feat: 创建统一的缩略图获取接口，使用视频实际尺寸

新增get_segment_thumbnail_base64接口:
- 根据segmentId统一获取缩略图base64数据URL
- 智能检查：数据库路径 -> 文件存在性 -> 自动重新生成
- 完整的错误处理和文件验证机制

 使用视频实际尺寸生成缩略图:
- 添加get_video_info方法获取视频元数据
- 保持原始宽高比，最大宽度160像素
- 支持音频流信息解析和完整的VideoMetadata结构

 代码优化:
- 简化前端缩略图加载逻辑，统一使用新接口
- 移除重复的generateSegmentThumbnail函数
- 清理不必要的参数传递和依赖项

 功能特点:
- 自动检测文件丢失并重新生成
- 使用视频原始尺寸保持最佳显示效果
- 统一的错误处理和缓存机制
- 减少代码重复，提高维护性

现在缩略图生成更加智能和高效，能够自动处理文件丢失的情况，并使用视频的实际尺寸生成最佳质量的缩略图。

apps/desktop/src-tauri/src/infrastructure/ffmpeg.rs

@@ -611,6 +611,95 @@ impl FFmpegService {
         Ok(())
     }
 
+    /// 获取视频信息
+    pub fn get_video_info(input_path: &str) -> Result<VideoMetadata> {
+        if !Path::new(input_path).exists() {
+            return Err(anyhow!("输入文件不存在: {}", input_path));
+        }
+
+        let output = Self::create_hidden_command("ffprobe")
+            .args([
+                "-v", "quiet",
+                "-print_format", "json",
+                "-show_format",
+                "-show_streams",
+                input_path
+            ])
+            .output()
+            .map_err(|e| anyhow!("执行ffprobe失败: {}", e))?;
+
+        if !output.status.success() {
+            let error_msg = String::from_utf8_lossy(&output.stderr);
+            return Err(anyhow!("ffprobe执行失败: {}", error_msg));
+        }
+
+        let json_str = String::from_utf8_lossy(&output.stdout);
+        let json: Value = serde_json::from_str(&json_str)
+            .map_err(|e| anyhow!("解析ffprobe输出失败: {}", e))?;
+
+        // 查找视频流
+        let streams = json["streams"].as_array()
+            .ok_or_else(|| anyhow!("未找到流信息"))?;
+
+        for stream in streams {
+            if stream["codec_type"].as_str() == Some("video") {
+                let width = stream["width"].as_u64().unwrap_or(0) as u32;
+                let height = stream["height"].as_u64().unwrap_or(0) as u32;
+                let duration = stream["duration"].as_str()
+                    .and_then(|s| s.parse::<f64>().ok())
+                    .unwrap_or(0.0);
+                let fps = stream["r_frame_rate"].as_str()
+                    .and_then(|s| {
+                        let parts: Vec<&str> = s.split('/').collect();
+                        if parts.len() == 2 {
+                            let num = parts[0].parse::<f64>().ok()?;
+                            let den = parts[1].parse::<f64>().ok()?;
+                            if den != 0.0 { Some(num / den) } else { None }
+                        } else {
+                            s.parse::<f64>().ok()
+                        }
+                    })
+                    .unwrap_or(0.0);
+
+                // 查找音频流信息
+                let mut has_audio = false;
+                let mut audio_codec = None;
+                let mut audio_bitrate = None;
+                let mut audio_sample_rate = None;
+
+                for audio_stream in streams {
+                    if audio_stream["codec_type"].as_str() == Some("audio") {
+                        has_audio = true;
+                        audio_codec = audio_stream["codec_name"].as_str().map(|s| s.to_string());
+                        audio_bitrate = audio_stream["bit_rate"].as_str()
+                            .and_then(|s| s.parse::<u64>().ok());
+                        audio_sample_rate = audio_stream["sample_rate"].as_str()
+                            .and_then(|s| s.parse::<u32>().ok());
+                        break;
+                    }
+                }
+
+                return Ok(VideoMetadata {
+                    width,
+                    height,
+                    duration,
+                    fps,
+                    codec: stream["codec_name"].as_str().unwrap_or("unknown").to_string(),
+                    bitrate: stream["bit_rate"].as_str()
+                        .and_then(|s| s.parse::<u64>().ok())
+                        .unwrap_or(0),
+                    format: json["format"]["format_name"].as_str().unwrap_or("unknown").to_string(),
+                    has_audio,
+                    audio_codec,
+                    audio_bitrate,
+                    audio_sample_rate,
+                });
+            }
+        }
+
+        Err(anyhow!("未找到视频流"))
+    }
+
     /// 检查 FFmpeg 版本
     pub fn get_version() -> Result<String> {
         let output = Self::create_hidden_command("ffmpeg")

