7d61c2f8f1
External vectors written by permissively licensed encoders at pinned revisions from synthetic pictures (tools/make_external.sh, provenance.json), generated vectors and negative controls, the facts each encoder was asked for, the LCEVC streams fetch.sh fetches by digest, and format_probe_verify.py, written from the two texts. Co-Authored-By: Claude Opus 5.5 <[email protected]>
42 lines
1.6 KiB
Python
42 lines
1.6 KiB
Python
"""Writes the synthetic pictures the external vectors are encoded from: planar samples of a
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fixed pattern, so the inputs are the same on every machine and hold no captured content.
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python3 -I yuv.py <out> <width> <height> <frames> <layout> <depth> [<shift>]
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<layout> is 420, 422, 444 (planes Y, Cb, Cr) or rgb (planes R, G, B). Samples above 8 bits
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are two bytes, little-endian. <shift> moves the pattern right by that many columns, the
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second view of a stereo pair.
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"""
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import sys
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def main(out, w, h, frames, layout, depth, shift=0):
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w, h, frames, depth, shift = int(w), int(h), int(frames), int(depth), int(shift)
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top = (1 << depth) - 1
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if layout == "rgb":
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planes = [(1, 1)] * 3
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else:
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sub = {"420": (2, 2), "422": (2, 1), "444": (1, 1)}[layout]
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planes = [(1, 1), sub, sub]
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data = bytearray()
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for f in range(frames):
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for p, (sx, sy) in enumerate(planes):
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pw, ph = (w + sx - 1) // sx, (h + sy - 1) // sy
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for y in range(ph):
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for x in range(pw):
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xs = (x * sx - shift) % w
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# a diagonal ramp, a checker and a moving bar, per plane
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v = (xs * 3 + y * sy * 5 + f * 7 + p * 40) * (top // 255 if top > 255 else 1)
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if ((xs // 8) + (y * sy // 8) + p) % 2:
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v += top // 6
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if (xs + f * 4) % w < 6:
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v = top - v % (top // 4 + 1)
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v %= top + 1
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data += bytes([v]) if depth <= 8 else v.to_bytes(2, "little")
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with open(out, "wb") as fh:
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fh.write(data)
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if __name__ == "__main__":
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main(*sys.argv[1:])
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