feat(video): 添加按时间间隔的帧提取模式并重构配置读取逻辑

- 新增 time_interval 帧提取模式，支持按指定时间间隔提取视频帧
- 重构 VideoAnalyzer 初始化代码，使用 getattr 统一获取配置参数
- 简化配置读取逻辑，移除冗余的 try-catch 结构
- 优化 _extract_frames_worker 函数参数，支持新的提取模式配置

src/chat/utils/utils_video.py

@@ -37,7 +37,12 @@ video_events = {}
 video_lock_manager = asyncio.Lock()
 
 
-def _extract_frames_worker(video_path: str, max_frames: int, frame_quality: int, max_image_size: int) -> List[Tuple[str, float]]:
+def _extract_frames_worker(video_path: str,
+                           max_frames: int, 
+                           frame_quality: int,
+                           max_image_size: int,
+                           frame_extraction_mode: str,
+                           frame_interval_seconds: Optional[float]) -> List[Tuple[str, float]]:
     """线程池中提取视频帧的工作函数"""
     frames = []
     try:
@@ -46,50 +51,85 @@ def _extract_frames_worker(video_path: str, max_frames: int, frame_quality: int,
         total_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
         duration = total_frames / fps if fps > 0 else 0
         
-        # 使用numpy优化帧间隔计算
-        if duration > 0:
-            frame_interval = max(1, int(duration / max_frames * fps))
+        if frame_extraction_mode == "time_interval":
+            # 新模式：按时间间隔抽帧
+            time_interval = frame_interval_seconds
+            next_frame_time = 0.0
+            
+            while cap.isOpened():
+                ret, frame = cap.read()
+                if not ret:
+                    break
+                
+                current_time = cap.get(cv2.CAP_PROP_POS_MSEC) / 1000.0
+                
+                if current_time >= next_frame_time:
+                    # 转换为PIL图像并压缩
+                    frame_rgb = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
+                    pil_image = Image.fromarray(frame_rgb)
+                    
+                    # 调整图像大小
+                    if max(pil_image.size) > self.max_image_size:
+                        ratio = self.max_image_size / max(pil_image.size)
+                        new_size = tuple(int(dim * ratio) for dim in pil_image.size)
+                        pil_image = pil_image.resize(new_size, Image.Resampling.LANCZOS)
+                    
+                    # 转换为base64
+                    buffer = io.BytesIO()
+                    pil_image.save(buffer, format='JPEG', quality=self.frame_quality)
+                    frame_base64 = base64.b64encode(buffer.getvalue()).decode('utf-8')
+                    
+                    frames.append((frame_base64, current_time))
+                    extracted_count += 1
+                    
+                    logger.debug(f"提取第{extracted_count}帧 (时间: {current_time:.2f}s)")
+                    
+                    next_frame_time += time_interval
         else:
-            frame_interval = 30  # 默认间隔
-            
-        # 使用numpy计算目标帧位置
-        target_frames = np.arange(0, min(max_frames, total_frames // frame_interval + 1)) * frame_interval
-        target_frames = target_frames[target_frames < total_frames].astype(int)
-        
-        for target_frame in target_frames:
-            # 跳转到目标帧
-            cap.set(cv2.CAP_PROP_POS_FRAMES, target_frame)
-            ret, frame = cap.read()
-            if not ret:
-                continue
-                
-            # 使用numpy优化图像处理
-            frame_rgb = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
-            
-            # 转换为PIL图像并使用numpy进行尺寸计算
-            height, width = frame_rgb.shape[:2]
-            max_dim = max(height, width)
-            
-            if max_dim > max_image_size:
-                # 使用numpy计算缩放比例
-                ratio = max_image_size / max_dim
-                new_width = int(width * ratio)
-                new_height = int(height * ratio)
-                
-                # 使用opencv进行高效缩放
-                frame_resized = cv2.resize(frame_rgb, (new_width, new_height), interpolation=cv2.INTER_LANCZOS4)
-                pil_image = Image.fromarray(frame_resized)
+            # 使用numpy优化帧间隔计算
+            if duration > 0:
+                frame_interval = max(1, int(duration / max_frames * fps))
             else:
-                pil_image = Image.fromarray(frame_rgb)
+                frame_interval = 30  # 默认间隔
+                
+            # 使用numpy计算目标帧位置
+            target_frames = np.arange(0, min(max_frames, total_frames // frame_interval + 1)) * frame_interval
+            target_frames = target_frames[target_frames < total_frames].astype(int)
             
