Support Custom FFmpeg Encoding Parameters in iw3 CLI （e.g specific using libx265)

[TheRainstorm]

Thanks for this great project! I noticed that iw3 defaults to H.264 encoding, which results in very high bitrates for 4K Full SBS videos. This causes stuttering and pixelation when playing back on my VR headset (Pico 4). Manually converting to H.265 (CRF 20) using ffmpeg fixes the issue, but it's an extra step.

Is it possible for iw3 CLI to generate h265 video directly? It may also help decreasing the video size.

[nagadomi]

Added support for libx265 f5ded90

For iw3.cli, you can use --video-codec libx265 option to output in h265/hevc.
I have not tested enough, so let me know if there are any problems.

Edit:
Sorry, I fixed the option example from ---video-codec libx265 to --video-codec libx265 (wrong number of hyphens).

[nagadomi]

Also, iw3 defaults to preset=ultrafast, you can reduce the file size by specifying --preset medium option.

[TheRainstorm]

For iw3.cli, you can use --video-codec libx265 option to output in h265/hvec.

Thanks for replying, I tried and it worked, thank you.

[diverswan9]

Using GUI...

[TheRainstorm]

you can reduce the file size by specifying --preset medium option

The file size does decrease. Here’s the data (Original video is at 3840x2160@60, duration is 00:01:00, and the generated full SBS video is at 7680x2160@60):

• Default h264: 933 MB
• h264 with preset "medium": 449 MB (artifacts reduced but still present)
• h265 with preset "medium": 275 MB (no artifacts when playback)

[nagadomi]

@diverswan9
Does that error always occur with other videos or any options?
I guess some incompatible option is being used, but I have no idea which one.

[diverswan9]

@diverswan9 Does that error always occur with other videos or any options? I guess some incompatible option is being used, but I have no idea which one.

I'll check... ahh! I had 'level' set at 4.1 for x264. Put it on 'auto' and worked fine... thanks!

[nagadomi]

@diverswan9
It seems that libx265 causes the error if the size of the video is out of level spec. It is more strict than libx264.

x265 [error]: picture dimensions are out of range for specified level

[nagadomi]

I added notes to the README about H.265 level problem and the large file size problem.

https://github.com/nagadomi/nunif/tree/master/iw3#video-codec
https://github.com/nagadomi/nunif/tree/master/iw3#large-video-file-size