Official Low GOP topic

plasmasmp

If you can't tell the difference, then you're not looking. Ever since the first test footage was out, the GH2 has had macroblocking in motion. This is fixed with the hack.

Shoot some iso 3200. It now looks incredible and can hit a 96mb average bitrate while maintaining that grain structure

dkitsov

@kae, what will you do about rolling shutter on your action sequences shot on GH2?

Butt

@dkitsov
Now why should the more high-quality I frames
Rolling Shutter produce more
as the Long-GOP?

dkitsov

@butt ????? has nothing to do with GOP. Sensor.

v10tdi

@dkitsov - I had the same question. But since it's nothing to do with GOP, probably better in PM or separate thread.

@ anyone else...
I've tried the various short GOP settings and I'm seeing/hearing poor behavior from 24p low GOP footage. Specifically, my frame rate is reporting at ~7fps (Movist. I'm on MBP - no streamparser). Perhaps my MBP is too slow? Also, audio pulses. FWIW - I notice same behavior with playback on Viera HDTV...

Butt

@dkitsov
Then we are indeed in agreement

bwhitz

@plasmasmp

+1

The hack also prevents the camera from throwing away details in the blacks. I don't fear shooting with parts of the image underexposed anymore... it looks great in all lighting situations now. Just shot some stuff last night at ISO 1250... the motion is great and the grain is amazing. It's the most film-like grain/noise I've seen out of a DSLR yet and the short-GOP motion is hands down better than what I'm seeing out of the AF-100 and NEX FS100.

proaudio4

Yes,
I'm currently using Kae's settings for 108024P but changed to 6 GOP. I may go 3, but right now 6 looks great. I'm also seeing shadow detail that would normally be grunge actually resolve!

Mark_the_Harp

Hi guys - has anyone seen less "banding" with these low-GOP settings? Just curious - EOSHD in another thread mentions that a possible cause of banding is the camera doing less "work" on an image which has low detail (like a sky gradient) and that could be contributing to banding because (he says) it's can't just be down to the bit depth. However, a low-GOP would force the camera to use higher amounts of data overall (regardless of scene detail) and it would be interesting to know if that changes the amount of gradient banding we see (for example, in blue sky / blurry foliage).

Oedipax

@Mark_the_Harp, I can't say for sure but the one and only (so far) write error I've gotten with @kae's settings came when I was filming a cloudy sky. It really surprised me because I thought for sure deep-focus foliage would do it, but that all held up just fine. When I tried the same shot again I had no errors.

Aleksandr_Oleynik

@Angry_C,
"I really would like to jump on this train, if someone shows the evidence. Until this, in my opinion everything is subjectively. I did a lot of tests and i´m a pixelpeeper, but i did not find decisive differences."

Decisive differences only in motion!

Butt

@nic2011
Yes, see here (seta.zip) - testet with the death testchart by pappasart

Butt

@nic2011
720 50/60p = average ~55MBit (death testchart pappasart)
1080/30p MJPeg = ~105MBit

The 105MBit 1080p MJPeg are for particular indoor shots (with film grain look something like the 35mm Kodak Film-Cams) - when shooting outdoors in bright sun can lead to a crash (will be improved...)

all AVCHD modes stable!!!

nic2011

Great! One more noob question: I see that 720p50 has the same gop like 720p60. Shouldn´t they be different?

Butt

@nic2011

First 720/50p = GOP3, unfortunately that was not so good
Change with latest seta.zip (settings @ @ kae and Butt) 720p GOP6 all: goes well - for both modes (50 and 60p)

nic2011

Aah OK, I thought it has to be different because normally a HD GOP in Pal lands is 12, and NTSC is 15. So 3 + 6 fits pretty well in 12, but 6 doesn´t fit in 15. But if this is not important everything seems to be fine. And yes, we´ll wait for a final stable MJPEG...

Butt

@nic2011
>but 6 doesn´t fit in 15<<br />
yes, but 6 fits in 30 (!?) . . .
GOP 5 and 10 is another option for 60p. . .

nic2011

That makes sence.
"The 105MBit 1080p .... when shooting outdoors in bright sun can lead to a crash (will be improved...)"

Is it possible to get a patch without changing the MJPEG mode until you have a really stable setting?

Vitaliy_Kiselev

@Butt
@nic2011

Use PM, do not turn topic into chat.

Butt

@nic2011

here it is: lowGOP-AVCHD and MJPEG 720p average with >110 Mbit and stable (setj.zip)
and
lowGOP-AVCHD only settings - no change in MJPEG mode (seth.zip)

Elenion

I noticed a very weird behaviour while transcoding the clips with 5dtorgb: it stop 4 frames before the end and of course it doesn't finish the transcoding process. It happens only with your latest settings (Kae+Butt) with 720p50. Everything goes fine with premiere mediaencoder.
In 5dtorgb i choose dnxhd 175mbit and the other default settings.

Do you have any ideas on why it happens? I have to make a music video next week and i need 5dtorgb :(

chip

Elenion,
I had the exact same problem...just before finishing 5DtoRGB stops transcoding no matter which settings. Using kae's GH2 hack settings as well.

Butt

@chip @Elenion
no plan - i use Vegas pro 10:
Native processing is no problem
Please in future: this is lowGOP-Thread - no Convert-Thread
see post from Vitaliy 1:25pm

Elenion

Yes but it happens only with the last low gop setting that you provided

Angry_C

@butt

What kind of SD Cards are you using to get these high bitrates?

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