fix(server): recover thumbnail generation for corrupt media

server/src/services/media.service.spec.ts

@@ -385,7 +385,7 @@ describe(MediaService.name, () => {
         ...getForGenerateThumbnail(asset),
         ...probeStub.noVideoStreams,
       });
-      await expect(sut.handleGenerateThumbnails({ id: asset.id })).rejects.toThrowError();
+      await expect(sut.handleGenerateThumbnails({ id: asset.id })).resolves.toBe(JobStatus.Failed);
       expect(mocks.media.generateThumbnail).not.toHaveBeenCalled();
       expect(mocks.asset.update).not.toHaveBeenCalledWith();
     });
@@ -543,6 +543,46 @@ describe(MediaService.name, () => {
       ]);
     });
 
+    it('should retry video thumbnail generation with a fallback filter chain when ffmpeg fails', async () => {
+      const asset = AssetFactory.from({ type: AssetType.Video, originalPath: '/original/path.ext' }).exif().build();
+      mocks.assetJob.getForGenerateThumbnailJob.mockResolvedValue({
+        ...getForGenerateThumbnail(asset),
+        ...probeStub.videoStream2160p,
+      });
+      mocks.media.transcode.mockRejectedValueOnce(new Error('ffmpeg was killed with signal SIGSEGV'));
+
+      await expect(sut.handleGenerateThumbnails({ id: asset.id })).resolves.toBe(JobStatus.Success);
+
+      // primary preview attempt (1) fails, then preview (2) and thumbnail (3) fallbacks run
+      expect(mocks.media.transcode).toHaveBeenCalledTimes(3);
+      expect(mocks.media.transcode).toHaveBeenCalledWith(
+        '/original/path.ext',
+        expect.any(String),
+        expect.objectContaining({
+          inputOptions: ['-sws_flags', 'accurate_rnd+full_chroma_int'],
+          outputOptions: expect.arrayContaining([
+            '-fps_mode',
+            'passthrough',
+            '-vf',
+            String.raw`select=eq(n\,0),scale=-2:1440:flags=lanczos+accurate_rnd+full_chroma_int:out_range=pc`,
+          ]),
+          twoPass: false,
+        }),
+      );
+      expect(mocks.asset.upsertFiles).toHaveBeenCalled();
+    });
+
+    it('should fail gracefully without throwing when media decoding is unsupported', async () => {
+      const asset = AssetFactory.from().exif().build();
+      mocks.assetJob.getForGenerateThumbnailJob.mockResolvedValue(getForGenerateThumbnail(asset));
+      mocks.media.decodeImage.mockRejectedValue(new Error('Input file contains unsupported image format'));
+
+      await expect(sut.handleGenerateThumbnails({ id: asset.id })).resolves.toBe(JobStatus.Failed);
+
+      expect(mocks.media.generateThumbnail).not.toHaveBeenCalled();
+      expect(mocks.asset.update).not.toHaveBeenCalled();
+    });
+
     it('should tonemap thumbnail for hdr video', async () => {
       const asset = AssetFactory.from({ type: AssetType.Video, originalPath: '/original/path.ext' }).exif().build();
       mocks.assetJob.getForGenerateThumbnailJob.mockResolvedValue({

server/src/services/media.service.ts

@@ -225,15 +225,21 @@ export class MediaService extends BaseService {
     }
 
     let generated: Awaited<ReturnType<MediaService['generateImageThumbnails']>>;
-    if (asset.type === AssetType.Video || asset.originalFileName.toLowerCase().endsWith('.gif')) {
-      this.logger.verbose(`Thumbnail generation for video ${id} ${asset.originalPath}`);
-      generated = await this.generateVideoThumbnails(asset, config);
-    } else if (asset.type === AssetType.Image) {
-      this.logger.verbose(`Thumbnail generation for image ${id} ${asset.originalPath}`);
-      generated = await this.generateImageThumbnails(asset, config);
-    } else {
-      this.logger.warn(`Skipping thumbnail generation for asset ${id}: ${asset.type} is not an image or video`);
-      return JobStatus.Skipped;
+    try {
+      if (asset.type === AssetType.Video || asset.originalFileName.toLowerCase().endsWith('.gif')) {
+        this.logger.verbose(`Thumbnail generation for video ${id} ${asset.originalPath}`);
+        generated = await this.generateVideoThumbnails(asset, config);
+      } else if (asset.type === AssetType.Image) {
+        this.logger.verbose(`Thumbnail generation for image ${id} ${asset.originalPath}`);
+        generated = await this.generateImageThumbnails(asset, config);
+      } else {
+        this.logger.warn(`Skipping thumbnail generation for asset ${id}: ${asset.type} is not an image or video`);
+        return JobStatus.Skipped;
+      }
+    } catch (error: any) {
+      // Corrupt/unsupported media: fail the job instead of throwing into indefinite retries.
+      this.logger.error(`Thumbnail generation failed for asset ${id} (${asset.originalPath}): ${error.message}`);
+      return JobStatus.Failed;
     }
 
     const editedGenerated = await this.generateEditedThumbnails(asset, config);
@@ -532,8 +538,19 @@ export class MediaService extends BaseService {
     const previewOptions = previewConfig.getCommand(TranscodeTarget.Video, videoStream, undefined, format ?? undefined);
     const thumbnailOptions = thumbConfig.getCommand(TranscodeTarget.Video, videoStream, undefined, format ?? undefined);
 
