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GH2 Color Banding Bashing
  • 54 Replies sorted by
  • sam_sticklandsam_stickland
    Are people really sure that 8 bit is the cause of this banding? I've never seen this sort of banding before on my DVD collection (all 8 bit), or on any of my Bluerays (all 8 bit), or on my LCD monitors (8 bit), or on anything played through my 8 bit graphics card (a Nvidia GTX460).

    In fact, even if I had a camera capable of recording 10 bits per channel, I don't actually own any hardware capable of the playing it back at anything greater than 8 bit.

  • Mark_the_HarpMark_the_Harp
    EDIT Just seen @sam_stickland comment above. I personally think 8-bit is the cause but equally @sam_stickland may be right.

    @Maxwell77My suggestion is to force a higher ISO (but stop down or use some ND filters) to introduce some noise to dither the image and then noise-reduce in post. Not ideal, I know, but I have shot something to deliberately provoke banding, with both low and high ISOs, and have seen the higher ISO apparently reduce the banding, which is why (like you) I have come to believe 8-bit is the cause. It might be my monitoring, of course, so take this as just an experiment. The problem is that you don't necessarily know when banding will be a problem, but I'm sure you will recognise those situations once you become aware of it.

    I'm pleased you like the GH2 - I think it's great too - so why not try this idea and see if it helps.
  • LPowellLPowell
    @Maxwell77
    As you suspect, banding (or "posterization" as it's called in graphic arts) on the GH1/2 is primarily due to the limitations of the 8-bit color depth of the AVCHD encoder. (The image sensor itself has 12-bit RGB photosensors.) Banding effects are inevitably worse in dimly lit, gradually contoured areas such as an evening sky. The reason this occurs is because the gamma curve used in the Rec. 709 video spec assigns only a 4-bit fraction of the 8-bit color space to the darker colors. As a result, there are far fewer gradations available for encoding darker colors than there are for brighter colors.

    For minimal banding, you'll want to use an AQ4 patch at a high bitrate with -2 Noise Reduction. As @Ian_T points out, this will also preserve more random noise, which may help mask banding contours. I doubt that short-GOP patches will improve banding, as they force the encoder to divide its available bitrate among more frequent I-frames, each of which requires a huge amount of data to encode at the highest quality.
  • sam_sticklandsam_stickland
    @LPowell Aha, that's interesting about Rec.709. It didn't occur to me that the colour space might be encoded in a non linear fashion. I was thinking in RGB terms. But Rec.709 is the colour space used in HDTV, so why doesn't the banding occur on HDTV signals? E.g. broadcast or non deep colour bluerays?
  • LPowellLPowell
    @sam_stickland
    It's because they have skilled technicians to master Blu-ray and broadcast video using professional multi-pass equipment that squeezes out maximum quality from the available bandwidth. An AVCHD video camera has to use a consumer-grade encoder to pump out video frames at a strict, inflexible pace in real-time using limited hardware resources. To do so reliably, compromises must be made.
  • AlexAlex
    if I create a sky like gradient in after Effects (blue to dark blue) in a 8bit timeline and render it into a h264 .mov, banding is very evident. If I do the same but out of an 16bit timeline, the banding effect is much less evident although the result is the same 8bit h264.

    As for the GH2, could it be that there is already banding before the image hits the encoder? Panasonic uses this "pulling-extra-sharpness-from-the-green-channel" trick. MAYBE this method produces the GH2 color problems because there is some serious internal color correction needed to bring the image back to natural. In favor of green, they sacrifice on red. The GH2 might have very shallow red info that gets stretched back to normal causing the banding.
    Do other AVCHD cams also have these green/yellow/banding problems like the GH2? To me it feels more like a "shit in shit out" problem (AVCHD not being the cause for the banding)

    the trick to fight banding in After Effects is to add some noise that dithers the banding away. Just like people suggest here for for the GH2. So pump up ISO and let there be noise and stop whining about a $900 cam not being the perfect no compromise film making tool.
  • oscillianoscillian
    @lpowell And I guess that exposing to the right helps, right? Maximize your gain without clipping essential parts with Smooth -2 contrast. I also use a cooler white balance to use more of the green channel. Works out fine in CC.
  • sam_sticklandsam_stickland
    @LPowell
    "It's because they have skilled technicians to master Blu-ray and broadcast video using professional multi-pass equipment that squeezes out maximum quality from the available bandwidth."

    But does that mean that if I had a 10 bit camera, and recorded something that would cause banding in a 8 bit camera, and then naively rendered that to an 8 bit Rec.709 file the banding would return?

    If I had access to a 10 bit camera I would test this, but I don't.
  • Mark_the_HarpMark_the_Harp
    A gradient is a great way to experiment but it's way worse in a real image with moving shots or changing exposires during a shot because you see a moving set of bands.

