fix: log on read_video_frame_at failure; os.path.join in stitch_video#155
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nikopueringer merged 1 commit intonikopueringer:mainfrom Mar 14, 2026
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Two small fixes in backend/: 1. backend/frame_io.py — read_video_frame_at() returned None silently when cap.read() failed (bad seek or truncated video). Unlike its sibling read_image_frame(), no warning was emitted, making the failure invisible to callers and log aggregation. Added logger.warning() with the frame index and path, matching the existing pattern in read_image_frame(). 2. backend/ffmpeg_tools.py — stitch_video() built the FFmpeg -i input path with string concatenation (in_dir + "/" + pattern), the only remaining hardcoded slash in the file. Replaced with os.path.join() for cross-platform consistency; os is already imported. No logic changes. 221 tests pass. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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What changed
Two small fixes in
backend/— no logic changes.1.
backend/frame_io.py— silentNoneinread_video_frame_at()When
cap.read()fails (bad seek, truncated video, corrupted file),read_video_frame_at()returnedNonewith no log output. Its siblingread_image_frame()already emitslogger.warning("Could not read frame: %s", fpath)in the same situation.read_video_frame_at()was inconsistent — the failure was completely invisible to callers and log handlers.Added
logger.warning("Could not read video frame %d from: %s", frame_index, video_path)immediately before thereturn None, matching the existing pattern.2.
backend/ffmpeg_tools.py— hardcoded/institch_video()The FFmpeg
-iinput path was built with string concatenation (in_dir + "/" + pattern), the only remaining hardcoded slash in the file after theos.path.joinfixes in PR #100. Replaced withos.path.join(in_dir, pattern);osis already imported at line 15.Why it was needed
Nonereturns make debugging failed video reads difficult — there's no log message to indicate which file or frame index caused the problem./breaks on Windows paths; the rest offfmpeg_tools.pyalready usesos.path.joinconsistently.How to verify