What tool to compare A/B compare frames between 2 vids?

[odditory]

Just curious what tool you guys use to A/B compare the same frame in two separate video files.

I just want to be able to scrutinize the same frame between different test encodes to determine optimal encoder settings. Also, should I be comparing the REFERENCE frame in each vid, or does it matter? If so, how do I know which frame the ref frame is?

Seems like analyzing encoder settings really consists of two parts: analyzing the "eye feel", as in what it looks like playing back in real time, and also analyzing the same individual frames between 2 videos.

forgive the n00bness..

thanks

[Dark Shikari]

There is no such thing as "the reference frame"; all non-B-frames are referenced at some point during the video.

The most important thing when comparing two frames is to make sure they are the same frame type, since different frame types have different quantizers. I-frames are the easiest to compare because their quality doesn't depend on that of the previous frame.

[odditory]

There is no such thing as "the reference frame"; all non-B-frames are referenced at some point during the video.

The most important thing when comparing two frames is to make sure they are the same frame type, since different frame types have different quantizers. I-frames are the easiest to compare because their quality doesn't depend on that of the previous frame.

That's what I meant - the I-Frame .. but couldn't remember the name. So how do I find the I-frame in a vid?

[Dark Shikari]

That's what I meant - the I-Frame .. but couldn't remember the name. So how do I find the I-frame in a vid?There are I-frames every --keyint frames, or at scenecuts. There are some free stream analyzers that let you see the frame types.

Its usually a pretty sure bet that any scenecut will be an I-frame.

Additionally, if you use the same firstpass file for both encodes, the frametype distribution will be exactly the same, eliminating any of these worries.

[odditory]

that said, what's a good tool (software program) to use for these comparisons? that's what I was mainly after.

[talen9]

Hmmm it's not exactly thought to be used in this way, but in Media Player Classic you can move to the next and previous I-frame with "Shift + Right arrow" and "Shift + Left Arrow" respectively.

Once you find a suitable frame for the comparing (and while the video is paused), with "Ctrl + G" you can see the number of the player which is currently visualized; open another instance of MPC with the second clip, "Ctrl + G" again and type in the chosen frame number .. that's it :p

Obviously, you have to be sure that the way the video is rendered is not affecting your evaluations ;)


PS: By default, if you open another multimedia file with MPC, it'll open in the already playing window (closing the first clip); you have to check "open a new player for each file played" from "View" -> "Options" -> "Player", to be able to open the two different clips you want to compare.

[Reuf Toc]

With avinaptic you can see frame distribution. Open your video, click on "DRF analysis" button. Video will be analysed... Once it's done click again on "DRF analysis" button and a graph where you can see several informations will show up.

[Avenger007]

what tool you guys use to A/B compare the same frame in two separate video files.
If you're using AviSynth scripts then try AvsP.
:search:

[ToS_Maverick]

how i compare videos:

vid1=directshowsource("Black.Pearl.Sample test crf 20 aq10 sens10 qcomp10 main.mkv", audio=false).lanczosresize(1280,536)
vid2=directshowsource("Black.Pearl.Sample test crf 20 aq10 sens10 qcomp10.mkv", audio=false).lanczosresize(1280,536)

vid1=vid1.subtitle("vid1", text_color=$ffffff)
vid2=vid2.subtitle("vid2", text_color=$ffffff)

interleave(vid1,vid2)

[Blue_MiSfit]

I do something along those lines as well. For comparing moving video, I find it easier (assuming I've got the screen real estate) to do:


a=avisource("video1.avi").subtitle("video2")
b=avisource("video2.avi").subtitle("video2")

StackVertical(a,b)


It makes moving comparison a lot easier, but obviously takes more screen size :) Also, I usually watch video at full screen, so this isn't the best "honest" comparison. Neither is frame by frame though, so I try to do a little bit of both.

~MiSfit