EXPLAINED: "24" verses "24A" at DVinfo.net

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Sony HVR-V1 / HDR-FX7
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Old December 22nd, 2006, 06:01 PM   #1
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EXPLAINED: "24" verses "24A"

Got this explanation from Sony today:

The "24A" mode is actually the same as the "24" mode provided by the prototypes. The A frame is always :00 because "repeat" frames are added to always complete a 15-frame GOP. Therefore, the TC accurately represents the "type" of frame in the 2-3 pulldown cadence.

Which is why EDIUS 4's "23.98 over 59.94" mode works correctly. It doesn't use the subcode data at all.

Vegas also uses the 24A mode to recognize and remove the 2:3 pulldown. (It appears the extra 6 frames per second are dropped during capture leaving a true 23.98 file.) And, Vegas seems to work fine with 24A.

The NEW "24"mode does generate not "repeat" frames so the last GOP of each shot may have fewer than 15-fames. Because the A-frame of the next shot doesn't always have a TC of :00, the subcode must be used. In this case, the captured file may be 30fps, and the subcode is used during playback. Or, the subcode may be used to drop frames during capture.

This is something those with new V1's may be able to check.

<<<<< Note, the "24" mode MAY not work with the 7.0c version of Vegas. So if you have a V1 and "24" doesn't work with Vegas, try "24A." >>>>>

So, why was the "24" mode included? Generally, the feeling was that Sony needed to provide a mode where people could shoot in 24p, but not experience "repeat" frames. Thus, the 24 mode is primarily for folks that want a "film style look" who rely on in-camera" editing for reducing the overall editing time of their projects.

Obviously, it is also good for anyone who needs to show video directly from the camera without pauses.

Now the Sony sheet that claims bringing 24A into a computer and playing it as a movie will remove the pauses, may be wrong. The pauses are likely removed only when any "repeat" frames are edited out.
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Old December 23rd, 2006, 03:02 AM   #2
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My head exploded whilst trying to read that.

Twice.

Am I understanding correctly when I assume that we are better off shooting 24A if we intend to edit on an app like Premiere Pro?

Or did I really not understand a word of it?
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Old December 23rd, 2006, 05:29 AM   #3
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Steve,

Are you any closer to understanding the reason for the difference in quality between progressive and interlaced on the V1U?

When I get my V1E back from being updated I'll check 25P vs 50i to see if it is similarly afflicted.

Do we know if the change in quality is down to current NLE handling of V1U progressive captures?

Cheers

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Old December 23rd, 2006, 06:59 PM   #4
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Originally Posted by Tony Tremble
Steve,

Are you any closer to understanding the reason for the difference in quality between progressive and interlaced on the V1U?
I don't think there is ANY quality difference.

When Sharpness is at 7 (normal = no change) there is zero difference in resolution.

At 5, the P is very slightly softer (look at the last two sets of images I posted) than I -- but since those shooting P always want it softer, how can that be a real problem? They get what they want.

And, if that's too soft, then use 6 or even 7. It's all up to you.
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Old December 23rd, 2006, 07:01 PM   #5
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Quote:
Originally Posted by John Hewat
Am I understanding correctly when I assume that we are better off shooting 24A if we intend to edit on an app like Premiere Pro?
No way to know before each NLE releases support. However, I'll bet 24A will be the most supported since it's the easist to implement.
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Old December 23rd, 2006, 11:50 PM   #6
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"extra 6 frames per second are dropped during capture leaving a true 23.98 file.) And, Vegas seems to work fine with 24A."

are you sure of the 23.98 ? not 23.976
since V4 or was it 5 Vegas has had the ability to get rid of pull down on SD.avi clips on the fly and the resulting clip are 23.976 ...
i had some problems with HD/SD clips ( transferred to hard drive ) that were NOT 23.976 in Vegas ... bottom line i was told by sony ( summer 06) Vegas is 23.976 ...
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Old December 23rd, 2006, 11:58 PM   #7
 
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Donatello,
You are correct. Vegas is 23.976.
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Old December 24th, 2006, 04:33 PM   #8
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Quote:
Originally Posted by Don Donatello
are you sure of the 23.98 ? not 23.976
In causual use one needs only to "round" to one or two digits after the decimal point to signal the TYPE of Region 60 video: 29.97, 30.0, 59.94, 60.0 -- and likewise with 24fps; 29.98 or 24.0.

Whatever problem you were having didn't involve the difference between 23.98 and 23.976 because they are exactly the same TYPE of video.

Region 50 folks are lucky because they only need to digits to define the type: 25 or 50.
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Old December 29th, 2006, 12:22 PM   #9
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Aaaah, 25/50 - the only true video format, as approved by God Himself!
25/50 - truly the superior video format, for the more discriminating of nations!
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