39 lines
1.6 KiB
Python
39 lines
1.6 KiB
Python
"""Size and a still frame of a clip, read straight from Zipline with ffprobe/ffmpeg, for Discord's link preview."""
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import json
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import subprocess
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import threading
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from functools import lru_cache
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# /v/ and /_site/thumb need no login: cap how many ffmpeg/ffprobe processes they can start at once
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SLOTS = threading.BoundedSemaphore(2)
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@lru_cache(maxsize=256)
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def video_size(url: str, length: str) -> tuple[int, int] | None:
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"""(width, height) of the first video stream; `length` is only part of the cache key (a reused name)."""
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cmd = ["ffprobe", "-v", "error", "-select_streams", "v:0",
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"-show_entries", "stream=width,height", "-of", "json", url]
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try:
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with SLOTS:
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result = subprocess.run(cmd, capture_output=True, timeout=10)
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stream = json.loads(result.stdout)["streams"][0]
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return int(stream["width"]), int(stream["height"])
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except (OSError, subprocess.TimeoutExpired, ValueError, KeyError, IndexError):
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return None
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@lru_cache(maxsize=64)
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def still_jpeg(url: str, length: str) -> bytes | None:
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"""One frame (1 s in, or the first one for very short clips) as a JPEG at most 720 px tall."""
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for seek in ("1", "0"):
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cmd = ["ffmpeg", "-v", "error", "-ss", seek, "-i", url, "-frames:v", "1",
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"-vf", "scale=-2:'min(720,ih)'", "-f", "image2", "-c:v", "mjpeg", "pipe:1"]
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try:
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with SLOTS:
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result = subprocess.run(cmd, capture_output=True, timeout=30)
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except (OSError, subprocess.TimeoutExpired):
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return None
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if result.returncode == 0 and result.stdout:
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return result.stdout
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return None
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