[MEncoder-users] Minimize posterization in areas of low contrast when downscaling HD h.264 to mpeg2video

[The Wanderer]

On 08/10/2009 08:17 PM, James Hastings-Trew wrote:

> L Lee wrote:
> 
>> Also, I discovered through testing that I can greatly improve
>> output quality for this process by including a vrc_minrate value
>> along side these mpeg2video options: 
>> vcodec=mpeg2video:vrc_buf_size=1835:vbitrate=9000:vrc_maxrate=9800.
>> 
>> That appears to work mainly by driving up output bitrate. I've been
>> setting a vrc_minrate value from 5000 to 5600. But I always get
>> this warning: "Warning min_rate > 0 but min_rate != max_rate isn't
>> recommended!" I have two questions about that. First, does the
>> warning actually mean
>> 
>> "Warning min_rate > 0 but min_rate <= max_rate isn't recommended!"
>> 
>> and if not, what does "!=" mean?
> 
> Generally speaking != means "not equal".  So the warning is saying
> "vrc_minrate and vrc_maxrate should equal each other", which sounds a
> bit whacky. Perhaps someone can explain.

No - it's saying "if vrc_minrate is not zero, then it's not recommended
for vrc_maxrate to not be equal to vrc_minrate". IOW, the only time when
nonzero vrc_minrate is recommended is when doing CBR video, which isn't
very common AFAIR.

Exactly why this isn't recommended, or whether the recommendation is
even correct any longer, I don't know.

-- 
       The Wanderer

Warning: Simply because I argue an issue does not mean I agree with any
side of it.

Secrecy is the beginning of tyranny.