Hi Peter,

Thanks very much, exactly the sort of practical advice I need.

I gather from much googling that there is no tool that will always give an accurate report on whether a video file is progressive or interlaced. But MediaInfo says my iPhone6S+ produces progressive files.

[I tried to insert a screenshot here but get "Error uploading". I'll try a URL instead.]

https://www.dropbox.com/s/6qeqxv3s2zmtv45/iPhone-MediaInfo.jpg?raw=1

I'll post separately on another point that arises here, namely why MediaInfo (and Apple documentation) show fps as 59.94 but MEPP Properties says 60.

Terry Pinnell, East Grinstead, UK

@terrypin

Hi Terry

. . . . . I gather from much googling that there is no tool that will always give an accurate report . . . . .

If the video is follows the appropriate standards for progressive or interlaced video the analysis software such as MediaInfo does not have any issue determining the mode.

The only case I know of,where software such as MediaInfo may have trouble and if it could analyse the video, is where the video is a mix of interlaced and progressive format within the same video stream. This is usually only done in TV streaming/digital broadcast, to reduce judder on panning or fast moving objects or save bandwidth on transmission with adverts, the playback device seamlessly switching between modes.

John EB

Even though choice A is half the frame rate, it should not theoretically look more jerky on pans etc. as it is interlaced and should export with half the alternate lines from each pair of adjacent frames in the 60P material. In so doing it will lose half the vertical resolution of the originally progressive material, but in practice this is hard to pick.

Peter

@Scenestealer

Hi Peter,

On studying this again I'm wondering if you have accidentally reversed A and B?

You recommend B in your previous para, but in the above you refer to A as 'half the frame rate', although it is 59.94. Also, you say it's interlaced, yet its label of NTSC FullHD 60p 16:9 (1920x1080; 59.94fps) implies it's progressive?

Here's my screenshot again for convenience:

As you've probably gathered, I find this whole subject quite confusing. From this thread and the others I've raised recently, here's a summary of points that still remain obscure to me:

1. When choosing project settings, am I right that users can ignore the offered drop-down list and simply specify tracks, width, height and fps?

2. Is the drop-down list asking users to make a choice about their input , which I'd asumed, or intended output which seems illogical but implied by showing NTSC and PAL labels on most options?

3. Or am I wrong? If so, and a user does choose from the drop-down list, is some other parameter set by MEP? Such as Progressive/Interlace, or NTSC/PAL? Where can I display those?

4. For those with a mixture of input sources like mine (described in my opening post), what is the consensus of expert opinion on the project settings? Base it on the dominant source? (iPhone 6S+ in my case.) Presumably with inevitable downsides? I'd have thought many users would have mixed sources, yet I see little discussion about it so assume it's of little consequence.

5. Apart from the MEP design flaw when saving still images (which I pointed out in my parallel post) I think the only other symptom of mismatched frame rates I've noticed is gaps between video clips that are occasionally less than a frame in duration. Is there one particular cause of that, or several?

6. In your post
https://www.magix.info/uk/forum/mep-v-mediainfo-frame-rate-disagreement--1230755/

you say "59.94 is the correct NTSC FR for 60p." I don't grasp the significance of the NTSC reference? I'm a PAL user and the choice of 59.94 is because that's the way Apple designed the iPhone! So I'd have expected you to say something like 59.94 is the correct FR for your dominant source."

7. Re that same post, I'm obviously aware that both MediaInfo and MEP recognise the variable nature of the material's FR, but is my conclusion correct: unlike MediaInfo, MEP does not correctly recognise 'the FR' (presumably embedded in the metadata)?

Terry, East Grinstead, UK

@terrypin

No Terry you reversed it - A should be above B in a list! (hehe!)

Sorry my mistake.

To your points and there is plenty of room for confusion on this.

1. Yes.
2. Well both. The Movie settings should match the (dominant in your case) source material to display it correctly during preview, but - whatever is set there (say an NTSC frame rate, or Progressive) is taken over more or less in the default export template when you choose Export to MPEG4 or whatever.
3. You would choose a preset from the dropdown that is the right FR and say Progressive, and then modify the frame size if there is not a suitable preset that matches all 3 parameters. Or - answer the prompt that asks you to set the Movie settings to the material you have dragged into the timeline.
4. I tried to answer that in my earlier comment.
5. I am not sure but I imagine it may be as a result of placing clips of marginal FPS within a movie set to a round FPS number.
6. The I phone is designed in USA which is an NTSC country. Anything above 50P is actually 59.94 to fit into the NTSC frequency but is called 60P for simplicity AFAIK. You will not find a 60P preset anywhere in MEP, only 59.94.
7. MEP could well report any FR number if you drag in variable frame rate material because it simply can not handle it, which is the reason for first converting it to a fixed FR (ie 59.94fps) in a 3rd party program.

