diff --git a/phase3_scripts/encode_all.sh b/phase3_scripts/encode_all.sh
new file mode 100755
index 0000000..b7261fb
--- /dev/null
+++ b/phase3_scripts/encode_all.sh
@@ -0,0 +1,25 @@
+#!/bin/bash
+SRC=$HOME/measurements/source/bbb_720p.mov
+OUT=$HOME/measurements/encoded
+LOG=$HOME/measurements/logs
+mkdir -p "$OUT" "$LOG"
+: > $LOG/encode.log
+
+encode() {
+  local label=$1; shift
+  local t0=$(date +%s)
+  echo "=== $label START $(date -Iseconds) ===" | tee -a $LOG/encode.log
+  ffmpeg -hide_banner -ss 0 -t 60 -i "$SRC" -pix_fmt yuv420p -an -y "$@" > $LOG/encode_$label.log 2>&1
+  local rc=$?
+  local t1=$(date +%s)
+  echo "=== $label END $(date -Iseconds) elapsed=$((t1-t0))s rc=$rc ===" | tee -a $LOG/encode.log
+}
+
+encode h264   -c:v libx264 -preset medium -crf 23 $OUT/bbb_60s_720p.h264.mp4
+encode hevc   -c:v libx265 -preset fast   -crf 28 $OUT/bbb_60s_720p.hevc.mp4
+encode mpeg2  -c:v mpeg2video -qscale:v 4 -f mpegts $OUT/bbb_60s_720p.mpeg2.ts
+encode vp8    -c:v libvpx -crf 30 -b:v 1500k -threads 8 -cpu-used 4 $OUT/bbb_60s_720p.vp8.webm
+encode vp9    -c:v libvpx-vp9 -crf 30 -b:v 0 -threads 8 -cpu-used 4 -row-mt 1 -tile-columns 2 $OUT/bbb_60s_720p.vp9.webm
+
+echo "=== ALL ENCODES DONE $(date -Iseconds) ===" | tee -a $LOG/encode.log
+ls -la $OUT/ | tee -a $LOG/encode.log
diff --git a/phase3_scripts/p3_bench.sh b/phase3_scripts/p3_bench.sh
new file mode 100755
index 0000000..1847c44
--- /dev/null
+++ b/phase3_scripts/p3_bench.sh
@@ -0,0 +1,42 @@
+#!/bin/bash
+# C5: per-codec FPS at N=3 runs. Wall-time measurement, no output file written.
+set -u
+OUT=$HOME/measurements/p3
+mkdir -p $OUT
+codecs=("h264:h264.mp4" "vp8:vp8.webm" "mpeg2:mpeg2.ts")
+
+for spec in "${codecs[@]}"; do
+  codec=${spec%%:*}; ext=${spec#*:}
+  cf=$HOME/measurements/encoded/bbb_60s_720p.${ext}
+  log=$OUT/bench_${codec}.log
+  > $log
+
+  echo "=== $codec ===" | tee $log
+  for run in 1 2 3; do
+    t0=$(date +%s.%N)
+    out=$(LIBVA_DRIVER_NAME=v4l2_request timeout 30 ffmpeg -hide_banner -benchmark -loglevel error \
+        -hwaccel vaapi -hwaccel_output_format vaapi \
+        -i "$cf" -vf "hwdownload,format=nv12" -f null - 2>&1 </dev/null)
+    t1=$(date +%s.%N)
+    el=$(awk "BEGIN { printf \"%.3f\", $t1-$t0 }")
+    fps_calc=$(awk "BEGIN { printf \"%.2f\", 1440.0 / ($t1-$t0) }")
+    fps_self=$(echo "$out" | grep -oE "fps=[ ]*[0-9.]+" | tail -1 | awk -F= "{print \$2}" | tr -d " ")
+    frames=$(echo "$out" | grep -oE "frame=[ ]*[0-9]+" | tail -1 | awk -F= "{print \$2}" | tr -d " ")
+    bench=$(echo "$out" | grep "^bench:" | tail -1)
+    echo "  run $run: elapsed=${el}s fps_calc=$fps_calc fps_self=$fps_self frames=$frames" | tee -a $log
+    [ -n "$bench" ] && echo "    $bench" | tee -a $log
+  done
+
+  # Compute mean and stddev
+  awk '/^  run/ { gsub("elapsed=","",$3); gsub("s","",$3); el[NR]=$3; sum+=$3; n++ }
+       END {
+         if (n>0) {
+           mean=sum/n
+           for (i in el) ss += (el[i]-mean)^2
+           sd=sqrt(ss/n)
+           printf "  N=%d mean=%.3fs sigma=%.3fs  fps=%.2f±%.2f\n", n, mean, sd, 1440/mean, 1440*sd/(mean*mean)
+         }
+       }' $log | tee -a $log
+done
+
+echo "=== done $(date -Iseconds) ==="
diff --git a/phase3_scripts/p3_bitexact.sh b/phase3_scripts/p3_bitexact.sh
new file mode 100755
index 0000000..948acbd
--- /dev/null
+++ b/phase3_scripts/p3_bitexact.sh
@@ -0,0 +1,68 @@
+#!/bin/bash
+# C3 + C4: per-codec frame-0 byte-compare + frame-30s SSIM Y, both against SW reference.
