feat(video): 添加源视频时长检测和帧冻结补足功能

- 探测源视频实际时长并计算变速后的有效时长
- 检测源视频时长不足的情况并记录警告日志
- 计算时长短缺并自动冻结最后一帧进行补足
- 更新 FFmpeg 命令构建逻辑以支持时长补足
- 合并转场 overlap 冻结和时长不足冻结的处理
- 添加必要的参数传递以支持时长检测功能

handlers/render_video.py

@@ -135,13 +135,36 @@ class RenderSegmentVideoHandler(BaseHandler):
                     logger.warning(f"[task:{task.task_id}] Failed to download overlay, continuing without it")
                     overlay_file = None
 
-            # 6. 计算 overlap 时长（用于转场帧冻结）
+            # 6. 探测源视频时长（仅对视频素材）
+            # 用于检测时长不足并通过冻结最后一帧补足
+            source_duration_sec = None
+            if not is_image:
+                source_duration = self.probe_duration(input_file)
+                if source_duration:
+                    source_duration_sec = source_duration
+                    speed = float(render_spec.speed) if render_spec.speed else 1.0
+                    if speed > 0:
+                        # 计算变速后的有效时长
+                        effective_duration_sec = source_duration_sec / speed
+                        required_duration_sec = duration_ms / 1000.0
+
+                        # 如果源视频时长不足，记录日志
+                        if effective_duration_sec < required_duration_sec:
+                            shortage_sec = required_duration_sec - effective_duration_sec
+                            logger.warning(
+                                f"[task:{task.task_id}] Source video duration insufficient: "
+                                f"effective={effective_duration_sec:.2f}s (speed={speed}), "
+                                f"required={required_duration_sec:.2f}s, "
+                                f"will freeze last frame for {shortage_sec:.2f}s"
+                            )
+
+            # 7. 计算 overlap 时长（用于转场帧冻结）
             # 头部 overlap: 来自前一片段的出场转场
             overlap_head_ms = task.get_overlap_head_ms()
             # 尾部 overlap: 当前片段的出场转场
             overlap_tail_ms = task.get_overlap_tail_ms_v2()
 
-            # 7. 构建 FFmpeg 命令
+            # 8. 构建 FFmpeg 命令
             output_file = os.path.join(work_dir, 'output.mp4')
             cmd = self._build_command(
                 input_file=input_file,
@@ -152,28 +175,29 @@ class RenderSegmentVideoHandler(BaseHandler):
                 lut_file=lut_file,
                 overlay_file=overlay_file,
                 overlap_head_ms=overlap_head_ms,
-                overlap_tail_ms=overlap_tail_ms
+                overlap_tail_ms=overlap_tail_ms,
+                source_duration_sec=source_duration_sec
             )
 
-            # 8. 执行 FFmpeg
+            # 9. 执行 FFmpeg
             if not self.run_ffmpeg(cmd, task.task_id):
                 return TaskResult.fail(
                     ErrorCode.E_FFMPEG_FAILED,
                     "FFmpeg rendering failed"
                 )
 
-            # 9. 验证输出文件
+            # 10. 验证输出文件
             if not self.ensure_file_exists(output_file, min_size=4096):
                 return TaskResult.fail(
                     ErrorCode.E_FFMPEG_FAILED,
                     "Output file is missing or too small"
                 )
 
-            # 10. 获取实际时长
+            # 11. 获取实际时长
             actual_duration = self.probe_duration(output_file)
             actual_duration_ms = int(actual_duration * 1000) if actual_duration else duration_ms
 
-            # 11. 上传产物
+            # 12. 上传产物
             video_url = self.upload_file(task.task_id, 'video', output_file)
             if not video_url:
                 return TaskResult.fail(
@@ -181,7 +205,7 @@ class RenderSegmentVideoHandler(BaseHandler):
                     "Failed to upload video"
                 )
 
