JVC says 24p part of HDV - will Sony follow suit?

[Mark Kubat]

Guys, any thoughts on JVC's assertion that HDV included 24p all along as reported in the "clarifying" press releases following NAB '05 as reported at DMN forums such as dvformat.com?

Are we thus likely to see some sort of concession by Sony to adopt "true" 24p on next version of FX1/Z1?

Any thoughts?

[Barry Green]

Can someone point out where JVC's statement is on that? I've heard mention that Dave Walton has said that a) ProHD is not actually a new format, and b) that 24P was always in the spec... but I haven't seen anything from JVC themselves about it. And the official press release for HDV makes no mention of either 24P or PCM audio.

In any case -- anything JVC does is likely to be completely unrelated to anything Sony does. They're really two very different formats, lumped together under a common name of "HDV", but when I was at the JVC booth they kept referring to the formats as "HDV1" and "HDV2". It appears that the limit of overlap between the two is that the manufacturers have agreed to make their products capable of playing back the other manufacturer's tape (but, only analog, no firewire output).

If Sony were to adopt 24p into a new HDV camera, they would likely do it within the 60i data stream. I sincerely doubt we'll see Sony adopting JVC's 720p implementation of HDV... I don't think Sony's ever made a 720p product of any type, have they?

[Steven White]

If Sony were to adopt 24p into a new HDV camera, they would likely do it within the 60i data stream.

I was thinking about how best to stick 1080p on an HDV stream. It strikes me that the best option is the following: instead of using a 2:3:3:2 pulldown, write the images in 30p with progressive flags, and store 24p with a 2:4:2:2 pulldown. The computer can "interpret" it exactly the same as a 2:3:3:2, except for the progressive encoder, there is absolutely NO difference between frame B and C in the ABCDE GOP. Futhermore, since each GOP in 1080p is 15 frames, this divides easily by 5, and there will be no problem getting 12 frames per GOP in this manner or having the pull-down go over multiple GOPs.

This combination would eliminate both interlace artifacts in the compression stage (which, I hypothesize are quite extreme - I'm waiting on a DVCPRO-HD vs. HDV codec test with both running interlaced encoding to see how bad the interlace artifacts are on a progressive frame), and make excellent use of the GOP system, since an identical frame carries virtually no information.

-Steve