@Derek-McArthur @Scenestealer @johnebaker

Hi Derek.

Have finished my own comparison on my machine. If you can, try doing the same on your machine please. You too please Peter.

I selected a frame from one of my 4K video clips in MEP 2022 and exported a BMP file with interpolation and one without.

I then imported them both into Photoshop exactly aligned to the pixel.

I then zoomed into various parts of the image to 1,200% where individual pixels become very visible.

By turning the top layer on and off and looking at individual and blocks of pixels I looked for changes across the image. I could find none. No stretching as in the previous experiment. Perfect match.

If you are seeing differences then I can only assume this is down to a graphics card difference in the handling of the two states of the images or something similar.

Ray.

Hi Ray

It's weird as some frames are perfect and some frames are quite far off, here is a split screen jpg of a frame which is off

The left is without interpolation and the right has it on by default

@CubeAce

Hi Ray

I suspect you are not seeing any difference when exporting as BMP, or any other image format, due to the technique of creating a still image from video.

The general technique, as I understand it, and applies to other video editors, relies on combining several frames eg I, and/or B, and/or P frames to build a composite image which is an average representation of the point on the timeline where the cursor is, if it falls on an I frame then that frame may potentially used, for other video formats that do not use I,B and P frames, in principle a similar method is used.

Whether the Interpolation option takes part in this I do not know, however I would suspect not as the rebuild already involves interpolation irrespective of the option setting.

John EB

@Derek-McArthur @CubeAce @johnebaker

Gee...Derek and I must have really good monitors or eyes or something, because the effect is very obvious in the grass in the bottom left quarter of the frame where the grass is moving in the wind creating the movement I alluded to, across the frame.

Another way that might make it more obvious is to slomo some footage with rapid movement then step through after exporting and bringing it back into the timeline.

as looking at a single frame, or stepping through frame by frame, is very much like looking at a single frame of a movie on 65 - 75 mm film - apparent lower quality.

To be fair a lot of that lower quality is caused by not having the benefit of the random nature of the film grain combining for a perceived smoothing of the grain effect when projected. Digital progressive frames should not suffer from this.

Peter

https://www.dropbox.com/t/ZOfvPncg31f6TsLl

Link to footage

@johnebaker

Hi John.

I chose BMP over jpeg or png due to the lack of compression of that format.

If what you are saying is true and as I can't tell if I have an I frame or not then in theory no still image should be showing a difference that people are saying they can see between the images previously shown.

Perhaps you are correct and a video clip is in order but I can't see a difference between clips on my system anyway.

To me there are too many variables in the problem to be sure what is happening. Does turning interpolation switch which GPU shows the image during playback or export for instance? I don't know.

There are also so many options on exporting that can make a video better or worse image quality wise that I wonder what amount of difference this one option makes. Also to what end is the final videos' proposed use? What restraints are there in bits used or effects / colour correction / sharpening /noise reduction, making?

Ray.

@Derek-McArthur, @Scenestealer

Derek

Thanks for the video clips - definitely noticeable on the Interpolated video.

Peter

. . . . Derek and I must have really good monitors or eyes or something, because the effect is very obvious in the grass in the bottom left quarter of the frame where the grass is moving in the wind creating movement I alluded to, across the frame. . . .

I agree the grass could be moving causing the effect, however due to the 'twist' in the fence posts further back in the scene cast doubt on the movement theory hence my question to Derek on how the images were 'captured'.

The videos however are even better- see about between 3 and 4 secs in when the guy front left raises his hat.

John EB

@Derek-McArthur @Scenestealer @johnebaker

Hi Derek.

OK I can see differences between the two and the one without is definitely sharper. No question.

That Then led me to look at the clips media info and there are slight variations in the average bit depths between the two with the interpolated video being very slightly smaller. Enough to make that much difference? possibly not. Enough to say the processing changed? probably.

The next step for me then is to replicate your findings and look at the MediaInfo data.

Out of interest what are your export settings as I don't use any of MEPs or VPXs presets but tend to rely on my own tweaked versions. Maybe that is the difference.

Ray.

It was just a quick preset MPEG-4 export