apps/desktop/src-tauri/src/lib.rs

@@ -75,6 +75,7 @@ pub fn run() {
             commands::material_commands::generate_video_thumbnail,
             commands::material_commands::generate_and_save_segment_thumbnail,
             commands::material_commands::read_thumbnail_as_data_url,
+            commands::material_commands::get_segment_thumbnail_base64,
             commands::material_commands::test_scene_detection,
             commands::material_commands::get_material_segments,
             commands::material_commands::test_video_split,

apps/desktop/src-tauri/src/presentation/commands/material_commands.rs

@@ -830,12 +830,33 @@ pub async fn generate_and_save_segment_thumbnail(
 
     // 生成缩略图（使用首帧）
     let timestamp = segment.start_time;
+
+    // 获取视频元数据来确定合适的缩略图尺寸
+    let video_info = FFmpegService::get_video_info(video_path)
+        .map_err(|e| e.to_string())?;
+
+    // 计算缩略图尺寸，保持宽高比，最大宽度160
+    let max_width = 160;
+    let (thumb_width, thumb_height) = if video_info.width > 0 && video_info.height > 0 {
+        let aspect_ratio = video_info.width as f64 / video_info.height as f64;
+        if video_info.width > max_width {
+            let new_width = max_width;
+            let new_height = (new_width as f64 / aspect_ratio).round() as u32;
+            (new_width, new_height)
+        } else {
+            (video_info.width, video_info.height)
+        }
+    } else {
+        // 如果无法获取视频尺寸，使用默认值
+        (160, 120)
+    };
+
     FFmpegService::generate_thumbnail(
         video_path,
         &thumbnail_path_str,
         timestamp,
-        160,
-        120
+        thumb_width,
+        thumb_height
     ).map_err(|e| e.to_string())?;
 
     // 保存缩略图路径到数据库
@@ -875,6 +896,117 @@ pub async fn read_thumbnail_as_data_url(file_path: String) -> Result<String, Str
     Ok(format!("data:image/jpeg;base64,{}", base64_data))
 }
 
