Python script to convert a LINE sticker pack to Telegram 100x100 px webm emojis (APNG -> GIF -> WEBM)

convert.py

import json
import shutil
import zipfile
import traceback
import ffmpeg
import requests

from typing import List
from pathlib import Path
from apnggif import apnggif
from bs4 import BeautifulSoup
from concurrent.futures import ThreadPoolExecutor
from werkzeug.utils import secure_filename

root = Path(__file__).parent.resolve(strict=True)
output = root / "output"

STORE_URLS = [
    "https://store.line.me/emojishop/product/612c6f89db3e594732668738/en",
    "https://store.line.me/emojishop/product/6303552f83603436e7d17900/en",
    "https://store.line.me/emojishop/product/62a6fb695658444ccadfba61/en",
    "https://store.line.me/emojishop/product/618dd49daf41c21b7b82cb21/en",
]

WORKERS_COUNT = 40
SIZE = (512, 512)
# 512x512: animated sticker
# 100x100: custom emoji

soups = [
    BeautifulSoup(requests.get(url).text, features="lxml")
    for url in STORE_URLS
]

results: List[Path] = []

for soup in soups:
    shutil.rmtree(output, ignore_errors=True)
    output.mkdir(exist_ok=True, parents=True)

    with ThreadPoolExecutor(WORKERS_COUNT) as pool:
        for sticker in soup.find_all("li", {"class": ["FnStickerPreviewItem"]}):
            data = json.loads(sticker.get("data-preview"))
            anim_id = data["id"]

            if data["type"] != "animation":
                print(f"Skipping {anim_id!r}: it's not animated")

            # print(json.dumps(data, indent=4))
            name = f"{anim_id}_animation"

            def worker(apng: Path, gif: Path, webm: Path, animation: str):
                try:
                    with apng.open("wb") as apng_file:
                        r = requests.get(animation)
                        for chunk in r.iter_content(chunk_size=4096):
                            apng_file.write(chunk)

                    apnggif(apng, gif)

                    # info = ffmpeg.probe(gif)
                    stream = ffmpeg.input(str(gif)).filter("scale", SIZE[0], SIZE[1]) # emoji size
                    stream = stream.trim(end=2.95) # max 3 seconds: https://core.telegram.org/stickers#video-requirements
                    stream = stream.setpts("PTS-STARTPTS")
                    stream = ffmpeg.output(stream, str(webm), format="webm", threads=16)
                    # print(stream.compile())
                    ffmpeg.run(stream, overwrite_output=True, quiet=False)

                    apng.unlink(missing_ok=True)
                    gif.unlink(missing_ok=True)
                except Exception:
                    traceback.print_exc()

            pool.submit(
                worker,
                apng=output / f"{name}.apng",
                gif=output / f"{name}.gif",
                webm=output / f"{name}.webm",
                animation=data["animationUrl"],
            )

    pack_name = soup.find("p", {"data-test": "emoji-name-title"})
    zip_path = root / (secure_filename(pack_name.get_text().strip()) + f"_{SIZE[0]}x{SIZE[1]}px.zip")

    with zipfile.ZipFile(zip_path, "w") as zipped:
        for file in output.glob("*.webm"):
            zipped.write(file, arcname=file.relative_to(output))

    results.append(zip_path)

print("Done!")
print("\n".join(map(str, results)))

requirements.txt

beautifulsoup4
ffmpeg-python
requests
werkzeug
apnggif
lxml