-            # 转换为base64
-            buffer = io.BytesIO()
-            pil_image.save(buffer, format='JPEG', quality=frame_quality)
-            frame_base64 = base64.b64encode(buffer.getvalue()).decode('utf-8')
-            
-            # 计算时间戳
-            timestamp = target_frame / fps if fps > 0 else 0
-            frames.append((frame_base64, timestamp))
+            for target_frame in target_frames:
+                # 跳转到目标帧
+                cap.set(cv2.CAP_PROP_POS_FRAMES, target_frame)
+                ret, frame = cap.read()
+                if not ret:
+                    continue
+                    
+                # 使用numpy优化图像处理
+                frame_rgb = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
+                
+                # 转换为PIL图像并使用numpy进行尺寸计算
+                height, width = frame_rgb.shape[:2]
+                max_dim = max(height, width)
+                
+                if max_dim > max_image_size:
+                    # 使用numpy计算缩放比例
+                    ratio = max_image_size / max_dim
+                    new_width = int(width * ratio)
+                    new_height = int(height * ratio)
+                    
+                    # 使用opencv进行高效缩放
+                    frame_resized = cv2.resize(frame_rgb, (new_width, new_height), interpolation=cv2.INTER_LANCZOS4)
+                    pil_image = Image.fromarray(frame_resized)
+                else:
+                    pil_image = Image.fromarray(frame_rgb)
+                
+                # 转换为base64
+                buffer = io.BytesIO()
+                pil_image.save(buffer, format='JPEG', quality=frame_quality)
+                frame_base64 = base64.b64encode(buffer.getvalue()).decode('utf-8')
+                
+                # 计算时间戳
+                timestamp = target_frame / fps if fps > 0 else 0
+                frames.append((frame_base64, timestamp))
         
         cap.release()
         return frames
@@ -120,54 +160,14 @@ class VideoAnalyzer:
             logger.warning(f"video_analysis配置不可用({e})，回退使用vlm配置")
         
         # 从配置文件读取参数，如果配置不存在则使用默认值
-        try:
-            config = global_config.video_analysis
-            self.max_frames = config.max_frames
-            self.frame_quality = config.frame_quality
-            self.max_image_size = config.max_image_size
-            self.enable_frame_timing = config.enable_frame_timing
-            self.batch_analysis_prompt = config.batch_analysis_prompt
-            # 新增的线程池配置
-            self.use_multiprocessing = getattr(config, 'use_multiprocessing', True)
-            self.max_workers = getattr(config, 'max_workers', 2)
-            self.frame_extraction_mode = getattr(config, 'frame_extraction_mode', 'fixed_number')
-            self.frame_interval_seconds = getattr(config, 'frame_interval_seconds', 2.0)
-            
-            # 将配置文件中的模式映射到内部使用的模式名称
-            config_mode = config.analysis_mode
-            if config_mode == "batch_frames":
-                self.analysis_mode = "batch"
-            elif config_mode == "frame_by_frame":
-                self.analysis_mode = "sequential"
-            elif config_mode == "auto":
-                self.analysis_mode = "auto"
-            else:
-                logger.warning(f"无效的分析模式: {config_mode}，使用默认的auto模式")
-                self.analysis_mode = "auto"
-                
-            self.frame_analysis_delay = 0.3  # API调用间隔（秒）
-            self.frame_interval = 1.0  # 抽帧时间间隔（秒）
-            self.batch_size = 3  # 批处理时每批处理的帧数
-            self.timeout = 60.0  # 分析超时时间（秒）
-            logger.info("✅ 从配置文件读取视频分析参数")
-            
-        except AttributeError as e:
-            # 如果配置不存在，使用代码中的默认值
-            logger.warning(f"配置文件中缺少video_analysis配置({e})，使用默认值")
-            self.max_frames = 6
-            self.frame_quality = 85
-            self.max_image_size = 600
-            self.analysis_mode = "auto"
-            self.frame_analysis_delay = 0.3
-            self.frame_interval = 1.0  # 抽帧时间间隔（秒）
-            self.batch_size = 3  # 批处理时每批处理的帧数
-            self.timeout = 60.0  # 分析超时时间（秒）
-            self.enable_frame_timing = True
-            self.use_multiprocessing = True  # 默认启用线程池
-            self.max_workers = 2  # 默认最大2个线程
-            self.frame_extraction_mode = "fixed_number"
-            self.frame_interval_seconds = 2.0
-            self.batch_analysis_prompt = """请分析这个视频的内容。这些图片是从视频中按时间顺序提取的关键帧。
+        config = global_config.video_analysis
+
+        # 使用 getattr 统一获取配置参数，如果配置不存在则使用默认值
+        self.max_frames = getattr(config, 'max_frames', 6)
+        self.frame_quality = getattr(config, 'frame_quality', 85)
+        self.max_image_size = getattr(config, 'max_image_size', 600)
+        self.enable_frame_timing = getattr(config, 'enable_frame_timing', True)
+        self.batch_analysis_prompt = getattr(config, 'batch_analysis_prompt', """请分析这个视频的内容。这些图片是从视频中按时间顺序提取的关键帧。
 
