diff --git a/4-seasons.sh b/4-seasons.sh
index a162db6..d362fbf 100755
--- a/4-seasons.sh
+++ b/4-seasons.sh
@@ -88,7 +88,7 @@ done > "$temp_file"
 echo "Step 1/2: encoding raw video..."
 ffmpeg -loglevel warning \
     -f concat -safe 0 -i "$temp_file" \
-    -c:v libx264 -pix_fmt yuv420p -crf "$CRF_SEASONS_RAW" -vsync 2 -an \
+    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_SEASONS_RAW" -vsync 2 -an \
     -y "$temp_video"
 
 raw_duration=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$temp_video")
@@ -102,7 +102,7 @@ final_file="$output_dir/${yesterday}_Mvt${MVT_NUM}-Day${DAY_OF_MVT}of${DAYS_IN_M
 if ! ffmpeg -loglevel warning \
     -i "$temp_video" \
     -vf "setpts=PTS/$speed_factor" \
-    -c:v libx264 -pix_fmt yuv420p -crf "$CRF_SEASONS_FINAL" \
+    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_SEASONS_FINAL" \
     -t "$target_per_clip" -an \
     -y "$final_file"; then
     rm -f "$final_file"
diff --git a/daily_sunrise_video.sh b/daily_sunrise_video.sh
index d5f15a9..d262b1f 100644
--- a/daily_sunrise_video.sh
+++ b/daily_sunrise_video.sh
@@ -110,7 +110,7 @@ raw_video=$(mktemp --suffix=.mp4)
 echo "Step 1/3: encoding raw video..."
 if ! ffmpeg -loglevel warning \
     -f concat -safe 0 -i "$temp_list" \
-    -c:v libx264 -pix_fmt yuv420p -crf "$CRF_SUNRISE" -vsync 2 -an \
+    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_SUNRISE" -vsync 2 -an \
     -y "$raw_video"; then
     "$SCRIPT_DIR/notify.sh" "FAILED: sunrise step 1/3 (encode) $current_date" \
         "ffmpeg raw encode from images failed — check: journalctl -u sky-cam-sunrise.service" || true
@@ -128,7 +128,7 @@ echo "Step 2/3: speed-adjust → $sped_video"
 if ! ffmpeg -loglevel warning \
     -i "$raw_video" \
     -vf "setpts=PTS/${speed_factor}" \
-    -c:v libx264 -pix_fmt yuv420p -crf "$CRF_SUNRISE" -an \
+    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_SUNRISE" -an \
     -y "$sped_video"; then
     rm -f "$sped_video"
     "$SCRIPT_DIR/notify.sh" "FAILED: sunrise step 2/3 (speed) $current_date" \
@@ -223,7 +223,7 @@ if [ -n "$DT" ]; then
     if ffmpeg -loglevel warning \
         -i "$work_video" \
         -vf "${DT}" \
-        -c:v libx264 -pix_fmt yuv420p -crf "$CRF_SUNRISE" \
+        -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_SUNRISE" \
         "${audio_out_flags[@]}" \
         -y "$final_video"; then
         step3b_ok=true
@@ -253,4 +253,14 @@ if $step3b_ok; then
     [ -f "$cam_audio" ] && rm -f "$cam_audio"
     "$SCRIPT_DIR/notify.sh" "Sunrise ready: $current_date" \
         "$(basename "$final_video") — ${actual_dur}s, sunrise at ${SR_TIME}" || true
+
+    # ── Rolling retention: delete sunrise videos older than SUNRISE_RETENTION_DAYS ─
+    retain="${SUNRISE_RETENTION_DAYS:-10}"
+    if [ "$retain" -gt 0 ]; then
+        deleted_old=$(find "$MOVIES_DIR/$CAM_NAME" \
+            -path "*/sunrise-only/*-daily-sunrise.mp4" \
+            -mtime +"$retain" -print -delete 2>/dev/null | wc -l)
+        [ "$deleted_old" -gt 0 ] && \
+            echo "Retention: deleted $deleted_old sunrise video(s) older than ${retain} days"
+    fi
 fi
diff --git a/montage-mvt.sh b/montage-mvt.sh
index c181583..e956178 100755
--- a/montage-mvt.sh
+++ b/montage-mvt.sh
@@ -133,7 +133,7 @@ ffmpeg -loglevel warning \
     -f concat -safe 0 -i "$concat_list" \
     -vf "scale=${VIDEO_W}:${VIDEO_H}:force_original_aspect_ratio=decrease,\
 pad=${VIDEO_W}:${VIDEO_H}:(ow-iw)/2:(oh-ih)/2,setsar=1" \
-    -c:v libx264 -pix_fmt yuv420p -crf "$CRF_MONTAGE" -an \
+    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_MONTAGE" -an \
     -y "$temp_concat"
 
