720p as 59.94 frames?

A

abeas

Well-known member
This has probably been asked, and I got too many results in search but I have a question about 720p30. Today I converted some MTS files shot at 720p30 in Toast 10 to Pro Res. I didn't try FCP, but should have to see if I would have got the same results. Anyways, can someone explain to me why 720p30 footage shows up as 59.94fps? My 1080p30 footage shows up as 29.97. Just curious why that is.
Thanks!

edit - forgive the typo on the thread name.......should be 59.94, not 59.97.
 
720/30P is recorded as "over 60", meaning the actual data stream is a 60p data stream. Each frame is followed by a "duplicate last frame" empty frame. So technically it's a 60p stream, even though only 30 unique frames are recorded.

Most software is smart enough to figure that out; I guess Toast 10 doesn't know how to automatically? Or maybe there's some setting for "detect duplicate frames" or something, that you didn't have set?

Anyone else using Toast having a problem with 720/30p?
 
Thanks Barry. Is 1080p30 recorded the same way? Seems Toast 10 was able to figure out the data stream for it, as it shows 1920x1080 29.97fps.
 
1080/30p is recorded "over 60i", but there's no frame duplication. Instead there's a flag to mark the frames as "progressive" instead of "interlaced".
 
I would guess that Toast, like just about everything else, considers 1080/60i to be "29.97," so if it sees a 60i stream (as it would with 30p-over-60), it will call it "29.97."

It's highly confusing, I know, but it's the way things are.
 
If you're wondering how to have it play at 60fps convert it in Cinema Tools. It's extremely easy....on a Mac. With it in your timeline simply control/click, show in finder, open with Cimema Tools, convert to 24 or 30 fps.
 
Is there a recent book or some place where one can really learn the ins and outs of the technical stuff about video? like how it actually works e.g. the 30p over 60i stuff.

:bath:
 
Barry_Green said:
720/30P is recorded as "over 60", meaning the actual data stream is a 60p data stream. Each frame is followed by a "duplicate last frame" empty frame. So technically it's a 60p stream, even though only 30 unique frames are recorded.

Anyone else using Toast having a problem with 720/30p?
Click to expand...

Why is 30p recorded as "over 60" when in 720 resolution.. but it isn't when reorded in 1080? Howcome they differ? And is this just on the hmc or do all cameras shooting 720/30p record over a 60p stream?

Thanks!

:bath:
 
Thomas Lew said:
Is there a recent book or some place where one can really learn the ins and outs of the technical stuff about video? like how it actually works e.g. the 30p over 60i stuff.

:bath:
Click to expand...

I would also be interested to know what books people recommend for general HD video techniques and technical education. Something easy to understand would be nice. I've already read Barry's book which was great for the HMC150 but would like to fill in the gaps with a general HD work flow book. thanks!

- Shawn
 
shawn.w said:
I would also be interested to know what books people recommend for general HD video techniques and technical education. Something easy to understand would be nice. I've already read Barry's book which was great for the HMC150 but would like to fill in the gaps with a general HD work flow book. thanks!

- Shawn
Click to expand...



Anyone?
 
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