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GH2 Cake v2.3: reliability and spanning in 720p, HBR, 24p, and VMM at 2-2.5x stock bit rates
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  • Thanks @_gl - just downloaded 3.64d and cake 1.1 and want to try exactly what you said above, so good to know my GH2 won't explode.

  • @_gl & @Mark_the_Harp : I believe you guys should wait for an updated patch since there's a lot of new GOP related settings that might need adjustment when transferred from the previous version.

  • @_gl, thanks for your report. But I've found that the rate limiting scheme in Cake 1.1 is not working in PTool 3.64d with the v1.1 firmware. For now I recommend sticking with the v1.0 firmware.

    I believe PTool 3.64d should work the same as PTool 3.63d on the v1.0 firmware, but I haven't confirmed that.

    My priority now will be getting HBR 1080/30p mode to work.

  • Are there any plans to port cake to HBR mode? :)

  • @balazer, good to know (about rate limiting not working in 1.1) - but what effect does this have? Is there no upper limit (potential for write errors), or does it reduce general quality?

  • @duartix @balazer Thanks guys - for the moment I'll try out Cake with the 1.0 firmware using the prev version of ptools. Cheers!

  • good to know (about rate limiting not working in 1.1)

    You can use same limiting approach, but patches that need to be used are not the same (as 3.63 had ability to replace scaling table to another, not to change it entirely).

  • @balazar Hi there - I'm a bit behind the times here but because my computer was in many pieces I wasn't able to try out Cake when it came out, on the 1.0 / 3.63d ptools, and then I didn't go for it on the new version of ptools 3.42d. But I thought I ought to try it on 1.0 / 3.63d and it's amazing! Thank you - really good stuff. Looks wonderful - and I appreciate your work on it. If you can sort it for 3.64d it will become my go-to setting, but until then I'll keep this one. Thank you!!

  • Thanks, Mark. Work on Cake for the 1.1 firmware is progressing well.

  • New version of Cake for the GH2 v1.1 firmware image and PTool 3.64d, in the second post of this topic:

    • Cake 1.2:

      • 24p and Variable Movie Mode at up to 80 Mbps

      • HBR 1080 25p & 30p, 1080i, and 720p at up to 50 Mbps (PAL and NTSC)

    Please test.

    HBR seems to use the same interlaced encoding that 1080i uses, so I was unable to make HBR stable and span at the same bit rates I could for 24p and VMM. The quality is still good, but begins to suffer with prolonged high motion or above ISO 1250.

    HBR 1080/25p is stable 10 Mbps higher than I set it, but it seems to share a setting with 1080/30p. I set it low enough to be stable with both. If you want 1080/25p and you don't care about 1080/30p, you can try raising Other Modes Top and Bottom bit rates by 10,000.

    I didn't try very hard to get 1080i and 720p to work at higher bit rates. It might be possible.

  • HBR 1080/25p bit rate settings are tied to 24p

    This is wrong

    because 1080/30p and 720/60p share GOP length and bit rate settings.

    Also wrong.

  • It is hard to understand that you are talking about.

    As you are changing totally unrelated thing and making absolutely unfounded conslusions.

  • Vitaliy, you are right. I made a mistake in my testing. All PAL and NTSC modes are working in Cake 1.2. There was no reason for me to make a separate PAL version.

  • Is it safe to use " Most to detail " for 1080p 30p HBR using Cake 1.2 ?

  • @balazer tested a little your settings 1.2. HBR mode: panning = 21165 kBits/s No moving objects and camera = 10739 kBts/s.
    So the bitrate in HBR is not so high.
    24P (moving) = 29443 kBts/s 24P still = 16766 kBts/s.
    1280x720 50p = 18737 kBts/s

    Playback in camera works, maybe sometime have to turn on and off to see the clips. Ex tele mode works.
    I´m using a SanDisk HD Video Extreme 30MB/s.
    There are changes in the Mjpeg too? Have some problem with it, don´t now if I made disorder in it settings, it don´t works..
    I´m new in the hack. Hope thys help and look forward for your cake.

  • @Kihlian : Please reformat your post. The moving/still conclusions are very confusing. (edit) Thanks!

  • Thank you @balazer for this great setting (not sure if I'm allowed to call it a patch any more)!

    My experiments with the prev version have been fantastically rewarding, and just tried the new version 1.2 with the 1.1 firmware / ptools 3.64d. Need to do a longer term experiment, but the pictures have a wonderful quality about them, and bitrates seem to work well to match the movement in the image. More importantly - looks absolutely great. Using a class 6 card, believe it or not!

    My first quick trial with 14-140 lens / 24H / Handheld with wild zooming and ISO160 gave a bit allocation: max 64 248 892 / avg 38 244 284 / min 15 309 758 and perfect picture quality throughout that clip, whatever movement was happening on screen. So obviously if the image needs a lot of bits, you will get them!

