Author Topic: MLV App Transcode and Import RAW2MLV produces wrong resolution  (Read 844 times)

tdbartley

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MLV App Transcode and Import RAW2MLV produces wrong resolution
« on: September 08, 2022, 02:13:41 AM »
I am trying to make a time lapse using MLV App's Transcode and Import feature. The input files are raw images from my 5D3 with full 5760x3840 resolution (3:2). However, after import, the canvas shown in the Transformation tab becomes 5792x3870 (Clip Information also shows 5792x3870). So not only has the resolution changed, but the aspect ratio has also been subtly altered.

I expected the canvas to be the original 5760x3840 resolution. Is this a bug, or is there something I am not understanding about the RAW2MLV process?

Walter Schulz

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Re: MLV App Transcode and Import RAW2MLV produces wrong resolution
« Reply #1 on: September 08, 2022, 02:45:35 PM »
5D3's sensor actually has a few "spare" pixels.
Are you sure about the exact numbers? I found "5796x3870".

tdbartley

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Re: MLV App Transcode and Import RAW2MLV produces wrong resolution
« Reply #2 on: September 08, 2022, 06:53:21 PM »
I can confirm that the .CR2 raw files show 5760x3840 in file properties. After transcode and import, MLV APP shows 5792x3870. It would surprise me if there are spare pixels hiding in the raw file that are not reflected in the file properties. At the same time, I can't see any obvious artifacts in the stretched image, so it at least does not look bad. It is a mystery to me where those extra pixels are coming from. Maybe RAW2MLV is resampling.

A single .CR2 is enough to reproduce this result, and I am including one here.

https://www.dropbox.com/s/my9iiygoxnbbi9q/3V1A0328.CR2?dl=0

I am using Windows 10 and MLV App v1.14.

Walter Schulz

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Re: MLV App Transcode and Import RAW2MLV produces wrong resolution
« Reply #3 on: September 08, 2022, 07:23:56 PM »
It would surprise me if there are spare pixels hiding in the raw file that are not reflected in the file properties.

Time to be surprised, then: Please open your CR2 and look for exif tags "SensorWidth" and "SensorHeight". You will be surprised by their values:
Code: [Select]
SensorWidth 5920
SensorHeight  3950
If you lookup 5D Mark III specs you will most likely find "Sensor pixels 22 Megapixel (effective). If you are lucky you will also find a second number "23 MegaPixel". Now do the math ...

You are also confusing CR2 and MLV.
MLV is not the same as CR2! It grabs its contents from liveview buffer and that is 5792x3870. Nobody has claimed your CR2 doesn't have 5760x3840! Yet. Because it has 5788x3862. Download RAWtherapee and open your CR2.

Altogether: Converted DNG is not stretched!

tdbartley

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Re: MLV App Transcode and Import RAW2MLV produces wrong resolution
« Reply #4 on: September 08, 2022, 08:27:12 PM »
Yes, I can confirm in the exif metadata:
Code: [Select]
SensorWidth 5920
SensorHeight 3950

And looking at RAWTherapee shows 5788x3862 as you say.

So including file properties (5760x3840) and the MLV generated by RAW2MLV (5792x3870), now we have four different values and none of them match. I'm sorry to say it, but now I am more confused than ever.

Quote
You are also confusing CR2 and MLV.

The only data coming off the camera card is the .CR2 file. The MLV is generated by RAW2MLV.

Quote
It grabs its contents from liveview buffer and that is 5792x3870.

How is this possible? Are you saying the contents from the liveview buffer is stored inside the .CR2 file?

I'm sorry for the trouble, I'm just trying to understand the process to ensure IQ is preserved through each step. If you say it is all correct and as expected I will trust you.

Walter Schulz

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Re: MLV App Transcode and Import RAW2MLV produces wrong resolution
« Reply #5 on: September 08, 2022, 09:04:05 PM »
Ah, I get it. It is time to ask the mage himself:

@ilia3101:
1) Question about resolution. You are generating MLV with 5972x3870, right? Shouldn't it be 5976x3870?
2) What are you doing with pixels not represented in CR2? 5788 -> 5972(5976) and 3862 -> 3870? Just paint it black? Just for curiosity ...

ilia3101

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Re: MLV App Transcode and Import RAW2MLV produces wrong resolution
« Reply #6 on: September 14, 2022, 08:56:42 AM »
Sorry I don’t get notified.

Raw2mlv is giving you as many pixels as possible (without exposing the raw file’s black borders), according to information provided by libraw… which might still be underreporting the actual size of the image area, but bettwr safe than sorry.

The official 5760x3840 size is slightly cropped in.

So yes, there are spare pixels.

You can’t resample raw files.