+/// 根据segmentId获取缩略图base64数据URL
+#[command]
+pub async fn get_segment_thumbnail_base64(
+    segment_id: String,
+    app_state: State<'_, AppState>,
+) -> Result<String, String> {
+    use crate::infrastructure::ffmpeg::FFmpegService;
+    use std::path::Path;
+    use std::fs;
+    use base64::{Engine as _, engine::general_purpose};
+
+    // 获取片段信息
+    let segment = {
+        let material_repository_guard = app_state.material_repository.lock().unwrap();
+        let material_repository = material_repository_guard.as_ref()
+            .ok_or("MaterialRepository未初始化")?;
+
+        material_repository.get_segment_by_id_sync(&segment_id)
+            .map_err(|e| e.to_string())?
+    };
+
+    let segment = match segment {
+        Some(s) => s,
+        None => return Err("片段不存在".to_string()),
+    };
+
+    // 检查数据库中是否已有缩略图路径
+    if let Some(ref thumbnail_path) = segment.thumbnail_path {
+        // 去掉Windows长路径前缀
+        let clean_path = if thumbnail_path.starts_with("\\\\?\\") {
+            &thumbnail_path[4..]
+        } else {
+            thumbnail_path
+        };
+
+        // 检查文件是否存在
+        if Path::new(clean_path).exists() {
+            // 文件存在，直接读取并返回
+            let file_data = fs::read(clean_path)
+                .map_err(|e| format!("读取缩略图文件失败: {}", e))?;
+
+            let base64_data = general_purpose::STANDARD.encode(&file_data);
+            return Ok(format!("data:image/jpeg;base64,{}", base64_data));
+        }
+    }
+
+    // 缩略图不存在或文件已丢失，需要重新生成
+    let video_path = &segment.file_path;
+
+    // 去掉Windows长路径前缀
+    let clean_video_path = if video_path.starts_with("\\\\?\\") {
+        &video_path[4..]
+    } else {
+        video_path
+    };
+
+    // 生成缩略图路径
+    let thumbnail_filename = format!("{}_thumbnail.jpg", segment.id);
+    let video_dir = Path::new(clean_video_path).parent()
+        .ok_or("无法获取视频文件目录")?;
+    let thumbnail_path = video_dir.join(thumbnail_filename);
+    let thumbnail_path_str = thumbnail_path.to_string_lossy().to_string();
+
+    // 获取视频信息来确定合适的缩略图尺寸
+    let video_info = FFmpegService::get_video_info(clean_video_path)
+        .map_err(|e| e.to_string())?;
+
+    // 计算缩略图尺寸，保持宽高比，最大宽度160
+    let max_width = 160;
+    let (thumb_width, thumb_height) = if video_info.width > 0 && video_info.height > 0 {
+        let aspect_ratio = video_info.width as f64 / video_info.height as f64;
+        if video_info.width > max_width {
+            let new_width = max_width;
+            let new_height = (new_width as f64 / aspect_ratio).round() as u32;
+            (new_width, new_height)
+        } else {
+            (video_info.width, video_info.height)
+        }
+    } else {
+        // 如果无法获取视频尺寸，使用默认值
+        (160, 120)
+    };
+
+    // 生成缩略图（使用首帧）
+    let timestamp = segment.start_time;
+    FFmpegService::generate_thumbnail(
+        clean_video_path,
+        &thumbnail_path_str,
+        timestamp,
+        thumb_width,
+        thumb_height
+    ).map_err(|e| e.to_string())?;
+
+    // 保存缩略图路径到数据库
+    {
+        let material_repository_guard = app_state.material_repository.lock().unwrap();
+        let material_repository = material_repository_guard.as_ref()
+            .ok_or("MaterialRepository未初始化")?;
+
+        material_repository.update_segment_thumbnail(&segment_id, &thumbnail_path_str)
+            .map_err(|e| e.to_string())?;
+    }
+
+    // 读取生成的缩略图文件并返回base64
+    let file_data = fs::read(&thumbnail_path_str)
+        .map_err(|e| format!("读取生成的缩略图失败: {}", e))?;
+
+    let base64_data = general_purpose::STANDARD.encode(&file_data);
+    Ok(format!("data:image/jpeg;base64,{}", base64_data))
+}
+
 /// 测试场景检测命令（用于调试）
 #[command]
 pub async fn test_scene_detection(file_path: String) -> Result<String, String> {

apps/desktop/src/components/MaterialSegmentView.tsx

@@ -107,33 +107,19 @@ const playVideoSegment = async (filePath: string, startTime: number, endTime: nu
   }
 };
 
-// 生成片段缩略图（使用首帧）
-const generateSegmentThumbnail = async (segment: SegmentWithDetails): Promise<string | null> => {
-  try {
-    const result = await invoke<string | null>('generate_and_save_segment_thumbnail', {
-      segmentId: segment.segment.id
-    });
 
-    return result;
-  } catch (error) {
-    console.error('生成缩略图失败:', error);
-    return null;
-  }
-};
 
 // 缩略图显示组件
 interface ThumbnailDisplayProps {
   segment: SegmentWithDetails;
   thumbnailCache: Map<string, string>;
   setThumbnailCache: React.Dispatch<React.SetStateAction<Map<string, string>>>;
-  generateSegmentThumbnail: (segment: SegmentWithDetails) => Promise<string | null>;
 }
 
 const ThumbnailDisplay: React.FC<ThumbnailDisplayProps> = ({
   segment,
   thumbnailCache,
   setThumbnailCache,
-  generateSegmentThumbnail
 }) => {
   const [loading, setLoading] = useState(false);
   const [thumbnailUrl, setThumbnailUrl] = useState<string | null>(null);
@@ -147,53 +133,28 @@ const ThumbnailDisplay: React.FC<ThumbnailDisplayProps> = ({
         setThumbnailUrl(thumbnailCache.get(segmentId) || null);
         return;
       }
-      // 首先检查数据库中是否已有缩略图
-      if (segment.segment.thumbnail_path) {
-        try {
-          console.log('读取缩略图:', segment.segment.thumbnail_path);
-          const dataUrl = await invoke<string>('read_thumbnail_as_data_url', {
-            filePath: segment.segment.thumbnail_path
-          });
-          console.log('获取到数据URL');
-          setThumbnailUrl(dataUrl);
-          // 更新缓存
-          setThumbnailCache(prev => new Map(prev.set(segmentId, dataUrl)));
-          return;
-        } catch (error) {
-          console.error('读取缩略图失败:', error);
-          // 如果读取失败，继续生成新的缩略图
-        }
-      }
 
