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[bblue]

I have madVR set to permit movie frame rates in the 23.9fps range by specifying 1080p23 in the frame rate line.

It works, except that when a movie is specified as 23.976 fps, madVR selects the display rate of 23.9142 fps.  If autoclock is enabled, that still works since the clock is shifted accordingly.  But if autoclock is off (due to bitstreaming) it causes frame drops and repeats.

I 'get' everyone's opinions about bitstreaming movies, so I can get around it with bitstreaming off and Dolby Output enabled in DSP.  But my real question is why madVR chooses 23.9142 when the source is 23.976 in the first place?  I could could choose 24fps as the madVR target, but that is also off from the movie, just by a smaller amount.

Is this a bug in madVR, or is there a different way to specify a frame rate more specifically?  (yes, I know that even if specific the clock differential may wander a bit)

Thanks.

--Bill

[6233638]

madVR is requesting the correct request rate, but there is often a lot of variance between the requested refresh rate, and what the video card actually outputs.
 
This is why Video Clock and similar solutions like ReClock exist.
It's a hardware issue rather than a software one, but one which can be worked around by monitoring the refresh rate and adjusting the output to match.
 
And since the original framerate that content is shot at is often 24fps (rather than 24/1.001) I would actually suggest using that as your refresh rate for all 23/24/25fps content.

[bblue]

madVR is requesting the correct request rate, but there is often a lot of variance between the requested refresh rate, and what the video card actually outputs.
 
This is why Video Clock and similar solutions like ReClock exist.
It's a hardware issue rather than a software one, but one which can be worked around by monitoring the refresh rate and adjusting the output to match.
 
And since the original framerate that content is shot at is often 24fps (rather than 24/1.001) I would actually suggest using that as your refresh rate for all 23/24/25fps content.

Really.  I had tried the alternate madVR setting to prefer 24fps for any 25fps movie, but in at least one case it really didn't work well.  I can't recall now whether that was with autoclock on or off.  So the English/UK 25 fps movies are just sped up 24fps?

I Didn't realize that the FPS requested by MadVR would only be approximated by the video card.  This one is an Asus (NVidia) GT640.  It's the only high (enough) performance card I could find that would fit in one slot.

Thanks, I'll revisit this.

--Bill

[6233638]

Really.  I had tried the alternate madVR setting to prefer 24fps for any 25fps movie, but in at least one case it really didn't work well.  I can't recall now whether that was with autoclock on or off.  So the English/UK 25 fps movies are just sped up 24fps?

If it's an actual film, 99% of the time it is exactly that - sped up from 24 to 25fps for PAL release.
Television content may natively be 25fps if it was shot there.

Video Clock is required for smooth playback if you are outputting 24Hz with a 25fps source.

I Didn't realize that the FPS requested by MadVR would only be approximated by the video card.  This one is an Asus (NVidia) GT640.  It's the only high (enough) performance card I could find that would fit in one slot.

With Nvidia cards it is possible to set custom video timings in the driver which may result in an output closer to your selected target, but many displays do not like syncing to anything but the official EIA/CEA Timings and won't display anything if you try this.
 
I have also found that the output can vary each time you do things like restart the system for example, so a custom timing might get you close to correct but only until you restart the PC.
 
Even then, you will never get an exact 24/1.001, so why even try when Video Clock completely solves the problem.

[Hendrik]

So the English/UK 25 fps movies are just sped up 24fps?

If they are UK productions, then not. UK or AU productions are actually filmed in 25 fps, and should not be slowed down. Probably mostly TV productions, like the BBC series, cinema movies are likely still filmed in 24p for the cinema projector.
If they are US productions re-mastered for the UK or other EU PAL countries, then quite likely yes.

Its usually only the case if you have a PAL DVD of a US movie, or recorded live TV from a PAL country of material originating in the US.

Even then there are slight problems though.
The DVD may  be mastered very cheap, and the audio is actually faster and higher pitch on the DVD, in that case you want to slow it down and reduce the pitch again.
However, they may also have taken a bit more care and increased the audio speed without messing with the pitch, so you would not want to change it.

In the end, there is no fire-and-forget solution to this problem.

[6233638]

If they are UK productions, then not. UK or AU productions are actually filmed in 25 fps, and should not be slowed down.

Perhaps shot-for-TV movies, but productions with any real budget would most likely have been shot at 24fps since it would have been shot on film.
 
It should be really obvious if a film is playing back slower than it should anyway.

[bblue]

I made some progress with the 23.97fps behavior I described earlier.  Last night I found that with or without bitstreaming enabled, madVR was setting the display to 50fps but then not able to adjust the differential even with bitstream off.  Naturally there were lots of frame drops and generally unstable video. 

I checked the movie files with mediainfo and found that they were basically 30fps interlaced and I hadn't enabled any deinterlace capabilities in madVR.  When I did, the picture stability improved, but it was still seeking out the 50fps display speed.  I ended up having to remove the 1080p50 'permission' entry in madVR so it would never select that.  THEN it correctly set to deinterlace mode 23.976, and outputted 1080p native to a 60Hz display. 

Drops all but went away (1 every 10-20 minutes or so, which I couldn't improve upon by changing various options.  No matter, though, as I couldn't see it in use.  Yes, smooth motion was enabled, but showed inactive in the OSD.  Now to try and find a 23.76 movie that is not interlaced and see what happens.  It's only in this configuration that I get drops on anything now, so that's good.

Thanks for the assistance guys.

--Bill