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Old 20th January 2009, 02:53   #1  |  Link
jdlk
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Mencoder CLI settings

Many moons ago, when I first decided to investigate video compression, I spent many (happy?) weeks in this forum investigating Divx/Xvid. I have vague memories of losing my mind playing with complex custom matrices and becoming totally confused.

And in the end, I said "to hell with all that" and settled on a very simple set of parameters for a Mencoder batch file, which I've used ever since for the vast majority of my stuff (conversion of UK MPEG2 TV broadcasts), to my complete satisfaction:

Code:
-sws 9 -vf scale=624:352,harddup -ovc xvid -xvidencopts fixed_quant=3 max_bframes=1 packed -oac mp3lame -lameopts vbr=0 br=128
But I've decided that it's about time I looked into AVC (particularly as I have a Popcorn Hour on the way to me). And I'll admit it, this time I'm trying to be slightly lazy. I'm trying to avoid that three weeks of head-scratching.

Which leads to my question. Given my ASP settings above, can anyone suggest a few Mencoder parameters which will give me an x264 starting point with vaguely similar quality to the above settings?

I suppose my key question is how does the x264 crf setting scale against the fixed_quant Xvid setting? Or is that a silly/controversial question (I've been out of the loop for a while)?
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Old 20th January 2009, 03:46   #2  |  Link
LoRd_MuldeR
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Quote:
Originally Posted by jdlk View Post
I suppose my key question is how does the x264 crf setting scale against the fixed_quant Xvid setting? Or is that a silly/controversial question (I've been out of the loop for a while)?
I think that is hard to say, because Xvid doesn't have any mode that works similar to x264's CRF mode. Also the meaning of the CRF values does depend on other settings.

I'd recommend you do some tests and find the highest possible CRF value, which still looks acceptable for you. A reasonable starting point may be around CRF=22.
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Old 20th January 2009, 03:48   #3  |  Link
Dark Shikari
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bframes=3:8x8dct:weightb:subme=7:ref=4:crf=22 is a good start.

Adjust crf accordingly to adjust quality.
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Old 20th January 2009, 05:19   #4  |  Link
jdlk
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Thank you both. That's very useful.
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