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[squeedle]

I love JRiver's "video clock" feature and love that I can set 25fps content to automatically play back at 24fps. But one vital piece is missing, namely that the audio should not only be stretched to fit, but should also be de-tuned to a 4% lower pitch.

I realize that video clock is making constant adjustments to audio and video speed to keep the two in sync, so generally speaking it would be undesirable to have pitch fluctuate. But in this one isolated scenario, where playback is set to a full 4% slower than source, I'd love to have the audio be re-pitched accordingly too. 4% is a big difference.

Is this possible?

[squeedle]

Please? Anyone? This has to be a fairly common issue. Would love a fix!

[RD James]

+1

[thecrow]

+ another 1

[squeedle]

PLEASE???

[squeedle]

If no one from JRiver replies to this thread, does that just mean this will never happen? How can I make sure they at least receive the suggestion?

[RoderickGI]

Jim, the boss, reads every post on the forum. So it has been seen. JRiver just don't get a chance to comment on every thread.

I recall a discussion in the past about this issue, and there was some agreement that some PAL content (European?) never gets the pitch adjusted for playback at 25fps anyway, so there was no need to adjust it back.

Also, my understanding is that Video Clock adjusts only the audio, to keep it in sync with the video frame rate. If the video is slowed (25 -> 24fps) then the pitch will drop, so shouldn't it be adjusted up if anything at all.

Some of the discussion went along the lines of;
Film shot at 24fps.
Converted to video.
Adjusted to 25fps (faster), so if done properly, pitched down to keep the pitch correct. If not done properly, no pitch adjustment. Punters (i.e. free to air viewers) get what they paid for the service, which was nothing.
If 25fps video was correctly identified as originally 24fps film, and played at 24fps, then whether a pitch adjustment was required depended on the original 24 to 25fps conversion.

Have a search around for the discussion, because from memory it highlighted the pros and cons of a pitch adjustment when playing 25fps video at 24fps, depending on the source and processing done on it. I believe the conclusion was the best result was to do nothing, but I could be remembering wrong.

Note: The above could all be rubbish, except for Jim reading every post, because I'm no expert.

[squeedle]

Thanks for the reply. I can confirm that I have PAL content where the pitch is indeed raised 4%. And I can also confirm that when JRiver slows it down to 96% speed, it does so without altering the pitch--it remains high, or identical to how it started.

If you think about it, that makes a lot of sense. Imagine you're watching a video, and VideoClock is making constant adjustments. You don't want it pitching up and down, you just want it stretching unobtrusively.

BUT it would be very nice to set a new baseline pitch of -4% for these PAL videos, before JRiver does it stretching. I very much hope that Jim considers this request.

[RD James]

If the video is slowed (25 -> 24fps) then the pitch will drop, so shouldn't it be adjusted up if anything at all.

I think the issue is that VideoClock adjusts Tempo, not Rate.
So it is preserving the wrong (higher) pitch of PAL films instead of correcting it when fixing the speed to play back at 24 FPS.
 
What probably needs to be done to fix this properly is to apply a pitch adjustment first at 25 FPS and then allow the Tempo control to do its thing. Then you won't have varying pitch if your refresh rate is not completely stable.

[JimH]

RoderickGI,
You're as good an expert as we have.  Thanks for your answer.

Jim

[squeedle]

Jim, should we all consider that a "no" then? No to having the option of resampling the audio to -4% before tempo corrections are done during playback?

[RD James]

I hope it's not a "no".
PAL content played at 24Hz typically needs pitched down. It is rare to find content which is pitch-corrected.
PAL content played at 50Hz typically does not require pitch correction as that is PAL native.
 
These should be the defaults, and ideally there would be a tag to invert this behavior for any rare exceptions to those rules.

[RoderickGI]

Thanks Jim.

First a correction of one of my points above. VideoClock does indeed adjust both the video and audio components of a movie, in order to play video smoothly. The video clock is adjusted to match the frame rate of the display, and the audio is then adjusted to match the video output. There is a VideoClock Wiki article that is worth reading over a few times, particularly the Target Ratio including PAL Speeddown section.

It confirms what I thought. If done correctly, the Pitch is adjusted down when PAL content that was originally shot at 23.97 fps and is recorded on disc or media at 25 fps, in order to correct the Pitch. So if you play back that 25 fps media at 24 (23.97) fps, then the Pitch needs to be adjusted up to correct it back to the original sound. So I guess the title of the thread is a little confusing.

I think the issue is that VideoClock adjusts Tempo, not Rate.

I was having trouble differentiating between the definitions of Tempo (synonyms: cadence, speed, rhythm, beat, time, pulse; measure, metre) and Rate, with respect to Pitch (synonyms: tone, timbre, sound, key, tonality, modulation, frequency), until I looked at the "Tempo & Pitch" settings in the DSP Studio, which simply defines a Rate change as a combination of a Tempo and Pitch change, "like speeding up or slowing down a record". I was overthinking it. 

Actually I was thinking maybe you could create a Convolution filter to change the Pitch for these videos, but then when I looked at the "Tempo & Pitch" controls in the DSP Studio, I see what you want is already there! Then it would be easy to create a Zone for when you want to adjust the Pitch, and a ZoneSwitch rule to switch to it.

