diff --git a/lib/encode/mp3 b/lib/encode/mp3
index d9fdc36..9b4148c 100644
--- a/lib/encode/mp3
+++ b/lib/encode/mp3
@@ -1,13 +1,30 @@
 #!/usr/bin/env bash
+
+# Copyright © 2012-2026 ScriptFanix
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# A copy of the GNU General Public License v3 is includded in the LICENSE file
+# at the root of the project.
+
 encodeFile::mp3() {
+	# Build lame ABR encode command with all available metadata
 	lameopts=(${ionice}lame --quiet --noreplaygain)
 	lameopts+=(-v --abr ${destinationquality[$destination]})
+	# Embed ID3 tags for each available metadata field
 	[ -n "$album"	] && lameopts+=(--tl "$album" )
 	[ -n "$artist"	] && lameopts+=(--ta "$artist")
 	[ -n "$genre"	] && lameopts+=(--tg "$genre")
 	[ -n "$title"	] && lameopts+=(--tt "$title")
 	[ -n "$track"	] && lameopts+=(--tn "$track")
 	[ -n "$year"	] && lameopts+=(--ty "$year")
+	# Extended tags using ID3v2 frames (TXXX for custom/non-standard fields)
 	[ -n "$albumartist" ] && lameopts+=(--tv TPE2="$albumartist")
 	[ -n "$composer" ] && lameopts+=(--tv TCOM="$composer")
 	[ -n "$performer" ] && lameopts+=(--tv TOPE="$performer")
@@ -18,6 +35,9 @@ encodeFile::mp3() {
 	[ -n "$replaygain_trk" ] \
 		&& lameopts+=(--tv "TXXX=REPLAYGAIN_TRACK_GAIN=$replaygain_trk")
 	[ -n "$disc"	] && lameopts+=(--tv TPOS="$disc")
+
+	# Handle noresample: force lame to use a specific sample rate to prevent
+	# lame's own automatic downsampling at low bitrates
 	if (( ${destinationnoresample[$destination]:-0} == 1 ))
 	then
 		# If 'rate' is not one of these value, it cannot be encoded to
@@ -25,6 +45,7 @@ encodeFile::mp3() {
 		# rate to use.
 		if [ -n "${destinationfrequency["$destination"]}" ]
 		then
+			# Target frequency was explicitly set; use that
 			case ${destinationfrequency["$destination"]} in
 				48000)	lameopts+=(--resample 48)	;;
 				44100)	lameopts+=(--resample 44.1)	;;
@@ -38,8 +59,10 @@ encodeFile::mp3() {
 			esac
 		elif (( rate > 48000 ))
 		then
+			# Source rate exceeds MP3 maximum; cap at 48kHz
 			lameopts+=(--resample 48)
 		else
+			# Use the source file's own sample rate
 			case $rate in
 				48000)	lameopts+=(--resample 48)	;;
 				44100)	lameopts+=(--resample 44.1)	;;
@@ -53,7 +76,11 @@ encodeFile::mp3() {
 			esac
 		fi
 	fi
+	# Append input WAV and output MP3 paths to complete the command
 	lameopts+=("$tempdir/$tmpfile.wav" "${destinationpath[$destination]}/$destdir/$destfile.mp3")
+
+	# Insert the encode task into the DB, linked to the decode (or sox) task
+	# Depend on sox task if it exists, else decode task
 	encodetaskid=$(
 		Insert tasks <<-EOInsert
 			key		${fileid}lame$destination
@@ -63,6 +90,9 @@ encodeFile::mp3() {
 			$(
 				for key in ${!lameopts[@]}
 				do
+					# Escape special characters that could
+					# interfere with bash glob/brace
+					# expansion
 					cleanedopts="${lameopts[key]//\&/\\\&}"
 					cleanedopts="${cleanedopts//\[/\\[}"
 					cleanedopts="${cleanedopts//\]/\\]}"
@@ -78,6 +108,8 @@ encodeFile::mp3() {
 			ascii		${destinationascii["$destination"]}
 		EOInsert
 	)
+	# Increment parent task's required_by counter so it won't clean up
+	# until all children finish
 	parent_required=$(
 		Select tasks required_by			\
 			<<<"id = ${soxtaskid:-$decodetaskid}"
@@ -85,5 +117,5 @@ encodeFile::mp3() {
 	Update tasks required_by $((++parent_required))	\
 		<<<"id = ${soxtaskid:-$decodetaskid}"
 	progressSpin
-	soxtaskid=''
+	soxtaskid=''	# Clear sox task ID so next destination starts fresh
 }
diff --git a/lib/encode/opus b/lib/encode/opus
index 29b833e..7c2ec11 100644
--- a/lib/encode/opus
+++ b/lib/encode/opus
@@ -1,9 +1,27 @@
 #!/usr/bin/env bash
+
+# Copyright © 2012-2026 ScriptFanix
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# A copy of the GNU General Public License v3 is includded in the LICENSE file
+# at the root of the project.
