Understanding 24p

[Steve Mullen]

Originally Posted by Heath McKnight

Hey, Cineform's now on Intel Macs! So that'll be something to check out.

Heath

The CODEC is available on Intel Macs.

Pulldown is removed in the CineForm Capture Utility. I don't think they are shipping this yet.

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The HV20 uses the same 2-3 pulldown as the Sony V1 in the "24" mode. No 2-3 MPEG-2 flags, just a 2-3 cadence. The A frame need not be the first frame. For this reason, I suspect FCP 6.0.2 will not work with "24P" mode.

When shooting 24fps with the V1 you should/must shoot using "24A mode.

"A" mode does NOT mean ADVANCED. It has nothing to with the HVX200's ADVANCED mode. It means "A frame." The first frame of every clip is always an A frame. This means the cadence need not be anaylized. So it EZ to find the 2 judder/split frames.

6.0.2 checks the MPEG-2 data stream. If the MPEG-2 flag indicates the stream is INTERLACE, capture proceeds as 1080i60. If the MPEG-2 flag indicates the stream is PROGRESSIVE, capture converts the two judder frames to two duplicate frames. Thus, every 5 frames there will be a duplicate frame. The file remains 1080i60.

Once in a 1080p24 Sequence, ONLY the 24p frames can be seen.

Canon's 24F mode is a 3rd way of recording 24fps in 60i. The 24 frames are MPEG-2 flagged in a 2-3 cadence. So the recording can be 60i. FCP reads the MPEG-2 flags and puts just the 24 frames into a file.

XDCAM HD and the EX1 in HQ mode do the same -- I think.

JVC uses a 4th way -- Repeat flags that create a 2-3 cadence in a 60p data stream.

[Joseph H. Moore]

The Cineform codec is in beta for Intel Macs, but not their applications. It's their apps that do the pulldown. At least that's my understanding having not actually used them.