About Film and Video Formats

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About Film and Video Formats

Postby Garrett Gilchrist » Sat Aug 10, 2013 6:01 pm

All these years restoring video and I still don't have a method to do smart inverse telecine on OSX. I have to outsource everything to the very clever Emulgator, who uses AviSynth, mainly. I am constantly running into video which doesn't have a clean 3:2 pulldown but which is instead a total mess of fields, often converted from PAL to NTSC in some unusual way. I simply don't have a method for how to work with this stuff and get clean frames out of it.

Hm.
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Re: About Film and Video Formats

Postby ctlw83 » Thu Aug 15, 2013 11:30 am

That is the problem with 2 different major frame-rates/encoding formats and with the variety of aspect ratios which materials can be scaled at. If you are trying to get a cohesive version of something with matching frame rate, color, and aspect ratio it can only be accomplished by converting formats and/or running something like AviSynth or VirtualDub, neither of which are the easiest to use.

On top of those issues, as with any conversion, there is always the possibility of quality/data loss or degradation in the conversion.
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Re: About Film and Video Formats

Postby Garrett Gilchrist » Thu Aug 15, 2013 12:04 pm

I just want to be able to do this sort of thing myself. Avisynth is "installed" on my Hackintosh, sort of, but I don't think it will ever actually work ...
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Re: About Film and Video Formats

Postby ctlw83 » Fri Aug 16, 2013 10:44 am

You could set up a moderately powered Linux machine or run Linux in virtualization and that would work.

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Re: About Film and Video Formats

Postby Garrett Gilchrist » Sun May 25, 2014 2:35 pm

Brief discussion of frame rates, again, from FB:

Nicholas P:
I'm looking around Walmart, and I see these fancy 240 hz TVs, which are supposed to remove blur from a TV and made everything move super smooth, even movies. I don't know why, but it just doesn't look right on movies designed for 24 frames per second. I remember I saw Wizard of Oz on one of those things, and the once grandiose, cinematic movie ended up looking like a cheap made for TV movie. And CGI movies end up looking like cut scenes from a video game, so I don't even want to know what a hand drawn animated film would look like on those things.


Ken C:
You don't want a 60Hz hdtv, because you can't take those 24fps films and properly do anything with them without 3:2 pulldown and other legacies of electrical voltage and fields vs. frames nonsense left over from NTSC. With 120Hz, each of 24 fps can be divided equally into 120, each frame on the screen for 5Hz before replaced by the next one, an equal amount of time per frame. The only reason you'd want 240Hz is if you were getting a 3D tv, where you'd want 24fps left eye, and 24fps right eye. You can always turn off the frame interpolation, which generates averaging between the frames to create frames that were never shot. It's evil, kill it with fire, although some industry professionals watch Dynamation with interpolation on, it's a look that is intended to be less cinematic, and more HolodeckTM.



As has been said -- It's motion estimation, which generates fake frames and makes film (24 frames per second) look a lot like video (60 frames per second). We're used to thinking that 60 frames per second is "cheap" looking (even though it's very smooth and ideal for sports footage) .... which is why Peter Jackson had a lot of blowback from shooting The Hobbit at 48 fps (which I actually liked). I have no idea what it would do to hand drawn animation. Bad things.

Motion estimation can be shut off.

Better, computer-generated motion estimation actually comes in handy for a lot of purposes -- slow motion, restoring missing frames, and restoring a "video look" to old TV shows that now only exist as film -- the Doctor Who DVDs swear by it, for example.

Film, shot at 24 frames per second, gives every frame a sort of weight and meaning. 60 (or 48) frames per second is like a waterfall of too much visual information coming at you, and doesn't have the same weight, since no individual frame is on the screen long enough for you to appreciate it.

Ken C:
I find it interesting that we settled on hard numbers like 24fps for film, 30fps (60 odd/even alternating fields per second) for NTSC, and for PAL, 25fps (50 odd/even alternating fields per second). For television, the reason came down to math and the frequency of available house current. It was a happy accident that film could be sped up to 25fps for PAL, but 3:2 pulldown with adjacent film frames overlapping as fields in the same frame has been the bane of anybody trying to edit anything in these formats, which no doubt Garrett could give us all an earful on.

What tends to be overlooked is that 24fps for film was settled upon, not as a highest standard, but because it was the slowest possible speed at which optical sound could be played back on film. Silent film tended toward 18fps (film isn't cheap!) or less, and was handcranked at many rates. I haven't done any research on how many silent films used automated mechanisms to lock down frame rates.

