Downsizing the resolution to 50%, but not the color quality

[poisondeathray]

I should clarify: I meant not a visible difference as shown in your bmp comparison (your screenshot shows a big difference in contrast, black & white levels, which is most certainly a playback / screenshot method issue)

A 1280x720 4:2:0 clip will have a Y' resolution of 1280x720, but only 640x360 of color resolution

A 640x360 4:2:0 clip will have a Y' res of 640x360, but only 320x180 of color resolution, so the color edges won't be as crisp - this is different than the levels issue your screenshot shows

[silencer]

@ DB83

I know the conversions are different. and yours was ah yea quick. Oh and did you know, also their file names are different? and did you know it is night here now? and here it is not raining at the moment, but there can be probably places somewhere in the world snowing currently? and 1+1=2

@ poisondeathray

no difference? screenshot problems? so only i see the difference when i watch and compare the videos?

when you watch the videos, please ensure you are using a color display, and not black white. this is really very important man.

come back next year or so, when you fixed your player issues and bought a color display.

[DB83]

Once again help is offered and the person who gets it knows more than those that offer.

Take it or leave it but do not get 'clever' with those that help.

[El Heggunte]

@ poisondeathray

no difference? screenshot problems? so only i see the difference when i watch and compare the videos?

when you watch the videos, please ensure you are using a color display, and not black white. this is really very important man.

come back next year or so, when you fixed your player issues and bought a color display.

You really misunderstood everything he said.
For now, I can only say this subject is much more complicated than you think

[deadrats]

is it just me or is "silencer" coming off like a complete dick?

maybe he should consider investing in a nice big cup of STFU.

[poisondeathray]

The other difference is DB's clip didn't take into account the SD conversion to Rec601 (usually when you downscale to SD, you need to convert as if it had used 601 , because the conversion to RGB for display will use Rec601, e.g. colormatrix in avisynth) - so technically it's not quite correct, but it's just a subtle shift in colors, not a levels shift such as in the bmp comparison

I'm 100% sure this is what is going on. I can prove it if you want

You definitely have a display and screenshot taking issue

[_Al_]

I did not change it to BT.601 in the previous post, changing it to BT.601 in Avisynth to consider SD resolution comes out like this:

[jagabo]

is it just me or is "silencer" coming off like a complete dick?

maybe he should consider investing in a nice big cup of STFU.

No, you're not the only one that comes off like a complete dick.

[DB83]

The other difference is DB's clip didn't take into account the SD conversion to Rec601

Can you do that in 'simple' tools such as avidemux (which is what I used to do the resize) ?. Could not see a filter for that.

[poisondeathray]

The other difference is DB's clip didn't take into account the SD conversion to Rec601

Can you do that in 'simple' tools such as avidemux (which is what I used to do the resize) ?. Could not see a filter for that.

no you can't in avidemux, unless they have added it recently?

Note - this 709/601 is not a big difference ( as the differences depicted in his "comparison".) Rec709 vs. 601 is just a slight shift

original, RGB using 709, then resize



original , RGB using 601, then resize


Save these to your desktop & flip back & forth


I believe his upper left screenshot in the bmp is correct - it shows VLC converting to RGB with 709 first (still 1280x720, RGB) , and then the resize. That's why the color borders will sharper, due to the chroma subsampling issue mentioned earlier (it has full 640x360 color, but a 640x360 4:2:0 conversion will only have 360x180 color information to begin with, no even taking into account compression issues down the line) . If VLC had resized then, converted to RGB with 709, the color borders would be slightly blurrier


Original,resized , then conversion to RGB using 709


Compare that last one with the other 709, and you will notice the thin edges around red lines is obscured. This is due to the loss in color resolution and subsampling . It's not a huge difference, but it's there

[DB83]

Well I do not have 20/20 vision and I certainly do not see any difference.

On a point of interest, I did a original to resize screen by screen comparison and, to be honest, on my own monitor I did not see the variances that the Op reports. As I said, if they are there then they can be easily corrected but if they are not then you are over-correcting.

[poisondeathray]

Did not see the difference between 709/601, or did not see the color sampling differences ?

If the latter, look closely under the right leg of the lady closest to the camera, notice the thin red line decal on the motor bike is less distinct. It's probably not the best screenshot to show the differences, but when you have thin red (or any color) lines, they become obscured. Color edges are less crisp. It also depends on which algorithm is being used by the player or application to convert back to RGB for display . Either way, it most viewers would be hard pressed to see the differences under normal playing conditions (human eyes are not as sensitive to color, one of the big reasons why 4:2:0 subsampling was chosen in the first place)

If the OP will entertain us , and view 1 video at a time, close the application, then open another video, to examine, I think he will be surprised.

[DB83]

pdr. I will have to take your word for it since my eyes do not differentiate.

[jagabo]

pdr. I will have to take your word for it since my eyes do not differentiate.

Drag both images to a folder on your computer. Use Windows' Picture and Fax viewer (AKA Photo Viewer) to view them. Flip back and forth using the left/right arrow keys. The differences will be very obvious.

Or drag them to a folder. Rename them 1.png and 2.png. Open 1.png in VirtualDub. 2.png will automatically be appended. Use left and right arrow keys to step back and forth between them.

[silencer]

@ poisendeathray

When I close all the apps and open only one video, there is no change. and it can not be a screenshot issue, as even without making the screenshot I can see that differences. But if you see all the videos different than to my screenshot then it can indeed be because of my screen or so and thus meaning independent from the screenshot.

in other words, it means you all see the converted videos with good colors not like on my screenshot? or i am the only one seeing only the original video in good colors?