-            # 12. 构建结果（包含 overlap 信息）
+            # 13. 构建结果（包含 overlap 信息）
             result_data = {
                 'videoUrl': video_url,
                 'actualDurationMs': actual_duration_ms,
@@ -310,7 +334,8 @@ class RenderSegmentVideoHandler(BaseHandler):
         lut_file: Optional[str] = None,
         overlay_file: Optional[str] = None,
         overlap_head_ms: int = 0,
-        overlap_tail_ms: int = 0
+        overlap_tail_ms: int = 0,
+        source_duration_sec: Optional[float] = None
     ) -> List[str]:
         """
         构建 FFmpeg 渲染命令
@@ -325,6 +350,7 @@ class RenderSegmentVideoHandler(BaseHandler):
             overlay_file: 叠加层文件路径（可选）
             overlap_head_ms: 头部 overlap 时长（毫秒）
             overlap_tail_ms: 尾部 overlap 时长（毫秒）
+            source_duration_sec: 源视频实际时长（秒），用于检测时长不足
 
         Returns:
             FFmpeg 命令参数列表
@@ -347,10 +373,12 @@ class RenderSegmentVideoHandler(BaseHandler):
         filters = self._build_video_filters(
             render_spec=render_spec,
             output_spec=output_spec,
+            duration_ms=duration_ms,
             lut_file=lut_file,
             overlay_file=overlay_file,
             overlap_head_ms=overlap_head_ms,
-            overlap_tail_ms=overlap_tail_ms
+            overlap_tail_ms=overlap_tail_ms,
+            source_duration_sec=source_duration_sec
         )
 
         # 应用滤镜
@@ -403,10 +431,12 @@ class RenderSegmentVideoHandler(BaseHandler):
         self,
         render_spec: RenderSpec,
         output_spec: OutputSpec,
+        duration_ms: int,
         lut_file: Optional[str] = None,
         overlay_file: Optional[str] = None,
         overlap_head_ms: int = 0,
-        overlap_tail_ms: int = 0
+        overlap_tail_ms: int = 0,
+        source_duration_sec: Optional[float] = None
     ) -> str:
         """
         构建视频滤镜链
@@ -414,10 +444,12 @@ class RenderSegmentVideoHandler(BaseHandler):
         Args:
             render_spec: 渲染规格
             output_spec: 输出规格
+            duration_ms: 目标时长（毫秒）
             lut_file: LUT 文件路径
             overlay_file: 叠加层文件路径（支持图片 png/jpg 和视频 mov）
             overlap_head_ms: 头部 overlap 时长（毫秒）
             overlap_tail_ms: 尾部 overlap 时长（毫秒）
+            source_duration_sec: 源视频实际时长（秒），用于检测时长不足
 
         Returns:
             滤镜字符串
@@ -496,20 +528,39 @@ class RenderSegmentVideoHandler(BaseHandler):
                 is_video_overlay=is_video_overlay,
                 overlap_head_ms=overlap_head_ms,
                 overlap_tail_ms=overlap_tail_ms,
-                use_hwdownload=bool(hwaccel_prefix)
+                use_hwdownload=bool(hwaccel_prefix),
+                duration_ms=duration_ms,
+                render_spec=render_spec,
+                source_duration_sec=source_duration_sec
             )
 
