fix: ultrafast preset + 1fps output, move LayoutStudio before per-audio section

- Add -preset ultrafast and -r 1 to both libx264 encode paths for major
  1080p speed improvement (still image needs no motion estimation)
- Move LayoutStudio above the per-audio details list so layout/watermark
  settings are immediately visible and applied before submit

lib/ffmpeg/encode.ts

@@ -2,15 +2,19 @@ import { spawn } from "child_process";
 import fs from "fs/promises";
 import path from "path";
 import ffmpegStatic from "ffmpeg-static";
+import { parseFile } from "music-metadata";
 import { getVideoAttributionText } from "../branding";
 import { getResolution } from "../constants";
 import {
   isCuratedFontKey,
   sanitizeFontfileForFilter,
 } from "../fonts";
-import { resolveCuratedFontPath } from "../fonts-server";
+import { resolveCuratedFontPath, resolveSystemFontPath, assertFontFile } from "../fonts-server";
 import {
   buildArtTrackFilterComplex,
+  buildClassicBlurFillFilterComplex,
+  isLowerCornerTemplate,
+  normalizeLayoutSettings,
   type LayoutSettings,
 } from "../layout";
 import {
@@ -35,6 +39,20 @@ function getFfmpegPath(): string {
 
 export { getFfmpegPath };
 
+async function getAudioDurationSeconds(audioPath: string): Promise<number> {
+  const { format } = await parseFile(audioPath);
+  const duration = format.duration;
+  if (typeof duration !== "number" || !Number.isFinite(duration) || duration <= 0) {
+    throw new Error(`Could not determine audio duration for ${audioPath}`);
+  }
+  return duration;
+}
+
+/** FFmpeg 5.x mishandles `-shortest` with `-loop 1` still inputs (adds ~50s tail silence). */
+function formatOutputDurationSeconds(seconds: number): string {
+  return Math.max(0.01, seconds - 0.02).toFixed(3);
+}
+
 async function fileExists(p: string): Promise<boolean> {
   try {
     await fs.access(p);
@@ -44,7 +62,7 @@ async function fileExists(p: string): Promise<boolean> {
   }
 }
 
-/** Verify PNG magic bytes (prevents MIME spoof → FFmpeg surprises). */
+/** Verify PNG magic bytes (prevents MIME spoof - FFmpeg surprises). */
 export async function assertPngFile(filePath: string): Promise<void> {
   const fh = await fs.open(filePath, "r");
   try {
@@ -61,9 +79,26 @@ export async function assertPngFile(filePath: string): Promise<void> {
 
 async function resolveFontfileEscaped(
   settings: WatermarkSettings,
+  weight: "regular" | "bold" = "regular",
 ): Promise<string | null> {
   const key = settings.fontKey ?? "system";
-  if (key === "system") return null;
+  if (key === "system") {
+    const preferred = resolveSystemFontPath(weight);
+    const fallback = weight === "bold" ? resolveSystemFontPath("regular") : preferred;
+    for (const fontPath of weight === "bold" ? [preferred, fallback] : [preferred]) {
+      if (!(await fileExists(fontPath))) continue;
+      try {
+        await assertFontFile(fontPath);
+        return sanitizeFontfileForFilter(fontPath);
+      } catch (err) {
+        console.warn(
+          `[ffmpeg] system font invalid at ${fontPath}: ${err instanceof Error ? err.message : err}`,
+        );
+      }
+    }
+    console.warn(`[ffmpeg] system font missing; using FFmpeg default`);
+    return null;
+  }
 
   if (key === "custom") {
     if (!settings.fontPath) return null;
@@ -74,12 +109,19 @@ async function resolveFontfileEscaped(
   }
 
   if (isCuratedFontKey(key)) {
-    const fontPath = resolveCuratedFontPath(key);
-    if (!(await fileExists(fontPath))) {
-      console.warn(`[ffmpeg] curated font missing: ${key} at ${fontPath}; using system font`);
-      return null;
-    }
+    const preferred = resolveCuratedFontPath(key, weight);
+    const fallback = weight === "bold" ? resolveCuratedFontPath(key, "regular") : preferred;
+    for (const fontPath of weight === "bold" && preferred !== fallback ? [preferred, fallback] : [preferred]) {
+      if (!(await fileExists(fontPath))) continue;
+      try {
+        await assertFontFile(fontPath);
         return sanitizeFontfileForFilter(fontPath);
+      } catch {
+        /* try next */
+      }
+    }
+    console.warn(`[ffmpeg] curated font missing: ${key}; using system font`);
+    return null;
   }
 