+set -u
+OUT=$HOME/measurements/p3
+mkdir -p $OUT
+codecs=("h264:h264.mp4" "vp8:vp8.webm" "mpeg2:mpeg2.ts")
+W=1280; H=720
+
+for spec in "${codecs[@]}"; do
+  codec=${spec%%:*}; ext=${spec#*:}
+  cf=$HOME/measurements/encoded/bbb_60s_720p.${ext}
+  log=$OUT/bitexact_${codec}
+  > $log
+
+  echo "=== $codec ===" | tee $log
+
+  # Frame 0 SW
+  ffmpeg -hide_banner -loglevel error -y -i "$cf" \
+      -frames:v 1 -f rawvideo -pix_fmt yuv420p $OUT/sw_${codec}_f0.yuv </dev/null
+  # Frame 0 HW
+  LIBVA_DRIVER_NAME=v4l2_request ffmpeg -hide_banner -loglevel error -y \
+      -hwaccel vaapi -hwaccel_output_format vaapi \
+      -i "$cf" -vf "hwdownload,format=nv12,format=yuv420p" \
+      -frames:v 1 -f rawvideo -pix_fmt yuv420p $OUT/hw_${codec}_f0.yuv </dev/null 2>/dev/null
+
+  sz_sw=$(stat -c%s $OUT/sw_${codec}_f0.yuv 2>/dev/null || echo 0)
+  sz_hw=$(stat -c%s $OUT/hw_${codec}_f0.yuv 2>/dev/null || echo 0)
+  sha_sw=$(sha256sum $OUT/sw_${codec}_f0.yuv 2>/dev/null | cut -c1-16)
+  sha_hw=$(sha256sum $OUT/hw_${codec}_f0.yuv 2>/dev/null | cut -c1-16)
+  diff_bytes=$(cmp -l $OUT/sw_${codec}_f0.yuv $OUT/hw_${codec}_f0.yuv 2>/dev/null | wc -l)
+  expected=$((W * H * 3 / 2))
+  c3_status=$([ "$sw_sw" = "$sha_hw" ] || [ "$diff_bytes" = "0" ] && echo "byte-identical" || echo "diff=$diff_bytes")
+
+  echo "  C3 frame-0:" | tee -a $log
+  echo "    sw size=$sz_sw sha=$sha_sw" | tee -a $log
+  echo "    hw size=$sz_hw sha=$sha_hw" | tee -a $log
+  echo "    diff_bytes=$diff_bytes  expected_size=$expected" | tee -a $log
+  if [ "$diff_bytes" = "0" ] && [ "$sz_sw" = "$expected" ]; then
+    echo "    -> C3 PASS (byte-identical)" | tee -a $log
+  else
+    # Compute SSIM on frame 0 as fallback
+    ssim_f0=$(ffmpeg -hide_banner -loglevel info -nostats \
+        -s ${W}x${H} -pix_fmt yuv420p -i $OUT/hw_${codec}_f0.yuv \
+        -s ${W}x${H} -pix_fmt yuv420p -i $OUT/sw_${codec}_f0.yuv \
+        -lavfi "[0:v][1:v]ssim" -f null - 2>&1 | grep -oE "Y:[0-9.]+" | head -1)
+    echo "    -> C3 byte diff present, frame-0 SSIM ${ssim_f0}" | tee -a $log
+  fi
+
+  # Frame 30s SW
+  ffmpeg -hide_banner -loglevel error -y -i "$cf" \
+      -vf "select=eq(n\,720)" -vsync 0 -frames:v 1 -f rawvideo -pix_fmt yuv420p $OUT/sw_${codec}_f720.yuv </dev/null
+  # Frame 30s HW
