Doom9's Forum - View Single Post - madVR - high quality video renderer (GPU assisted)

voyager6868 · 23rd November 2018, 09:17

From what I can tell madVR doesn't do 3:2 pulldown properly (see more technical details below). That is, if I play a 24fps video on a 60Hz display, it doesn't seem to show a regular cadence of AAABBCCCDDEEEFF etc.

A few points I'd like to make in favor of fixing this:

Many TVs can automatically do reverse pulldown if the cadence is proper and can show the video without judder. With an unpredictable cadence like madVR appears to provide, this isn't possible.

So, why not just switch the video mode to 24Hz? One, it takes a few seconds for some TVs to switch (blank screen while it does so) between modes, and two (this may be uncommon) some TVs have different input lag at 24Hz versus 60Hz, so the lipsync setting on a receiver needs to be regularly adjusted back and forth (mine has a difference of 110ms).

Further, some users may have a screen that does not support 24Hz and are used to this type of judder (e.g., North American users), so don't want to devote the processing power to enabling smooth motion (or are more bothered by the smooth motion artifacts that this judder). The current implementation is more jarring than typical judder as it appears to be more unpredictable.

My methodology:

1. Download the test here:
https://www.rtings.com/images/test-m...15/305_24p.mp4

2. Ensure your screen is set up to reverse the 3:2 pulldown. On many Samsung TVs, for example, this can be done by turning on Auto Motion Plus, Custom, setting both sliders to 0. If your screen can't do this, you can still run the test, it will just have a different ideal result.

3. Play the video in MPCHC with madVR output.

4. While playing the video, take a 1-second exposure of the screen (this can be done, for example, using the Camera app in Pro mode on many recent Samsung phones)

Ideal result: If your screen does the pulldown, you should see 24 equally bright squares. If your screen does not, you should see a regular checkerboard pattern.

Result with current madVR: Squares appear to have random brightness with no discernible pattern.

Result with YouTube in Chrome browser (search rtings judder test), YouTube app on AppleTV, Infuse 5 on AppleTV, Windows 10 stock media player is the ideal result as above.

So, madVR seems to be an outlier with regards to this support.

If I use Handbrake to set the video's FPS to 60, everything looks correct in madVR, so seems clear it is the 3:2 pulldown algorithm that is at fault.

23rd November 2018, 09:17	#53715 \| Link
voyager6868 Registered User Join Date: Apr 2015 Posts: 6	Request for implementing proper 3:2 pulldown From what I can tell madVR doesn't do 3:2 pulldown properly (see more technical details below). That is, if I play a 24fps video on a 60Hz display, it doesn't seem to show a regular cadence of AAABBCCCDDEEEFF etc. A few points I'd like to make in favor of fixing this: Many TVs can automatically do reverse pulldown if the cadence is proper and can show the video without judder. With an unpredictable cadence like madVR appears to provide, this isn't possible. So, why not just switch the video mode to 24Hz? One, it takes a few seconds for some TVs to switch (blank screen while it does so) between modes, and two (this may be uncommon) some TVs have different input lag at 24Hz versus 60Hz, so the lipsync setting on a receiver needs to be regularly adjusted back and forth (mine has a difference of 110ms). Further, some users may have a screen that does not support 24Hz and are used to this type of judder (e.g., North American users), so don't want to devote the processing power to enabling smooth motion (or are more bothered by the smooth motion artifacts that this judder). The current implementation is more jarring than typical judder as it appears to be more unpredictable. My methodology: 1. Download the test here: https://www.rtings.com/images/test-m...15/305_24p.mp4 2. Ensure your screen is set up to reverse the 3:2 pulldown. On many Samsung TVs, for example, this can be done by turning on Auto Motion Plus, Custom, setting both sliders to 0. If your screen can't do this, you can still run the test, it will just have a different ideal result. 3. Play the video in MPCHC with madVR output. 4. While playing the video, take a 1-second exposure of the screen (this can be done, for example, using the Camera app in Pro mode on many recent Samsung phones) Ideal result: If your screen does the pulldown, you should see 24 equally bright squares. If your screen does not, you should see a regular checkerboard pattern. Result with current madVR: Squares appear to have random brightness with no discernible pattern. Result with YouTube in Chrome browser (search rtings judder test), YouTube app on AppleTV, Infuse 5 on AppleTV, Windows 10 stock media player is the ideal result as above. So, madVR seems to be an outlier with regards to this support. If I use Handbrake to set the video's FPS to 60, everything looks correct in madVR, so seems clear it is the 3:2 pulldown algorithm that is at fault.