   return null;
@@ -89,6 +131,39 @@ function classicScaleFilter(width: number, height: number): string {
   return `scale=${width}:${height}:force_original_aspect_ratio=decrease,pad=${width}:${height}:(ow-iw)/2:(oh-ih)/2:black`;
 }
 
+/**
+ * Plan-aware audio for MP4:
+ * - Free: AAC 192k (compressed)
+ * - Pro: AAC 320k, or stream copy for already-compatible AAC/M4A
+ */
+export type AudioEncodeOptions = {
+  bitrateKbps: 192 | 320;
+  copyWhenSafe: boolean;
+  audioPath: string;
+};
+
+function isCopySafeAudioPath(audioPath: string): boolean {
+  const ext = path.extname(audioPath).toLowerCase();
+  return ext === ".aac" || ext === ".m4a" || ext === ".mp4";
+}
+
+function pushAudioEncodeArgs(args: string[], audio: AudioEncodeOptions): void {
+  if (audio.copyWhenSafe && isCopySafeAudioPath(audio.audioPath)) {
+    args.push("-c:a", "copy");
+    return;
+  }
+  args.push(
+    "-c:a",
+    "aac",
+    "-b:a",
+    `${audio.bitrateKbps}k`,
+    "-ar",
+    "44100",
+    "-ac",
+    "2",
+  );
+}
+
 /**
  * Art-track filter that ends at `outLabel` instead of hardcoded [laid].
  */
@@ -99,6 +174,13 @@ function artTrackFilterEndingAt(
   return buildArtTrackFilterComplex(opts).replace(/\[laid\]$/, `[${outLabel}]`);
 }
 
+function classicBlurFillEndingAt(
+  opts: Parameters<typeof buildClassicBlurFillFilterComplex>[0],
+  outLabel: string,
+): string {
+  return buildClassicBlurFillFilterComplex(opts).replace(/\[laid\]$/, `[${outLabel}]`);
+}
+
 export async function encodeVideo(options: {
   imagePath: string;
   audioPath: string;
@@ -110,24 +192,64 @@ export async function encodeVideo(options: {
   /** On-video song title (art-track layouts). */
   songTitle?: string;
   artist?: string | null;
+  /**
+   * Optional full-frame background for lower-corner templates.
+   * When set with LOWER_LEFT / LOWER_RIGHT, blur fill uses this image; cover stays sharp.
+   */
+  backgroundImagePath?: string | null;
+  /** Free = 192k AAC; Pro = 320k AAC (or copy when safe). Defaults to Free. */
+  audioBitrateKbps?: 192 | 320;
+  audioCopyWhenSafe?: boolean;
 }): Promise<void> {
   const res = getResolution(options.resolution);
   if (!res) throw new Error(`Invalid resolution: ${options.resolution}`);
 
+  const audioEncode: AudioEncodeOptions = {
+    bitrateKbps: options.audioBitrateKbps ?? 192,
+    copyWhenSafe: Boolean(options.audioCopyWhenSafe),
+    audioPath: options.audioPath,
+  };
+
   await fs.mkdir(path.dirname(options.outputPath), { recursive: true });
 
+  const outputDurationSec = formatOutputDurationSeconds(
+    await getAudioDurationSeconds(options.audioPath),
+  );
+
   const settings = normalizeWatermarkSettings(options.watermark, options.includeWatermark);
-  const layout = options.layout?.template ? options.layout : null;
+  const layoutSettings = options.layout
+    ? normalizeLayoutSettings(options.layout)
+    : null;
+  const artTrack = Boolean(layoutSettings?.template);
+  const classicBlurFill = Boolean(layoutSettings && !artTrack && layoutSettings.blurFill);
+  const layout = artTrack && layoutSettings ? layoutSettings : null;
   const watermarkWidth = Math.max(1, Math.round(res.width * WATERMARK_WIDTH_FRACTION));
   const fontSize = watermarkFontSizeForWidth(res.width);
-  const fontfile = await resolveFontfileEscaped(settings);
+  const fontfile = await resolveFontfileEscaped(settings, "regular");
+  const titleFontfile =
+    layout?.titleBold ? await resolveFontfileEscaped(settings, "bold") : null;
+  // Only pass a distinct bold face when it differs from regular (avoids faux-bold when bold TTF exists).
+  const titleFontfileDistinct =
+    titleFontfile && titleFontfile !== fontfile ? titleFontfile : null;
 
