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Blending a GOP3 and a GOP1 mode into one setting - posssible?
  • karlkarl

    I will soon be on a short trip where I would like try fundamentally different settings in the same situations. Uploading new firmware in the field is not really an option, so I wondered whether it would be possible to blend at least two different modes into one.

    I understand that is not possible to e.g. use a GOP1 setting for 24H and a GOP3 setting for 24L, but would it be possible to e.g. use a GOP3 setting for 24H/L and a GOP1 setting for HBR?

    And apart from being possible - would such a blend be useful for comparison, or are those modes depending so much on parameters not subject to ptools that any comparison of IQ would be moot?

  • 6 Replies sorted by
  • driftwooddriftwood

    Yes, or the other way round. GOP1 for 24p and GOP3 for HBR. A new setting in the Quantum series is coming this week incorporating this with dedicated matrices. Lookout for 'Crossfire' by the weekend.

  • towitowi

    but only for HBR in NTSC mode. In PAL mode the 24p & 1080i50 GOP length setting is coupled ...

  • CRFilmsCRFilms

    Are you sure it will work for HBR 60i? The low GOP mods I've tried with the GH1 produced random I frames at 2, 6, 8, etc..., intervals, never what it should be. 50i however did work with a GOP2 and was somewhat stable.

    Have you tried low GOP on the 60i settings before or do you assume they'd work because they work on 24p?

  • karlkarl

    @driftwood: Sounds very interesting, and I will certainly try it!

    Yet my question was actually more like "Can I extract e.g. the 24H-related settings from two different settings files (prepared by different authors) and combine them such that I can use either setting, chosen by the cameras recording mode?". I guess that this would be possible only if there are parameter sets for different modes that ptools can set completely independend of each other, and which are not influenced by other parameters (like FPS rate) which are fixed for the mode. The longer I think of this, the less likely it seems possible to me, but maybe I am mistaken.

  • karlkarl

    When I prepared the "chimera" amalgamation from FlowMotion 2.0 and GOLGOP3-13 today, I also tried whether I could merge an additional "GOP1" mode into the setting (by using the "HBR" mode, while sacrificing the PAL modes) - I used Canis Majoris Night as a source for the HBR settings.

    It actually worked so far that HBR mode recorded AVCHD with GOP1, while 24H/L recorded GOP3 and 720p60 recorded GOP9. The HBR GOP1 recordings had a bitrate of ~128MBit/s.

    But I could not get the HBR mode to become reliable, sometimes the recording (on a SanDisk 64G 95MB/s) stopped, sometimes the camera even crashed and needed power-cycling. Thus I removed the GOP1 setting (power cycling is just not an option when I am underwater... even an "accidental" shot in HBR could ruin the rest of the dive when the camera is stuck...).

    But it seems that at least theoretically, GOP3 and GOP1 settings for 1080p could coexist.

  • bubbabubba

    @Driftwood

    I cannot wait to get "Crossfire!"

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