[FFmpeg-user] denoise after scaling or before?

[Paul B Mahol]

On 4/23/19, Michael Koch <astroelectronic at t-online.de> wrote:
> Am 23.04.2019 um 11:43 schrieb Jon bae:
>> Hello,
>> I just have an general question:
>>
>> As I know denoiser are specialized to specific noise pattern.
>>
>> Makes it a different when I denoise after scaling a video, or is the
>> quality better when I denoise before scaling.
>>
>> In terms of speed it would be better for me, denoising after scaling, but
>> when the quality is better, then I would go that way.
>
> You could try both versions simultaneously and compare them with hstack:
>
> ffmpeg -i in.mov -i in.mov -filter_complex
> "[0]scale=640:400,atadenoise[a];[1]atadenoise,scale=640:400[b];[a][b]hstack"
> out.mov
>
> There are at least six different denoisers available: atadenoise, bm3d,
> dctdnoiz, fftdenoiz, owdenoise and vaguedenoiser

You missed nlmeans.