diff --git a/rc_shared.sh b/rc_shared.sh
index 59b4984..ffac48c 100644
--- a/rc_shared.sh
+++ b/rc_shared.sh
@@ -823,7 +823,7 @@ function pv-test {
 
 	# Loop Data #
 
-	declare -l {vpreset,crf,vbr,abr,achannel,afreq}s="default"
+	declare -l {vpreset,crf,vbr,abr,achannel,afreq,over,under}s="default"
 
 	echo -e " * * Loop Settings * * \n"
 
@@ -852,6 +852,20 @@ function pv-test {
 	fi
 	echo -e "  video bitrates: '$vbrs'\n"
 
+	if [[ "$vcodecs" == *"libsvtav1"* ]]; then
+		read -p "Please provide any over percentages for libsvtav1: [default] " test_overs
+		if [[ -n "$test_overs" ]]; then
+			overs="$test_overs"
+		fi
+		echo -e "  over percentages: '$overs'\n"
+
+		read -p "Please provide any under percentages for libsvtav1: [default] " test_unders
+		if [[ -n "$test_unders" ]]; then
+			unders="$test_unders"
+		fi
+		echo -e "  under percentages: '$unders'\n"
+	fi
+
 	acodecs="aac libopus"
 	read -p "Please provide the audio codecs to test: [$acodecs] " test_acodecs
 	if [[ -n "$test_acodecs" ]]; then
@@ -920,9 +934,10 @@ function pv-test {
 		echo -e " * Testing with 'pv2' complete! * \n"
 	fi
 
+	# TBD - Do multiplication with `wc` rather than a loop here.
 	count=0
-	for vcodec in $vcodecs; do for vpreset in $vpresets; do
-		for crf in $crfs; do for vbr in $vbrs; do
+	for vcodec in $vcodecs; do for vpreset in $vpresets; do for crf in $crfs; do
+		for vbr in $vbrs; do for over in $overs; do for under in $under; do
 			for acodec in $acodecs; do for abr in $abrs;
 				do for achannel in $achannels; do for afreq in $afreqs; do
 					for ext in $exts; do
@@ -930,8 +945,8 @@ function pv-test {
 					done
 				done done
 			done done
-		done done
-	done done
+		done done done
+	done done done
 	plural=""
 	if (( $count != 1 )); then
 		plural="s"
@@ -940,8 +955,8 @@ function pv-test {
 
 	count=0
 	unset vcodec vpreset crf vbr acodec abr ext
-	for vcodec in $vcodecs; do for vpreset in $vpresets; do
-		for crf in $crfs; do for vbr in $vbrs; do
+	for vcodec in $vcodecs; do for vpreset in $vpresets; do for crf in $crfs; do
+		for vbr in $vbrs; do for over in $overs; do for under in $under; do
 			for acodec in $acodecs; do for abr in $abrs;
 				do for achannel in $achannels; do for afreq in $afreqs; do
 					for ext in $exts; do
@@ -972,9 +987,38 @@ function pv-test {
 						if [[ "$crf" != "default" ]]; then
 							bitrate="-crf $crf"
 						fi
+						declare {o,u}fn=""
 						if [[ "$vbr" != "default" ]]; then
 							if [[ "$vcodec" == "libsvtav1" ]]; then
-								bitrate="$bitrate -svtav1-params rc=1:tbr=$vbr:overshoot-pct=0:undershoot-pct=100"
+								#bitrate="$bitrate -svtav1-params rc=1:tbr=$vbr:overshoot-pct=0:undershoot-pct=100"
+
+								declare {o,u}=""
+								if [[ "$over" != "default" ]]; then
+									o=":overshoot-pct=$over"
+									ofn="-o$over"
+								fi
+								if [[ "$under" != "default" ]]; then
+									u=":undershoot-pct=$under"
+									ufn="-u$under"
+								fi
+
+								if [[ "$crf" == "default" ]]; then
+									# Variable Bitrate, rate passed should be the TARGET, not the max.
+									# Can control the params which allow the target to go up and down, but defaults are okay.
+									# Seems better to not try and force this to imitate "-b:v -minrate -maxrate -bufsize"
+									# Will definitely want to use a slower preset to ensure the quality stays consistent.
+
+									# Can be done like this if not changing over or under.
+									#bitrate="-b:v $vbr"
+
+									# rc=1, over defaults to 25, under defaults to 50
+									# rc=2, over defaults to 25, under defaults to 25
+									bitrate="-svtav1-params rc=1:tbr=${vbr}${o}${u}"
+								else
+									# Capped CRF, when both a CRF and bitrate are passed.
+									# Better to use high CRF with low BR than high BR with low CRF (produces artifacts/tearing).
+									bitrate="-svtav1-params rc=0:crf=${crf}:mbr=${vbr}${o}${u}"
+								fi
 							else
 								bitrate="$bitrate -b:v $vbr -minrate 0 -maxrate $vbr -bufsize $vbr"
 							fi
@@ -1003,7 +1047,7 @@ function pv-test {
 							frequency="-ar $afreq"
 						fi
 
