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View Full Version : shooting "native 24P" vs. not with it???



Nicholas Natteau
06-28-2010, 04:06 PM
Under what circumstances would it be appropriate to check "Native 24P" in the firmware hack?

When should you shoot native 24P and when is not advisable to shoot it?

PappasArts
06-28-2010, 04:09 PM
Under what circumstances would it be appropriate to check "Native 24P" in the firmware hack?

When should you shoot native 24P and when is not advisable to shoot it?

I guess that's up to you whether your want to or not. However quality reasons are pretty clear.

Take a look at the 24PN Native vs 24 over 60i: http://www.dvxuser.com/V6/showthread.php?t=214735
Third picture down is the 24PN stuff...

Pappas

Cassius
06-28-2010, 04:23 PM
Use it when you have do-overs available. Reliability is the problem.

Filmkid2003
06-28-2010, 04:29 PM
PappasArts, what brand and type of SDHC card are you using? I am using a Patriot 16GB Class 10 SDHC card and I can't even get up to the "C" Settings (50,52,60) with Native 24p (using ptools v3.37d). I get a "cannot record motion picture due to write speed limitations of memory card" error message and have to take out the battery to "unfreeze" the camera. Now, if I go down to the "B" settings (32,34,40) with Native 24p checked, I can film to my heart's content with no problems. If I leave Native 24p unchecked, I can go up to the "D" settings and beyond with no problems.

PappasArts
06-28-2010, 05:37 PM
PappasArts, what brand and type of SDHC card are you using?
.

I'm using Sandisk Extreme 8gigs

http://www.sandisk.com/products/imaging/sandisk-extreme-sdhc-cards-

Pappas

Filmkid2003
06-28-2010, 08:07 PM
Thanks, PappasArts. If you don't mind me asking, what were your bitrate and GOP settings for the AVCHD footage you took when you compared the AVCHD codec to the MJPEG codec? Also, have you had any issues shooting at those AVCHD settings with the 8GB Sandisk card?

cbrandin
06-29-2010, 08:36 AM
I've analyzed the Native 24p stuff in some detail. There are many strange things that happen - rogue frames, missing frames, wrong GOP lengths, I frames that are sometimes key frames and sometimes not (whatever a non key I frame is).

I'll be damned if I can see any visual changes or anomalies associated with any of this strangeness.

However, there is the stability issue, which is real. What happens is that there are huge "rogue" frames that effectively double the instantaneous data rate for 1/2 second (typically) when they occur. In my tests I get these rogue frames about 5% of the time, and often that results in a write error. Also, I get rogue frames whenever Native 24p is checked, no matter what other settings are (they even appear when the only patch applied is Native 24p and all other settings are factory defaults).

Chris

cbrandin
06-29-2010, 09:26 AM
In my tests I've never captured two GOP's in a row with rogue frames. It's gotten close, though. My guess is that if you get two of three GOP's in a row with rogue frames the camera can't keep up and either locks up or produces a write error message - and you lose the clip.

Chris