Animators often find ourselves working with musical intervals, and it is interesting to note how many factors of 24 lead to even beats per second. 1, 2, 3, 4, 6, 8, 12, 24--it isn't fun to work at 30fps--1, 2, 3, 5, 6, 10, 15 30. I wonder if that was a factor in selecting the number 24 and not 23 or 25. I also find it fascinating that the onset of the broadcast of radio entertainment and its popularity is roughly simultaneous with the beginning of sound on film, although both couldn't have happened without a certain level of sophistication in recording and playback.


As Ken just said, the frame rates of 24, 25, 50 and 60 (and now 48, on the Hobbit films) came about entirely due to the limitations of technology at the time, and what sort of acceptable frame rate could be gotten. The silent era averaged around 18 fps and was not consistent. Today, that feels like a very low frame rate - although in the digital era we've seen lower.

We're used to those major frame rates now. That's the only reason that 60 frames per second (or 50, or 48) seems "cheap." We're used to those frame rates only being used for broadcast video, like sports, the news, soap opera, sitcoms, old Doctor Who … Peter Jackson's The Hobbit is a very expensive series of films, and the 48fps version reveals detail, texture and subtlety not present in the 24fps version. But to most people it looks "cheap" that way, and to everyone it looks strange and wrong. A football game at 24 frames per second would also look pretty awful.

You almost never see anything shot at 30 frames per second - it looks too fast. And a super-high frame rate like 100 fps looks eerily real to us, like it's suddenly a hologram. That's only been attempted as proof of concept tests.

We like 24 frames per second on films specifically because it's a fairly low frame rate. On the big screen a large amount of black appears inbetween the frames, and each frame is on the screen long enough for us to see it clearly, and for it to have time to breathe. Every frame has a certain weight and meaning. That has its limits though. A movie on the big screen is a little bit flickery and it can be hard to take in everything due to the screen's size. Then you get the Hobbit movies - running at twice the frame rate, it's simply too much information compared to what we're used to - everything flows together like water and you don't see individual frames so much as you see the liquid movement of it all.

With the advent of DVD and digital editing, we can actually edit at 24 frames per second and release that on "video" - a DVD or HD release - without any problem. We can also work at 25 frames per second or 30 or whatever we feel like. This is a big step up from the limitations of the past.

The real problem is when we convert from one frame rate to another, as it's extremely destructive. For example, trying to fit a 25 or 50 frame per second PAL video into a 60 frame per second NTSC DVD. At a lower resolution, too! Or vice versa. It's very difficult to unpack those fields once they've all been converted. Not so hard to convert them - hard to undo the damage. I generally can't do it myself, and I'm very good with video otherwise - I call in a specialist from Germany (depending on how busy he is) and it takes him quite a bit of time and programming tricks.

The only smart way to work is to keep whatever you're working on in its original format and frame rate - but that means releasing PAL discs to American audiences, and vice versa, which simply isn't done. I do it, but the studios don't. Any DVD player could play either PAL or NTSC, but this functionality is usually locked out to discourage piracy and importing.

And the American format - either 24 or 60 frames - leads the way in HD. In these digital days, there is no reason that material couldn't be encoded at its original frame rate, but studios basically won't do that if it means releasing PAL or NTSC material in the "wrong" part of the world. Blu-Rays tend to be at the NTSC frame rates regardless - the PAL spec drags way behind. I remember for awhile, recent Doctor Who stories (25 fps) were only being released as 60i NTSC Blu-Rays. Fans had to resort to versions recorded off of television to get away from all that interlacing.

60 frame per second video, or 50 frame per second video, is interlaced -- two different images [fields] sharing one frame, on alternating lines. It's irritating to work with, as if anything goes wrong - if those alternating lines blur together, like when resizing the image of uploading it to Youtube or so on - it becomes an absolute mess and there's no way to fix that. It's very easy for that to happen - especially now when non-professionals are working with and uploading video without understanding the archaic complexities of these formats .... and there's virtually nothing that can be done about it once the damage is done.

http://media.tumblr.com/f5f79b830c2144a ... rn5wp6.png

Mind you, technology gets better all the time and I've seen miracles happen. I've seen the color recovered from black and white film reels of old Doctor Whos, because the onscreen dot patterns that give PAL video its color (entirely different from the much cruddier NTSC "color burst" buried at screen bottom) could sort of still be deciphered by a very clever computer program, in spite of all the warping, shaking and damage that had been done to the original video signal when it was filmed off of a screen in 16mm. Should have been impossible, but somehow isn't. They haven't figured out how to unpick the interlacing, but if they can unpick the color it might genuinely be possible.

Ken C:
I knew I'd get a terrific essay out of you, Garrett! In theaters that still show film, a shutter mechanism is necessary to stop the light while the intermittent mechanism transports the film, pausing briefly to display the picture. Because the flywheel needs to be balanced, and also to reduce the perception of 24 pulses of darkness per second, or flickering, each frame is blanked at least once, sometimes twice, so we see film with light pulsing either 48fps, or 72fps, depending whether or not the shutter flywheel has 2, or 3, blades. After each new frame is displayed, it's blanked out either once or twice before being blanked out to be replaced by the subsequent frame.


