2008 December 5th, 15:34
Another possible angle of attack on 24p
Would it be possible to write a tool to analyze the PF24 stream from the HV20/30 and insert the appropriate pulldown flags without trans/re-coding the image data?
Premiere Pro CS4 now automatically detects and removes pulldown if the appropriate flags are present. 24F .m2t files from my XH-A1 open as 23.9xxfps progressive and edit easily on a 24p HDV timeline without rendering. If one could do the analysis to guess the pulldown sequence and simply insert the flags into PF24, one might achieve the same result quickly without trading off quality or file size.
I would consider writing such a tool myself if I could find appropriate specifications and could wade through the patent licensing. Not having said specifications, I can't even evaluate the feasibility of the approach, and after some amount of searching, I haven't found anyone who has looked at this.
If this has already been asked and answered and I just didn't find it, you may feel free to browbeat me for my ignorance. (You might also consider pointing me to the answer.)
I'm working with Adobe Creative Suite Production Premium CS4 on Windows XP, but I will admit a certain fondness for my old axe, Vegas Pro 8.
2008 December 5th, 15:47
Formerly Known As "Aramis"
24F is recorded on tape and output via FireWire as progressive. No analysis is needed.
Some say that 24P video from Sony cameras like the V1 has pulldown flags in it, but information is scarce and contradicting, even from one source like Sony itself. One source says that Vegas can handle 24P because it has flags, another source says that Vegas can handle 24A but not 24p. A Sony's brochure says that 24A guarantees that all clips start with the A frame, which makes pulldown removal easy, so maybe there are no flags at all.
I had (and still have) an impression that pulldown flags are inserted into progressive video for rendering on non-24fps devices, I could not find any evidence that pulldown flags are inserted into interlaced video.
If you are good with hacking others' software, try decompiling Vegas's plugin that loads 24A video. Do they use flags or do they rely on A-frame always being the first frame of a clip?
2008 December 5th, 16:15
2008 December 5th, 18:45
Yeah XH-A1 24F stores only 24 fps stream to the video tape, without any pulldown inserted.