high quality ugoira

[aeosynth]

Hi, the default settings for ugoira conversion can give a lot of artifacts. Could there be a simple quality option to make high quality conversions? I don't know enough (anything) about video to come up with the right settings on my own.

[kattjevfel]

PixivUtil2 uses -lossless 1 -vsync 2 -r 999 -pix_fmt yuv420p with libvpx-vp9, which shouldn't have any loss in quality, I haven't tested this myself in gallery-dl yet but I have no reason to believe it wouldn't work here as well.

[wankio]

  "postprocessors": [
                {
                    "name": "ugoira",
                    "extension": "webm",
                   "ffmpeg-location": "C:\\ffmpeg\\bin\\ffmpeg.exe",
"ffmpeg-args":["-c:v", "libvpx-vp9", "-an", "-b:v", "2M"]
                }
]       

you can have your own setting by change ffmpeg commands, i have no problem at all

[mikf]

There is now --ugoira-conv-lossless that uses the VP9 lossless option, which should produce the highest quality possible.

The default settings, which are the same as used by Danbooru by the way, are

"postprocessors": [{
    "name"          : "ugoira",
    "ffmpeg-args"   : ("-c:v", "libvpx", "-crf", "4", "-b:v", "5000k"),
    "ffmpeg-twopass": True,
    "whitelist"     : ("pixiv", "danbooru")
}]

You can put this in your config and increase the target bitrate to something that suits your needs. The crf value is already as low as possible, according to the VP8 encoding guide

If you want to use VP9 instead, try ["-c:v", "libvpx-vp9", "-b:v", "0", "-crf", "30"] for ffmpeg-args and adjust crf down until you get a satisfactory result. From the VP9 encoding guide:

The CRF value can be from 0–63. Lower values mean better quality. Recommended values range from 15–35, with 31 being recommended for 1080p HD video. See ​this guide for more info.