Ad 1:
Try adding the -pix_fmt yuv420p10le
option (e.g. before -vf)
. Or only -pix_fmt +
for using the same pixel format as the input video has..
If it doesn't help, you obviously have an inappropriate, albeit more common FFmpeg version — only for 8-bit colors. (Your original video uses 10-bit colors, and FFmpeg will try use the best 8-bit pixel format in this case -— with the colors' degradation, of course.)
FFmpeg may be built for 8-bit colors or for 10-bit colors, or — in recent time — for both of them (for your HEVC encoded video).
So you need to build (or obtain by other way) version for 8-/10- or 10-bit color depth.
Ad 2:
Bitrate of 1700
is very low -— only 1700 bits per second, i. e. about 212 bytes per second.
To reach such a low bitrate and at the same time reach your 23.98
frames per second, the encoder is limited with average size for 1 frame about 212 / 24 = 9 bytes only!
Did you see a picture of such small memory? It has almost no information, so the gray image.
You probably wanted 1700k (Kilobits per second) — or, more probably — 170k:
-b:v 170k
so correct your command in this way.
Addendum to Ad 1:
You use the (default) 4:2:0 chroma subsampling (with inevitable color and contrast degradation). Try
Try the maximum quality, i.e. 4:4:4 (no subsampling), or - maybe— if it will be sufficient for you -— 4:2:2.
To reach this, use -pix_fmt yuv444p10le
and change the video profile to main444-10 (with option -profile:v main444-10
).