Video Clip Editor

Use when the user asks to trim, cut, rename, or make a shareable clip from a local video file. Prefer deterministic ffmpeg/ffprobe work and keep the source untouched.

Workflow

1. Inspect the input first:
   • ls -lh <input>
   • ffprobe -hide_banner -show_format -show_streams -print_format json <input>
   • Do not assume an extension; SSR/Matroska files may have no suffix.
2. Choose the output path:
   • Write beside the input unless the user asks otherwise.
   • Use a clean, descriptive basename from the requested title/game, e.g. clip-2026-08-16_01.00.00.mkv.
   • Preserve the original file. If the output exists, use a suffix or ask before overwriting.
   • Default to .mkv for Matroska/WebM input or unknown/no-extension containers. Use .mp4 only when codecs/container compatibility is intended.
   • Keep the temporary file in the same intended container as the final output: use .tmp.mkv for Matroska and .tmp.mp4 for MP4. Renaming a Matroska file to .mp4 does not convert its container.
3. Convert time ranges carefully:
   • If the user says from A to B, compute duration as B - A and use -ss A -t duration.
   • Example: 00:00:03 to 00:05:23 is 00:05:20, not 00:05:23 of output.
4. Pick the cut method:
   • Fast/lossless attempt when approximate keyframe boundaries are acceptable:

     ffmpeg -hide_banner -y -ss START -i INPUT -t DURATION -map 0 -c copy -avoid_negative_ts make_zero OUTPUT.tmp.CONTAINER

   • CONTAINER must match the intended final container, for example mkv or mp4.
   • Always probe the result. If duration includes preroll, starts early, or misses the requested boundary, replace it with an accurate re-encode.
   • Accurate default for user-facing clips:

     ffmpeg -hide_banner -y -i INPUT -ss START -t DURATION -map 0 \
       -c:v libx264 -preset veryfast -crf 22 -pix_fmt yuv420p \
       -c:a aac -b:a 128k OUTPUT.tmp.CONTAINER

   • Use libx265 only when the user asks for HEVC/smaller output or the existing workflow clearly prefers HEVC; it is slower and may be less broadly shareable.
5. Verify before reporting done:
   • Probe duration, size, codecs, dimensions, and container:

     ffprobe -hide_banner -show_entries format=format_name,duration,size:stream=index,codec_name,codec_type,width,height,avg_frame_rate \
       -of default=noprint_wrappers=1 OUTPUT.tmp.CONTAINER

   • Check the duration is within normal encoder tolerance of the requested duration.
   • Confirm the probed container matches the intended final extension.
   • If verification passes, move/rename the temp file to the final output path without changing container type.
6. Final response:
   • Give the final absolute path.
   • State the requested source range and final probed duration.
   • Mention the original was left untouched.

Notes

• Stream copy is not enough by itself for exact starts: keyframes can preserve a few seconds of preroll. Treat ffprobe as the judge.
• For game clips, 1080p/60 H.264 CRF 22 with AAC 128k is a good default balance of speed, compatibility, and size.
• Do not delete source videos or failed outputs unless the user explicitly asks; overwrite temp files freely.