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

[L Lee]

On 8/11/09 9:35 AM, "L Lee" <llee040 at sbcglobal.net> wrote:

> On 8/10/09 10:46 PM, "The Wanderer" <wanderer at fastmail.fm> wrote:
> 
>> On 08/10/2009 08:17 PM, James Hastings-Trew wrote:
>> 
> 
>>> 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.
> 
> If I use the following options and values, I don't get a warning, but the
> bitrate goes well above 7200. Any idea why? Thanks.
> 
> vcodec=mpeg2video:vrc_buf_size=1835:vbitrate=7200:
> vrc_maxrate=7200:vrc_maxrate=7200
>

I now realize at least one reason I didn't get responses to this. I meant
that I set the values the same for each bitrate option, one of which was
vrc_minrate, so the above example should have consisted of these
specifications rather than those that actually appeared:

vcodec=mpeg2video:vrc_buf_size=1835:vbitrate=7200:vrc_minrate=7200:vrc_maxra
te=7200

Laine Lee