-    await this.mediaRepository.transcode(asset.originalPath, previewFile.path, previewOptions);
-    await this.mediaRepository.transcode(asset.originalPath, thumbnailFile.path, thumbnailOptions);
+    try {
+      await this.mediaRepository.transcode(asset.originalPath, previewFile.path, previewOptions);
+      await this.mediaRepository.transcode(asset.originalPath, thumbnailFile.path, thumbnailOptions);
+    } catch (error: any) {
+      // Primary chain can SIGSEGV on very short videos; retry once with the fallback.
+      this.logger.warn(
+        `Thumbnail generation failed for asset ${asset.id} (${asset.originalPath}): ${error.message}. Retrying with fallback filter chain.`,
+      );
+      const fallbackPreviewOptions = previewConfig.getFallbackCommand(TranscodeTarget.Video, videoStream);
+      const fallbackThumbnailOptions = thumbConfig.getFallbackCommand(TranscodeTarget.Video, videoStream);
+      await this.mediaRepository.transcode(asset.originalPath, previewFile.path, fallbackPreviewOptions);
+      await this.mediaRepository.transcode(asset.originalPath, thumbnailFile.path, fallbackThumbnailOptions);
+    }
 
     const thumbhash = await this.mediaRepository.generateThumbhash(previewFile.path, {
       colorspace: image.colorspace,

server/src/utils/media.ts

@@ -471,17 +471,12 @@ export class BaseHWConfig extends BaseConfig {
 }
 
 export class ThumbnailConfig extends BaseConfig {
-  static create(config: SystemConfigFFmpegDto): VideoCodecSWConfig {
+  static create(config: SystemConfigFFmpegDto): ThumbnailConfig {
     return new ThumbnailConfig(config);
   }
 
-  getBaseInputOptions(videoStream: VideoStreamInfo, format?: VideoFormat): string[] {
-    // skip_frame nointra skips all frames for some MPEG-TS files. Look at ffmpeg tickets 7950 and 7895 for more details.
-    const options =
-      format?.formatName === 'mpegts'
-        ? ['-sws_flags', 'accurate_rnd+full_chroma_int']
-        : ['-skip_frame', 'nointra', '-sws_flags', 'accurate_rnd+full_chroma_int'];
-
+  // workaround for https://fftrac-bg.ffmpeg.org/ticket/11020
+  private getColorMetadataOptions(videoStream: VideoStreamInfo): string[] {
     const metadataOverrides = [];
     if (videoStream.colorPrimaries === ColorPrimaries.Reserved) {
       metadataOverrides.push('colour_primaries=1');
@@ -495,11 +490,22 @@ export class ThumbnailConfig extends BaseConfig {
       metadataOverrides.push('transfer_characteristics=1');
     }
 
-    if (metadataOverrides.length > 0) {
-      // workaround for https://fftrac-bg.ffmpeg.org/ticket/11020
-      options.push(`-bsf:${videoStream.index}`, `${videoStream.codecName}_metadata=${metadataOverrides.join(':')}`);
+    if (metadataOverrides.length === 0) {
+      return [];
     }
 
+    return [`-bsf:${videoStream.index}`, `${videoStream.codecName}_metadata=${metadataOverrides.join(':')}`];
+  }
+
+  getBaseInputOptions(videoStream: VideoStreamInfo, format?: VideoFormat): string[] {
+    // skip_frame nointra skips all frames for some MPEG-TS files. Look at ffmpeg tickets 7950 and 7895 for more details.
+    const options =
+      format?.formatName === 'mpegts'
+        ? ['-sws_flags', 'accurate_rnd+full_chroma_int']
+        : ['-skip_frame', 'nointra', '-sws_flags', 'accurate_rnd+full_chroma_int'];
+
+    options.push(...this.getColorMetadataOptions(videoStream));
+
     return options;
   }
 
@@ -518,6 +524,32 @@ export class ThumbnailConfig extends BaseConfig {
     ];
   }
 
+  // No skip_frame nointra, which can drop every frame of a short video.
+  getFallbackBaseInputOptions(videoStream: VideoStreamInfo): string[] {
+    return ['-sws_flags', 'accurate_rnd+full_chroma_int', ...this.getColorMetadataOptions(videoStream)];
+  }
+
+  // First frame only; thumbnail=12 + reverse can SIGSEGV on short videos when the pipeline is empty.
+  getFallbackFilterOptions(videoStream: VideoStreamInfo): string[] {
+    return [String.raw`select=eq(n\,0)`, ...super.getFilterOptions(videoStream)];
+  }
+
+  getFallbackCommand(target: TranscodeTarget, video: VideoStreamInfo): TranscodeCommand {
+    const options: TranscodeCommand = {
+      inputOptions: this.getFallbackBaseInputOptions(video),
+      outputOptions: [...this.getBaseOutputOptions(), '-fps_mode', 'passthrough', '-v', 'verbose'],
+      twoPass: false,
+      progress: { frameCount: video.frameCount, percentInterval: 5 },
+    };
+    if ([TranscodeTarget.All, TranscodeTarget.Video].includes(target)) {
+      const filters = this.getFallbackFilterOptions(video);
+      if (filters.length > 0) {
+        options.outputOptions.push('-vf', filters.join(','));
+      }
+    }
+    return options;
+  }
+
   getPresetOptions() {
     return [];
   }