Official Low GOP topic

bkmcwd

@Stray
I also think that the problem is caused as you say.

The scene in the first valleys up to the third is seen suitably to the leaf that is reflected on a full screen of focus momentarily though there are some valleys in B frame.
On the other hand, I think that anything has not occurred momentarily of the valley afterwards.

bdegazio

@Stray
"Looks like the cadence problem happened around frame 580 or so, I frames drop a lot in size there in some of it. Did the focus change or was the shot mostly static in that section ?"

Uh oh - it looks like that was right where the focus got nice and sharp. (Take a look at the vimeo link. Frame 580 is right at about 24.2 seconds - it's actually the frame that's displayed in @bkmcwd's streamparser screen shot.)

chip

@driftwood
well done man! Footage looks and 'feels' stunning, going to test some more today. Thanks VK and Chris too.

Stray

@bkmcwd Looks like the cadence problem happened around frame 580 or so, I frames drop a lot in size there in some of it. Did the focus change or was the shot mostly static in that section ?

bkmcwd

@driftwood
@V&C&all
Thank you for your great works!
This post is first of mine.

I cannot understand detailed logic, but can do test.

This is just a motion test footage with driftwood's 100Mbps,3GOP setting.

lenuisible

@dirftwood (and all), what particular parameter in your settings fixed the different problems everyone else had ? I suppose it doesn't span, does it ?

Thanks all !

Mihuel

@driftwood
Good job !!! Thanks !!!!

danyyyel

What are the pros and cons of having a lower AQ 2 and higher bitrate rather than 4 for gradients etc

Vitaliy_Kiselev

@randolfo
This is why you need reading skills :-) Don't be lazy.

randolfo

It will come to a final setting? and in what post? Too many posts.

Vitaliy_Kiselev

@driftwood

cosimo_bullo

You go out dancing for a few hours and then come back to this! Holy crap!!! Well done all. @driftwood - your enthusiastic posts are high in value (!) and it's just delightful to see the community come together like this and break limits. Great.

driftwood

I'm leaving this short GOP 3 at 140mbps for now as anything above this (like 200mbps) appears to be a waste of bitrate. Multiplier for FB1 FB2 and limit has been currently left at x 2 (though 1.5 has been suffice). AQ left at 2 as 3 kept dying on pappas chart after 30 seconds. T4 = T1 seems to cure the cadence. More tests tomoz.

cbrandin

@driftwood

Yeah, I agree. I think you've maxed out I frames - no reason to go above 1.5x. Actually, I'd try maybe going to AQ=3 and see if I frames get bigger. You may actually max out at 88M. I think you have about hit the limit. Past where you are I think all you'll get is artificially big B frames.

Chris

peterdv_dot_com

@driftwood Thanks for that confirmation.

VLC reports a playback stream bitrate of ~95mbs for my static & moving shrubbery of death clip. This is the first time my GH2 has recorded this "scene" w/o what I call "buzzy" compression artifacts along the edges of all the leaves, twigs, etc. The video looks really good -- relatively clean & natural -- which is saying a lot. Cheers.

Edit: My clips log & transfer & edit into FCP 7, too.

Here's a sample:

driftwood

@cbrandin 3 x multiplier on the FBs seems hardly worth it. Your thoughts?

driftwood

@peterdv_dot_com playback fine on my 'around the room' recordings. However, death chart wont playback.

plasmasmp

This will only work with a card that can write as fast as a Sandisk Extreme Pro. 176mb has the unstable issue, but 24L produces perfectly stable 134mb average video. All other GOP settings are unstable. I went 4x multiplier and AQ 4. Maybe finding the sweet spot for the buffers will fix the b-frame issue at 176

bdegazio

Where's all that extra bitrate going? The I-frame sizes are not that much bigger than your 100 mps test. The b-frames are noticeably larger, but I don't think they could account for an extra 100 mbps.

edit - I notice that the effective bitrate is actually "only" around 115 mbs, despite your setting of 200 mbs. Perhaps you've hit a limit here? Maybe you could push it by setting AQ higher?

driftwood

GOP 3 , 200mbps, FB1/FB2/FBL x 3 multiplier. Death Chart stable at 2 minutes still. Your thoughts?

stoney

Mistakenly 132Mbps was set. Wow. Still stable. Yielding 129Mbps average bitrate. Graph looks great, but too high...

110Mbps makes 1GB clip in a minute. 16GB card can record 16mins.

peterdv_dot_com

@driftwood Sorry if this is a dumb question, but do your recordings using these settings play in camera?

I just did a quick test using your settings (3 gop) outdoors in fading daylight (shrubbery of death) with lumix 20mm lens, 24H, full manual, SanDisk Extreme 8GB.

My cam will show 1st frame of each clip in cam's playback mode, but not play it. However the clips play on my Mac and look very good so far. As expected, or ?

Thanks to Vitaliy, Chris, & all.

bwhitz

Great work people!!! Been waiting for 1 GOP!!!

driftwood

@cbrandin trying it right now...

stoney

Cheers!!!

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