    The first time I saw it was in 5D mkII footage, and that put me off getting one of those cameras, quite a while before I was even thinking of getting a GH2.
  • sam_sticklandsam_stickland
    I don't ever recall seeing it on my old DVX100B, but perhaps that was just dumb luck.
  • Mark_the_HarpMark_the_Harp
    Don't think I ever saw it with my XHA1 cams either.
  • LPowellLPowell
    @oscillian
    Yes, high exposure and low contrast gives you the best chance to avoid banding in dark areas.

    @sam_stickland
    Yes, if you casually render a low-bitrate, 8-bit Rec. 709 video, you can readily produce banding in areas of smooth, dark gradients.

    Banding isn't usually as visible in old-school videotape footage. The interlaced 60i footage tended to obscure gradients with jitter and random noise.
  • sam_sticklandsam_stickland
    @LPowell Why would the low-bitrate be a factor in 8 bit created banding? While a low bitrate render might have more macro blocking etc. isn't the bitrate separate from the resolution of the colour space? A higher bitrate can't magic more colours into a pre-defined colourspace, no?

    Thanks for your answers btw :) I'm going to China for a fortnight but when I get back I'm definitely going to experiment with various Rec 709 renders to further my understanding. (I'll create the gradients directly in AE)

    S
  • StrayStray
    @sam_stickland No, but a lower bitrate increases block size and therefore banding, just like a colour gradient compressed into a jpeg set at a low quality level creates more banding.
  • LPowellLPowell
    A low bitrate may also force the encoder to use larger quantization factors, which can coarsen the granularity of the color data to even less than 8-bit resolution.
  • proaudio4proaudio4
    I'm surprised this troll thread is still open... Really all complaints and no substance. Sounds like a case of buyer's remorse, and it's not the GH2! LOL

  • Maxwell77Maxwell77
    Thank you for the many responses. I appraise this really. Unfortunately, I think, there will be no solution for the banding problem. 8 Bit and perhaps a not so good video encoder in the GH2 causes this problem... And its true: You will never know when banding is a problem. I had shot some videos at sunrise without banding... But on a a few other videos I get huge banding problems... It is also hard to see in the LCD display...I guess we have to live with this constriction. Perhaps a new AVCHD specification will solve this problem...By the way, I cannot imagine that color banding was a problem in DV-material...But I am not sure at the moment. DV is also 8 Bit... Probably the combination of 8 Bit and a not so good consumer encoder in the GH2 is really the reason for the banding... We should contact some of the GH2 develpers... It would be very exciting what this person will say about the whole issue. ;)
  • otcxotcx
    If one make a product, there will always be hapy and unhapy customers. GH2 is good cam, but it is not RED.
    Hack improves cam a lot, but do not make miracles. It is pointles to say that there is a problem, if you can not show where. My friend said that GH2 is no match to canon eaven he was not ever seen or try GH2. I think he is wrong, but it is not my problem anyway. I have shoot lot of nature clips with just 14-140 lens and banding has never been a problem. Of course i can make situation wher it will be a broplem, but most probaply other cams would also fail there. And yes i can show it.
  • brianlucebrianluce
    You should learn to shoot with your GH2. Although from what it sounds like, nothing short of a Panavision Genesis will ever satisfy you.

  • otcxotcx


    pass: GH2

    Like this. But it could be corrected quite easely.
    Right camera settings (everything is auto and zoom is full)
    Lightning (light is just in bunny)
    post (no post here)
  • MihuelMihuel
    I read this discussion and I feel that to some child does not like the toy he got from his mother. GH2 or 5dmarkII Canon cameras are created primarily to photographing. They also have additional functions filming. If someone is able to use these functions- very well, and if it considers that it does not let you buy a film camera. You can not complain that the hammer does not fulfill the function vibrator. If you can please a woman with a hammer is good for you, but do not cry if you fail. Because it's childish.
  • Maxwell77Maxwell77
    @Mihuel
    Hey, I got my GH2 from my father and not from my mother... ;) Ha, ha... But seriously...
    I guess we can close this topic... Any further discussion will make no sense.
  • Vitaliy_KiselevVitaliy_Kiselev
    @Maxwell77

    So, my understanding is that your goal had been to chit chat.
    And I still see no your examples.
  • woody123woody123
    Will the film modes @cbrandin is working on have any effect on the banding issue?

    Example: The sunset profile on the Sony NEX-5N as tested by @EOSHD.


    Can Panasonic "Film Mode" and Sony "Profile" be compared functionally, or are they dissimilar beasts?
  • killagramkillagram
    Would a polarization filter negate some of the banding side effects?

    I've been using driftwood's GOP1 IntraPure settings and it's greatly reduced posterization, but not entirely.
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