initial commit

scripts/mkv-to-readme-video.sh

@@ -0,0 +1,87 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+usage() {
+  cat <<'EOF'
+Usage:
+  scripts/mkv-to-readme-video.sh <input.mkv>
+
+Description:
+  Generates two browser-friendly files next to the input file:
+  - <name>.mp4  (H.264 + AAC, prefers NVIDIA GPU if available)
+  - <name>.webm (AV1/VP9 + Opus, prefers NVIDIA GPU if available)
+EOF
+}
+
+if [[ "${1:-}" == "-h" || "${1:-}" == "--help" ]]; then
+  usage
+  exit 0
+fi
+
+if [[ $# -ne 1 ]]; then
+  usage
+  exit 1
+fi
+
+if ! command -v ffmpeg >/dev/null 2>&1; then
+  echo "Error: ffmpeg is not installed or not in PATH." >&2
+  exit 1
+fi
+
+input="$1"
+
+if [[ ! -f "$input" ]]; then
+  echo "Error: input file not found: $input" >&2
+  exit 1
+fi
+
+dir="$(dirname "$input")"
+filename="$(basename "$input")"
+base="${filename%.*}"
+
+mp4_out="$dir/$base.mp4"
+webm_out="$dir/$base.webm"
+
+has_encoder() {
+  local encoder="$1"
+  ffmpeg -hide_banner -encoders 2>/dev/null | grep -qE "[[:space:]]${encoder}[[:space:]]"
+}
+
+echo "Generating MP4: $mp4_out"
+if has_encoder "h264_nvenc"; then
+  echo "Using GPU encoder for MP4: h264_nvenc"
+  ffmpeg -y -i "$input" \
+    -c:v h264_nvenc -preset p5 -cq 20 \
+    -profile:v high -pix_fmt yuv420p \
+    -movflags +faststart \
+    -c:a aac -b:a 160k \
+    "$mp4_out"
+else
+  echo "Using CPU encoder for MP4: libx264"
+  ffmpeg -y -i "$input" \
+    -c:v libx264 -preset slow -crf 20 \
+    -profile:v high -level 4.1 -pix_fmt yuv420p \
+    -movflags +faststart \
+    -c:a aac -b:a 160k \
+    "$mp4_out"
+fi
+
+echo "Generating WebM: $webm_out"
+if has_encoder "av1_nvenc"; then
+  echo "Using GPU encoder for WebM: av1_nvenc"
+  ffmpeg -y -i "$input" \
+    -c:v av1_nvenc -preset p5 -cq 30 -b:v 0 \
+    -c:a libopus -b:a 128k \
+    "$webm_out"
+else
+  echo "Using CPU encoder for WebM: libvpx-vp9"
+  ffmpeg -y -i "$input" \
+    -c:v libvpx-vp9 -crf 32 -b:v 0 \
+    -c:a libopus -b:a 128k \
+    "$webm_out"
+fi
+
+echo "Done."
+echo "MP4:  $mp4_out"
+echo "WebM: $webm_out"