Find duplicate and torn frames

[jaidek]

Hi All,

I would like to be able to feed avisyth a 720p 60fps file and it analyze the actual frame rate and percentage of torn frames. Something like:

Input file length - 00:01:00 (3600 frames@60fps)
Output log - 1400 unique frames (actual rate 23.3fps) with 100 torn frames (14%)

Any information on how this can be achieved would be appreciated.

Thank you

[hanfrunz]

Hi jaidek,
can you upload an example video clip?

[jaidek]

Hey Hanfrunz,

Thanks for the help! I am currently at work and have limited videos on hand. But I have uploaded one to our website. This video does have visible frame tearing, but appears to be running at full fps. I will upload a video tonight that has duplicate frames. If you need something specific, please let me know and I can upload additional videos.

Here is a link to the download:
http://www.lensoftruth.com/media/ps3_mirrors_edge_kate.zip

Thanks again!

[jaidek]

Here is another video for you to check out. This one doesn't appear to have any frame tearing, but is running at a lower frame rate (captured at 60fps but appears to be 30fps).

http://www.lensoftruth.com/media/prince_of_persia.zip

I will check around tonight and see if I have a video that has both issues present.

Thanks!

[hanfrunz]

clip2 is realy 30fps, you can use selecteven() or selectodd() to get 30fps. The first one is 60fps, but the frames are blended togehter. I have no idea how to fix that.

[jaidek]

Hey hanfrunz,

Thanks for the help. Unfortunately selecting even or odd frames doesn't help me much. Some of the videos I have, captured at 60fps, will throw in random repeat frames (the PS3/Xbox 360 can't keep up with the frame rate so tosses in a duplicate). This is what I need to find out. How many unique frames a video has and how many duplicate frames a video has. I will upload shorter, full 60fps videos when I get a chance.

I found this on another forum regarding the methods of finding duplicate and torn frames with Avisynth. BTW, "GRID" is a game:

Methodology then. The fps detector counts the number of duplicated frames in its sample. The actual amount of screen being measured can be preset. To measure a precise fps, only one line of 1280 pixels from the centre of the screen is sampled.

To measure the amount of torn frames, the whole screen is sampled. Dupe frames from this test minus the dupe frames from the one line test are worked out as a percentage of the whole sample. This should work on any 2VBL game, like Race Driver GRID appears to be. Bear in mind that this percentage is of the entire 60fps output of the console, not of the measured frame rate.

In the case of GRID it also appears to be the case that the whole game isn't v-locked on PS3, and the more challenging intro sections on the 360 version can also tear. However, in-game 360 appears to be v-locked.

So how sensitive is the scanner? Will sampling just one line fool the scanner if the actual screen is completely static to the human eye? No, the scanner is actually so sensitive that even when the camera is static and there's no perceived movement at all, we can still detect a 30fps update. Here we are in GRID, at 0mph.

I am not a coder unfortunately, so I have no idea how to achieve this. I am trying to obtain this information for our video game blog. We compare cross platform games in order to inform consumers which version is visually superior and preforms better at the technical level. For those who are interested, here is one of our comparison videos.
http://www.lensoftruth.com/?p=1343 (scroll down to the bottom of the page for the videos)

Any help on how this can be achieved would be awesome.

Thanks again

[thetoof]

Not quite what you want, but you could use Dedup to check how many frames are considered as unique in a sample (can't test atm and honestly dling a 270mb file is a little turn off ;)).

[jaidek]

Thanks for the suggestion. Also, I am sorry about the large file sizes, these are HD videos. I have re-uploaded smaller clips, here are the links:

http://www.lensoftruth.com/media/prince_of_persia.zip (55mb)
http://www.lensoftruth.com/media/ps3_mirrors_edge_kate.zip (25mb)

The videos are the same as before, the Prince of Persia video appears to have duplicate frames and the Mirror's Edge video has the frame tearing. You will see the most frame tearing during the hug sequence. Also, the apparent frame blending is the games motion blur.

Once again, thanks for the help.