56 lines
1.4 KiB
Bash
56 lines
1.4 KiB
Bash
#!/bin/bash
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set -e
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# This script allows me to take mp4 files and clip+slow them down for interesting slow mo clips :^)
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# Magic is at the bottom the rest is just interfacing
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if [ -z "$3" ]; then
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cat <<- EOF
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Usage: slow-mo.sh /path/to/file.mp4 HH:MM:SS[.ms] HH:MM:SS[.ms]
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Note:
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.ms (miliseconds) optional as they are not required to make this script work but
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ffmpeg does understand the field
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Alternative flags( environment variables ):
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REMOVE_AUDIO
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When this is set the audio output is disabled
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SLOW_RATE
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2.0 => Half speed
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3.0 => 3x slower
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Formula is 1 / RATE => OutputRate
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EOF
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exit 0
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fi
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# If this gets set then we do not create the first clip with audio
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case "$REMOVE_AUDIO" in
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true)
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echo "Audio: DISABLED"
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FFMPEG_COPY="-c copy -an"
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;;
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*)
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echo "Audio: ENABLED"
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FFMPEG_COPY="-c:v copy"
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;;
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esac
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# Aliasing input variables
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input="$1"
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starttime="$2"
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endtime="$3"
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SLOW_RATE=2.0
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# Make ffmpeg be quiet
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LOG="-loglevel error"
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clip="$input-clip.mp4"
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echo "Cutting desired section from $2 to $3..."
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ffmpeg $LOG -y -i "$input" -ss "$starttime" -to "$endtime" $FFMPEG_COPY "$clip"
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echo "Slowing down video now"
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ffmpeg $LOG -y -i "$clip" -vf "setpts=$SLOW_RATE*PTS" "$input.slow.mp4"
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