+  LIBVA_DRIVER_NAME=v4l2_request ffmpeg -hide_banner -loglevel error -y \
+      -hwaccel vaapi -hwaccel_output_format vaapi \
+      -i "$cf" -vf "hwdownload,format=nv12,format=yuv420p,select=eq(n\,720)" \
+      -vsync 0 -frames:v 1 -f rawvideo -pix_fmt yuv420p $OUT/hw_${codec}_f720.yuv </dev/null 2>/dev/null
+
+  diff720=$(cmp -l $OUT/sw_${codec}_f720.yuv $OUT/hw_${codec}_f720.yuv 2>/dev/null | wc -l)
+  ssim=$(ffmpeg -hide_banner -loglevel info -nostats \
+      -s ${W}x${H} -pix_fmt yuv420p -i $OUT/hw_${codec}_f720.yuv \
+      -s ${W}x${H} -pix_fmt yuv420p -i $OUT/sw_${codec}_f720.yuv \
+      -lavfi "[0:v][1:v]ssim" -f null - 2>&1 | grep -oE "[YUV All]:[0-9.()+ ]+" | tr "\n" " ")
+
+  echo "  C4 frame-720 (t=30s):" | tee -a $log
+  echo "    diff_bytes=$diff720  ssim: $ssim" | tee -a $log
+done
+
+echo "=== done $(date -Iseconds) ==="
diff --git a/phase3_scripts/p3_engage.sh b/phase3_scripts/p3_engage.sh
new file mode 100755
index 0000000..7f90547
--- /dev/null
+++ b/phase3_scripts/p3_engage.sh
@@ -0,0 +1,63 @@
+#!/bin/bash
+# C1 + C2 + C6 instrumentation: per-codec decode with strace (ioctl) + lsof (fds) + dmesg before/after.
+# Decodes 30 frames into a tmp file to verify HW engagement; doesn't measure FPS.
+set -u
+OUT=$HOME/measurements/p3
+mkdir -p $OUT
+codecs=("h264:rkvdec:h264.mp4" "vp8:hantro:vp8.webm" "mpeg2:hantro:mpeg2.ts")
+
+# C6 pre: dmesg snapshot
+sudo dmesg --time-format=ctime > $OUT/dmesg.pre.txt
+
+for spec in "${codecs[@]}"; do
+  codec=${spec%%:*}; route=$(echo $spec | cut -d: -f2); ext=${spec##*:}
+  cf=$HOME/measurements/encoded/bbb_60s_720p.${ext}
+  log=$OUT/engage_${codec}
+  rm -f $log.{strace,lsof,stderr,nv12} 2>/dev/null
+
+  echo "=== $codec ($route) ===" | tee $log.summary
+
+  # Launch in background, track PID; lsof+strace alongside
+  LIBVA_DRIVER_NAME=v4l2_request strace -ff -o $log.strace -e trace=ioctl,openat \
+      ffmpeg -hide_banner -loglevel error \
+      -hwaccel vaapi -hwaccel_output_format vaapi \
+      -i "$cf" -vf "hwdownload,format=nv12" -frames:v 30 \
+      -f rawvideo -pix_fmt nv12 -y $log.nv12 \
+      > $log.stderr 2>&1 &
+  pid=$!
+
+  # Wait briefly then lsof
+  sleep 0.6
+  if kill -0 $pid 2>/dev/null; then
+    lsof -p $pid 2>/dev/null | grep -E "/dev/(video|media|dri)" > $log.lsof
+  fi
+  wait $pid; rc=$?