+
 encodeFile::opus() {
+	# Build opusenc VBR encode command
 	opusencopts=(${ionice}opusenc --quiet)
 	opusencopts+=(--bitrate ${destinationquality[$destination]})
+	# Add Forward Error Correction if a packet loss percentage was
+	# configured
 	[ -n "${destinationloss["$destination"]}" ]	\
 	&& opusencopts+=(--expect-loss "${destinationloss["$destination"]}")
+	# Embed Ogg comment tags
 	[ -n "$albumartist" ] && opusencopts+=(--comment "ALBUMARTIST=$albumartist")
 	[ -n "$album"	] && opusencopts+=(--comment "ALBUM=$album")
 	[ -n "$artist"	] && opusencopts+=(--artist "$artist")
@@ -20,6 +38,8 @@ encodeFile::opus() {
 		&& opusencopts+=(--comment)				\
 		&& opusencopts+=("REPLAYGAIN_TRACK_GAIN=$replaygain_trk")
 	[ -n "$title"	] && opusencopts+=(--title "$title")
+	# Split "track/total" format: opusenc uses separate TRACKNUMBER and
+	# TRACKTOTAL fields
 	[ -n "$track"	] && opusencopts+=(--comment "TRACKNUMBER=${track%/*}")
 	[ -n "${track#*/}" ] && opusencopts+=(--comment "TRACKTOTAL=${track#*/}")
 	[ -n "$year"	] && opusencopts+=(--comment "DATE=$year")
@@ -31,6 +51,8 @@ encodeFile::opus() {
 			fileid		$destfileid
 			filename	$destdir/$destfile.opus
 			$(
+				# Escape special characters that could
+				# interfere with bash glob/brace expansion
 				for key in ${!opusencopts[@]}
 				do
 					cleanedopts="${opusencopts[key]//\&/\\\&}"
@@ -48,6 +70,8 @@ encodeFile::opus() {
 			ascii		${destinationascii["$destination"]}
 		EOInsert
 	)
+	# Increment parent task's required_by counter so it won't clean up
+	# until all children finish
 	parent_required=$(
 		Select tasks required_by			\
 			<<<"id = ${soxtaskid:-$decodetaskid}"
diff --git a/lib/encode/vorbis b/lib/encode/vorbis
index 40007c6..1de3f16 100644
--- a/lib/encode/vorbis
+++ b/lib/encode/vorbis
@@ -1,6 +1,23 @@
 #!/usr/bin/env bash
+
+# Copyright © 2012-2026 ScriptFanix
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# A copy of the GNU General Public License v3 is includded in the LICENSE file
+# at the root of the project.
+
 encodeFile::vorbis() {
+	# Build oggenc quality-based encode command
+	# (-Q = quiet, -q = quality level)
 	oggencopts=(${ionice}oggenc -Q -q ${destinationquality[$destination]})
+	# Embed Ogg comment tags using oggenc's -c "FIELD=value" syntax
 	[ -n "$albumartist" ] && oggencopts+=(-c "ALBUMARTIST=$albumartist")
 	[ -n "$album"	] && oggencopts+=(-l "$album")
 	[ -n "$artist"	] && oggencopts+=(-a "$artist")
@@ -17,6 +34,7 @@ encodeFile::vorbis() {
 	[ -n "$title"	] && oggencopts+=(-t "$title")
 	[ -n "$track"	] && oggencopts+=(-N "$track")
 	[ -n "$year"	] && oggencopts+=(-d "$year")
+	# -o output must come before input for oggenc
 	oggencopts+=(-o "${destinationpath[$destination]}/$destdir/$destfile.ogg" "$tempdir/$tmpfile.wav")
 	encodetaskid=$(
 		Insert tasks <<-EOInsert
@@ -25,6 +43,8 @@ encodeFile::vorbis() {
 			fileid		$destfileid
 			filename	$destdir/$destfile.ogg
 			$(
+				# Escape special characters that could
+				# interfere with bash glob/brace expansion
 				for key in ${!oggencopts[@]}
 				do
 					cleanedopts="${oggencopts[key]//\&/\\\&}"
@@ -42,6 +62,8 @@ encodeFile::vorbis() {
 			ascii		${destinationascii["$destination"]}
 		EOInsert
 	)
+	# Increment parent task's required_by counter so it won't clean up
+	# until all children finish
 	parent_required=$(
 		Select tasks required_by			\
 			<<<"id = ${soxtaskid:-$decodetaskid}"