ai-agent-book 精选快照（<2MB 代码与文档，来自 github.com/bojieli/ai-agent-book）

chapter5/video-edit/validation/preflight-reference.py

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+"""
+本文件由 blender_editor.generate_bpy_script() 自动生成（实验 5-6）。
+执行：blender --background --python edit.py
+它把一条剪辑计划翻译成 Blender 视频序列编辑器（VSE）的 API 调用序列。
+"""
+import os
+import bpy
+
+SRC = '/Users/boj/book/ai-agent-book/chapter5/video-edit/validation/source_cache/big-buck-bunny-trailer-480p.mov'
+OUT = '/Users/boj/book/ai-agent-book/chapter5/video-edit/validation/preflight-reference.mp4'
+FPS = 25
+START = 9.0       # 目标片段起点（秒）
+END = 11.0           # 目标片段终点（秒）
+SUBTITLE = 'BIG BUNNY' # None 或字幕文本
+SLOWMO = 1.5     # None 或放慢倍率（factor>1 表示放慢 factor 倍）
+
+scene = bpy.context.scene
+scene.render.fps = FPS
+scene.render.fps_base = 1.0
+scene.render.resolution_x = 854
+scene.render.resolution_y = 480
+scene.render.resolution_percentage = 100
+
+# 清掉可能存在的旧序列，保证幂等
+if scene.sequence_editor:
+    bpy.ops.sequencer.select_all(action='SELECT')
+    bpy.ops.sequencer.delete()
+se = scene.sequence_editor_create()
+
+start_frame = int(round(START * FPS))
+dur_frames = max(1, int(round((END - START) * FPS)))
+
+# 1) 导入影片 + 音轨（new_sound 在无音轨素材上会抛 RuntimeError，忽略即可）
+movie = se.sequences.new_movie(name="clip", filepath=SRC, channel=1, frame_start=1 - start_frame)
+try:
+    sound = se.sequences.new_sound(name="audio", filepath=SRC, channel=2, frame_start=1 - start_frame)
+except RuntimeError:
+    sound = None
+
+# 2) 裁剪 [START, END]：偏移掉片头，再固定成片时长
+for strip in (movie, sound):
+    if strip is None:
+        continue
+    strip.frame_offset_start = start_frame
+    strip.frame_final_duration = dur_frames
+
+top_channel = 3
+
+# 3) 慢动作：SPEED 特效条（MULTIPLY 模式，speed_factor = 1/倍率）
+if SLOWMO:
+    speed = se.sequences.new_effect(
+        name="slowmo", type='SPEED', channel=top_channel,
+        frame_start=1, frame_end=1 + dur_frames, seq1=movie,
+    )
+    speed.use_default_fade = False
+    speed.speed_control = 'MULTIPLY'
+    speed.speed_factor = 1.0 / SLOWMO
+    top_channel += 1
+    # 放慢后成片总帧数按倍率拉长
+    render_dur = int(round(dur_frames * SLOWMO))
+    movie.frame_final_duration = render_dur
+else:
+    render_dur = dur_frames
+
+# 4) 字幕：TEXT 特效条，底部居中带半透明底框
+if SUBTITLE:
+    txt = se.sequences.new_effect(
+        name="subtitle", type='TEXT', channel=top_channel,
+        frame_start=1, frame_end=1 + render_dur,
+    )
+    txt.text = SUBTITLE
+    txt.font_size = 100
+    txt.location = (0.5, 0.12)
+    txt.align_x = 'CENTER'
+    txt.align_y = 'BOTTOM'
+    txt.use_box = True
+    txt.box_color = (0.0, 0.0, 0.0, 0.6)
+
+# 5) 渲染范围 + 输出为 mp4(H.264+AAC)
+scene.frame_start = 1
+scene.frame_end = render_dur
+
+r = scene.render
+r.image_settings.file_format = 'FFMPEG'
+r.ffmpeg.format = 'MPEG4'
+r.ffmpeg.codec = 'H264'
+r.ffmpeg.audio_codec = 'AAC'
+r.filepath = OUT
+os.makedirs(os.path.dirname(OUT) or ".", exist_ok=True)
+
+bpy.ops.render.render(animation=True)
+print("BLENDER_RENDER_DONE", OUT)