[FFmpeg-user] For discussion: A better video notation.

[Mark Filipak (ffmpeg)]

On 02/04/2021 07:20 PM, Carl Zwanzig wrote:
> On 2/4/2021 3:50 PM, Mark Filipak (ffmpeg) wrote:
>> For discussion: A better video notation.
> 
> Well, none of them go with the industry standards like 1920p30 or 480i29.97...

Those, more standard notations are where I began. But in order to differentiate between all the 
formats that are simply called "30i", for example, I had to start adding letters that just made it 
all too cryptic. A couple of days ago I realized that if I simply differentiated based on PPS 
(pictures per second), then it became relatively simple. I'm sure you'll agree that a 24PPS movie 
that's been hard-telecined and encoded as 29.9FPS is still 24 pictures/second.

>... Consider that the main 
> notation expresses resolution and frame/field rate of
> the encoded video itself and isn't concerned with how those frames were
> generated. It sounds like you're trying to express how something was
> processed before being put into that encoding/container.

Yes! Exactly! When one is trying to recreate the original presentation, "how those frames were 
generated" is crucial.

> For instance-
>> 59.9SPS at 29.9FPS       (aka "30i") NTSC broadcast TV interlaced to 29.9FPS.
> 480i29.97 is understood to be digital "NTSC" with non-square pixels and drop-frame rate. It's often 
> shortened to "480i" since NTSC seldom occurs in the wild as non-drop-frame. Nothing else is 
> particularly needed.

But it does occur in the wild. It's interlaced to frames, and players generally decomb it, but 59.9 
scans/second set to 29.9 frames/second is very common, especially in special feature documentaries 
that are made for TV and later included on DVDs and BDs.

> Later,
> 
> z!

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