View Full Version : testing - Crazy Banding, low bitrates, wassup???
Matthew Bennett
09-12-2008, 05:01 PM
(edit)
Still, getting crazy ugly banding, very low bitrates. Wassup?
A couple of particularly heinous examples: I really haven't seen banding to this extreme on anyone else's clips... my camera is averaging around 6700 k per second for a 720p clip... with sound..
http://www.qmediasolutions.com/guest/CAMERA_TESTS/Ouch_1.jpg
http://www.qmediasolutions.com/guest/CAMERA_TESTS/Ouch_2.jpg
My first clips look terrible!
ANY ADVICE??
Colorspace, picture settings, etc..
Sorry, also using fully manual lenses, not sure exactly which type but there from the 70's you know the types..
ryan brown
09-12-2008, 06:05 PM
I love that you have an "Andomedized" DVX, and you can't figure out the D90!!
Ironic? I do believe so.
Sorry, I'm of no help whatsoever... I still haven't picked up the D90. Someone will chime in I'm sure. Are you sure you're in HD shooting mode, and not a lower quality?
Thebes
09-12-2008, 08:27 PM
Looks like its very underexposed? Standard sensor to JPEG mapping wouldn't work well. A custom curve might pull usable detail out of it. I noticed my bitrate goes down with underexposed footage, but I've never pushed it so low... At least with still jpegs (so I guess with mjpeg too), file size is a function of compression and detail... your shot has little exposure and hence little detail.
If you are trying to do the "Kholi trick", you need to lock exposure with the AE-L button (hold it down constantly, or set it in the menu to hold), and then after exposure is locked you need to open up the lens to a wider aperture (like with -3ev of exposure comp, start with an aperture of f5.6, enter LiveView, immediately lock exposure, open the iris to f2, then shoot).
Kholi
09-12-2008, 09:23 PM
I've see the banding on the Nikon LCD but not so much in the footage. Aside from that, I think it's best to just expect it given the nature of the compression. Canon? Do ya hear me!?
http://www.dvxuser.com/V6/showthread.php?t=146661
If you haven't already, take a read of the first four posts. Hope some of that helps.
never had a video camera before? or a photo one?
underexposed images have a small dynamic range.
shoot in better light, change the look in post
it's funny that you've changed gamma or brightness expecting to gain exposure levels :)))
not even raw images would fix your mess
Matthew Bennett
09-13-2008, 09:14 AM
never had a video camera before? or a photo one?
underexposed images have a small dynamic range.
shoot in better light, change the look in post
it's funny that you've changed gamma or brightness expecting to gain exposure levels :)))
not even raw images would fix your mess
Whoo, did I give the impression I just came out of the womb? Sorry to confuse,
I just wasn't aware that there was a bottomless floor on how much the jpeg compression would want to simplify the image. If you point the camera into a dark area, it seems to want to throw a jpeg party and bring the bitrate to almost nothing, instead of attempting to use it's bandwidth to render a smooth representation of the darks.
I've probably just hit a 'worse case scenario' here...
Yes, time to shoot something well-lit and nice, and figure out how to 'boss the d90 around'
Matthew Bennett
09-13-2008, 09:16 AM
It's like you have to "trick" the camera into using all it's bitrate as well by presenting it with a detailed scene with lots of dynamic range.
Thebes
09-13-2008, 12:39 PM
If you want to shoot in such low key conditions, I think that a custom curve will map the sensor detail to higher RGB values, then you can squeeze it back down to shadows in post and have smooth shadow details.
At least that is my understanding of what custom curves can do. Of course you do risk crushing your few highlights...