GH2 AVCHD spanning

sohus — Wed, 28 Sep 2011 07:01:41 +0000

Spanning is discussed a lot on these forums. It probably doesn't matter that much if you are a narrative filmmaker, but it is very problematic if you shoot events, documentaries, interviews, weddings where you can't have the camera stop recording. These people still want to shoot at the best possible settings, which is not really possible at this moment. I think the goal should be a 24H and 24L settings (in one set) with 24H not spanning but shooting higher quality and 24L spanning reliably (ideally all settings would span, but I don't think that is possible). Spanning is also very important if you shoot dual system audio as it safes a lot of time syncing clips.

What we know:

@KAE's 65M settings spanned (PTool 3.61)

After the release of PTool 3.62, spanning became more of an issue (at least it appeared to). Does this have something to do with the AQ settings that were opened up?

With PTool 3.62D, I have confirmed the following settings to be spanning:
@CBrandin 44M/32M at 24L setting (32M) --> GOP12, 32M, AQ4 (44M setting is not spanning)
Stock settings

Let me know if you know other settings with good quality and reliability that do span.

These two examples are extremes in terms of bitrate so I am pretty sure the bitrate alone is not the sole cause.

Driftwood's setting has no AQ set and the iFrames are smaller than most other settings (around 6MB instead of 8 - 11 MB) for most other settings. It also has no P & B frames (does the codec still need to work as hard?). Furthermore, it is GOP1 instead of GOP 3/6/12/ It would be nice if we could pin down what affects spanning: bitrate, AQ settings, GOP settings, memory card speed, scene detail (extreme: death chart). What makes that KAE's setting spanned with 3.61 but @CBrandin's 66M setting does not span? Is there someone who has an idea about this?

Ideally, I hope we can create a setting (ideally a 24L setting ) that spans at a decent bitrate (say 44M - 66M - 88M).

Looking forward to your thoughts and experiences on this matter.

Smoothest hack, intra, macroblocking... Noob questions !

TruHype — Wed, 03 Jul 2013 18:17:07 +0000

Hello,

Attention, noob questions ahead !

I would like to know a few things : - Which is the smoothest hack on the GH2 ? (All the detail, no macro-blocking) - What does "Intra" or "AVC-Intraa" mean ? - What is Auto Quantitizer ? I'm not sure if a higher number means a better image (lower compression) or it's the inverse. What is better, AQ0 (all to motion), or AQ4 (all to details) ? - What does GOP stand for, and there is "Low-GOP", but then does that mean there's "high GOP" ? What are 12/15 GOP, 3 GOP and 6 GOP ? - What are P-frames, B-frames... ? - What is "Matrix" and "444 Matrix" ? - On some settings there's written "14-16 QP", or "QP16". What does QP mean ?

I've not seen much smooth looking GH2 videos on Youtube (unlike the canon videos), lots of them have a lot of macroblocking or whatever and causes the video not to be smooth, and sometimes there are some sort artifacts (I think it's because of the compression or something...). I'm a bit of a pixel-peeper :P Could someone explain me the causes of the un-smoothness, and why are some videos really clean compared to others ?

Example of smooth videos I've found :

(his videos are all smooth and clean)

PS : Can someone give me the link to download the 244mb/s hack ?

And here on EOSHD there's an article about Intra :

http://www.eoshd.com/content/4452/gh2-gets-avchd-intra-at-176mbit

But I still don't understand the difference between the 176mbit so-called "Intra" hack and any other one ! I'm confused...

Please answer !

Thank You.

Tagged with aq - Personal View Talks

GH2 AVCHD spanning

Smoothest hack, intra, macroblocking... Noob questions !