I do really notice the blanking on the big screen - you get used to it quickly as a different experience, but we're spoiled a bit with LCD monitors and things. You don't notice the blanking and refresh rate on a tube CRT television or a monitor or even, often, on film --- until you try to point a camcorder at it and suddenly see all these black patches covering half the picture!

They'd hire special technicians if they needed to have a TV monitor playing in a feature film, to run the video at the exact same rate as the film camera! Not an easy task I'd wager ....

When I'm doing my restoration projects I often have to deal with both NTSC and PAL and 24p material in the same project -- and I just pick whichever frame rate will do the least damage when I convert whatever isn't that .....

Standard-definition PAL is a larger frame vertically, and has more stable color (though usually quite subtle and grey due to the fashion of the times). It would make for better source material, except that so often it's just been badly converted from some American tape --

Meanwhile we've all dealt with VHS tapes that have been copied over and over again until they look awful - especially NTSC tapes where the color is long gone. I still deal with that all the time on these projects. The video delivered for the Thief Recobbled project was both the best and worst material I've ever dealt with - and every source had its own, bizarre problems - often dealt with by my technician in Germany, Christoph Nass.

We are spoilt in these digital days. None of this would have been remotely possible in a home setting before 1998, and only remotely possible then.

And film, especially black and white film, is still the only storage medium that's still going to be here a few decades from now ....
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Re: About Film and Video Formats

Postby Garrett Gilchrist » Fri Aug 08, 2014 2:20 pm

I have a few VHS tapes that I want to 'archive' by saving them to my PC.

I was wondering what hardware and software you'd recommend.

My main worry is keeping quality as good as possible. For example, I'm guessing they'll be interlaced (is all VHS interlaced?), so I don't want to accidentally deinterlace them.

They are mostly home-movies, but I also have a few TV recordings and a couple of official VHSs.

I haven't got a DVD recorder or a MiniDV camcorder, but could buy one if that'd be best. Or would something else be better?


Yes, all VHS is interlaced. A DVD recorder or MiniDV (even Digital8) camcorder would be fine. Both have their pluses and minuses. A DVD recorder is very compressed, but you'll probably be compressing the material into DVD format anyway, and this is a lot less work.

A MiniDV camcorder captures in higher quality to begin with. It has some issues with color quality, where saturated colors can look blocky, but a VHS tape is already soft enough that this is unlikely to come up - and there are filters which can soften the color as needed. A miniDV recording would be more work as you would then [probably] convert this to a smaller, more web-friendly format. Probably DVD. MiniDV material is normally about 14 GB per hour, and would fit on three DVDs like that.

You can capture MiniDV material with programs like Adobe Premiere and Final Cut Pro on Macs -- apparently VirtualDub and Quicktime work fine as well, so there are free solutions. There are various programs that will capture video, but may screw up the interlacing. I've heard of VirtualVCR and Ulead Video Studio and many others. You will need a 1394 Firewire input, which not all computers have anymore. I understand there are other solutions involving USB or maybe HDMI, but Firewire is the capture solution I'm familiar with.

A DVD recorder is probably your simplest solution here, in terms of work! I would also recommend, if you're willing to spend the money and looking for quality, getting a high quality SVHS VCR to play the tapes on. If you're very concerned about quality and using a DVD recorder I might also recommend recording the material multiple times, and at a higher quality rate, so that it might eventually be restored if need be. Many of the Jim Henson Hour restorations came from playing the same tape multiple times.

You may have issues with officially-released VHSes due to Macrovision copy protection. That being said, officially-released VHSes with copy protection often become officially-released DVDs available elsewhere.
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Re: About Film and Video Formats

Postby Garrett Gilchrist » Wed Aug 13, 2014 2:24 am

A package of Virtualdub with video filters.

http://www.digitalfaq.com/forum/video-c ... s-pre.html
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Re: About Film and Video Formats

Postby Garrett Gilchrist » Fri Jul 03, 2015 7:47 pm

Adobe Premiere editing dates to 1992 (in primitive form), and digital video was coming into vogue for the consumer by the mid to late 90s (starting in 1995). I seem to recall that digital MiniDV shooting and editing was becoming somewhat common by 1998, and very common by 2001. Personally, I did my first fully digital edits in 2001.

The 24p Panasonic DVX-100 came out in 2002, and DVCPRO HD came out in 2000.

Premiere 1.0 preview, 1990:
https://www.youtube.com/watch?v=wowW8qHlmzY

Premiere 4.2, 1996 ...

https://www.youtube.com/watch?v=8gVj7ygYNEo
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