal and we have to get rid of it ourselves ? Its also visible when im playing back clips in camera.


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Ok after some tests i figured out it happens only when im using fps override mode, it records fine without this black bar when im not using fps override. So i guess its a bug ?