Sync audio/video files in some format in SRC to another format in DST.

syncxcode

#!/bin/bash
# usage: syncxcode SRC DST
set -eu

max_procs=3
src_format=flac
dst_format=mp3

function sync {
    set -eu
    local file=${1:?no filepath given}; shift
    # Declare rel on separate line to avoid masking realpath's return value.
    local rel
    rel=$(realpath --relative-to "$src_dir" "$file")
    local src=$src_dir/$rel
    local dst=$dst_dir/${rel%.*}.$dst_format
    if [[ -e "$dst" ]]; then
        echo "= $rel"
        return
    fi
    echo "> $rel"
    mkdir -pv "$(dirname "$dst")"
    ffmpeg -loglevel error -i "$src" "$dst"
}
export -f sync


src_dir=$(realpath "${1:?no source dir given}"); shift
dst_dir=$(realpath "${1:?no destination dir given}"); shift

export src_dir dst_dir dst_format
# The first argument to bash is the name of the shell, used in error and
# warning messages.
find "$src_dir" -type f -name "*.$src_format" -print0 \
    | xargs -P $max_procs -I{} -0 bash -c 'sync "$1"' bash {}