[MEncoder-users] DVD->mkv. 2pass or CQ?

[belcampo]

Andrew Berg wrote:
> C.M. Burns wrote:
>> Later I read that encoding using "constant quality" is usually better if
>> filesize does not matter...
>> Do you have any suggestions?
> As far as efficiency (the number of bits needed for a given quality)
> goes, 2-pass and CRF are the same. For the same number of bits, you will
> get the same quality.
> If you need a specific size or average bitrate and are willing to take
> whatever quality it gives you, 2-pass is the way to go. If you want a
> specific quality and are willing to take whatever size/bitrate it gives
> you, CRF is the better choice. You mentioned that you are going for as
> little quality loss as possible; CRF is better for that (you'd have to
> /guess/ a good bitrate if you used 2-pass). A good CRF value for DVDs is
> between 18 and 20 (the lower the value, the higher the quality and
> bitrate). You'll have to experiment a bit to find the right value for
> yourself, since it depends on your settings and what you consider
> acceptable quality. CRF does not need to be adjusted for different types
> of content since it will automatically increase or decrease the bitrate
> as needed. It does need to be adjusted for different encoder settings
> and especially for different resolutions.
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CRF default value is 22 AFAIK, a value of 26 is for most people not 
noticeable as 'lesser quality'.
Quality on size is as follows

-rw-r--r-- 1 mythtv users 4999084 2009-10-08 13:45 qmax22.h264
-rw-r--r-- 1 mythtv users 4172889 2009-10-08 13:43 qmax23.h264
-rw-r--r-- 1 mythtv users 3830912 2009-10-08 13:42 qmax24.h264
-rw-r--r-- 1 mythtv users 3507513 2009-10-08 13:41 qmax25.h264
-rw-r--r-- 1 mythtv users 2958534 2009-10-08 13:41 qmax26.h264
-rw-r--r-- 1 mythtv users 2555711 2009-10-08 13:40 qmax27.h264
-rw-r--r-- 1 mythtv users 2217555 2009-10-08 13:39 qmax28.h264
-rw-r--r-- 1 mythtv users 1889831 2009-10-08 13:38 qmax29.h264
-rw-r--r-- 1 mythtv users 1618039 2009-10-08 13:49 qmax30.h264
-rw-r--r-- 1 mythtv users 1420451 2009-10-08 13:48 qmax31.h264
-rw-r--r-- 1 mythtv users 1193767 2009-10-08 13:47 qmax32.h264