iiiGerardoiii/trim.lua

Trim mode for mpv — Turn mpv into lossless video editor.

✂️ trim.lua

mpv script to create a "precise" clip of video files without transcoding.

❓ Differences from the other similar scripts

• trim.lua is aimed only for extraction of clips with no-transcoding. Encodings will never be occured.
• Without encoding, video trimming becomes tricky.
  • Without transcoding, points you can specify to trim is limited to keyframes.
  • Tested several softwares on macOS and as far as I know there is no software that can do it accurately. Well, there is, but none were perfect nor lightweight.
  • This script is here to achieve accuracy as much as possible — Making a clip from a file within minimum keyframe distance, without transcoding.

In short, trim.lua turns mpv into a simple lossless video editor.

📦 Install

curl https://raw.githubusercontent.com/aerobounce/trim.lua/master/trim.lua >> ~/.config/mpv/scripts/trim.lua

• If your shell has PATH to ffmpeg and ffprobe you're ready to use.
  • If not, rewrite them accordingly.

local ffmpeg_bin = "ffmpeg"
local ffprobe_bin = "ffprobe"

⚠️ Requirements

• ffmpeg
• ffprobe
• osascript (Only on macOS to post notification on completion)

✂️ Usage

Enable trim.lua

• h or k

Save Trim Positions

To write out a clip, press either of the keys twice with the same start / end position.
To quit Trim Mode, close mpv instance.

• h Save Trim Start Keyframe
• k Save Trim End Position

Seeking

• shift + LEFT Seek to the Previous Keyframe
• shift + RIGHT Seek to the Next Keyframe
• shift + h Seek to the Saved Trim Start Keyframe
• shift + k Seek to the Saved Trim End Position

ℹ️ To create a valid file

• Beggining of the trim position must be a keyframe.
• End position can be any point.

🗜 Concat with ffmpeg

After splitting, you can concat them with a script something like this.

CLIPS=("example_1.mp4" "example_2.mp4")
DESTINATION="concat_example.mp4"

ffmpeg \
    -hide_banner \
    -loglevel verbose \
    -f concat \
    -safe 0 \
    -auto_convert 0 \
    -err_detect ignore_err \
    -i <(
        while read -r; do
            echo "file '$REPLY'"
        done <<< "${CLIPS[*]}"
    ) \
    -copy_unknown \
    -map_chapters 0 \
    -c copy \
    "$DESTINATION"

Known Issue

• Any embedded media other than video / audio will be lost, such as embedded subtitles. This will unlikely be fixed.