feature: H.264 script

2026-08-23 23:53:27 +00:00
parent 07c376408a
commit 47fc6867bf
1 changed files with 126 additions and 0 deletions
@@ -0,0 +1,126 @@
+#!/usr/bin/env bash
+# dji264 - convert DJI Action 4 clips (10-bit HEVC) to 8-bit H.264 for DaVinci Resolve.
+#
+# Free Resolve on Windows cannot decode 10-bit HEVC, so Action 4 footage imports with
+# audio but no video. This re-encodes to 8-bit H.264, which Resolve decodes natively.
+#
+#   dji264                    convert every .MP4 in the current directory
+#   dji264 clip.MP4           convert one file
+#   dji264 /path/to/shoot     convert every .MP4 in that directory
+#   dji264 -o D:\out *.MP4    choose the output directory
+#   dji264 -b 90M clip.MP4    override the video bitrate
+#   dji264 -f clip.MP4        re-convert even if a good output already exists
+#
+# Output lands in an H264/ subdirectory beside each source unless -o is given.
+
+set -uo pipefail
+
+BITRATE=${BITRATE:-70M}      # VBR target
+MAXRATE=${MAXRATE:-95M}      # ceiling; keep ~1.35x the target
+BUFSIZE=${BUFSIZE:-140M}
+OUTDIR=""
+FORCE=0
+
+die() { echo "dji264: $*" >&2; exit 1; }
+
+usage() { sed -n '2,20p' "$0" | sed 's/^# \{0,1\}//'; exit 0; }
+
+while getopts ":o:b:m:fh" opt; do
+  case $opt in
+    o) OUTDIR=$OPTARG ;;
+    b) BITRATE=$OPTARG ;;
+    m) MAXRATE=$OPTARG ;;
+    f) FORCE=1 ;;
+    h) usage ;;
+    \?) die "unknown option -$OPTARG (try -h)" ;;
+    :)  die "-$OPTARG needs a value" ;;
+  esac
+done
+shift $((OPTIND - 1))
+
+command -v ffmpeg  >/dev/null || die "ffmpeg not found on PATH"
+command -v ffprobe >/dev/null || die "ffprobe not found on PATH"
+
+# Collect inputs: files as given, directories expanded to their .MP4 contents.
+inputs=()
+if [ $# -eq 0 ]; then set -- .; fi
+for arg in "$@"; do
+  if [ -d "$arg" ]; then
+    while IFS= read -r f; do inputs+=("$f"); done \
+      < <(find "$arg" -maxdepth 1 -type f \( -iname '*.mp4' -o -iname '*.mov' \) | sort)
+  elif [ -f "$arg" ]; then
+    inputs+=("$arg")
+  else
+    echo "  skip (not found): $arg" >&2
+  fi
+done
+[ ${#inputs[@]} -gt 0 ] || die "no input files found"
+
+probe() { ffprobe -v error -select_streams v:0 -show_entries "$2" -of default=nw=1:nk=1 "$1" 2>/dev/null; }
+
+ok=0; failed=0; skipped=0
+started=$(date +%s)
+
+for src in "${inputs[@]}"; do
+  base=$(basename "$src"); stem=${base%.*}
+  dest_dir=${OUTDIR:-"$(dirname "$src")/H264"}
+  mkdir -p "$dest_dir" || die "cannot create $dest_dir"
+  out="$dest_dir/$stem.mp4"
+
+  # Source facts we need: frame count (to verify against), fps (to size the GOP),
+  # timecode (to carry across), and pixel format (to spot footage that needs no work).
+  src_frames=$(probe "$src" stream=nb_frames)
+  rfr=$(probe "$src" stream=r_frame_rate)
+  pixfmt=$(probe "$src" stream=pix_fmt)
+  tc=$(ffprobe -v error -select_streams v:0 -show_entries stream_tags=timecode \
+        -of default=nw=1:nk=1 "$src" 2>/dev/null | head -1)
+
+  [ -n "$rfr" ] || { echo "  skip (no video stream): $base"; skipped=$((skipped+1)); continue; }
+
+  # DJI records a keyframe roughly every 0.5s. NVENC would otherwise default to a
+  # 250-frame GOP, which makes the result far worse to scrub than the source for no
+  # saving - at this bitrate the extra keyframes are free.
+  gop=$(awk -v r="$rfr" 'BEGIN{split(r,a,"/"); d=(a[2]?a[2]:1); f=a[1]/d;
+                               g=int(f/2+0.5); if(g<1)g=1; print g}')
+
+  case $pixfmt in
+    yuv420p) echo "  note: $base is already 8-bit - Resolve can read it as-is" ;;
+  esac
+
+  # Idempotent: leave a previous good conversion alone unless -f.
+  if [ $FORCE -eq 0 ] && [ -f "$out" ]; then
+    if [ -n "$src_frames" ] && [ "$(probe "$out" stream=nb_frames)" = "$src_frames" ]; then
+      echo "  skip (already converted): $base"; skipped=$((skipped+1)); continue
+    fi
+  fi
+
+  echo "==> $base  (${rfr} fps, GOP $gop, $BITRATE VBR)"
+  ffmpeg -y -v error -stats -hwaccel cuda -i "$src" \
+    -map 0:v:0 -map 0:a:0 \
+    -c:v h264_nvenc -preset slow -rc vbr \
+    -b:v "$BITRATE" -maxrate "$MAXRATE" -bufsize "$BUFSIZE" \
+    -pix_fmt yuv420p -profile:v high -g "$gop" -bf 3 -spatial-aq 1 \
+    -color_primaries bt709 -color_trc bt709 -colorspace bt709 \
+    ${tc:+-timecode "$tc"} \
+    -c:a copy \
+    "$out" 2>&1 | tr '\r' '\n' | tail -1
+  rc=${PIPESTATUS[0]}
+
+  # Verify rather than trust. A dropped USB drive mid-encode leaves a *playable* but
+  # truncated file and ffmpeg still tears down cleanly, so the frame count is the
+  # check that actually catches it.
+  out_frames=$(probe "$out" stream=nb_frames)
+  if [ "$rc" -ne 0 ]; then
+    echo "    FAILED  ffmpeg exit $rc"; failed=$((failed+1))
+  elif [ -n "$src_frames" ] && [ "$out_frames" != "$src_frames" ]; then
+    echo "    FAILED  truncated: $out_frames of $src_frames frames"; failed=$((failed+1))
+  else
+    sz=$(stat -c%s "$out" 2>/dev/null || echo 0)
+    echo "    ok  $out_frames frames  $(awk -v s="$sz" 'BEGIN{printf "%.2f GB", s/1073741824}')"
+    ok=$((ok+1))
+  fi
+done
+
+printf '\n%d converted, %d skipped, %d failed  (%dm%02ds)\n' \
+  "$ok" "$skipped" "$failed" $(( ($(date +%s)-started)/60 )) $(( ($(date +%s)-started)%60 ))
+[ "$failed" -eq 0 ]