tail效果

entity/ffmpeg.py

@@ -308,6 +308,19 @@ class FfmpegTask(object):
                         effect_index += 1
                         filter_args.append(f"{video_output_str}trim=start={skip_seconds},setpts=PTS-STARTPTS[v_eff{effect_index}]")
                         video_output_str = f"[v_eff{effect_index}]"
+                elif effect.startswith("tail:"):
+                    param = effect.split(":", 2)[1]
+                    if param == '':
+                        param = "0"
+                    tail_seconds = float(param)
+                    if tail_seconds > 0:
+                        effect_index += 1
+                        # 首先获取视频总时长，然后计算开始时间
+                        # 使用reverse+trim+reverse的方法来精确获取最后N秒
+                        filter_args.append(f"{video_output_str}reverse[v_rev{effect_index}]")
+                        filter_args.append(f"[v_rev{effect_index}]trim=duration={tail_seconds},setpts=PTS-STARTPTS[v_trim{effect_index}]")
+                        filter_args.append(f"[v_trim{effect_index}]reverse[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]")