71 lines
2.3 KiB
Bash
71 lines
2.3 KiB
Bash
#!/usr/bin/env bash
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# Use this to normalize the audio of a video using the average loudness, or RMS-based normalization.
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# This does not re-encode the video.
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#
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# Inspired by https://superuser.com/a/323127 and https://superuser.com/a/1312885
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if which tput >/dev/null 2>&1; then
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ncolors=$(tput colors)
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fi
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if [ -t 1 ] && [ -n "$ncolors" ] && [ "$ncolors" -ge 8 ]; then
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RED="$(tput setaf 1)"
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GREEN="$(tput setaf 2)"
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YELLOW="$(tput setaf 3)"
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BLUE="$(tput setaf 4)"
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MAGENTA="$(tput setaf 5)"
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CYAN="$(tput setaf 6)"
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BOLD="$(tput bold)"
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NORMAL="$(tput sgr0)"
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else
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RED=""
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GREEN=""
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YELLOW=""
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BLUE=""
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MAGENTA=""
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CYAN=""
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BOLD=""
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NORMAL=""
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fi
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if [[ $1 == "" ]]; then
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printf "${BOLD}${RED}Usage: $0 <filename> <optional output name>${NORMAL}\n"
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exit 1
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fi
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filename=$(basename -- "$1")
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extension="${filename##*.}"
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filename="${filename%.*}"
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output_name="$2"
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if [[ $output_name == "" ]]; then
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output="${filename}_normalized_audio.$extension"
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else
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output="${output_name}.$extension"
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fi
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printf "\n${YELLOW}${BOLD}Normalizing audio in $filename.$extension | output: $output${NORMAL}\n"
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# This is done in two passes. The first pass will compute the mean loudness and
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# the second pass will normalize the audio using the mean as the target.
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# -vn, -sn, and -dn tells ffmpeg to ignore non-audio streams during the analysis. This speeds things up.
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ffmpeg -i "$filename.$extension" -af "volumedetect" -vn -sn -dn -f null /dev/null
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#ffmpeg -i "$filename.$extension" -c:v copy -ac 1 "$output"
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printf "\n${GREEN}${BOLD}Done normalizing audio in $filename.$extension | output: $output${NORMAL}\n\n"
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#---------------------------------------
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# This seems better. 2 pass using loudnorm filter.
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# 1st pass: ffmpeg -i "$filename.$extension" -pass 1 -filter:a loudnorm=print_format=json -vn -sn -dn -f null /dev/null
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# 2nd pass: ffmpeg -i "$filename.$extension" -c:v copy -pass 2 -filter:a loudnorm=linear=true:measured_I=$input_i:measured_LRA=$input_lra:measured_tp=$input_tp:measured_thresh=$input_thresh "$output"
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# TODO: extract the $input_i, input_lra, etc from the 1st pass output so that this can be automated.
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# TODO: stackoverflow said if there are subtitles or multiple vid streams then add "-map 0" before the output name. Test this.
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# TODO: disable the log file or just delete it after normalizing.
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