HTH

Peter

@terrypin

Hi Terry.

You are fretting over old tech problems.

First question is why are there so many frame rates?

Basically historical, based on mechanical needs of the equipment of the time. Mostly irrelevant in today's workspace with a few exceptions.

At first, the first truly variable frame rate was the hand cranked film camera where it was up to the cameraman to keep a steady movement on the hand crank but could for instance slow down his motion to produce a high speed chase sequence assuming when the film was shown that at the other end the film was shown at a steady pace throughout. Then clockwork and eventually electric motors took over giving for the first time an ability to reproduce a steady frame rate for both recording and playback. The cameras could still vary the rate for cinematic reasons but the projectors needed to be set so that audiences across different locations had similar viewing experiences. It was decided that 24fps was fast enough for the human eye not to see the flicker between frames but slow enough to allow some motion blur on each frame to give a smoother looking playback. Very few cine film frames are tack sharp due to movement and would not make good still images.

By the time TV came along it was decided that the frame rate should be increased slightly with the Europeans going for 25fps and the Americans with 30fps. This had more do do with not have problems with flicker being produced synchronised to the local mains frequency than anything else. Also I think although I'm only guessing here, that to get to higher frame rates may have been troublesome for gear based around valve technology. Then by the time we get to the digital age LCD panels etc. had up the refresh rates to between 60-75Hz or higher.

Conversions of material from one frame rate to another often ends up with made up additional frames of frames being dropped. So conventional wisdom deem such material be best left alone unless there was a need for it to be changed. Remember seeing old films where the soundtrack sounded out of tune or American series with similar sound and sometimes colour problems?

While some problems remain, like trying to get a PAL system DVD player to play video at a different frame rate is not a good idea, you can now get such devices that are region free but increasingly as with everything streaming off the internet is becoming rapidly more the norm with only the older generations needing to feel they own something solid like a disk.

Frame rates now are considered more of a tool to help with motion and exposure problems unless you are professional and adhearing to broadcast standards or have some other preference, artistic, or specific needs.

Ray.

@CubeAce

Thanks Ray, appreciate that thorough historical background. Makes interesting reading and provides helpful context.

As soon as I get my settings performing sweetly I’ll cheerfully stop fretting about the details. Even if puzzling stuff about MEP behaviour remains!

Terry

Hi Terry,

I've been following this. Judging from what you have said about having no problems with what you were already doing, I would say that if it ain't broke, don't fix it.

@CubeAce

Hi Ray,

My first camera was my father's, a Kodak crank up (no batteries required) 8mm, 16fps. The films scanned at 20fps, came into VPX at 16fps, and the project set at 29.97 worked just fine. The program is amazing at getting it right sometimes.

John CB

@browj2@browj2

My first full time job after working as stage crew at a local theater was checking feature film prints straight from the laboratory using a Steinbeck editing table, hand cranked for a London company based in Charring Cross Road. I think it was from the 1930s and close to an antique when I first got my hands on it. Mainly I looked for physical defects in the film such as sprocket damage or emulsion problems. I then progressed to film editing before moving across to the sound department which I found more rewarding. Steinbeck editing tables were highly prized back then. American made, they used counter rotating prisms to show the image via a magnifying lens rather than going through moving gates that opened and closed as each frame passed that the British machines used. They more closely resembled projector tech than editing tables with a smaller back-light bulb to illuminate the passing film. You had to brake the rotating plates that held the film by hand and if you got it wrong you ended up with a pile of film at your feet. Not good in a white glove department 😊.

Film was still joined with acetate glue and a small fine haired brush after scraping the emulsion side of the film with a blade in what resembled a small guillotine with a clamp either side for splicing and a push pull blade that glided over the emulsion side of the film to scrape the emulsion away. Later on a very clear sticky tape that didn't degenerated when exposed to heat came along that took over. The cleaning materials used for film were so toxic when breathed in that the unions made you drink a pint of milk a day to help clear your airways. Whether it actually had any benefit I couldn't tell you but it was similar to pure isopropyl alcohol but stinkier 😬. Working in rooms that had poor ventilation at best you could get quite light headed by the end of the day. Come to think of it, it could be why I have to use a Ventolin inhaler now and then which I never needed as a kid.

Ray.

@CubeAce You were probably using Carbon tetrachloride which was eventually banned. Back in the 60s in UK we used it for cleaning our 8mm films. It made my fingers go white. We subsequently changed to Trichloro ethylene found in dry cleaning solutions when Carbon tetrachloride was banned.

