feat(entity/ffmpeg.py): 添加grid4效果支持在ffmpeg.py中增加了对grid4效果的支持。该功能允许用户通过指定参数来创建一个四宫格视频布局，每个格子显示不同的视频片段，并且可以设置延迟时间以实现更丰富的视觉效果。具体改动包括：

- 解析`grid4`效果的参数，如果未提供则默认为1。
- 根据提供的或默认的分辨率分割视频流为四个部分。
-为每个分割后的视频流应用缩放和时间延迟处理。
- 创建黑色背景并使用overlay滤镜将处理后的视频流放置于正确的位置上，形成最终的四宫格布局。

entity/ffmpeg.py

@@ -353,6 +353,42 @@ class FfmpegTask(object):
                         effect_index += 1
                         filter_args.append(f"{video_output_str}trim=end={show_seconds}[v_eff{effect_index}]")
                         video_output_str = f"[v_eff{effect_index}]"
+                elif effect.startswith("grid4:"):
+                    param = effect.split(":", 2)[1]
+                    if param == '':
+                        param = "1"
+                    delay_seconds = float(param)
+                    effect_index += 1
+
+                    # 获取分辨率，如果没有设置则使用默认值
+                    if self.resolution:
+                        width, height = self.resolution.split('x')
+                    else:
+                        width, height = "1920", "1080"  # 默认分辨率
+
+                    # 计算四宫格中每个象限的大小
+                    grid_width = int(width) // 2
+                    grid_height = int(height) // 2
+
+                    # 分割视频流为4份
+                    filter_args.append(f"{video_output_str}split=4[grid_v1_{effect_index}][grid_v2_{effect_index}][grid_v3_{effect_index}][grid_v4_{effect_index}]")
+
+                    # 创建黑色背景
+                    filter_args.append(f"color=black:size={width}x{height}:duration=1[bg_{effect_index}]")
+
+                    # 缩放每个视频流到绝对尺寸
+                    filter_args.append(f"[grid_v1_{effect_index}]scale={grid_width}:{grid_height}[v1_scaled_{effect_index}]")
+                    filter_args.append(f"[grid_v2_{effect_index}]scale={grid_width}:{grid_height},tpad=start_duration={delay_seconds}[v2_scaled_{effect_index}]")
+                    filter_args.append(f"[grid_v3_{effect_index}]scale={grid_width}:{grid_height},tpad=start_duration={delay_seconds*2}[v3_scaled_{effect_index}]")
+                    filter_args.append(f"[grid_v4_{effect_index}]scale={grid_width}:{grid_height},tpad=start_duration={delay_seconds*3}[v4_scaled_{effect_index}]")
+
+                    # 使用overlay将四个视频流叠加到四个位置
+                    filter_args.append(f"[bg_{effect_index}][v1_scaled_{effect_index}]overlay=0:0:shortest=1[grid_step1_{effect_index}]")
+                    filter_args.append(f"[grid_step1_{effect_index}][v2_scaled_{effect_index}]overlay=w/2:0:shortest=1[grid_step2_{effect_index}]")
+                    filter_args.append(f"[grid_step2_{effect_index}][v3_scaled_{effect_index}]overlay=0:h/2:shortest=1[grid_step3_{effect_index}]")
+                    filter_args.append(f"[grid_step3_{effect_index}][v4_scaled_{effect_index}]overlay=w/2:h/2:shortest=1[v_eff{effect_index}]")
+
+                    video_output_str = f"[v_eff{effect_index}]"
                 ...
             if self.resolution:
                 filter_args.append(f"{video_output_str}scale={self.resolution.replace('x', ':')}[v]")