change_mask.py

import cv2
import numpy as np
import os

# 路径配置
input_path  = "/mnt/prev_nas/qhy/MagicMotion/assets/mask_trajectory/mammoth_rhino.mp4"
output_path = "/mnt/prev_nas/qhy/MagicMotion/assets/mask_trajectory/mammoth_rhino_frozen_pink_bgr_range.mp4"

# 你已经验证通过的两个参考颜色（BGR）
pink_bgr = np.array([77, 80, 119], dtype=np.float32)  # #77504D
red_bgr  = np.array([33, 37, 117], dtype=np.float32)  # #752521

# 阈值（根据你单帧测试结果，目前用 30，如果想收紧可以再调小）
T_pink = 30.0
T_red  = 30.0

def get_color_masks_bgr(frame_bgr):
    """
    输入: frame_bgr: uint8, HxWx3
    输出: pink_mask, red_mask (bool 的 HxW)
    使用 BGR 空间的欧式距离 + 阈值来划分粉色和红色。
    """
    img = frame_bgr.astype(np.float32)
    pixels = img.reshape(-1, 3)

    dist_to_pink = np.linalg.norm(pixels - pink_bgr, axis=1)
    dist_to_red  = np.linalg.norm(pixels - red_bgr,  axis=1)

    h, w = frame_bgr.shape[:2]
    pink_mask = (dist_to_pink < T_pink).reshape(h, w)
    red_mask  = (dist_to_red  < T_red ).reshape(h, w)

    # 冲突点按“谁近归谁”分配
    both = pink_mask & red_mask
    if both.any():
        idx_flat = np.where(both.ravel())[0]
        closer_to_pink = dist_to_pink[idx_flat] <= dist_to_red[idx_flat]

        both_y, both_x = np.where(both)
        for i, (y, x) in enumerate(zip(both_y, both_x)):
            if closer_to_pink[i]:
                red_mask[y, x] = False
            else:
                pink_mask[y, x] = False

    return pink_mask, red_mask

def main():
    cap = cv2.VideoCapture(input_path)
    if not cap.isOpened():
        raise RuntimeError(f"无法打开视频: {input_path}")

    fps = cap.get(cv2.CAP_PROP_FPS)
    width  = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
    height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))

    # 先用 mp4v 写 mp4，如果要 H.264 可以再用 ffmpeg 转
    fourcc = cv2.VideoWriter_fourcc(*"mp4v")
    out = cv2.VideoWriter(output_path, fourcc, fps, (width, height))
    if not out.isOpened():
        cap.release()
        raise RuntimeError("VideoWriter 打开失败")

    # ---------- 第一帧：冻结粉色 ----------
    ret, first_frame = cap.read()
    if not ret:
        cap.release()
        out.release()
        raise RuntimeError("无法读取第一帧")

    pink_mask_first, _ = get_color_masks_bgr(first_frame)

    frozen_pink = np.zeros_like(first_frame)
    frozen_pink[pink_mask_first] = first_frame[pink_mask_first]

    # 回到第一帧，从头处理整段视频
    cap.set(cv2.CAP_PROP_POS_FRAMES, 0)

    frame_idx = 0
    while True:
        ret, frame = cap.read()
        if not ret:
            break

        _, red_mask = get_color_masks_bgr(frame)

        # 当前帧红色部分
        red_part = np.zeros_like(frame)
        red_part[red_mask] = frame[red_mask]

        # 背景黑 + 冻结粉色 + 当前红色
        combined = np.zeros_like(frame)
        combined += frozen_pink
        combined += red_part

        out.write(combined)
        frame_idx += 1
        if frame_idx % 50 == 0:
            print(f"已处理帧数: {frame_idx}")

    cap.release()
    out.release()
    print("处理完成，输出文件:", output_path)

if __name__ == "__main__":
    main()