Best Gop numbers for FHD/SH PAL

M

mimirsan

Well-known member
Hi all
Im sure there's info somewhere among the multiple threads...but I cant seem find the best GOP numbers for PAL SH/FHD (50i/25p)
I currently trying out "13" without native but unsure what the correct way to approach the best number....would like to eek the best quality from Avchd.
Many thanks!
 
Last edited:
Smaller Number = better quality.

On my GF1 running PAL 25fps I have it set to "6" with no issues. I have not tried lower values.
 
Hi!
I´ve tested a few numbers on GOP with my PAL GH1(3) and, so far, I´ve getting very nice and stable/ reliable results likethis:
With Native 25p ticked ON.
- FHD GOP = 6
- SH GOP = 12

I haven´t tested smaller values than 12 so far in SH mode (720p/ 50), but in my sperience GOP=12 looks better than GOP=13 as that was my previous setting until yesterday when I changed it to 12!
Hope this helps! ;)
Good look!
Asier.
 
Thanks guys using 12...cant say I can notice a big difference....but looks better than it was with just the c settings ;-)
 
MarekV said:
Yeah... That's bad..

Do you have higher STABLE settings then c) ? + this GOP ?
Click to expand...

I use (from pappasarts)


Video Bitrate FHD/SH=58000000
Video Bitrate H=50000000
Video Bitrate L=32000000
Overall Bitrate=60000000
Limiting Bitrate=68000000
720p50 GOP Size=12
720p60 GOP Size=15
1080p25 GOP Size=12
1080p24 GOP Size=15

Gives you more bitrate than c settings...looks a lot better ;-)
 
mimirsan,

I tried your settings shooting AVCHD 25p on a SanDisk Extreme 111 16Gb card on a fairly high detail shot. Tripod mounted wirh stock 14-140 lens.
I couldn't go for more than a few seconds before 'card unable to write fast enough' message arrived.
I'm back on the 'C' settings which is proving very reliable for the above settup.
I will start to experiment with change the GOP values though.

David
 
Thanks David!
Do you have any systematic testing way for testing the GOP values? I can help... i will be on trip from Europe to Japan next week and I want take a GH1 for filming and I need the best settings... So I will be also testing this weekend .. So what is your way to test the AVCHD now? :-)
 
Postfade said:
mimirsan,

I tried your settings shooting AVCHD 25p on a SanDisk Extreme 111 16Gb card on a fairly high detail shot. Tripod mounted wirh stock 14-140 lens.
I couldn't go for more than a few seconds before 'card unable to write fast enough' message arrived.
I'm back on the 'C' settings which is proving very reliable for the above settup.
I will start to experiment with change the GOP values though.

David
Click to expand...

Im using a sandisk extreme 3 16gb also and have shot with the kit lense my very busy garden...
do have native 24/25p ticked?
I dont ...I still have 50/60i wrapper...the native 24/25p patch is buggy...you WILL get write errors with it ticked on.
 
MarekV said:
Do you have any systematic testing way for testing the GOP values?
Click to expand...
Using cbrandin's GH13 Stream Parser, I've seen rare, non-fatal errors in FHD videos with GOP lengths of 12 or less. These are isolated GOP's that contain a sequence of severely truncated P-frames. They're hard to spot since their only visual effect is to cause the video to appear paused during their duration.

To flush these errors out, I took 60-second videos of static scenes with the camera mounted on a tripod. I then inspected each GOP individually using Stream Parser. The truncated P-frames contain only a single 192-byte data packet.
 
Thanks for reply Ipowell ... and btw. what is the best bit-rate "inspector" 100% working with GH13 files? I tested like 15 different software but I still don´t have the best one I think... What you are using?
 
Thanks dude! :-) .. sorry for the wrong name :-) It will never happen again .. lpowell
.. Now let´s test you new AVCHD settings :-)
 
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