@ericlnz

That rings a bell.

We had it in large brown glass bottles with what looked like Bakelite screw tops on. Plain paper labels. Because of the constant editing and cleaning the smell was always present.

Hi Terry,

I've been following this. Judging from what you have said about having no problems with what you were already doing, I would say that if it ain't broke, don't fix it.

Hi John,

Agreed. As per my comment in

https://www.magix.info/uk/forum/choosing-project-frame-rate-setting--1230646/

'As you may gather, I'm conflicted between "If it aint broke, dont fix it" and my curiosity!'

Curiosity loses, for now at least. Today I'm back to the 25 and 50 fps settings I was using before.

Terry

 

'As you may gather, I'm conflicted between "If it aint broke, dont fix it" and my curiosity!'

Curiosity loses, for now at least. Today I'm back to the 25 and 50 fps settings I was using before.

Hi Terry,

Remember what happened to the cat.

Glad to see that you're back on track. I have mixed clips in my current project - 29.97 from the GoPro, and 30fps from Magix Travel Maps. I set my project at 29.97 and do not adjust my project when the message pops up. Then I cut up and stretch out the TM video to slow it way down. I have no problems with my projects at 29.97, so I don't even try anything else.

We have too many distractions affecting production. I'm now on the LIFO method, desperately trying to complete last Saturday's walk on Mount St-Bruno with friends, and trying to make something from nothing. All other started projects get pushed back.

Time to add some music to this project, so I started with Soundtrack Maker, Chillout Vol. 2, for the first part (55s) and it made a nice song but put in a bird chirping the same chirp every second; most distracting and annoying. To distract me even more, Soundtrack Maker uses Soundpool loops and a file .MMM that can be opened with MusicMaker. Hoping to be able to modify the track, I opened the .MMM file, which is huge and contains several songs, and played around with that. Then I got distracted by offers in the Store and my unused coupons, so I had to listen to a dozen or so Soundpools, check whether or not I had them, etc., and purchase some. Then, well, maybe use another coupon for another instrument that I won't play. Then I had to play around with a new Soundpool. I never got around to fixing up the music. Time wasted; the day was done.

Today, I have to clean up the wood storage areas as tomorrow I'll be receiving 15 cords of firewood (renewable energy) to be hauled in the back and stacked for the winter. Will I finish this St-Bruno project sometime soon?

It's a good thing we're retired.

John CB

@browj2

Hi John,

You and me both. Parallels here for all your project and productivity challenges! No wood chopping though. Just hedge cutting.

So how did we have time for hobbies before retirement, as I don’t have enough now?

Terry, East Grinstead, UK

We subsequently changed to Trichloro ethylene found in dry cleaning solutions when Carbon tetrachloride was banned.

Unfortunately Tricholoroethylene was almost as bad - a cumulative poison that caused liver damage IIRC. That was replaced by Trichloroethane in my early career.

I used to service those Steenbeck (not Steinbeck Ray) machines - flatbed's - and they were quite clever the way they used the multi faceted prism as a shutter, forming a coherent image only when the facet was more or less parallel to the film.

@terrypin

As you may gather, I'm conflicted between "If it aint broke, dont fix it" and my curiosity!'

"Nothing ventured nothing gained" is another saying too. It's is good to question your methods from time to time, looking for a better way, and you often learn other useful stuff in the process. For me, attempting to answer questions on this Forum works a bit like that too, as it questions my own knowledge and forces me to confirm and research sometimes, and to think a bit deeper.

And you did mention some issues: - Apart from the MEP design flaw when saving still images (which I pointed out in my parallel post) I think the only other symptom of mismatched frame rates I've noticed is gaps between video clips that are occasionally less than a frame in duration. Is there one particular cause of that, or several?

BTW re your question 7) . I came across a question about the wrongly reported frame rate in an MEP warning window with Variable Frame Rate footage, that was answered by John EB about a year ago where the topic starter saw 3.5fps for some 60P material.

I hope my comments have been worthwhile to you.

Best

Peter

@Scenestealer

Quite right Peter. Slip of the brain on my part. Too many years past, and too many DAWS built since. 😊

The only servicing my bench ever saw was when the winding handle unscrewed itself which I was not allowed to put back on myself or the unions would walk out. Seriously.

About the gaps between takes that are not whole frames. Right clicking the gap gives the option to fill the gap with a frame (A whole frame) making the gap larger than it is already but more annoyingly gives a wider gap in the audio at the same time. I notice this on long takes where my camera splits the files when reaching the 4GB limit so it doesn't just happen on mismatched frame rate clips. I think these are the 'Gaps' MEP reports as seeing on converting. Could it be a GOP structure thing having to 'join' the two takes?