From df1f8f488994dcedc656ee1eae2f2f87f258cff1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luk=C3=A1=C5=A1=20Kucharczyk?= <lukas@kucharczyk.xyz>
Date: Sat, 8 Oct 2022 00:30:24 +0200
Subject: [PATCH] strip_track_except: improve detect if more than 1 track is
 present detect if undesired tracks are present show progress bar using pv

---
 strip_track_except.sh | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/strip_track_except.sh b/strip_track_except.sh
index 24f764f..539b0e3 100755
--- a/strip_track_except.sh
+++ b/strip_track_except.sh
@@ -10,5 +10,15 @@ FILENAME=$1
 LANGUAGE_TO_KEEP="${2:-jpn}"
 echo -n "Processing "
 colorprint "$FILENAME"
+
+# capture JSON output and remove the excessively large code_private_data field
+JSON_OUTPUT=$(mkvmerge -J "$FILENAME" | jq '[ .tracks[] | select(.type=="audio") | del(.properties.codec_private_data) ]')
+TRACK_COUNT=$(echo "$JSON_OUTPUT" | jq length)
+# check if more than 1 audio track is present
+[[ $TRACK_COUNT -lt 2 ]] && echo -e "\tFile has only 1 track, skipping." && exit 1
+# check if tracks other than the one to keep are present
+UNDESIRED_TRACK_COUNT=$(echo "$JSON_OUTPUT" | jq '[.[] | select(.properties.language!="$LANGUAGE_TO_KEEP")] | length')
+[[ $TRACK_COUNT -lt 2 ]] && echo -e "\tFile has only '$LANGUAGE_TO_KEEP' tracks, skipping." && exit 1
 FILENAME_WITHOUT_EXT=${FILENAME%.*}
-ffmpeg -i "$FILENAME" -map 0:v -map 0:a:m:language:${LANGUAGE_TO_KEEP} -map 0:s -c copy "${FILENAME_WITHOUT_EXT}.converted.mkv"
+echo -e "\tRemoving all audio tracks except '$LANGUAGE_TO_KEEP' tracks..."
+pv "$FILENAME" | ffmpeg -i pipe:0 -map 0:v -map 0:a:m:language:${LANGUAGE_TO_KEEP} -map 0:s -c copy -v warning "${FILENAME_WITHOUT_EXT}.converted.mkv"