scripts/split-media-file.sh at master · langenhagen/scripts · GitHub

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#!/usr/bin/env bash
# Split a video/audio file into many based on a separate timestamps list.
#
#   Usage: ./split-media-file.sh input.webm timestamps.txt
#
# The timestamps file should have following format:
#
#   0:00 - Introduction
#   1:23 - Chapter 1
#   34:56 - Chapter 2
#   1:02:34 - The rest of the file
#   [...]
#
# author: andreasl
print_help() {
    cat <<'EOF'
Usage: split-media-file.sh [OPTIONS] <input-file> <timestamps-file>

Split a media file into multiple chapter files using timestamps.

Options:
  -h, --help  Show this help message and exit

Timestamps file format:
  0:00 - Introduction
  1:23 - Chapter 1
  34:56 - Chapter 2
  1:02:34 - The rest of the file
EOF
}

if [[ "$1" == "-h" || "$1" == "--help" ]]; then
    print_help
    exit 0
fi

if [[ $# -ne 2 ]]; then
    print_help >&2
    exit 1
fi

input_file="$1"
timestamps_file="$2"

# Detect audio codec
codec=$(ffprobe \
    -v error \
    -select_streams a:0 \
    -show_entries stream=codec_name \
    -of default=noprint_wrappers=1:nokey=1 \
    "$input_file")

# Map codec to container/extension
case "$codec" in
opus)
    out_ext="opus"
    out_fmt="opus"
    ;;
aac)
    out_ext="m4a"
    out_fmt="ipod"
    ;;
mp3)
    out_ext="mp3"
    out_fmt="mp3"
    ;;
vorbis)
    out_ext="ogg"
    out_fmt="ogg"
    ;;
*)
    out_ext="audio"
    out_fmt=""
    ;;
esac

lines=()
# the `-n` test keeps a final line that is not terminated by a newline
while IFS= read -r timestamps_line || [ -n "$timestamps_line" ]; do
    lines+=("$timestamps_line")
done <"$timestamps_file"

for ((i = 0; i < ${#lines[@]}; i++)); do
    printf -v num "%04d" $((i + 1))

    line="${lines[i]}"
    start_time="${line%% - *}"
    title="${line#* - }"

    # Check next line for end timestamp
    if ((i + 1 < ${#lines[@]})); then
        next_line="${lines[i + 1]}"
        next_start_time="${next_line%% - *}"
        ffmpeg \
            -hide_banner \
            -nostdin \
            -i "$input_file" \
            -ss "$start_time" \
            -to "$next_start_time" \
            -c copy \
            -vn ${out_fmt:+-f "$out_fmt"} \
            "${num}_${title}.${out_ext}"
    else
        ffmpeg \
            -hide_banner \
            -nostdin \
            -i "$input_file" \
            -ss "$start_time" \
            -c copy \
            -vn ${out_fmt:+-f "$out_fmt"} \
            "${num}_${title}.${out_ext}"
    fi
done