[FFmpeg-user] how to re-add original audio delay back into a 2-inputfile ffmpeg transcode

[hydra3333 at gmail.com]

> On Behalf Of Carl Eugen Hoyos
> Sent: Friday, July 31, 2020 8:27 AM
>> I have a .mpg with interlaced mpeg2 and ac3 audio, which needs 
>> converting to progressive .mp4 avc/aac.
>>
>> The interlaced video is a bit grainy etc so I hope to deinterlace and 
>> clean it up using vapoursynth CUDA filters
>
> I am curious:
> What are the advantages of these filters over the de-interlacers provided by FFmpeg?
>
> Carl Eugen

Primarily speed and simplicity and the availability of a wide range of filters in vapoursynth including some gpu accelerated filters.

The deinterlacer is Nvidia's which here is combined with a file pre-parser (DGIndexNV) which also checks and caters for issues.

Combined with CUDA filters into the same .vpy (for simplicity), the CUDA filter speeds are extreme (hundreds of fps) as compared to other noise/sharpening filtering approaches according to a couple of dumb comparison tests I ran eg yadif/nlmeans.