diff --git a/celeste/ffmpeg.sh b/celeste/ffmpeg.sh
index 24f6214..84cf17a 100644
--- a/celeste/ffmpeg.sh
+++ b/celeste/ffmpeg.sh
@@ -1,65 +1,90 @@
 #!/bin/bash
 
 
-# Where screenshots are saved
+# Where screenshots are saved.
+# SC_ROOT/SC_DIR should contain episode screenshot directories
 SC_ROOT="model_data/current"
-
-# WILL BE DELETED
-OUTPUT_DIR="model_data/video_output"
+SC_DIR="screenshots"
 
 
-# To make with fade in and out:
-# ffmpeg -framerate 30 -i %03d.png -vf "scale=1024x1024:flags=neighbor,fade=in:0:45,fade=out:1040:45" out.webm
+# Select a temporary working directory
+# if false, uses ramdisk.
+# set to true if ramdisk overflows.
+if false; then
+	OUTPUT_DIR="model_data/video_output"
 
-render_dir () {
+	# This directory will be deleted.
+	# Make sure it doesn't already exist.
+	if [ -e "$OUTPUT_DIR" ]; then
+		echo "$OUTPUT_DIR exists, exiting. Please delete it manually."
+		exit 1
+	fi
+	mkdir -p $OUTPUT_DIR
+
+else
+	OUTPUT_DIR=$(mktemp -d)
+fi
+
+
+# Usage:
+# render_episode <src_dir> <output_name>
+#
+# Turns a directory of frame screenshots into a video.
+# Applies upscaling. We do it early, because upscaling
+# after encoding will exaggerate artifacts.
+render_episode () {
 	ffmpeg \
 		-y \
 		-loglevel quiet \
 		-framerate 30 \
-		-i $1/hackcel_%003d.png \
+		-i "$1/hackcel_%003d.png" \
 		-c:v libx264 \
-		-pix_fmt yuv420p \
-		$OUTPUT_DIR/${1##*/}.mp4
+		-crf 20 \
+		-preset slow \
+		-tune animation \
+		-vf "scale=1024x1024:flags=neighbor" \
+		"$2.mp4"
 }
 
-# Todo: error out if exists
-mkdir -p $OUTPUT_DIR
 
 
 echo "Making episode files..."
-for D in $SC_ROOT/screenshots/*; do
+for D in "$SC_ROOT/$SC_DIR"/*; do
 	if [ -d "${D}" ]; then
-		render_dir $D
+		render_episode "$D" "$OUTPUT_DIR/${D##*/}"
 	fi
 done
 
-echo "Done."
 
 
-# Generate video for each run
-for f in $OUTPUT_DIR/*.mp4; do
-	echo file \'$f\' >> video_merge_list
+echo "Merging..."
+for f in "$OUTPUT_DIR"/*.mp4; do
+	echo file \'$f\' >> "$OUTPUT_DIR/video_merge_list"
 done
 
+
+
 # Merge videos
 ffmpeg \
 	-loglevel error -stats -y \
 	-f concat \
 	-safe 0 \
-	-i video_merge_list \
-	-vf "scale=1024x1024:flags=neighbor" \
-	$SC_ROOT/1x.mp4
+	-i "$OUTPUT_DIR/video_merge_list" \
+	"$SC_ROOT/1x.mp4"
+echo ""
+echo "Making accelerated video..."
+
 
-rm video_merge_list
 
 # Make accelerated video
 ffmpeg \
 	-loglevel error -stats -y \
-	-i $SC_ROOT/1x.mp4 \
+	-i "$SC_ROOT/1x.mp4" \
 	-framerate 60 \
 	-filter:v "setpts=0.125*PTS" \
-	$SC_ROOT/8x.mp4
+	"$SC_ROOT/8x.mp4"
 
-echo "Cleaning up..."
 
+
+echo "Cleaning up...."
 rm -dr $OUTPUT_DIR