Complete VIDEO-001 through VIDEO-004 software video studies

tests/test_video004_keyframe.py

@@ -0,0 +1,25 @@
+"""Усиление опорного кадра проверяется двумя потерями в одном блоке."""
+
+from __future__ import annotations
+
+import json
+
+from tools.video004_transport import (
+    BASELINE_160, BASELINE_320, CODEC_RESULTS, _frames, simulate,
+)
+
+
+def test_double_keyframe_loss_needs_two_parity_symbols() -> None:
+    codec = json.loads(CODEC_RESULTS.read_text(encoding="utf-8"))
+    baseline = json.loads(BASELINE_320.read_text(encoding="utf-8"))
+    baseline_160 = json.loads(BASELINE_160.read_text(encoding="utf-8"))
+    combined, _ = _frames("NORMAL", 640, 360, 10, baseline["windows"][0],
+                          codec, baseline_160)
+    frames = [frame for frame in combined if frame.stream_id == 0x56303334]
+    base = simulate(frames, 10, "2/3", 8, 1, ("keyframe_double", 2))
+    boosted = simulate(frames, 10, "2/3", 8, 1, ("keyframe_double", 2),
+                       keyframe_boost=True)
+    assert base["displayed_frames"] == 55
+    assert base["unrecoverable_blocks"] == 1
+    assert boosted["displayed_frames"] == 60
+    assert boosted["parity_recoveries"] == 2