720p50 with 4:2:2 ?

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Psyco

Member
Hello,

long time reader first time poster;-) First: Thanks to Tester13/Vitaly !!! You saved my day, week, month,.. :-P


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There is no 4:2:2 colour option in the AVCHD setting - would it be possible to get it?
Or, does it work to set 30fps->50fps without droped frames in mjpeg mode?

My thoughts:

50p is much better :2vrolijk_08: I really hate that choppy outdated look in cinemas!

Doing the data rate math:

Pal vs. NTSC fps -> 50/60 = 83,3%
720p50 vs. 1080p25 -> (1280*720*50)/(1920*1080*25) = 88.8%

-> a net data rate compared to 1080p30 of only 74%

Now cranking up the colour data from 4:0:2 to 4:2:2 -> 8/6 = 133,3%

Combining both would give a data rate of 98.8%.

So, the overall data rate of a 720p50 4:2:2 video is about the same as 1080p30 4:0:2, an the GH1 should be able to handel it quite well.

Does this make sense?


Cheers


PS: No, I really don't want 25p or 24p - I like MOTION ;-)
 
Hmm, aren't these soaps also shot in 24/25/30p?

To give it the cinematic look has nothing to do with 24p - making things blury is just old.

24 fps was set up as the minimum frame rate when human beeings start to see it as motion instead of a series of individual pictures (to make it as cheap as possible), BUT our eyes are capable of a much higher temporal resolution.

As long as motion is slow or the camera is far away 24p is ok, but when getting close in fast motion scenes produces only flickering annoying "temporal-mud".

Everybody is so into 1080p because of its high resolution and hacks its cam to get rid of this mud...
...but the same people want temporal mud as bad as possible :shocked:

But thats ok, everybody has a different taste.

The questions remain: How do i get 720p50 4:2:2 out of my GH13?

Thanks
 
Psyco said:
The questions remain: How do i get 720p50 4:2:2 out of my GH13?
Click to expand...
At the moment you can't. Specifications for AVCHD (the only mode that supports 720p50 natively) only state 4:2:0 sampling (not 4:0:2 by the way). 4:2:2 sampling has been achieved in MJPEG mode, however you are limited to 30fps. If sensor mode research succeeds in feeding 720p50 footage into MJPEG encoder then we may have something.
 
Ok, so after getting used to the known features I will jump in to the sensor research :-)

By the way, does anybody know which encoding chip is used in the GH1?

There might be some "magic numbers" for the bit rates to get maximum quality (thinking of pixel pipelines on graphics cards).
 
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