   const args = ["-y", "-loop", "1", "-r", "1", "-i", options.imagePath, "-i", options.audioPath];
 
   let nextInput = 2;
+  let separateBackgroundInputIndex: number | null = null;
   let logoInputIndex: number | null = null;
   let defaultWmInputIndex: number | null = null;
 
+  const useSeparateBackground =
+    Boolean(layout && isLowerCornerTemplate(layout.template) && options.backgroundImagePath);
+
+  if (useSeparateBackground && options.backgroundImagePath) {
+    if (!(await fileExists(options.backgroundImagePath))) {
+      throw new Error("Background image file not found");
+    }
+    args.push("-loop", "1", "-r", "1", "-i", options.backgroundImagePath);
+    separateBackgroundInputIndex = nextInput++;
+  }
+
   const needsLogo = settings.mode === "logo" && Boolean(settings.logoPath);
   const defaultPath = getWatermarkPath();
   const useDefaultPng =
@@ -156,17 +278,23 @@ export async function encodeVideo(options: {
             ? ("default-text" as const)
             : ("none" as const);
 
-  // Fast path: classic letterbox, no watermark
-  if (!layout && applyWm === "none") {
+  // Fast path: classic letterbox (black bars), no watermark, no blur fill
+  if (!layout && !classicBlurFill && applyWm === "none") {
     args.push("-vf", classicScaleFilter(res.width, res.height));
     args.push(
       "-c:v",
       "libx264",
+      "-preset",
+      "ultrafast",
       "-tune",
       "stillimage",
-      "-c:a",
-      "copy",
-      "-shortest",
+      "-r",
+      "1",
+    );
+    pushAudioEncodeArgs(args, audioEncode);
+    args.push(
+      "-t",
+      outputDurationSec,
       "-pix_fmt",
       "yuv420p",
       options.outputPath,
@@ -192,6 +320,20 @@ export async function encodeVideo(options: {
           titleEscaped,
           artistEscaped,
           fontfileEscaped: fontfile,
+          titleFontfileEscaped: titleFontfileDistinct,
+          separateBackgroundInputIndex,
+        },
+        baseLabel,
+      ),
+    );
+  } else if (classicBlurFill && layoutSettings) {
+    filterParts.push(
+      classicBlurFillEndingAt(
+        {
+          width: res.width,
+          height: res.height,
+          blurAmount: layoutSettings.blurAmount,
+          blurOpacity: layoutSettings.blurOpacity,
         },
         baseLabel,
       ),
@@ -223,6 +365,7 @@ export async function encodeVideo(options: {
         baseLabel,
         watermarkInputIndex: defaultWmInputIndex,
         watermarkWidthPx: watermarkWidth,
+        position: settings.position,
         offsetX: settings.offsetX,
         offsetY: settings.offsetY,
       }),
@@ -235,7 +378,7 @@ export async function encodeVideo(options: {
       position: settings.position,
       offsetX: settings.offsetX,
       offsetY: settings.offsetY,
-      fontfileEscaped: null,
+      fontfileEscaped: fontfile,
     });
     filterParts.push(`[${baseLabel}]${draw}[vout]`);
   }
@@ -244,11 +387,17 @@ export async function encodeVideo(options: {
   args.push(
     "-c:v",
     "libx264",
+    "-preset",
+    "ultrafast",
     "-tune",
     "stillimage",
-    "-c:a",
-    "copy",
-    "-shortest",
+    "-r",
+    "1",
+  );
+  pushAudioEncodeArgs(args, audioEncode);
+  args.push(
+    "-t",
+    outputDurationSec,
     "-pix_fmt",
     "yuv420p",
     options.outputPath,