Official Low GOP topic, series 5

rikyxxx

@towi you're welcome.

Whenever I can help, even a little bit, someone who makes settings for the benefit of all of us, I'm glad to do it.

towi

@Stray

"Sounds like chris's original 66M patch"

cbrandin 66M is 66M/32M/24M (22Mx3 / 16Mx2 / 12Mx2).

let's wait and see :-)

mozes

Just downloaded the file that @flaschus posted with his changes with the one from @bkmcwd.
But when i pointed my gh2 to some tree's it crashes after 2 seconds in HBR.
i use the sandisk Extreme HD Video 30mb/s
720 works fine..

I do like the image for so far i can judge now, and did some changing in the settings.
Not much, but enough to make HBR running without errors now.
i changed the gop and gop table for 50i to the same as 720.
Even in tele mode it runs without errors...
720 screen in 3200 iso, and HBR 200 iso
I stop making my own patch.
You guys are to good ;-)

Kihlian

@mozes @flaschus I also tied the flaschus settings but in 720 50p give only 15000 Kbts/s, to low.

towi

please do NOT use these settings

Stray

@towi Nice1, amazing work.

towi

@Stray

thanks!

just fortunate coincidence :-)

towi

also spans on SanDisk 95MB/s in 24L mode. SanDisk 30MB/s is just running ... (edit: success!)

flaschus

no way @towi!

u have perfected a 6gop and i didnt notice bcuz its name was PAL... hahah,,,

this is awesome! I can't wait to give it a test... in NTSC of course... ya!

towi

@flaschus

I think it should be fine in NTSC mode (GOP=9 in NTSC modes!)... but I hope @bkmcwd or @driftwood will optimize NTSC modes further (you'll need appropriate GOP-tables).

It's getting even better: the damn thing also works fine on my old class 6 SanDisk 20MB/s cards ... including spanning in HBR (25p) and 24L modes.

:-)

driftwood

@towi Excellent work. All looks good when pushed on the death charts. Now show me some graphs using real life footage... so I can get an idea where to help.

towi

@driftwood

I will... I just need some daylight to do so.

When testing I had issues with an uneven (actually totally "broken") cadence in NTSC modes with the GOP tables from bkmcwd's "Natural" setting. I've modified the GOP tables... and finally removed them at all. Without success. This is why I had to set 9GOP for NTSC modes. At the price of smaller I-Frames and... well... a longer GOP.

bkmcwd

@towi

Nice work! :-)

"optimize NTSC modes further"

I'll try!

rikyxxx

@towi Fantastic work, thanks a lot!

Achieving spanning even with class some 6 cards is great.

rikyxxx

P.S. this seems to confirm @balazer 's theory on spanning:

Shorter GOPs span at higher bit rates. GOP12 spans at 32 Mbps; GOP6 at 60 Mbps; GOP3 at 80 Mbps; GOP1 at 88 Mbps or perhaps higher. My theory is that the camera is writing a GOP at a time to the memory card, and that the write operation needs to complete in less than some length of time for spanning to succeed.

towi

@rikyxxx

PAL64 (64M for FSH/HBR, GOP=6) does not span. Maybe it would span in a modfied version... but at least in its present form it does not span. However SPAN50 spans at around 50M (in 24L and HBR25p modes, GOP=6).

@bkmcwd

as to the NTSC version of SPAN50 ... I think I'll give 6GOP it one last try with Q18 or Q20.

bkmcwd

@towi

"I think I'll give 6GOP it one last try with Q18 or Q20."

Go for it! :-)

Although I tried many things, it is difficult to make span possible with cards other than SanDisk SDXC. Since frame size becomes quite small in motion, I would like to raise a little bit rate.

minger

@towi What did I do wrong? As I mentioned earlier, at HBR25p PAL64 spanned on my GH2. It's your setting though...

towi

@minger

Nothing wrong :-) It depends on the bitrate actually utilzed. If you shoot, say, a barely lit interview with shallow DOF it's very well possible that many patches will span. SPAN50 also spans when you shoot scenes that utilze pretty high bitrates.

rikyxxx

@towi I'm considering to switch to your new SPAN50.

But there's one thing that "concerns" me...

Let me first preface (and underline again) that I'm not good at making setting, so if I'm going to ask you something "stupid" please forgive me :-)

Now let's go to the point.

I've noted in settings like Flow-motion and GOP3ZILLA that average B-frames size was about 1/4 or 1/5 of average I-frame size. In SPAN50 the I/B-frames size ratio goes down to 1/10 instead, so my question is: aren't these B-frames a little bit too small to do a good job?

towi

@rikyxxx

Before you consider to "switch" patches you should first try SPAN50.

As to the ratio of I-, P- and B-Frames it is (partly) controlled by the matrix. With static scenes (like a death chart shot off a monitor) P- and B-Frames might look small (in this patch) ... but things look completey different with motion. Depending on the actual scene the HQ matrix will also produces pretty large P- and B-Frames ... Just try it...

rikyxxx

@towi

Sorry, I didn't realize those charts were from static footage. You're right about trying patches (preferably a lot of them and deeply) before considering to switch from one to another, but it would require an amount of time I cannot afford to spend, so first I consider, then I try and eventually I switch (or not).

Let's go trying :-)

bkmcwd

@ someone who loves Sedna. :-)

Although I was making the "All 6GOP" setting now, I made the test setting in parallel. (Since 6GOP differs in a situation from 3GOP, I have not made it well yet. )

Since I was not satisfactory with the result of previous version of "GOLGOP3-13 + SednaAQ1A", I improved. However, I am not sure whether this is good or not. Please try, if there are those interested. Especially I would like to know evaluation of 24p. Many thanks!

*EDIT:The bit rate of 24p becomes high from previous versions.

konjow

thanks Towi I think span50 ia going to be my new patch

towi

please do NOT use these settings

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