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    #11
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    Quote Originally Posted by siberia88 View Post
    Well I lowered it to 6 and it doesn't seem to be that great. In highly detailed scenes it's choppy even though the bitrate is slightly higher.... unless I did something wrong.
    I am getting 33 to 41mbps, just stayed with gop 7 dont realy know why,very sharp and no banding...did you use the new ptool?...check settings again


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    #12
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    I'm using Ptool v3.56d and i altered the gop in the "Patches for end users" section. Is that how you did it?


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    #13
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    ....am using the ptool 3.61d load the latest ipowell 100mbps 24p patch and just change the gop to 7. its realy stable and picture is excellent


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    #14
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    While you're free to modify patch settings as you see fit, I don't recommend reducing the GOP-length of any of the AVCHD modes. This may appear to work fine at lower bitrates, but as the bitrate approaches the 100Mbps peak, the reliability of the patch may falter, as I found it to be very sensitive to GOP-length.

    The 100Mbps Max Latitude Native 24/25p Patch is optimized for highest reliability in Native 24/25p mode at 100Mbps, and will not necessarily produce a high average bitrate in all circumstances. To insure high quality results, I recommend shooting in sharp focus under well-illuminated circumstances, using a shutter speed of at least 1/50 second PAL or 1/60 second NTSC.


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    #15
    Senior Member Kubrick71's Avatar
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    Quote Originally Posted by lpowell View Post
    The 100Mbps Max Latitude Native 24/25p Patch is optimized for highest reliability in Native 24/25p mode at 100Mbps, and will not necessarily produce a high average bitrate in all circumstances. To insure high quality results, I recommend shooting in sharp focus under well-illuminated circumstances, using a shutter speed of at least 1/50 second PAL or 1/60 second NTSC.
    Does that mean using this patch and shooting 1080/24p at 1/50 isn't recommended? By chance, is there a specific patch which does produce a high average bitrates in all circumstances?


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    #16
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    The 100Mbps Max Latitude Native 24/25p Patch can produce the highest peak bitrate of all the GH1 patches I've published. It is definitely the one I recommend for high-contrast Native 24/25p recording. All AVCHD encoders are designed to minimize their average bitrate for highest compression efficiency. Average bitrates reported by utilities such as MediaInfo are indicative of how tightly the AVCHD file is compressed and do not necessarily correspond to image quality.


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    #17
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    well i used the new ptool and lowered the gop to 7. It's pretty much the same to me maybe slightly better. The video crashes at around the 45-50mbps average as usual but i guess the lower gop crashes more frequently. I suppose it's better on average? i haven't done substantial testing but i'll take your word for it. I'd be interested to see what happens at an even lower gop

    edit: too many glitches in more demanding compositions. Not necessarily a frequent thing but it doesn't really seem worth it at least for me. The disparity of quality doesn't seem great enough to risk reliability. Though I wonder if getting a better card might help.
    Last edited by liscos909; 07-25-2011 at 07:54 PM.


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    #18
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    There are different ways to determine bitrate. Some programs show the reported bitrate - which may or may not reflect the true bitrate. StreamParser ignores all that and calculates the bitrate based on datarate over time.

    Chris


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    #19
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    I lowered the GOP to 3 and while the bitrate jumps the actual quality is virtually indistinguishable. How much does it really affect the image? I wonder if altering the GOP actually does anything for the quality of the image.


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