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[Ton]

I already asked this in another thread, started by me, but probably it was overlooked. It was not exactly on-topic and at the end of the thread.
When I want to use Videoclock and PAL Speeddown (for PAL 25fps content), can I set Display Settings to 24 Hz for PAL (25/50fps) ? After having read about the subject in the Wiki, I assume that it is o.k., but I would like to be sure.

[NickF]

I would really like to get a clear answer on this myself.  I have copied the wiki answer on this:

Target Ratio (PAL Slowdown)
VideoClock also adjusts the clock rate slightly to achieve an "ideal" ratio between the monitor refresh rate and video frame rate. This ensures, for example, that playing a 23.97 fps movie on a 24.0 Hz display will have a perfect 1:1 relationship. This is done by altering the audio clock by the tiny fraction 23.97/24.00. This removes the annoying occasional video stutter that would happen without this adjustment. The tiny audio change is inaudible.

This feature is also useful for PAL content that's 25 fps. When playing 25 fps content on a 24 Hz display, a 1:1 ratio will be achieved.

VideoClock is willing to adjust the clock by up to 5% if it will result in a perfect ratio between the video and monitor rates.

The first part of this answer isn't PAL Speeddown.  What is actually happening is that the video is being speeded up slightly to match the frame rate of the display and so is the audio.  The fps of the video file will be set at 23.97.  The auto display settings changer will select 23/24 to set the graphics card to the right rate.  VideoClock will adjust the system clock to make these match.

The second part is what you are referring to which is PAL Speeddown.  If this is to work, something has to tell the graphics card to select 24Hz under the right circumstances.  As far as I'm aware, this can only happen in two places in MC17, one is by using the Display Settings and the auto display settings changer and the other is by specifying display modes in madVR.  If it is the first, the file fps has to be set to 23.97.  If you rely on madVR to set your frame rate, I think the value in the stream will be 25Hz so that isn't going to work.

So it seems to me that the only answer is to change the file fps setting to 23.97.

There is the question of TV series sold on DVD.  I am not an expert here and would appreciate some confirmation, or otherwise, but I assume these will generally be shot on video cameras which run at 25 fps in the UK.  So that means that they need to be played back at this rate.

Nick.

[Sandy B Ridge]

I think a major problem is knowing at what rate the media was mastered at originally. You could take a guess that most US TV series were 24 FPS and most UK TV series as 25 FPS. Films are tricky, but you'd have to have a punt at mostly 24 FPS.

All would be labelled in the stream (probably) as 25/50 in Europe. So I think the only way is to manually adjust the FPS tag to what you think it should be.

The classic (and often quoted) example is The Simpsons. Those who watch it regularly will get tuned into the tone of the theme tune, and visiting across the pond (in whichever direction) will get the Theme tune at a different pitch.

Good point about MadVR. I can see this being a battle between MadVR refresh changer and the MC one.

SBR

[jmone]

I gave up long ago worrying about PAL Speeddown as I just don't see how you are going to automatically workout how to correctly identify what happened when mastering the PAL disc eg was the content:
- Native PAL that was just mastered to a PAL DVD
- Native NTSC that was telecine and then speed up, and what if they OPTIONALLY applied Pitch Correction to the Audio?
- Native Film that was speed up, and what if they also OPTIONALLY applied Pitch Correction to the Audio?

Unless you can find the above out you will not know what content to slow down, and if you do which subset of these then also need to be (reverse) pitch corrected....

It's all ugly so, I try to avoid buying DVD's all together as most content is now on Blu.....

[Sandy B Ridge]

I gave up long ago worrying about PAL Speeddown as I just don't see how you are going to automatically workout how to correctly identify what happened when mastering the PAL disc eg was the content:
- Native PAL that was just mastered to a PAL DVD
- Native NTSC that was telecine and then speed up, and what if they OPTIONALLY applied Pitch Correction to the Audio?
- Native Film that was speed up, and what if they also OPTIONALLY applied Pitch Correction to the Audio?

Unless you can find the above out you will not know what content to slow down, and if you do which subset of these then also need to be (reverse) pitch corrected....

It's all ugly so, I try to avoid buying DVD's all together as most content is now on Blu.....

Yes, exactly!

Even with blu you're not guaranteed to get the right fps either. I have a couple of blurays that are unfortunately 50i. Now, do I deinterlace and slow down to 24p or what?! Playing them in 50p don't seem to have pulldown judder, so maybe they were 'films' mastered at 50 fps?? The Kings Speech is one of them - I can't imagine that this wasn't mastered at 24 fps.

SBR

[jmone]

I have a few 50 and 60i Blus and they are all correctly mastered as they are either television productions or concert videos.  I'm sure there are some dodgy encodes around but no worse than some of the poor quality transfers that they have done.  Just checked my copy of the Kings Speech and it is 23.976... sure you don't have a DVD

[Sandy B Ridge]

Just checked my copy of the Kings Speech and it is 23.976... sure you don't have a DVD

I guess a bluray for me to add to the PAL slowdown pile. ....
I have no idea why they released a 'special' version for the UK at 50i and yet a 23p for the rest of the world. Just a pain in the bottom. Should've bought the Australian version, maybe, but that is probably overdubbed in funny accents. G'day mate!

SBR

[jmone]

Ha!  The movie is about an Ozzie teaching the head POM how to speak

[NickF]

So I accept that this isn't simple and probably can't be fully automated.  There are some complexities in PAL Speeddown, but what I really wanted to know was whether VideoClock was doing something clever here to automatically select the correct playback frame frequency and it seems it isn't.  I think the wiki should be updated as it is currently a bit misleading.

Once the frequency has been selected, either by auto display changer or madVR, VideoClock does a very good job.

I think we need a section in the wiki on Display Settings.  There have been quite a few questions on the subject.  I might have a go if I find a few minutes.  Perhaps it should be "Smooth Video Playback".

Nick.

[jmone]

Like this? = http://wiki.jriver.com/index.php/Video_Playback_Customization

I added it pre Video Clock so it will no doubt need updating but anyone can edit the Wiki!

[NickF]

Like this? = http://wiki.jriver.com/index.php/Video_Playback_Customization

I added it pre Video Clock so it will no doubt need updating but anyone can edit the Wiki!

Sorry, I missed this!  Some good info but probably should now focus on VideoClock.  I assumed I could use my forum credentials to contribute to wiki but apparently not.  I can't see any way of registering.  How did you get access?

Nick.

[jmone]

Seems only admins can now create a user account!

[jmone]

OK - I can still log in to the wiki so if you want to make any changes to this bit add the TXT to this post and I'll update it.