    The clip below is my second test, this time with much less movement which gives rates of max 33 278 556 / avg 29 741 610 / min 22 451 166. This shows the encoder is really responding well to need and giving exactly what it says on the tin - constant quality. Have a look at the raw mts (link below) shot at ISO320 using the 14-140 at f5 and 1/25, on 24H using standard film setting and -2,0,0,-2. Ignore the crappy on-mic sound of course - it's cold at home and the harps don't like that. Download and play with the original mts if you want as I think it takes grading well. It seems to produce a sort of "rounded" quality to the image. Don't know if that sounds flaky, but it looks nice even using the Panasonic lenses!

    Link if you can't see it below is http:// vimeo.com /37112107 (just remove the gaps)

  • Nice cake with beautiful music, cheers Mark

  • Mark, thanks for testing. Looks good. (and sounds good!) The on-board mics are not terrible, but do you know how one would mic a harp? I may be able to recommend a mic that you can plug straight into the GH2.

    @estib, you should not change the Auto Quantizer setting in Cake. Cake uses a constant quantization parameter. If you want higher quality, you can try changing the Quantizer for 1080 (or 720) modes to 20 or 18.

    @Kihlian, thanks for testing. Glad to know ETC mode works - I hadn't tested that myself. The bit rate will be high only when the video demands it. HBR is the same quality as 24p, just with a lower limit. MJPEG settings were copied straight from Flow Motion 1.0 without testing. You can try using them as they are, or remove all of them.

  • I've done a quick outdoor comparison of Cake 1.2 vs Chris 66 (1.0E firmware). Two GH2 bodies mounted side-by-side (my 3D rig). Stats:

    24H, 1min 39s, ISO160, (IIRC) F4.0

    Cake 1.2: 592MB (Min/Ave/Max) = 48,505 / 49,162,211 / 81,036,126

    Chris 66 : 603MB (Min/Ave/Max) = 48,505 / 50,170,214 / 70,510,484

    Check out the attached pics (Still|Motion|More Motion). To my tired eyes they look very similar, but the still shot looks more detailed with Cake (check the finest tree branches that seem to smudge more with Chris66), but it seems that Chris' holds onto more detail during motion. However it could also just be differences in firmware (1.1 is supposed to have different NR), lenses and/or focus. Opinions?

    I also don't see much motion difference in general (at least single-stepping), so I'm not sure low GOP really makes much difference to that. (I'll look at it again tomorrow with fresh eyes).

    Still.png
    1920 x 1080 - 3M
    Motion.png
    1920 x 1080 - 2M
    MotionFaster.png
    1920 x 1080 - 2M
  • Thanks for testing. A short GOP was not my goal with this approach. If you can get all of the frames to be equal quality, the GOP length doesn't matter so much. The short GOP was necessary to make spanning work at these bit rates. Cake should achieve the same quality on every frame, motion or not, so long as the bit rate limit is not hit. Chris's 66 Mbps settings can look very good, but it depends on the shooting conditions. With low noise and low detail, it looks good. But when the detail or noise go up a bit, the B-frames become lower quality than the other frames. My approach is an attempt to prevent that. Chris is using a lower quantization parameter than I am. If you want the constant quality VBR approach with higher quality, you can change the quantizer to a lower value. You can also raise the 24p high top bit rate limit, though you'll lose spanning if you're not using the 95 MB/sec 64-GB card.

  • Hi @balazer @gameb Thanks! I was being a real tart in not actually tuning the thing - as for mics I do have a few but didn't bother for this test. I'm very impressed with the low noise levels (which I think are a result of the 1.1 firmware rather than the hack?) and the general quality of images - given this was in a fairly dark room at ISO320. I've had a go at doing some subtle corrections to the video I uploaded and really your patch does seem to cope well with a bit of messing about in post. I've done a repost of it with a bit of correction to give it some warmth and intimacy here: http:// vimeo.com /37143813 (remove gaps in url to visit vimeo page) or see below:

    Can't wait to do more video with it!

    @_gl Great test - to me that's really helpful. Interesting about the bitrates you were getting - and how close they were between your two patches. I've been using Chris's 66/44 patch on the 1.0 firmware up until now. I think you're right that 1.1 does have better NR in my limited experience of it so far.

    @balazer (post above this) what exactly might I change where you say "If you want the constant quality VBR approach with higher quality, you can change the quantizer to a lower value". That's got me intrigued - if I can get even better with my very lowlife SD card. Where is that in ptools?

  • To increase quality, in PTool go to Patches for testers, AVCHD Movie Mode, Quantizer, and then set the 1080 and/or 720 quantizer values. Try 20 or 18. If you go too low, the bit rate will bump up against the limit.

    The low noise levels come from using a low ISO and using encoder settings that don't add (much) compression noise. 320 gives exceptionally low noise when you avoid the ISO noise bug.

  • @_gl - Extraordinary test! Great stuff.

    @Mark the harp - Holy crap, you actually play the harp?!!! Great!