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    #11
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    Quote Originally Posted by cbrandin View Post
    Yes, I've checked and it is always the last frame.

    chris
    This is long known quirk of GH1 video encoder.
    Seems to be some bug or wrong parameters set used.
    All GH1 encoder style breaks basic rules, as it depends on special settings for predefined modes instead of making general and scalable solution.
    Plus error processing is non-existent.


     

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    #12
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    Is much known about the CODEC code? This looks like the product of a bad conditional statement that is causing a subroutine to be called before it should be. Perhaps a combination of P and I frame subroutines being called when only one should be called. This should be patchable if the error is something like a more-than-or-equal instead of a more-than conditional. The instructions for both should be the same length.

    Chris


     

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    #13
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    No, it is just seems like proper P frame with some garbage in it.
    We need better analazying tools to understand it.
    And if you think that codec disassembly is similar to C code with comments you are badly wrong :-)


     

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    #14
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    I know. I do patent forensics work for a living, so I'm well aware how cryptic disassembled code is. Still... if the code location that is executed at the transition between frame types is known it might not be so hard to find the problem. If it's unknown, however, that's another thing altogether.

    Chris


     

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    #15
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    Somebody - I think it was Barry - determined that the color sampling was better in native 24p mode. Was this test done with pulldown processed wrapped video? If not, I can run some tests with wrapped video that has had the pulldown removed with NeoScene compared to native 24p video also processed with NeoScene.

    Chris


     

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    #16
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    I did test and verify that the native 24p mode uses the proper progressive color encoding system, whereas using the 60i wrapper causes it to use the interlaced 4:2:0 color system, yes.


     

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    #17
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    OK, thanks.

    Chris


     

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    #18
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    I ran some tests with the "C" settings (50, 52, 60) with Native 24p not checked on a Transcend 16 GB class 10 card (this is totally reliable for me producing no pulses and no failures) and here are some results:

    As I suspected higher shutter speed and lower Noise reduction both have an effect because they create more fine detail. Here are some numbers:

    All clips were the same subject (bushes and flowers in a breeze - lots of detail)and ran 30 seconds producing a file size of 168-171 Megabytes.

    At 1/500 and NR -2 the peak frame size was 649536
    At 1/125 and NR 0 the peak frame size was 566400
    At 1/50 and NR -2 the peak frame size was 515328
    At 1/50 and NR 0 the peak frame size was 488832

    I assume, because the average data rate was always virtually identical, that these numbers mean that the increased peak frame sizes is at the expense of detail in other frames. Obviously it would be foolish to sharpen in camera (I assume that would raise the peak frame size too) because that's better done in post anyway. There is a case for letting the camera do noise reduction - which is somewhat contrary to current thinking.

    Chris


     

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    #19
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    Vitaliy,

    You may want to have a look at this thread (starting half way down the page): http://www.dvxuser.com/V6/showthread...213908&page=19


    Someone has managed to get two I frames in a row in AVCHD mode:



    Chris


     

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    #20
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    Note that it really is two I frames in a row, and not a bad display of the stream, there are 11 P frames on either side of the two I frames. The GOP is apparently set to 12.

    Chris


     

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