-						newfile="_${size_in}p_${vcodec}-${vpreset}-${crf}-${vbr}_${acodec}-${abr}-${achannel}-${afreq}.${ext}"
+						newfile="_${size_in}p_${vcodec}-${vpreset}-${crf}-${vbr}${ofn}${ufn}_${acodec}-${abr}-${achannel}-${afreq}.${ext}"
 						echo -e " * Parameters for this test: $newfile * \n"
 
 						if [[ -e "$newfile" ]]; then
@@ -1052,8 +1096,8 @@ function pv-test {
 					done
 				done done
 			done done
-		done done
-	done done
+		done done done
+	done done done
 
 	## Finish ##
 
@@ -1066,62 +1110,62 @@ function pv-test {
 
 # 20260914 - After playing with pv-test for a while.
 function pv3 {
-		  org="$1"
-		  out="$2"
-		  echo "Processing '$org' to '$out' using AV1 and OPUS."
+	org="$1"
+	out="$2"
+	echo "Processing '$org' to '$out' using AV1 and OPUS."
 
-		  ## Versions ##
+	## Versions ##
 
-		  # v0
-		  scale=-1:720
-		  preset=0 # took 20 minutes where preset 2 was under 2 minutes
-		  crf=18
-		  vbr=2000k # this is creating 2Mbps files, not maxxing at 2.
-		  overshoot=0
-		  undershoot=100
+	# v0
+	scale=-1:720
+	preset=0 # took 20 minutes where preset 2 was under 2 minutes
+	crf=18
+	vbr=2000k # this is creating 2Mbps files, not maxxing at 2.
+	overshoot=0
+	undershoot=100
 
-		  # v1
-		  preset=2 # WAY faster and still great.
-		  crf=28 # much smaller filesize
+	# v1
+	preset=2 # WAY faster and still great.
+	crf=28 # much smaller filesize
 
-		  # v2
-		  # Try to mimic h264 better.
-		  vbr=1000k
-		  overshoot=100
+	# v2
+	# Try to mimic h264 better.
+	vbr=1000k
+	overshoot=100
 
-		  # v3
-		  # Fix weird aspect ratios.
-		  scale="1280:720,setsar=1"
+	# v3
+	# Fix weird aspect ratios.
+	scale="1280:720,setsar=1"
 
-		  ## Main ##
+	## Main ##
 
-		  echo -e "\n * Original File * \n"
-		  ffprobe -i "$org"
+	echo -e "\n * Original File * \n"
+	ffprobe -i "$org"
 
-		  echo -e "\n * Starting Processing *\n"
-		  date
-		  set -x
-		  ffmpeg -nostdin -hide_banner -loglevel level+warning \
-					 -i "$org" \
-					 -c:v libsvtav1 \
-					 -preset $preset \
-					 -filter:v scale=$scale \
-					 -crf $crf \
-					 -svtav1-params rc=1:tbr=${vbr}:overshoot-pct=${overshoot}:undershoot-pct=${undershoot} \
-					 -c:a libopus \
-					 -filter:a dynaudnorm=f=33:g=65:p=0.66:m=33.3 \
-					 -movflags +faststart \
-					 "$out"
-		  status="$?"
-		  set +x
+	echo -e "\n * Starting Processing *\n"
+	date
+	set -x
+	ffmpeg -nostdin -hide_banner -loglevel level+warning \
+		-i "$org" \
+		-c:v libsvtav1 \
+		-preset $preset \
+		-filter:v scale=$scale \
+		-crf $crf \
+		-svtav1-params rc=1:tbr=${vbr}:overshoot-pct=${overshoot}:undershoot-pct=${undershoot} \
+		-c:a libopus \
+		-filter:a dynaudnorm=f=33:g=65:p=0.66:m=33.3 \
+		-movflags +faststart \
+		"$out"
+	status="$?"
+	set +x
 
-		  if [[ "$status" != 0 || ! -s "$out" ]]; then
-					 echo "Failed, deleting output."
-					 mv -v "$out" ~/TRASH/
-					 return $status
-		  fi
+	if [[ "$status" != 0 || ! -s "$out" ]]; then
+		echo "Failed, deleting output."
+		mv -v "$out" ~/TRASH/
+		return $status
+	fi
 
-		  echo -e "\n * Success! *"
+	echo -e "\n * Success! *"
 }