use custom path for ffmpeg/ffprobe binaries

AAXtoMP3

@@ -34,6 +34,7 @@ authorOverride=             # Override the author, ignoring the metadata
 audibleCli=0                # Default off, Use additional data gathered from mkb79/audible-cli
 aaxc_key=                   # Initialize variables, in case we need them in debug_vars
 aaxc_iv=                    # Initialize variables, in case we need them in debug_vars
+ffmpegPath=                 # Set a custom path, useful for using the updated version that supports aaxc
 
 # -----
 # Code tip Do not have any script above this point that calls a function or a binary.  If you do
@@ -88,6 +89,8 @@ while true; do
     --keep-author     ) keepArtist="$2";                                                shift 2 ;;
                       # Author override
     --author          ) authorOverride="$2";                                            shift 2 ;;
+                      # Ffmpeg path override
+    --ffmpeg-path     ) ffmpegPath="$2";                                                shift 2 ;;
                       # Command synopsis.
     -h | --help       ) printf "$usage" $0 ;                                            exit ;;
                       # Standard flag signifying the end of command line processing.
@@ -212,6 +215,16 @@ else
     SED="gsed"
 fi
 
+# Use custom ffmpeg (and ffprobe) binary ( --ffmpeg-path flag)
+if [ -n "$ffmpegPath" ]; then
+  FFMPEG="$ffmpegPath/ffmpeg"
+  FFPROBE="$ffmpegPath/ffprobe"
+else
+  FFMPEG="ffmpeg"
+  FFPROBE="ffprobe"
+fi
+
+debug_vars "ffmpeg/ffprobe paths" FFMPEG FFPROBE
 
 # -----
 # Detect which annoying version of grep we have
@@ -242,7 +255,7 @@ fi
 
 # -----
 # Detect ffmpeg and ffprobe
-if [[ "x$(type -P ffmpeg)" == "x" ]]; then
+if [[ "x$(type -P "$FFMPEG")" == "x" ]]; then
   echo "ERROR ffmpeg was not found on your env PATH variable"
   echo "Without it, this script will break."
   echo "INSTALL:"
@@ -255,7 +268,7 @@ fi
 
 # -----
 # Detect ffmpeg and ffprobe
-if [[ "x$(type -P ffprobe)" == "x" ]]; then
+if [[ "x$(type -P "$FFPROBE")" == "x" ]]; then
   echo "ERROR ffprobe was not found on your env PATH variable"
   echo "Without it, this script will break."
   echo "INSTALL:"
@@ -409,7 +422,7 @@ validate_aax() {
   set +e errexit
 
   # Take a look at the aax file and see if it is valid. If the source file is aaxc, we give ffprobe additional flags
-  output="$(ffprobe -loglevel warning ${decrypt_param} -i "${media_file}" 2>&1)"
+  output="$("$FFPROBE" -loglevel warning ${decrypt_param} -i "${media_file}" 2>&1)"
 
   # If invalid then say something.
   if [[ $? != "0" ]] ; then
@@ -422,7 +435,7 @@ validate_aax() {
 
   # This is a big test only performed when the --validate switch is passed.
   if [[ "${VALIDATE}" == "1" ]]; then
-    output="$(ffmpeg -hide_banner ${decrypt_param} -i "${media_file}" -vn -f null - 2>&1)"
+    output="$("$FFMPEG" -hide_banner ${decrypt_param} -i "${media_file}" -vn -f null - 2>&1)"
     if [[ $? != "0" ]] ; then
       log "ERROR: Invalid File: ${media_file}"
     else
@@ -492,7 +505,7 @@ validate_extra_files() {
 save_metadata() {
   local media_file
   media_file="$1"
-  ffprobe -i "$media_file" 2> "$metadata_file"
+  "$FFPROBE" -i "$media_file" 2> "$metadata_file"
   if [[ $(type -P mediainfo) ]]; then
     echo "Mediainfo data START" >> "$metadata_file"
     # Mediainfo output is structured like ffprobe, so we append it to the metadata file and then parse it with get_metadata_value()
@@ -693,7 +706,7 @@ do
 