-      // 如果数据库中没有缩略图，则生成新的
+      // 使用新的统一接口获取缩略图
       setLoading(true);
       try {
-        const thumbnailPath = await generateSegmentThumbnail(segment);
-        if (thumbnailPath) {
-          try {
-            console.log('生成的缩略图路径:', thumbnailPath);
-            const cleanPath = thumbnailPath.replace(/^\\\\\?\\/, '');
-            const dataUrl = await invoke<string>('read_thumbnail_as_data_url', {
-              filePath: cleanPath
-            });
-            console.log('转换为数据URL成功');
-            setThumbnailUrl(dataUrl);
+        console.log('获取片段缩略图:', segmentId);
+        const dataUrl = await invoke<string>('get_segment_thumbnail_base64', {
+          segmentId: segmentId
+        });
+        console.log('获取缩略图成功');
+        setThumbnailUrl(dataUrl);
 
-            // 更新缓存
-            setThumbnailCache(prev => new Map(prev.set(segmentId, dataUrl)));
-          } catch (error) {
-            console.error('读取生成的缩略图失败:', error);
-          }
-        }
+        // 更新缓存
+        setThumbnailCache(prev => new Map(prev.set(segmentId, dataUrl)));
       } catch (error) {
-        console.error('加载缩略图失败:', error);
+        console.error('获取缩略图失败:', error);
       } finally {
         setLoading(false);
       }
     };
 
     loadThumbnail();
-  }, [segment.segment.id, segment.segment.thumbnail_path, thumbnailCache, setThumbnailCache, generateSegmentThumbnail]);
+  }, [segment.segment.id, thumbnailCache, setThumbnailCache]);
 
   return (
     <div className="w-20 h-16 bg-gray-100 rounded-lg flex items-center justify-center flex-shrink-0 overflow-hidden">
@@ -352,7 +313,6 @@ export const MaterialSegmentView: React.FC<MaterialSegmentViewProps> = ({ projec
             segment={segment}
             thumbnailCache={thumbnailCache}
             setThumbnailCache={setThumbnailCache}
-            generateSegmentThumbnail={generateSegmentThumbnail}
           />
 
           {/* 内容信息 */}
@@ -501,8 +461,8 @@ export const MaterialSegmentView: React.FC<MaterialSegmentViewProps> = ({ projec
                 key={option.value}
                 onClick={() => setSelectedClassification(option.value)}
                 className={`inline-flex items-center px-3 py-1.5 rounded-full text-sm font-medium transition-colors ${selectedClassification === option.value
-                    ? 'bg-blue-100 text-blue-800 border border-blue-200'
-                    : 'bg-gray-100 text-gray-700 hover:bg-gray-200 border border-gray-200'
+                  ? 'bg-blue-100 text-blue-800 border border-blue-200'
+                  : 'bg-gray-100 text-gray-700 hover:bg-gray-200 border border-gray-200'
                   }`}
               >
                 <span>{option.label}</span>
@@ -526,8 +486,8 @@ export const MaterialSegmentView: React.FC<MaterialSegmentViewProps> = ({ projec
                 key={option.value}
                 onClick={() => setSelectedModel(option.value)}
                 className={`inline-flex items-center px-3 py-1.5 rounded-full text-sm font-medium transition-colors ${selectedModel === option.value
-                    ? 'bg-green-100 text-green-800 border border-green-200'
-                    : 'bg-gray-100 text-gray-700 hover:bg-gray-200 border border-gray-200'
+                  ? 'bg-green-100 text-green-800 border border-green-200'
+                  : 'bg-gray-100 text-gray-700 hover:bg-gray-200 border border-gray-200'
                   }`}
               >
                 <span>{option.label}</span>