Well, so I'm led to believe, that 25p and 30p frame modes aren't officially supported within the HDMI spec. So what happens is that the camera sends the progressive signal as 25PsF or 30PsF, which is the 25p/30p frame rates in a 50/60 interlaced wrapper.
You don't lose any quality but there is a little faffing around at the edit stage (edit in 50i/60i and keep the field order at none or progressive). Your 25p or 30p signal is still there.
Sorry if this has moved away from the photo aspect of the D800 but, for me, this is quite important and still relates to the D800.
25p and 30p frame modes aren't officially supported within the HDMI spec.
Fist of all in the USA, we use 24 FPS (23.997) or 30 FPS (29.997), not 25. 24 comes from the crank speed of the original movie films and has remained in use do this day, even in digital motion pictures. 25p or 50i was not used in the USA but perhaps this is the standard in the UK and other countries.
But are you suggesting that progressive video is not supported over HDMI? This is the first that I have ever heard that Progressive video is NOT supported over HDMI or that there is some sort of quality issue from converting progressive frames to fields and splicing them back to progressive frames again at the TV. Where are you getting this information from?
I'm no expert but I do know that when I play a blu-ray disc it says that it outputs a 1080 line progressive video over my HDMI cable to my progressive 1080p TV. I am not sure if it is 24fps (source frame rate for film) or 30 fps, but it is certainly supposed to be progressive. I would tend to doubt that my blu-ray player is taking 2 Progressive video frames and converting them to interlaced fields before it passes them through the HDMI to the TV. This is something that I have never heard of before.
"P" means progressive, ie full "frames" and not "interlaced". Standard Definition (SD) can be progressive or interlaced depending on the source and/or viewing device. Typically, SD material is (in the USA) considered to be about 480 vertical lines of resolution maximum (although NTSC does officially support more), where as HD is at least 720.
I think the D800 has the option of recording at SD or HD formats, but I do not know what the HDMI direct output is, but I would guess that it matches whatever setting that you have it to record to. Both your resolution, frame rate and i/p settings will probably output at whatever you set them to record at. But this is just a guess. Even my D3 can send a video feed out at either 720p or 1080i and I am pretty sure that 1080i is 60 fields per second and 720p is 30 frames per second for the D3. The D800 also may be able to output directly at 24 frames per second. If so, this will be of significant interest to filmmakers and I would guess that it does allow this ability.
I suspect the D800 is different in this regard than previous models since it touts uncompressed live video over HDMI. I'm assuming that the D800 will be about to output at 1080p over HDMI for the live video at least. But this will be something to watch for.
If it turns out that the D800 can output 1080p-30p/24p and outputs over HDMI in the 4-2-2 color space, this will be an impressive video device for sure for film-makers who want to capture uncompressed video. For the rest of us, 1080p compressed video using the file on the card, should be pretty darn good too.
Fri 09-Mar-12 06:47 AM | edited Fri 09-Mar-12 03:32 PM by Robman3
I suppose I could have looked all of that up, sometimes it is best to ask others here.
The debate lingers now with the 5DIII, using I slices/frames only for output and the native ISO hitting 25,000+.
That will still only output 4.2.0 but the Canon set infers that moire/aliasing are all but eliminated in the new body,plus the high ISO is "noise" free. A compelling case for film makers.
TBD I suppose, and the difference for the D800 still has no ready answers, as to the density for the native MP files in FX, or DX mode as far as actual hands on testing is concerned. 36 for the 800, 24 for the MK3 and 18 for the D4.
Nikon also touts negligible moire etc, plus the direct HDMI out, so we'll see which compression algorithms are static via these new sensors, in actual real time.
So far, the videos from both brands are impressive and would be, given that crew aspects, are used to stage promo content.