-        # 6. 帧冻结（tpad）- 用于转场 overlap 区域
+        # 6. 帧冻结（tpad）- 用于转场 overlap 区域和时长不足补足
         # 注意：tpad 必须在缩放之后应用
         tpad_parts = []
+
+        # 计算是否需要额外的尾部冻结（源视频时长不足）
+        extra_tail_freeze_sec = 0.0
+        if source_duration_sec is not None:
+            speed = float(render_spec.speed) if render_spec.speed else 1.0
+            if speed > 0:
+                # 计算变速后的有效时长
+                effective_duration_sec = source_duration_sec / speed
+                required_duration_sec = duration_ms / 1000.0
+
+                # 如果源视频时长不足，需要冻结最后一帧来补足
+                if effective_duration_sec < required_duration_sec:
+                    extra_tail_freeze_sec = required_duration_sec - effective_duration_sec
+
         if overlap_head_ms > 0:
             # 头部冻结：将第一帧冻结指定时长
             head_duration_sec = overlap_head_ms / 1000.0
             tpad_parts.append(f"start_mode=clone:start_duration={head_duration_sec}")
-        if overlap_tail_ms > 0:
+
-            # 尾部冻结：将最后一帧冻结指定时长
+        # 尾部冻结：合并 overlap 和时长不足的冻结
-            tail_duration_sec = overlap_tail_ms / 1000.0
+        total_tail_freeze_sec = (overlap_tail_ms / 1000.0) + extra_tail_freeze_sec
-            tpad_parts.append(f"stop_mode=clone:stop_duration={tail_duration_sec}")
+        if total_tail_freeze_sec > 0:
+            # 将最后一帧冻结指定时长
+            tpad_parts.append(f"stop_mode=clone:stop_duration={total_tail_freeze_sec}")
 
         if tpad_parts:
             filters.append(f"tpad={':'.join(tpad_parts)}")
@@ -539,7 +590,10 @@ class RenderSegmentVideoHandler(BaseHandler):
         is_video_overlay: bool = False,
         overlap_head_ms: int = 0,
         overlap_tail_ms: int = 0,
-        use_hwdownload: bool = False
+        use_hwdownload: bool = False,
+        duration_ms: int = 0,
+        render_spec: Optional[RenderSpec] = None,
+        source_duration_sec: Optional[float] = None
     ) -> str:
         """
         构建包含特效的 filter_complex 滤镜图
@@ -557,6 +611,9 @@ class RenderSegmentVideoHandler(BaseHandler):
             overlap_head_ms: 头部 overlap 时长
             overlap_tail_ms: 尾部 overlap 时长
             use_hwdownload: 是否使用了硬件加速解码（已在 base_filters 中包含 hwdownload）
+            duration_ms: 目标时长（毫秒）
+            render_spec: 渲染规格（用于获取变速参数）
+            source_duration_sec: 源视频实际时长（秒），用于检测时长不足
 
         Returns:
             filter_complex 格式的滤镜字符串
@@ -615,14 +672,30 @@ class RenderSegmentVideoHandler(BaseHandler):
                 current_output = effect_output
                 effect_idx += 1
 
-        # 帧冻结（tpad）- 用于转场 overlap 区域
+        # 帧冻结（tpad）- 用于转场 overlap 区域和时长不足补足
         tpad_parts = []
+
+        # 计算是否需要额外的尾部冻结（源视频时长不足）
+        extra_tail_freeze_sec = 0.0
+        if source_duration_sec is not None and render_spec is not None and duration_ms > 0:
+            speed = float(render_spec.speed) if render_spec.speed else 1.0
+            if speed > 0:
+                # 计算变速后的有效时长
+                effective_duration_sec = source_duration_sec / speed
+                required_duration_sec = duration_ms / 1000.0
+
+                # 如果源视频时长不足，需要冻结最后一帧来补足
+                if effective_duration_sec < required_duration_sec:
+                    extra_tail_freeze_sec = required_duration_sec - effective_duration_sec
+
         if overlap_head_ms > 0:
             head_duration_sec = overlap_head_ms / 1000.0
             tpad_parts.append(f"start_mode=clone:start_duration={head_duration_sec}")
-        if overlap_tail_ms > 0:
+
-            tail_duration_sec = overlap_tail_ms / 1000.0
+        # 尾部冻结：合并 overlap 和时长不足的冻结
-            tpad_parts.append(f"stop_mode=clone:stop_duration={tail_duration_sec}")
+        total_tail_freeze_sec = (overlap_tail_ms / 1000.0) + extra_tail_freeze_sec
+        if total_tail_freeze_sec > 0:
+            tpad_parts.append(f"stop_mode=clone:stop_duration={total_tail_freeze_sec}")
 
         if tpad_parts:
             tpad_output = '[v_tpad]'