 请提供详细的分析，包括：
 1. 视频的整体内容和主题
@@ -177,7 +177,35 @@ class VideoAnalyzer:
 5. 整体氛围和情感表达
 6. 任何特殊的视觉效果或文字内容
 
-请用中文回答，分析要详细准确。"""
+请用中文回答，分析要详细准确。""")
+        
+        # 新增的线程池配置
+        self.use_multiprocessing = getattr(config, 'use_multiprocessing', True)
+        self.max_workers = getattr(config, 'max_workers', 2)
+        self.frame_extraction_mode = getattr(config, 'frame_extraction_mode', 'fixed_number')
+        self.frame_interval_seconds = getattr(config, 'frame_interval_seconds', 2.0)
+        
+        # 将配置文件中的模式映射到内部使用的模式名称
+        config_mode = getattr(config, 'analysis_mode', 'auto')
+        if config_mode == "batch_frames":
+            self.analysis_mode = "batch"
+        elif config_mode == "frame_by_frame":
+            self.analysis_mode = "sequential"
+        elif config_mode == "auto":
+            self.analysis_mode = "auto"
+        else:
+            logger.warning(f"无效的分析模式: {config_mode}，使用默认的auto模式")
+            self.analysis_mode = "auto"
+            
+        self.frame_analysis_delay = 0.3  # API调用间隔（秒）
+        self.frame_interval = 1.0  # 抽帧时间间隔（秒）
+        self.batch_size = 3  # 批处理时每批处理的帧数
+        self.timeout = 60.0  # 分析超时时间（秒）
+        
+        if config:
+            logger.info("✅ 从配置文件读取视频分析参数")
+        else:
+            logger.warning("配置文件中缺少video_analysis配置，使用默认值")
         
         # 系统提示词
         self.system_prompt = "你是一个专业的视频内容分析助手。请仔细观察用户提供的视频关键帧，详细描述视频内容。"
@@ -296,7 +324,9 @@ class VideoAnalyzer:
                     video_path,
                     self.max_frames,
                     self.frame_quality,
-                    self.max_image_size
+                    self.max_image_size,
+                    self.frame_extraction_mode,
+                    self.frame_interval_seconds
                 )
             
             # 检查是否有错误
@@ -318,7 +348,6 @@ class VideoAnalyzer:
     async def _extract_frames_fallback(self, video_path: str) -> List[Tuple[str, float]]:
         """帧提取的降级方法 - 原始异步版本"""
         frames = []
-        frame_count = 0
         extracted_count = 0
         cap = cv2.VideoCapture(video_path)
         fps = cap.get(cv2.CAP_PROP_FPS)