Unfortunately the DSP Studio Pitch adjustment doesn't work when VideoClock is turned on. Maybe it could work with VideoClock switched on, but that would require a change by JRiver. A Convolution filter may suffer the same effect, with VideoClock undoing what the filter did.

Anyway, back to the start point I guess.

PS: I did play with the Pitch with VideoClock turned off, and a 4% adjustment was very minor. Perhaps noticeable with high resolution audio, but with the sample video I was using, not really noticeable at all.

[squeedle]

I don't know about "done correctly", but in reality, the most common scenario is that PAL DVD's have a higher pitch and play back 4% faster natively. I'm talking about commercially produced major studio film DVD releases here.

When they are slowed back down to the correct speed (4% slower) in JRiver, that fixes the speedup issue *but DOES NOT fix the pitch-up issue*. I'm not sure why JRiver deemed it important to offer the ability to correct the speed but not the pitch, they seem equally important to me.

So no, the need is NOT to pitch-up the audio further, the need is the opposite, to pitch it back DOWN to normal.

And there isn't really any need to use "high resolution" anything to notice this. If you compare a properly pitched NTSC DVD with its PAL counterpart, you will hear that in the PAL version everyone has a higher voice and the music is all in a higher key, etc. Resolution doesn't factor into this.

Thanks for your replies. I just want to be clear on this.

[RoderickGI]

Yep, I understand. We are not disagreeing here. It is just that the actual situation needs to be understood before any corrective action can be taken.

Based on your observations of commercial PAL DVDs produced by major studios, when a 24fps movie is converted to PAL and recorded on disc or media at 25fps, resulting in a higher pitch and 4% faster playback, the conversion process increases the rate (Tempo and Pitch) of the movie (24 to 25fps) and does not adjust the Pitch down. Apparently the commercial studios do not think the 4% Pitch increase is significant enough to fix. i.e. They don't do the conversion the correctly.

That all comes back then to RD Jame's comment;

I think the issue is that VideoClock adjusts Tempo, not Rate.
So it is preserving the wrong (higher) pitch of PAL films instead of correcting it when fixing the speed to play back at 24 FPS.
 
What probably needs to be done to fix this properly is to apply a pitch adjustment first at 25 FPS and then allow the Tempo control to do its thing. Then you won't have varying pitch if your refresh rate is not completely stable.

Very succinct and in retrospect the complete answer.

VideoClock adjusts the Tempo and not the Rate (Tempo and Pitch), so it does not precisely reverse what the studios did. In fact MC must have to do extra work to retain the Pitch at the levels of the DVD, while adjusting the Tempo down.

If the studios had done the correct thing, and adjusted the Pitch down, MC would also be doing the right thing, by retaining the Pitch as it is on the DVD. I suspect that is the assumption behind the current functionality; that the studios have done the correct Pitch down in producing the DVD.

The problem is, for which movies and/or studios has the correct thing been done? Hence there would need to be a way to handle the issue whether the conversion has been done correctly or not. If the DSP Pitch adjustment worked with VideoClock on, a Zone would fix the problem.

Being Australian, I have probably always heard my movies at a higher Pitch than they were recorded. George Clooney does have a squeaky voice, doesn't he?

[squeedle]

Based on the fact that all PAL DVD's have a 4% speedup, I think it's logical to assume that a corresponding 4% pitch-up is also likely, as has been the case in every one I have compared side-by-side with an NTSC counterpart. For whatever reason, the studios have gone this route, and I think it's stupid, but it is what it is.

And yes, MC is doing extra work by time-stretching the audio without altering the pitch. It wasn't even possible to do that until the past 10 years or so without adding in lots of artifacts. It's impressive how well it does it. But its job would be even easier if it started with a baseline of *resampling* (google it if this term is not familiar, but in short it affects both the playback time and pitch in the same ratio) the audio at 104% before doing its tempo-trickery.

Jim, et al, please consider adding this functionality.

[BillT]

Based on the fact that all PAL DVD's have a 4% speedup, I think it's logical to assume that a corresponding 4% pitch-up is also likely, as has been the case in every one I have compared side-by-side with an NTSC counterpart. For whatever reason, the studios have gone this route, and I think it's stupid, but it is what it is.

It isn't stupid at all, it's a consequence of history and physical media.

Europe has broadcast 24fps film at 25fps since the advent of television, as the only practicable way of doing it in analogue days. If you speed up analogue media the pitch will go up, and there was no way of changing that. Most people were unaware of the pitch change. No doubt it's irritating if you have perfect pitch, but they're aren't that many people who have that and I guess they're used to it.

When DVD's were introduced the practice continued, presumably partly historically and partly as there was still no practicable pitch changing capability. Once you have gone down this route it makes sense to keep to it; it's even more confusing if you have some pitch corrected DVDs and some uncorrected ones.

Having watched 24fps films on TV with the wrong pitch for all of my life and not caring about the issue, I'm somewhat mystified by the obsession!

[thecrow]

Having watched 24fps films on TV with the wrong pitch for all of my life and not caring about the issue, I'm somewhat mystified by the obsession!

If that does not bother you I would guess you would also not be interested in using the 24fps playback for PAL DVDs feature we are discussing here either. As I cannot understand why you would want to correct one and then go out of your way not to correct the other?

[squeedle]

^ YES, exactly my point.