   # Display the total length of the audiobook in format hh:mm:ss
   # 10#$var force base-10 interpretation. By default it's base-8, so values like 08 or 09 are not octal numbers
-  total_length="$(ffprobe -v error ${decrypt_param} -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "${aax_file}" | cut -d . -f 1)"
+  total_length="$("$FFPROBE" -v error ${decrypt_param} -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "${aax_file}" | cut -d . -f 1)"
   hours="$((total_length/3600))"
   if [ "$((hours<10))" = "1" ]; then hours="0$hours"; fi
   minutes="$((total_length/60-60*10#$hours))"
@@ -712,8 +725,8 @@ do
   if [ "${continue}" == "0" ]; then
     # This is the main work horse command.  This is the primary transcoder.
     # This is the primary transcode. All the heavy lifting is here.
-    debug 'ffmpeg -loglevel error -stats ${decrypt_param} -i "${aax_file}" -vn -codec:a "${codec}" -ab ${bitrate} -map_metadata -1 -metadata title="${title}" -metadata artist="${artist}" -metadata album_artist="${album_artist}" -metadata album="${album}" -metadata date="${album_date}" -metadata track="1/1" -metadata genre="${genre}" -metadata copyright="${copyright}" "${output_file}"'
+    debug '"$FFMPEG" -loglevel error -stats ${decrypt_param} -i "${aax_file}" -vn -codec:a "${codec}" -ab ${bitrate} -map_metadata -1 -metadata title="${title}" -metadata artist="${artist}" -metadata album_artist="${album_artist}" -metadata album="${album}" -metadata date="${album_date}" -metadata track="1/1" -metadata genre="${genre}" -metadata copyright="${copyright}" "${output_file}"'
-    </dev/null ffmpeg -loglevel error \
+    </dev/null "$FFMPEG" -loglevel error \
       -stats \
       ${decrypt_param} \
       -i "${aax_file}" \
@@ -761,7 +774,7 @@ do
       if [ "$((${loglevel} > 1))" == "1" ]; then
         log "Extracting cover into ${cover_file}..."
       fi
-      </dev/null ffmpeg -loglevel error -activation_bytes "${auth_code}" -i "${aax_file}" -an -codec:v copy "${cover_file}"
+      </dev/null "$FFMPEG" -loglevel error -activation_bytes "${auth_code}" -i "${aax_file}" -an -codec:v copy "${cover_file}"
     fi
   fi
 
@@ -842,7 +855,7 @@ do
         #ffmpeg version 4+ and on the output for all older versions.
         split_input=""
         split_output=""
-        if [ "$(($(ffmpeg -version | $SED -E 's/[^0-9]*([0-9]).*/\1/g;1q') > 3))" = "1" ]; then
+        if [ "$(($("$FFMPEG" -version | $SED -E 's/[^0-9]*([0-9]).*/\1/g;1q') > 3))" = "1" ]; then
           split_input="-ss ${chapter_start%?} -to ${chapter_end}"
         else
           split_output="-ss ${chapter_start%?} -to ${chapter_end}"
@@ -856,7 +869,7 @@ do
           if [ "$((${loglevel} > 1))" == "1" ]; then
             log "Splitting chapter ${chapternum}/${chaptercount} start:${chapter_start%?}(s) end:${chapter_end}(s)"
           fi
-          </dev/null ffmpeg -loglevel quiet \
+          </dev/null "$FFMPEG" -loglevel quiet \
             -nostats \
             ${split_input} \
             -i "${output_file}" \
@@ -907,7 +920,7 @@ do
       if [ "${audibleCli}" == "1" ]; then
         mv "${tmp_chapter_file}" "${output_directory}/${currentFileNameScheme}.chapters.txt"
       else
-        ffprobe -i "${aax_file}" -print_format csv -show_chapters 2>/dev/null | awk -F "," '{printf "CHAPTER%d=%02d:%02d:%02.3f\nCHAPTER%dNAME=%s\n", NR, $5/60/60, $5/60%60, $5%60, NR, $8}' > "${output_directory}/${currentFileNameScheme}.chapters.txt"
+        "$FFPROBE" -i "${aax_file}" -print_format csv -show_chapters 2>/dev/null | awk -F "," '{printf "CHAPTER%d=%02d:%02d:%02.3f\nCHAPTER%dNAME=%s\n", NR, $5/60/60, $5/60%60, $5%60, NR, $8}' > "${output_directory}/${currentFileNameScheme}.chapters.txt"
       fi
       mp4chaps -i "${output_file}"
     fi