feat: add mp4 transcode job and variant record

apps/worker/src/__tests__/transcode-plan.test.ts

@@ -0,0 +1,10 @@
+import { test, expect } from "bun:test";
+import { shouldTranscodeToMp4 } from "../transcode";
+
+test("transcode runs for non-mp4 videos", () => {
+  expect(shouldTranscodeToMp4({ mimeType: "video/x-matroska" })).toBe(true);
+});
+
+test("transcode skips for mp4", () => {
+  expect(shouldTranscodeToMp4({ mimeType: "video/mp4" })).toBe(false);
+});

apps/worker/src/index.ts

@@ -7,7 +7,8 @@ import { closeDb } from "@tline/db";
 import {
   handleCopyToCanonical,
   handleProcessAsset,
-  handleScanMinioPrefix
+  handleScanMinioPrefix,
+  handleTranscodeVideoMp4
 } from "./jobs";
 
 console.log(`[${getAppName()}] worker boot`);
@@ -30,6 +31,7 @@ const worker = new Worker(
     if (job.name === "scan_minio_prefix") return handleScanMinioPrefix(job.data);
     if (job.name === "process_asset") return handleProcessAsset(job.data);
     if (job.name === "copy_to_canonical") return handleCopyToCanonical(job.data);
+    if (job.name === "transcode_video_mp4") return handleTranscodeVideoMp4(job.data);
 
     throw new Error(`Unknown job: ${job.name}`);
   },

apps/worker/src/jobs.ts

@@ -27,10 +27,14 @@ import {
   copyToCanonicalPayloadSchema,
   enqueueCopyToCanonical,
   enqueueProcessAsset,
+  enqueueTranscodeVideoMp4,
   processAssetPayloadSchema,
   scanMinioPrefixPayloadSchema,
+  transcodeVideoMp4PayloadSchema,
 } from "@tline/queue";
 
+import { shouldTranscodeToMp4 } from "./transcode";
+
 const allowedScanPrefixes = ["originals/"] as const;
 
 function assertAllowedScanPrefix(prefix: string) {
@@ -584,6 +588,10 @@ export async function handleProcessAsset(raw: unknown) {
         where id = ${asset.id}
       `;
 
+      if (asset.media_type === "video" && shouldTranscodeToMp4({ mimeType: asset.mime_type })) {
+        await enqueueTranscodeVideoMp4({ assetId: asset.id });
+      }
+
       // Only uploads (staging/*) are copied into canonical by default.
       if (asset.active_key.startsWith("staging/")) {
         await enqueueCopyToCanonical({ assetId: asset.id });
@@ -606,6 +614,91 @@ export async function handleProcessAsset(raw: unknown) {
   }
 }
 
+export async function handleTranscodeVideoMp4(raw: unknown) {
+  const payload = transcodeVideoMp4PayloadSchema.parse(raw);
+  const db = getDb();
+  const s3 = getMinioInternalClient();
+
+  const [asset] = await db<
+    {
+      id: string;
+      bucket: string;
+      active_key: string;
+      mime_type: string;
+    }[]
+  >`
+    select id, bucket, active_key, mime_type
+    from assets
+    where id = ${payload.assetId}
+    limit 1
+  `;
+
+  if (!asset) throw new Error(`Asset not found: ${payload.assetId}`);
+
+  if (!shouldTranscodeToMp4({ mimeType: asset.mime_type })) {
+    return { ok: true, assetId: asset.id, skipped: "already_mp4" };
+  }
+
+  const tempDir = await mkdtemp(join(tmpdir(), "tline-transcode-"));
+
+  try {
+    const containerExt = asset.mime_type.split("/")[1] ?? "bin";
+    const inputPath = join(tempDir, `input.${containerExt}`);
+    const getRes = await s3.send(
+      new GetObjectCommand({
+        Bucket: asset.bucket,
+        Key: asset.active_key,
+      }),
+    );
+    if (!getRes.Body) throw new Error("Empty response body from S3");
+    await streamToFile(getRes.Body as Readable, inputPath);
+
+    const outputPath = join(tempDir, "mp4_720p.mp4");
+    await runCommand("ffmpeg", [
+      "-i",
+      inputPath,
+      "-vf",
+      "scale=-2:720",
+      "-c:v",
+      "libx264",
+      "-preset",
+      "fast",
+      "-crf",
+      "23",
+      "-c:a",
+      "aac",
+      "-b:a",
+      "128k",
+      "-movflags",
+      "+faststart",
+      "-y",
+      outputPath,
+    ]);
+
+    const derivedKey = `derived/video/${asset.id}/mp4_720p.mp4`;
+    await uploadObject({
+      bucket: asset.bucket,
+      key: derivedKey,
+      filePath: outputPath,
+      contentType: "video/mp4",
+    });
+
+    await upsertVariant({
+      assetId: asset.id,
+      kind: "video_mp4",
+      size: 720,
+      key: derivedKey,
+      mimeType: "video/mp4",
+      width: null,
+      height: 720,
+    });
+
+    return { ok: true, assetId: asset.id, key: derivedKey };
+  } finally {
+    await rm(tempDir, { recursive: true, force: true });
+  }
+}
+
 export async function handleCopyToCanonical(raw: unknown) {
   const payload = copyToCanonicalPayloadSchema.parse(raw);
 

apps/worker/src/transcode.ts

@@ -0,0 +1,3 @@
+export function shouldTranscodeToMp4(input: { mimeType: string }) {
+  return input.mimeType !== "video/mp4";
+}