@Lpowell thanks

I think that the dreams of many of us Pal users hit a wall! :(

@LPowell

"In the AVCHD encoder, Panasonic chose to crush the bottom 16 levels (out of 256) of the luma scale to zero, probably to make dimly-lit amateur videos look cleaner"

Certainly not to safe amateurs from screwing up their shots. This is due to TV standards - broadcast signals (for instance ITU-R BT.709) have different levels than computer signals. TV = 16-235 (also called "studio swing"); computer = 0-255 (also called "full swing"). The GH2 respects this standard so that blacks below RGB 16/16/16 are clipped (while there is some headroom maintained for the whites ... whites do not clip at RGB 235/235/235) This is why the display and also the Histogram changes on the GH2 when you start to record video (on the left end of the Histogram the blacks switch from full black to TV-black and the contrast of the image on the LCD consequently is increased).

" will be using HBR only in cases where I need a synced sound track." We've already done so on one big job and it was a godsend! So much easier to sync to the audio when there's an audio track on the camera too. And while HBR may never catch 24p on the GH2, an 80mbps 30 with audio is nothing to sneeze at!

@LPowell

"Panasonic should have scaled the RAW data so that the full range of analog sensor response was scaled to fit within the 16-235 studio swing. Instead, they shortchanged us by encoding the RAW data into the 8-bit full-scale, 0-255 range, and then crushed the near-black data in the range of 0-15 to zero"

actually this is not what I am seeing...?! Of course the LCD crushes the blacks but the actual footage in fact contains the full range of luminance as measured with the "photo"-histogram (or "full" histogram). The whole image then get's "compressed" into studioswing. Or to put it simpler: I don't see any crushed blacks (other than really underexposed scens). Or did I get you wrong?

Yes, I do, in fact, see the difference. The most obvious is the lower resolution of the HBR shot. It could be just that particular frame that you chose or some inadequate de-interlacing, but it’s there and it’s very obvious.

Noise-wise, I can’t say much. There’s difference in the noise, but to truly compare it, I’d have to look at the actual footage, not individual frames.

There’s also some difference in the way the “rainbow bar” of the Transcend card has been rendered in the two shots, and macro-blocking is more visible on the vertical black plastic part in the center of the videotape cartridge on the HBR shot. That, however, is also not very representative, as I might be looking at a 24H I-frame vs., say, an HBR B-frame.

assemble the 2 images in Photoshop on layers and compare them turning on/off the upper layer. The difference is remarkable! This is a close shot where resolution difference is not so apparent. The same comparision with a wide angle shooting a highly detailed landscape scene will make the difference very clear.

@LPowell

How does one do "a negative pedestal correction in post-production"? I have no clue but it seems as if I should. I short explanation would be really appreciated.

@LPowell

Interesting. Here’s what wiki has to say about NTSC-J:

The black level and blanking level of the NTSC-J signal are . . . at 0 IRE . . . , while in American NTSC, black level is slightly higher (7.5 IRE) than blanking level.

I wonder if that has something to do with the problem you’re describing.

@Mr_Moore

ok, you won, but it`s extreme pixelpeeping, noone would see the differences watching this clips on tv. Ok, testing and pixelpeeping apparently has become a popular sport, at least on these websites.

okay - I got it now. Thanks!

@LPowell "HBR mode is actually nothing more than FSH mode scanned at 25p and encoded at 50i, and is not even flagged as a 25PsF progressive file. As a result, you may need to manually indicate that it is progressive rather than interlaced when bringing it into an editor."

Same like Blu-Ray Standard: 50i or 24p with 1080. Pal world is a mess. 99% percent of Computer Monitors are derived from NTSC´s 60Frame/Fields timebase. No way to watch fluent motion in 25P/50i without dedicated video cards like matrox/Aja etc. Even many Pal-Flatscreen TV´s i tested for editing demand 60i over HDMI when connected to my Mac or a PC. Was lucky to buy an old Viera Plasma from a friend which demands 50I/50p over HDMI

Hope, those examples help a bit. Again, just for testing blacks. I am not able to export a mts frame grab directly. Have to export to prores422HQ using 5dtorgb, then I export the frame. Hope it does not alter things too much. Interesting the blacks on my flatscreen with Flow Motion. When raising the black level on "Flow Motionv11Blacks", I see large dark areas with a slight tint of red, but blocks of pure darker black in those ares as well... This effect is not so apparent with Quantum.

@balazer Good work, I see what you mean about luma being scaled to 235 even though it occasionally extends up to 255. I think that probably is due to minor encoding discrepancies which are handled safely by the extra headroom above 235. This does support @towi's claim that the GH2 follows the studio-swing standard, with input levels to the AVCHD encoder limited to a range of 16-235.

On the dark end of the scale, however, I've seen decoded AVCHD files that produce RGB values below 16. Here's an example of a Color Finesse screen in After Effects:

In the upper left panel, you can see how close the luma channel gets to the IRE 0 line. Notice also that the Pedestal setting is at zero, i.e. uncorrected. On the right just below the image frame is an eye dropper that I used to grab a sample from one of the darkest spots in the image. It reads:

Red: 3

Green: 0

Blue: 15

This is the smoking gun. Although technically, this pixel value is close to the studio-swing black level of 16, in practice, its perceptual luminance is near zero (because G = 0). If we boost the gamma of the entire image, these near-black pixels will remain perceptually close to zero. The result in this sample footage is the appearance of blotchy dark spots (AKA "blocking"), as seen in the cropped image on the left:

The cure for this encoding flaw is a small negative Pedestal adjustment that lowers all pixel RGB values by 15. This eliminates the black-level gap and allows us to then boost the gamma without producing blotches. The result is shown in the cropped image on the right.

@LPowell. Lee, I tested the Flow motion v1.1 today. I used Panasonic 14-140mm lens, AF(on), OIS(on), zooming, Sandisk Extreme 32GB 30mb/s card. Outdoors was overcast shooting mountains and trees. I am an NTSC user.

All of the NTSC recording modes (24H, 24L, 1080i60 FSH/FH, HBR, 720p60 SH/H, MJPEG HD, VGA) worked flawlessly in normal and EXTC mode. 80% slomo worked fine too. Bit rates ranged from 15mb in FH to 70+mb in 24H. 1080i60 FSH and HBR had the same bit rates.

An hour later, sun came out and I did some more testing under sunlight and more detail shots of the trees with zooming. I was able to push 24p to over 100mb with no problems. However, 1080i60, 720p60 and HBR began to have write errors once pushed above 65mb.

The video quality is very good and motion is smooth also specially with 720p. This is one of the most all around capable and stable patches I have tested. It took the combo patch of driftwood Seaquake and Ralph_B Sanity to have similar stable results. Congrats for a nice patch and kudos for all the hard work.