[Pixiv] Retaining ugoira_meta(.json) and Losslessly Converting Ugoira to Video Format When Downloading Pixiv Ugoira

[tglsf]

Retaining ugoira_meta(.json) When Downloading Pixiv Ugoira

1. Currently, when downloading Pixiv ugoira, the program does not retain ugoira_meta(.json), which contains the duration of each frame. Sometimes, I need this metadata for manual image conversion.

2. When downloading ugoira as a ZIP file, no FPS or frame delay information is included. If exported as GIF or MP4, the program assigns a constant frame rate. However, some ugoira animations do not use a constant frame rate, which is why I perform manual conversion.

Losslessly Converting Ugoira to Video Format

3. The program currently converts ugoira to H.264, but we can instead convert it to MJPEG using stream copy, making the process lossless:

ffmpeg -framerate 30 -i %6d.jpg -c copy out.mkv

4. Using VFR Mode: As mentioned earlier, some ugoira animations do not use a constant frame rate, meaning each frame has a different duration. I usually use the following command to save the video in VFR mode:

ffmpeg -f concat -safe 0 -i inputlist.txt -sws_flags lanczos+bitexact+full_chroma_int+full_chroma_inp+accurate_rnd -fps_mode vfr -c libx264 -preset slower -crf 24 -color_range 2 -pix_fmt yuv420p -movflags +write_colr out.mp4
Content of inputlist.txt:

file 'C:\input\000000.jpg'
duration 0.05
file 'C:\input\000001.jpg'
duration 0.10
...

(Using this method, redundant frames can also be removed with -vf mpdecimate=hi=1:lo=1:frac=1:max=0:keep=0, further reducing storage space.)

[mikf]

You can achieve most, maybe even all, of what you listed with appropriate config and ugoira post processor settings (see https://gdl-org.github.io/docs/configuration.html) and having a mkvmerge binary in PATH. #6147 has some more useful information.

To get "simple" lossless ugoira, even -o ugoira=original --ugoira copy as CLI options would be enough.

{
    "extractor": {
        "pixiv": {
            "ugoira": "original",
            "postprocessors": [
                {
                    "name": "metadata",
                    "event": "post,skip",
                    "filename": "{id}.json"
                },
                {
                    "name": "ugoira",
                    "metadata": true,
                    "keep-files": true,
                    "extension": "mkv",
                    "ffmpeg-args": ["-c", "copy"]
                },
                {
                    "name": "ugoira",
                    "mode": "archive",
                    "metadata": true,
                    "keep-files": false
                }
            ]
        }
    }
}

[Hrxn]

                {
                    "name": "ugoira",
                    "metadata": true,
                    "keep-files": true,
                    "extension": "mkv",
                    "ffmpeg-args": ["-c", "copy"]
                },

What does "metadata": true do here, isn't this only useful for "mode": "archive" ugoira post-processors?

[tglsf]

@mikf

Thank you for your helpful reply.

When using mkvmerge, it seems to use my temp directory. I want it to run in my RAM disk instead of the hard drive to speed up processing and reduce disk writes. Is there an option to change this setting?

[mikf]

@Hrxn
You are correct. "metadata": true doesn't do anything here, but it at least doesn't hurt to have it enabled just in case.

@tglsf
There is no direct option to set the temp directory location, but you should be able to influence it using environment variables: tempfile.gettempdir()

[1223334444abc]

It is still recommended that when using "ugoira": "original", you should be able to obtain the specific interval for each frame and write it into the image file name.

[mikf]

Use an f-string and access {frames[num]['delay']}

$ gallery_dl -f "\fF {id}_p{num}_{frames[num]['delay']}ms.{extension}" -o ugoira=original https://www.pixiv.net/artworks/101003492
./pixiv/14164502 1586611428/101003492_p0_125ms.png
./pixiv/14164502 1586611428/101003492_p1_125ms.png
...

[1223334444abc]

Use an f-string and access {frames[num]['delay']}

$ gallery_dl -f "\fF {id}_p{num}_{frames[num]['delay']}ms.{extension}" -o ugoira=original https://www.pixiv.net/artworks/101003492
./pixiv/14164502 1586611428/101003492_p0_125ms.png
./pixiv/14164502 1586611428/101003492_p1_125ms.png
...

This worked, thank you.