Update Frames parameter documentation across Clone-Video.md, Create-Clip.md, Get-FramesRange.md and SKILL.md to clarify range validation behavior (start-end format rejects reversed ranges and out-of-bounds ends with exit code 1, single positive numbers clamp to last frame instead of erroring), add encoder/filter prerequisites table to SKILL.md listing libx264/libx265/libvpx-vp9/libopus/libmp3lame/libaom-av1/libwebp requirements per script with task-specific check guidance using ffmpeg -encoders,

skill/Get-FramesRange.md

@@ -10,8 +10,8 @@ Extracts a specific range of frames from a video file to PNG images.
 
 ## Frame Range Formats
 
-- **`start-end`**: Extract frames from start to end index (e.g., `100-200`)
-- **`positive_number`**: Extract frames from 0 to that number (e.g., `50` extracts frames 0-50)
+- **`start-end`**: Extract frames from start to end index (e.g., `100-200`). Both ends must lie inside the video, and `start` must not be greater than `end`. Otherwise the script stops with exit code `1`.
+- **`positive_number`**: Extract frames from 0 to that number (e.g., `50` extracts frames 0-50). A single number past the last frame is clamped to the last frame (`150` on a 100-frame video gives frames 0 to 99).
 - **`-negative_number`**: Extract the last N frames (e.g., `-10` extracts frames 90 to 99 of a 100-frame video; `-1` extracts the last frame only)
 - **`%`**: The last frame index. Alone (`%`) it extracts only the last frame. In a range it is the end of the range:
     - `%` - Extract only the last frame