[MEncoder-users] hqdn3d=2:1:2 & -ovc x264

[Grozdan]

On Thu, Jul 1, 2010 at 10:32 AM, Bernd Butscheidt <bbutscheidt at yahoo.de> wrote:
> On Tue, Jun 29, 2010 at 10:00 PM, Goga777 <goga777 at bk.ru> wrote:
>>> > I read somewhere that there is not any sense to use -vf hqdn3d=2:1:2 with -ovc x264 because it's
>>> > useless
>>>
>
>>>denoisers and encoders are not mutually exclusive so whomever wrote
>>>what you read is, to say it politely, silly :)
>
>>>If you have a very noisy picture and you want to clean it up, of
>>>course you'll use a denoiser. This will also make the content better
>>>compressible as a clean picture is easier to compress than a noisy
>>>one, which means with (too much) noise in the picture, the encoder
>>>will try to preserve it so it'll spend more bits for that. The
>>>downside of denoising is that no denoiser is perfect and at times will
>>>mistake areas that are *not* noise for noise so it'll throw them out,
>>>thus reducing a bit of detail. How much and how often a denoiser will
>>>do that depends on how it works. There are much better denoisers
>>>around than hqdn3d, but unfortunately mplayer doesn't have a better
>>>one so hqdn3d is considered its "best" denoiser
>
> I even use hqdn3d together with x264 as default at the moment. The picture looks cleaner overall and the onepass encoding is up to five frames per second faster. I cannot not say so far that any loss of detail was visible at the end, but sure, if you like a very crisp picture you would choose noise instead of denoising anyway I guess.

Denoisers *always* throw away detail as there's no perfect denoise
algorithm that can say what is noise and what is not, thus leaving it
alone. Even the best denoisers around throw away detail and mistake it
to be noise. The question is how often they do that and how much they
throw away. However, it is not like they'll throw away so much that
it'll become blatantly obvious each time you see the content. It's
usually a (very) minimal amount that gets thrown away

>
> The manpage suggests another noise reduction within the x264-options:
>
> nr=<0-100000>
> Noise reduction, 0 means disabled. 100-1000 is a useful range for typical content, but you may want to turn it up a bit more for very noisy content (default: 0). Given its small impact on speed, you might want to prefer to use this over filtering noise away with video filters like denoise3d or hqdn3d.
>
> Does someone has experiences with this as an alternative for hqdn3d regarding quality?

It's an average denoiser as there are much better ones. It's
comparable to hqdn3d but can be faster and also worse than it. I stick
with hqnd3d as I'm used to it and it delivers good enough results for
me

>
>
>
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