 # ── Step 2: Speed-adjust — saved permanently so music/overlay failure is recoverable ─
@@ -146,7 +146,7 @@ sped_file="$output_dir/${MVT_START}_${SEASON}_Mvt${MVT_NUM}-Sped.mp4"
 if ! ffmpeg -loglevel warning \
     -i "$temp_concat" \
     -vf "setpts=PTS/$speed_factor" \
-    -c:v libx264 -pix_fmt yuv420p -crf "$CRF_MONTAGE" -an \
+    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_MONTAGE" -an \
     -t "$music_duration" -y "$sped_file"; then
     rm -f "$sped_file"
     "$SCRIPT_DIR/notify.sh" "FAILED: montage step 2/3 (speed) $SEASON Mvt$MVT_NUM ($ASTRO_YEAR)" \
@@ -198,7 +198,8 @@ if ffmpeg -loglevel warning \
 "[0:v]fade=t=in:st=0:d=${FADE_DUR},fade=t=out:st=${fade_out_start}:d=${FADE_DUR},${DT}[vout];\
 [1:a]afade=t=in:st=0:d=${FADE_DUR},afade=t=out:st=${fade_out_start}:d=${FADE_DUR}[aout]" \
     -map "[vout]" -map "[aout]" \
-    -c:v libx264 -pix_fmt yuv420p -c:a aac -b:a "$AUDIO_BITRATE" \
+    -c:v libx265 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_MONTAGE_FINAL" \
+    -tag:v hvc1 -c:a aac -b:a "$AUDIO_BITRATE" \
     -t "$music_duration" -y "$output_file"; then
     rm -f "$sped_file"
     echo "Done: $output_file"
diff --git a/sky-cam.conf b/sky-cam.conf
index 87fb9d8..a1f719b 100644
--- a/sky-cam.conf
+++ b/sky-cam.conf
@@ -217,20 +217,28 @@ SUNRISE_TARGET_SECS=10
 SUNRISE_OVERLAY_ENABLED=true
 # Opacity of the sunrise-time text (0.0 = invisible, 1.0 = fully opaque).
 SUNRISE_OVERLAY_OPACITY=0.45
+# Delete daily sunrise videos older than this many days (rolling window).
+# Set 0 to keep forever.
+SUNRISE_RETENTION_DAYS=10
 
 # ── Video encoding quality ────────────────────────────────────────────────────
 # FFmpeg CRF: lower = higher quality / larger files.  Typical range 18–30.
 #   18 ≈ visually lossless     23 = ffmpeg default     28 = smaller/lower
-# Different scripts use different defaults by design — intermediate/draft
-# encodings use a higher CRF (smaller files, quality less critical), while
-# final "polished" outputs use a lower CRF for better quality.
-# Each is independent — changing one does NOT change the others.
+# H.265 (libx265) CRF is not directly comparable — H.265 CRF 22 ≈ H.264 CRF 26
+# in visual quality but ~40-50% smaller file.  Final montages use H.265;
+# intermediates (deleted after use) stay H.264.
 #
-CRF_SUNRISE=28        # daily_sunrise_video.sh   — daily Mattermost upload
-CRF_SEASONS_RAW=28    # 4-seasons.sh             — raw concat before speed-adjust
-CRF_SEASONS_FINAL=26  # 4-seasons.sh             — final daily clip (goes into montage)
-CRF_MONTAGE=26        # montage-mvt.sh           — concat and speed-adjust and final
-AUDIO_BITRATE=192k    # montage-mvt.sh           — music track on movement montages
+# ENCODE_PRESET: slow = better compression, same CRF quality, ~2× encode time.
+# Use 'medium' on slower machines, 'slow' or 'slower' on fast ones.
+# All encodes run at night so 'slow' is the right default.
+#
+CRF_SUNRISE=28           # daily_sunrise_video.sh   — daily Mattermost upload (H.264)
+CRF_SEASONS_RAW=28       # 4-seasons.sh             — raw concat before speed-adjust (H.264)
+CRF_SEASONS_FINAL=26     # 4-seasons.sh             — final daily clip (goes into montage) (H.264)
+CRF_MONTAGE=28           # montage-mvt.sh           — intermediate concat + sped steps (H.264)
+CRF_MONTAGE_FINAL=22     # montage-mvt.sh           — final archive montage (H.265)
+ENCODE_PRESET=slow       # ffmpeg preset for all encodes (slow/medium/fast)
+AUDIO_BITRATE=192k       # montage-mvt.sh           — music track on movement montages
 
 # ── Montage attribution overlay ───────────────────────────────────────────────
 # A translucent bar across the top of each movement montage, naming the
@@ -254,12 +262,15 @@ MONTAGE_ATTR_FADE=1    # attribution fade-in and fade-out length (seconds)
 # CAM_RTSP_<cam> goes in .env (see bottom of this file), not here.
 
 # Seconds between captured frames (applies to all cameras).
-# 10 = one frame every 10 s → 8640 frames/day → good timelapse density.
+# Lower = smoother timelapse + larger storage footprint:
+#   10 s →  8,640 frames/day ~2.5 GB/day     (default, good balance)
+#    5 s → 17,280 frames/day ~5 GB/day        (smoother motion)
+#    2 s → 43,200 frames/day ~12 GB/day       (very smooth, high storage)
+# CAPTURE_STALE_SECS should always be at least 2× CAPTURE_INTERVAL.
 CAPTURE_INTERVAL=10
 
 # Seconds without a new frame before the watchdog sends a stall notification.
-# Should be at least 2× CAPTURE_INTERVAL.  A recovery notification fires
-# automatically when frames start arriving again.
+# A recovery notification fires automatically when capture resumes.
 CAPTURE_STALE_SECS=30
 
 # ── Sunrise audio capture ──────────────────────────────────────────────────────