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Old 7th June 2017, 06:36   #18  |  Link
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Join Date: Sep 2003
Posts: 2,100
Thanks for the B-Frame strategy explanation, I think I understand it now. Well, one thing I still don't understand:
For the second pass b_strategy is not defined. Which means that the default b_strategy = 0 (max number of B_Frames) is used for the second pass. Does b_sensitivity have any effect at all if b_stragey is not = 1?
Adjusts how sensitively vb_strategy=1 detects motion and avoids using B-frames
What I want to say is that for the second pass b_strategy should be set to 1 if using b_sensitivity=10. If b_stragety is not set then b_sensitivity has no effect. Or am I misundestanding something here?

Oops, I totally overlooked this one:
vb_strategy=<0−2> (pass one only)
So if b_strategy cannot be used for the second pass what does b_sensitivity actually do for the second pass?
I hate the FFmpeg documentation...

For the GOP size the FFmpeg default is 12 which I use anyways, no matter if my target is PAL, NTSC or Pulldown. Using a GOP size of 15 or 18 I found that the slightly better compression for larger GOP sizes does not make up for the loss in quality, especially for GOP 18. It would be nice if FFmpeg had an Auto-GOP feature like HCenc...


Last edited by manolito; 7th June 2017 at 06:50.
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