But I think the last pic on your post is nice and I can see the difference, it is better than what I see from the previous converted video. upload the recent one 709 that i can check

[poisondeathray]

pdr. I will have to take your word for it since my eyes do not differentiate.

nah, it was a bad example, unless you're a pixel peeper and used to seeing these things.

Can you see the difference here? look at the text clarity e.g. the green word "title" .






I took an 1280x720 RGB image, converted it to YV12 at 1280x720 to simulate the "original", then either 1) converted to RGB then resized it , or 2) resized it , then convert to RGB

#1
ImageSource("testchart720.tif")
converttoyv12(matrix="rec709")
converttorgb(matrix="rec709")
bicubicresize(640,360)

#2
ImageSource("testchart720.tif")
converttoyv12(matrix="rec709")
bicubicresize(640,360)
converttorgb(matrix="rec709")

[poisondeathray]

@ poisendeathray

When I close all the apps and open only one video, there is no change. and it can not be a screenshot issue, as even without making the screenshot I can see that differences. But if you see all the videos different than to my screenshot then it can indeed be because of my screen or so and thus meaning independent from the screenshot.

in other words, it means you all see the converted videos with good colors not like on my screenshot? or i am the only one seeing only the original video in good colors?

But I think the last pic on your post is nice and I can see the difference, it is better than what I see from the previous converted video. upload the recent one 709 that i can check

Yes they all look similar, I only check the original, DB83's and _AL_'s newest one (with the exeption of the slight Rec709/601 and/or chroma sampling differences) , but I think everyone will agree they look similar, not like the huge differences in your comparison.bmp , I check in a variety of media players

The big differences in your comparison.bmp are due to levels and contrast - that's most certainly a configuration/playback issue, and/or the method of taking screenshots. Most common cause is different renderer is being used (it's easy to replicate your results using different renderers, the exact same video looks completely different as in your screenshots), but it might be something else like graphics card settings

1st reboot the computer, then try another media player e.g. MPCHC, KMplayer, SMplayer, PotPlayer (again, close all applications, only open 1 video at a time)

[deadrats]

is it just me or is "silencer" coming off like a complete dick?

maybe he should consider investing in a nice big cup of STFU.

No, you're not the only one that comes off like a complete dick.

yes, but i've been here for nearly 8 years, (s)he's been here for less than a month, there needs to be a rule that you must be a member for at least a year before you can act like a dick.

[DB83]

@pdr

With the test-cards the differences are more than obvious. Cheers.

[silencer]

@ poisondeathray

I compared the videos with the following players now: VLC, Windows Media Player, Quicktime, MPCHC and KMplayer.
Independent from starting order they all come to the same result: Only the original video looks fine with the colours in all of them (except in Quicktime - less color), all other converted ones both yours and mine clearly suffer with colors as in my screenshot.

I then watched all of them on a different computer, and all the conversions, both yours and mine, seems really fine as you said, at least the colors much better than in the screenshot. My previous conversions were also fine.

it was also good to check with the new players, unfortunately they dont improve the color quality of the converted videos same as watching them on a different pc or like you, while the original remains similar good even without changing the player settings.

We now can conclude that it has something to do only with my pc, not much with the conversions. just weak colors when I watch the converted videos. It may be a configuration issue?

Why do and can they differ? what could be the difference? what can I try to fix that?

[poisondeathray]

The "colors" look different between your top left and top right comparison, but it's actually due the Y' levels that are different

It's definitely a playback configuration issue - the fact that you tried on another computer and it was ok prooves this

99% of the time something like this happens where 1 video looks ok, it's due to different renderer - so check task manager that the player (or any other video application that might use the video graphics overlay, not just video player) is actually closed before you open another instance . If the original process "hangs" before you open another video player , the new instance will use a different renderer . Also try, play the original video, close it, open the original video again


These 3 are all from _Al_'s last video , the only difference between 1&2 is the renderer (it's the exact same video, played in the same player)

1) original, how it looks normally played


2) changed renderer to vrm9 (renderless) - notice the waveform, how the black and white point are adjusted - this looks similar to your Top Right comparison (I would guess maybe vrm9 or vrm7 were used in that one)


3) same as #2, but used a levels filter to try match back to the original

[silencer]

@ poisendeathray

I have tried your instruction, checked the task manager for any players. I understand and can follow you. Even when I restart the PC and play the converted first, there is no change. with all the mentioned players and any combinations, they deliver me the same result: all the converted with weak, only the original with good colors at any time (except in Quicktime player, looks same pattern like in converted). I think then there should be a tiny information in the file that differs and decides how to play them?

What else would you suggest me to try?

[poisondeathray]

Yes, there are flags can be used in videos that some players can read and it will change how the player displays, but its not applicable in your case (those samples didn't use flags)

Something else is wrong with your setup, and configuration but I don't know what. Maybe check your video card drivers and settings . Sorry I don't know what else it could be or what to suggest

[Noahtuck]

is it just me or is "silencer" coming off like a complete dick?

maybe he should consider investing in a nice big cup of STFU.

No, you're not the only one that comes off like a complete dick.

I bet no one thought this was still around!!!

https://forum.videohelp.com/threads/188374-STFU-picture-Depository

https://forum.videohelp.com/threads/188374-STFU-picture-Depository?p=1864620&viewfull=1#post1864620

LMAO!!!!