Attempting 16fps Video From Regular 8mm Films

[jamworks]

I have read several forums where post production professionals warn that video with a non-standard frame rate (such as 16fps) is not possible.

A few months ago, I used a service to transfer silent regular 8mm films to high definition on the MMII, using an AJA card, and encoding to 444 RBG 10-bit uncompressed, 1920 x 1080 (full raster) video, at the standard frame rate of 23.976fps.

Now that I have the latest version of Photoshop, which includes the video editing features, I did a test consisting of the following steps:

1.) I converted one of the HD video files to approximately 2,000 individual DPX frames, using AJA QTToDPXTranslator. This process put the DPX files in a folder.

2.) In Photoshop, I used Open…, checked Image Sequence, and selected the first DPX file in the folder.

3.) A Frame Rate dialog box came up. I selected Custom and typed in 16 (the frame rate of the original film.)

(The sequence of approximately 2,000 frames appeared in a timeline in Photoshop. I did not attempt to play it, because I don't have a system that can handle uncompressed HD video. But I scrubbed through it.)

4.) I selected Export…Render Video, and selected the H.264 codec and frame rate of 16fps.

5.) I tested playback of the resulting 16fps video (H.264 video in MP4 container) on a few different systems.

The 16fps video plays smoothly with Quicktime Player 7 and 10, and VLC, on my current model iMac.

The 16fps video also plays smoothly on my WD TV Live Streaming Media Player, on a U.S.B thumb drive, over HDMI to a Samsung HDTV.

However, the 16fps video stutters during playback with Windows Media Player and Quicktime for Windows on my MSI Wind netbook with an Atom processor. VLC on the netbook didn't like it at all, only showing a distorted image.

So, it seems, the H.264 standard supports non-standard frame rates, but some processors can't handle it?

[Will2]

Are you trying to do that just to see if it's possible? You'd want the video at 23.976 to display on a modern LCD HD TV.

I may be missing something but I'm confused on this point:

If you had the film transferred to a frame rate of 23.976 and the regular 8 film was most likely shot at 16 or 18fps, when you saved out the individual frames did you remove the pull down? You didn't get a frame-by-frame transfer; the service would have had to add in frames to fill-out to 23.976.

In other words, it seems you're taking a lot of unnecessary steps to down-covert back to 16fps. Can't you just put it through something like Apple's Compressor or Adobe's Media Encoder and wind up with the same thing? You're not starting with 1 to 1 film to video frames.

[jamworks]

Yes, I did get a frame-by-frame transfer, which plays at the wrong speed. That was intentional, in order to get a frame for frame transfer.

Once converted to DPX, frames per second is moot.

And the point of creating true 16fps video is to avoid creating extra frames, in order for it to play at the correct speed.

[jamworks]

P.S. Turns out, my MSI Wind netbook, with an Atom processor, has trouble playing any 1080p video, regardless of whether the frame rate is 15fps, 16fps, 23.976fps, or 29.97fps. So 16fps was not the culprit.

[carllooper]

And the point of creating true 16fps video is to avoid creating extra frames, in order for it to play at the correct speed.

All speeds are correct if you add the correct number of frames. For example, for playback at 24 you would have to add 8 additional frames per second. For playback at 16 you would add zero frames.

One reason you might want to avoid adding extra frames is just file size. However in H.264. redundant frames would be optimised away anyway so you wouldn't actually see any appreciable difference in file size.

Nice idea though. 16 fps film looks great. I love the motion blur at that rate.

Carl

[jamworks]

Nice idea though. 16 fps film looks great. I love the motion blur at that rate.

I'm not sure whether you're being facetious. I think the WD TV Live Streaming Media Player and Samsung HDTV do a superb job with it.

No motion blur to speak of.

[carllooper]

No I'm being genuine.

I shot some Super8 many years ago at 16 fps and ensured it was played back at the same rate (which meant adding duplicate frames for 24 fps playback). There were still only 16 original frames per second during projection. The duplicate frames are just there, of course, to ensure a faster rate projection doesn't speed up the original motion.

The result of shooting 16fps was that the moving figures in the film had more motion blur than they otherwise might had they been shot at 24 fps. This was exactly the effect I was after - more motion blur. The film was aiming to reproduce the look and feel of silent cinema. It was shot on TriX as welll. The result was stunning. It was as if watching a 1920s film. The actors were dressed in 1920s sci-fi shooting each other with ray guns. Looked like Metropolis.

Carl

[jamworks]

Ah, I see. You mean capturing a desired film look. At first, I thought you were referring to an artifact on HDTV's.

[VideoFred]

It is very simple.

1) Start with a frame to frame transfer. One film frame = one digital frame.

2) Do not use all those exotic codecs, uncompressed RGB is the best.

3) Set play speed of the digital file to 16 (with VirtualDub).
No additional frames will be added, only the play speed will change.

4) Save this file with XVid to a portable USB HD.
Xvid will not add any duplicate frames, it accepts any play speed.

5) Connect the portable HD to your HDTV.
Most HDTV's can deal with the XVid codec

6) Your file should play at 16fps, progressive, no duplicate frames, just like the original film.

Fred.

[jamworks]

Thanks, Fred.