# -*- coding: utf-8 -*-
"""按 aigc-idea-impression 抽帧 SOP 提取视频关键帧（双因素 + 首尾 + 5s 长间隔补帧）。
规避原 SOP bash 版的 bc 依赖与 Windows CRLF 坑：全部用 Python 调度 ffmpeg/ffprobe。
用法：
  python extract_frames.py --dir <视频目录(自动找首个.mp4)> --out <帧输出目录> --ff <ffmpeg bin 目录>
"""
import argparse, glob, os, re, subprocess, sys


def run(cmd):
    return subprocess.run(cmd, capture_output=True, text=True, encoding="utf-8", errors="replace")


def probe(video, ffprobe):
    r = run([ffprobe, "-v", "error", "-select_streams", "v:0",
             "-show_entries", "stream=width,height", "-show_entries", "format=duration",
             "-of", "default=nk=1:nw=1", video])
    vals = [x.strip() for x in r.stdout.split("\n") if x.strip()]
    w = int(vals[0]); h = int(vals[1]); dur = float(vals[2])
    return w, h, dur


def scene_times(video, vf, ffmpeg):
    """对给定 -vf 跑一次 scene 检测，解析所有 pts_time。"""
    r = run([ffmpeg, "-i", video, "-vf", vf + ",showinfo", "-vsync", "vfr", "-f", "null", "-"])
    out = set()
    for line in r.stderr.splitlines():
        m = re.search(r"pts_time:([0-9.]+)", line)
        if m:
            out.add(round(float(m.group(1)), 4))
    return sorted(out)


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--dir", required=True, help="含 .mp4 的目录")
    ap.add_argument("--out", required=True, help="帧输出目录")
    ap.add_argument("--ff", default=r"D:\ComfyUI_windows\ffmpeg-8.0.1-full_build\bin",
                   help="ffmpeg/ffprobe 所在 bin 目录")
    args = ap.parse_args()

    ffmpeg = os.path.join(args.ff, "ffmpeg.exe")
    ffprobe = os.path.join(args.ff, "ffprobe.exe")
    vids = sorted(glob.glob(os.path.join(args.dir, "*.mp4")))
    if not vids:
        print("✗ 目录里没有 .mp4：%s" % args.dir); sys.exit(1)
    video = vids[0]
    print("视频：%s" % video)

    w, h, dur = probe(video, ffprobe)
    print("分辨率=%dx%d  时长=%.2fs" % (w, h, dur))

    # 字幕区 = 底部 15%（横屏 B 站常用；竖屏改 1/4 即可）
    sh = max(1, int(h * 0.15)); sy = h - sh
    crop_vf = "crop=%d:%d:0:%d" % (w, sh, sy)

    t_a = scene_times(video, "select='gt(scene,0.3)'", ffmpeg)            # ① 画面变化
    t_b = scene_times(video, "%s,select='gt(scene,0.1)'" % crop_vf, ffmpeg)  # ② 字幕变化
    t_c = scene_times(video, "select='gt(scene,0.05)'", ffmpeg)          # ③ 低阈值补漏
    print("scene 0.3=%d  字幕区 0.1=%d  0.05=%d" % (len(t_a), len(t_b), len(t_c)))

    times = sorted(set(t_a) | set(t_b) | set(t_c))
    times.append(0.0)                       # 首帧
    times.append(max(0.0, round(dur - 0.3, 3)))  # 尾帧
    times = sorted(set(times))

    # ④ 长间隔强制补帧（>5s 补中点）
    filled = []
    for i, t in enumerate(times):
        filled.append(t)
        if i > 0:
            gap = t - times[i - 1]
            if gap > 5:
                filled.append(round((t + times[i - 1]) / 2, 3))
    times = sorted(set(filled))
    print("最终帧数（含首尾+补帧）：%d" % len(times))

    os.makedirs(args.out, exist_ok=True)
    for i, t in enumerate(times, 1):
        tt = t
        if t > dur:
            tt = max(0.0, dur - 0.3)
        outp = os.path.join(args.out, "c_%04d_%.3fs.jpg" % (i, t))
        r = run([ffmpeg, "-y", "-ss", "%.3f" % tt, "-i", video,
                 "-frames:v", "1", "-q:v", "2", outp])
        if r.returncode != 0:
            print("  ✗ 帧 %d 失败：%s" % (i, r.stderr[-200:]))
    print("✓ 抽帧完成 → %s" % args.out)


if __name__ == "__main__":
    main()