Help with options while switching from x264 to x265

[sienipulla]

Hello!

I've been recording some of my NES game playthroughs using an emulator called FCEUX. I found a nice tutorial for capturing and converting them here:
http://tasvideos.org/EncodingGuide/VideoDumping.html#FceuFceux

The settings are as follows:

fceux --subtitles 0 --slstart 0 --slend 239 --xscale 1 --yscale 1 --special 0
--pal 0 --sound 1 --soundq 1 --soundrate 48000 --volume 150 --trianglevol 256
--square1vol 256 --square2vol 256 --noisevol 256 --pcmvol 256 --mute 1
--nospritelim 1 --no-config 1 --videolog "ffmpeg -f s16le -ar 48000 -channels 1
-i /path/to/soundpipe/s.log -f rawvideo -r 60.0998 -s 256x224 -pix_fmt bgr24
-i - -c:a pcm_s16le -c:v libx264rgb -qp 0 -pix_fmt rgb24 output.mkv"
--playmov movie.fm2 rom.nes

In which the relevant part is:

ffmpeg -f s16le -ar 48000 -channels 1 -i /path/to/soundpipe/s.log -f rawvideo
-r 60.0998 -s 256x224 -pix_fmt bgr24 -i - -c:a pcm_s16le -c:v libx264rgb -qp 0
-pix_fmt rgb24 output.mkv

And of course as many have switched to begin using x265, I decided that I would too. So I tried to convert those options for the libx265 codec:

ffmpeg -f s16le -ar 48000 -channels 1 -i /path/to/soundpipe/s.log -f rawvideo
-r 60.0998 -s 256x224 -pix_fmt bgr24 -i - -c:a pcm_s16le -c:v libx265rgb -qp 0
-pix_fmt rgb24 output.mkv

So the first error was:

Unknown encoder 'libx265rgb'".

So I simply changed it to "libx265".

The next error was:

Incompatible pixel format 'rgb24' for codec 'libx265', auto-selecting format 'gbrp'".

I have no idea how to fix this. Even after some serious google-fu.

The next error was:

[rawvideo @ 0x257a440] Invalid buffer size, packet size 65536 < expected frame_size 172032
Error while decoding stream #1:0: Invalid argument

I have no idea about this either. What does this mean?

The final question is about quality. Previously with x264 I used the option "qp 0", but now I'm beginning to think it is way overkill for my purpose. So I'm thinking along these lines:

ffmpeg -f s16le -ar 48000 -channels 1 -i /path/to/soundpipe/s.log -f rawvideo
-r 60.0998 -s 256x224 -pix_fmt bgr24 -i - -c:a pcm_s16le -c:v libx265 -crf 14
-preset veryslow -pix_fmt rgb24 output.mkv

The preset veryslow is fine for me, since I don't care about speed. But what would you suggest for the CRF value for an emulation content such as this? For audio I'm recoding the mono wav using neroAacEncoder -q 4, since that is a good middle ground in my opinion.

Thanks in advance!

[Selur]

Incompatible pixel format 'rgb24' for codec 'libx265', auto-selecting format 'gbrp'".

I have no idea how to fix this.

Doesn't seem like an error, but more a warning/notice.
Calling:

ffmpeg -h encoder=libx265

should give you something like:

Encoder libx265 [libx265 H.265 / HEVC]:
    General capabilities: dr1 delay threads
    Threading capabilities: other
    Supported pixel formats: yuv420p yuvj420p yuv422p yuvj422p yuv444p yuvj444p gbrp yuv420p10le yuv422p10le yuv444p10le gbrp10le yuv420p12le yuv422p12le yuv444p12le gbrp12le gray gray10le gray12le
libx265 AVOptions:
  -crf               <float>      E..V....... set the x265 crf (from -1 to FLT_MAX) (default -1)
  -qp                <int>        E..V....... set the x265 qp (from -1 to INT_MAX) (default -1)
  -forced-idr        <boolean>    E..V....... if forcing keyframes, force them as IDR frames (default false)
  -preset            <string>     E..V....... set the x265 preset
  -tune              <string>     E..V....... set the x265 tune parameter
  -profile           <string>     E..V....... set the x265 profile
  -x265-params       <dictionary> E..V....... set the x265 configuration using a :-separated list of key=value parameters

(notice the 'Supported pixel formats')
-> so if you want to get rid of the warning, use '-pix_fmt gbrp' at the end not '-pix_fmt rgb24'.

[rawvideo @ 0x257a440] Invalid buffer size, packet size 65536 < expected frame_size 172032
Error while decoding stream #1:0: Invalid argument

I have no idea about this either. What does this mean?

Usually hapen is input format and pix_format doesn't match. Since it's a problem with the decoding of the input stream I'm wondering why this would work when using x264,..

But what would you suggest for the CRF value for an emulation content such as this?

No clue, that is a question only your eyes can tell you.

[sienipulla]

Ok, thank you very much for your reply. This clears things. And I think you are spot on about the quality issue, I will just have to do comparisons