Quantcast KVCD: GOP Numbers Confusion? - digitalFAQ.com Forums [Archives]
  #1  
08-17-2004, 06:46 AM
AdamJ AdamJ is offline
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Can someone please tell me if these are correct or wrong (shown in the order as Tmpgenc).

PAL

1
25
2
1
25

NTSC Film

1
24
2
1
24

NTSC

1
30
2
1
30
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  #2  
08-17-2004, 07:09 AM
Boulder Boulder is offline
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Looks correct to me.
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  #3  
08-17-2004, 07:11 AM
Dialhot Dialhot is offline
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There is no NTSC settings with "30". Use "24" either if you are encoding in 23.976 or 29.970.
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  #4  
08-17-2004, 07:22 AM
Boulder Boulder is offline
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Oh, you're right, forgot about that. In fact, you're better off using 24 as max GOP length in all cases since 25 will produce the same result (24-frame GOPs).
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  #5  
08-17-2004, 07:34 AM
AdamJ AdamJ is offline
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I was confused because of the below info.

Thanks for the replies.


Quote:
Optional Recommendations:

For optimal encoding on natural material ( movies, new computer generated films ), we recommend to match the KVCD "Notch" Quantization Matrix with a maximum GOP size of 24 pictures for NTSCFilm (23.976fps), 25 pictures for PAL (25fps) or 30 pictures for NTSC (29.97fps).
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  #6  
08-18-2004, 02:05 AM
Dialhot Dialhot is offline
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Where did you find this ?
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  #7  
08-19-2004, 06:00 AM
gamma gamma is offline
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You can find this on the kvcd.net site, by "official specifications".
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  #8  
08-19-2004, 06:27 AM
Dialhot Dialhot is offline
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No-one never pointed that

A GOP with 30 pictures is too long. I never noticed that this was indicated in the spec

But perhaps I'm the only one that find this too long ?
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  #9  
08-19-2004, 08:57 AM
jorel jorel is offline
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Quote:
Originally Posted by Dialhot
No-one never pointed that

A GOP with 30 pictures is too long. I never noticed that this was indicated in the spec

But perhaps I'm the only one that find this too long ?
not alone Phil, 30 is too long and give problems.
...a long time in a distant galaxy...
"Posted: Thu Jul 10, 2003 12:21 pm...
My "breathing" problems is caused for GOP 30 cos
if i adjust the Gop to 24 or 18,the sample "pulse" less. ..."
here: http://www.kvcd.net/forum/viewtopic.php?t=4972&start=0
(my 4th post)

and the conclusion....
"Posted: Fri Jul 11, 2003 2:40 am...
results changing the GOP values with same source size:...."
http://www.kvcd.net/forum/viewtopic....r=asc&start=16
(my 5th post here)
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  #10  
08-19-2004, 10:57 AM
Dialhot Dialhot is offline
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Quote:
Originally Posted by jorel
not alone Phil, 30 is too long and give problems.
...a long time in a distant galaxy...
"Posted: Thu Jul 10, 2003 12:21 pm...
My "breathing" problems is caused for GOP 30 cos
if i adjust the Gop to 24 or 18,the sample "pulse" less. ..."
Thank you for your helpfull memory Jorel (as always )
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  #11  
08-19-2004, 12:18 PM
AdamJ AdamJ is offline
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Will stick to 24.

Thanks Phil.
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  #12  
08-19-2004, 12:47 PM
kwag kwag is offline
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A GOP size of 30 works great on 30fps AND action movies.
It you are encoding low action scenes or dramas, then use a GOP size of 24.
If you want to be 100% safe, go for a GOP of 24.
If you want BEST compression at 30fps, use a GOP size of 30

-kwag
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