FFmpeg png to dnxhd mov error

Hi there

I'm trying to make a create a dnxhd mov with ffmpeg but can't seem to get the codec working.

I've created a 1920x1080 .png to convert into .mov format

My command is as follows:

C:\Users\jared.glass>C:\Users\jared.glass\Desktop\mov_test\ffmpeg.exe -i C:\User
s\jared.glass\Desktop\mov_test\Untitled_1.png -vcodec dnxhd -b:v 120m -an -y C:\
Users\jared.glass\Desktop\mov_test\dnx_hd_test.mov

and the error message:

Input #0, image2, from 'C:\Users\jared.glass\Desktop\mov_test\Untitled_1.png':
Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
Stream #0:0: Video: png, rgb24, 1920x1080, 25 tbr, 25 tbn, 25 tbc
Incompatible pixel format 'rgb24' for codec 'dnxhd', auto-selecting format 'yuv4
22p10le'
[buffer @ 000000000035D630] w:1920 h:1080 pixfmt:rgb24 tb:1/1000000 sar:0/1 sws_
param:flags=2
[buffersink @ 000000000035D870] auto-inserting filter 'auto-inserted scale 0' be
tween the filter 'src' and the filter 'out'
[scale @ 000000000035DB00] w:1920 h:1080 fmt:rgb24 sar:0/1 -> w:1920 h:1080 fmt:
yuv422p10le sar:0/1 flags:0x4
<u>[dnxhd @ 00000000003645B0] video parameters incompatible with DNxHD</u>
Output #0, mov, to 'C:\Users\jared.glass\Desktop\mov_test\dnx_hd_test.mov':
Stream #0:0: Video: dnxhd, yuv422p10le, 1920x1080, q=2-1024, 90k tbn, 25 tbc

Stream mapping:
Stream #0:0 -> #0:0 (png -> dnxhd)
<u>Error while opening encoder for output stream #0:0 - maybe incorrect parameters
such as bit_rate, rate, width or height</u>


Any ideas pls?