+
+  # Aggregate
+  size=$(stat -c%s $log.nv12 2>/dev/null || echo 0)
+  expected=$((30 * 1280 * 720 * 3 / 2))  # 30 frames yuv420p 720p
+  size_ok=$([ "$size" = "$expected" ] && echo "ok" || echo "MISMATCH (expected=$expected)")
+
+  vidioc=$(grep -h "VIDIOC_S_EXT_CTRLS\|VIDIOC_QUERYCAP\|VIDIOC_QBUF\|VIDIOC_DQBUF" $log.strace.* 2>/dev/null | wc -l)
+  media_q=$(grep -h "MEDIA_REQUEST_IOC_QUEUE\|MEDIA_REQUEST_IOC_REINIT" $log.strace.* 2>/dev/null | wc -l)
+  fd_count=$(wc -l < $log.lsof 2>/dev/null || echo 0)
+
+  {
+    echo "  rc=$rc  size=$size  size_ok=$size_ok"
+    echo "  ioctl V4L2 (S_EXT_CTRLS+Q/DQBUF+QUERYCAP)=$vidioc"
+    echo "  ioctl MEDIA_REQUEST_*=$media_q"
+    echo "  open V4L2/media/DRI fds=$fd_count"
+    if [ -s $log.lsof ]; then
+      echo "  fds:"
+      awk '{print "    " $9}' $log.lsof | sort -u
+    fi
+  } | tee -a $log.summary
+done
+
+# C6 post
+sudo dmesg --time-format=ctime > $OUT/dmesg.post.txt
+echo
+echo "=== dmesg diff (new lines since pre) ==="
+diff $OUT/dmesg.pre.txt $OUT/dmesg.post.txt | head -20
+
+echo "=== done $(date -Iseconds) ==="
diff --git a/phase3_scripts/safe_probe.sh b/phase3_scripts/safe_probe.sh
new file mode 100755
index 0000000..ea17fd2
--- /dev/null
+++ b/phase3_scripts/safe_probe.sh
@@ -0,0 +1,26 @@
+#!/bin/bash
+# Safe baseline probe — only the 3 codecs that should work on this kernel.
+# HEVC SKIPPED (oopses kernel rkvdec_hevc_prepare_hw_st_rps).
+# VP9 SKIPPED (mainline-rc3 RK3588 rkvdec doesn't expose V4L2_PIX_FMT_VP9_FRAME).
+# AV1 SKIPPED (libva backend iter38b only probes 2 fds, not the av1-vpu-dec at /dev/media3).
+echo "=== ampere baseline: libva HW decode probe (H.264 + VP8 + MPEG-2) ==="
+for codec in h264 vp8 mpeg2; do
+  case $codec in
+    h264)  cf=$HOME/measurements/encoded/bbb_60s_720p.h264.mp4 ; route="rkvdec /dev/video1" ;;
+    mpeg2) cf=$HOME/measurements/encoded/bbb_60s_720p.mpeg2.ts ; route="hantro /dev/video2" ;;
+    vp8)   cf=$HOME/measurements/encoded/bbb_60s_720p.vp8.webm ; route="hantro /dev/video2" ;;
+  esac
+  t0=$(date +%s.%N)
+  out=$(LIBVA_DRIVER_NAME=v4l2_request timeout 12 ffmpeg -hide_banner -loglevel error \
+      -hwaccel vaapi -hwaccel_output_format vaapi \
+      -i "$cf" -vf "hwdownload,format=nv12" -f null - 2>&1 </dev/null)
+  rc=$?
+  t1=$(date +%s.%N)
+  el=$(awk "BEGIN { printf \"%.2f\", $t1-$t0 }")
+  status=$([ $rc -eq 0 ] && echo "OK" || echo "FAIL rc=$rc")
+  fps=$(echo "$out" | grep -oE "fps=[ ]*[0-9.]+" | tail -1)
+  frames=$(echo "$out" | grep -oE "frame=[ ]*[0-9]+" | tail -1)
+  err=$(echo "$out" | grep -iE "error|invalid|failed|not supported|unable" | head -1)
+  printf "  %-6s  %-25s  %s  elapsed=%ss  %s %s  %s\n" "$codec" "$route" "$status" "$el" "${frames}" "${fps}" "$err"
+done
+echo "=== done $(date -Iseconds) ==="