evOo-local/packages/adapters/src/media/platform-export.test.ts

import { MEDIA_PLATFORM_PROFILES } from "@rakazo/contracts";
import { describe, expect, it } from "vitest";
import type { ExportMeasurement } from "./platform-export.js";
import {
  BITRATE_TOLERANCE,
  checkExport,
  DURATION_TOLERANCE_MS,
  describeSkipped,
  durationIssues,
  LOUDNESS_TOLERANCE_LU,
  MIN_VIDEO_KBPS,
  needsLoudnessFix,
  platformTarget,
  sizeBudgetKbps,
  sizeFixKbps,
  TRUE_PEAK_TOLERANCE_DB,
} from "./platform-export.js";

const tiktok = MEDIA_PLATFORM_PROFILES.tiktok;

/** A clean 30 s TikTok render; tests override what they examine. */
function measured(overrides: Partial<ExportMeasurement> = {}): ExportMeasurement {
  return {
    width: 1080,
    height: 1920,
    fps: 30,
    codec: "h264",
    durationMs: 30_000,
    sizeBytes: 20_000_000,
    videoKbps: 5000,
    loudness: {
      integratedLufs: -14.2,
      truePeakDb: -1.3,
      rangeLu: 4,
      thresholdLufs: -24.5,
      offsetLu: 0.1,
    },
    ...overrides,
  };
}

function loudness(integratedLufs: number, truePeakDb = -2) {
  return { integratedLufs, truePeakDb, rangeLu: 4, thresholdLufs: -30, offsetLu: 0 };
}

describe("platform targets", () => {
  it("renders to the profile and caps the bitrate below its size limit for long videos", () => {
    expect(platformTarget(tiktok, "blur", 30_000)).toEqual({
      width: 1080,
      height: 1920,
      fit: "blur",
      maxFps: 30,
      maxBitrateKbps: 8000,
      integratedLufs: -14,
      truePeakDb: -1,
    });
    // 287 MB over 10 minutes leaves about 3.6 Mbps of video after headroom and audio.
    const tenMinutes = platformTarget(tiktok, "crop", 600_000).maxBitrateKbps;
    expect(tenMinutes).toBe(sizeBudgetKbps(tiktok, 600_000));
    expect(tenMinutes).toBeGreaterThan(3000);
    expect(tenMinutes).toBeLessThan(3700);
    expect(tenMinutes * 600 + 160 * 600).toBeLessThan(287 * 8000);
    expect(sizeBudgetKbps(tiktok, 1e9)).toBe(MIN_VIDEO_KBPS);
  });
});

describe("duration limits", () => {
  it("refuses videos past the limits, with a small tolerance for container rounding", () => {
    expect(durationIssues(tiktok, 600_000 + DURATION_TOLERANCE_MS)).toEqual([]);
    expect(durationIssues(tiktok, 720_000)).toEqual([
      { code: "too_long", maxMs: 600_000, actualMs: 720_000 },
    ]);
    expect(durationIssues(tiktok, 3000 - DURATION_TOLERANCE_MS)).toEqual([]);
    expect(durationIssues(tiktok, 2000)).toEqual([
      { code: "too_short", minMs: 3000, actualMs: 2000 },
    ]);
  });

  it("words a skipped platform for the bot with what to do about it", () => {
    expect(describeSkipped(tiktok, durationIssues(tiktok, 720_000))).toBe(
      "Not exported for TikTok: 720 s is longer than its 600 s limit; trim the video first.",
    );
    expect(describeSkipped(tiktok, durationIssues(tiktok, 1500))).toBe(
      "Not exported for TikTok: 1.5 s is shorter than its 3 s minimum; use a longer video.",
    );
  });
});

describe("platform check", () => {
  it("passes a render within every tolerance", () => {
    expect(
      checkExport(
        tiktok,
        measured({
          videoKbps: 8000 * (1 + BITRATE_TOLERANCE),
          fps: 30.2,
          loudness: loudness(-14 - LOUDNESS_TOLERANCE_LU, -1 + TRUE_PEAK_TOLERANCE_DB),
        }),
      ),
    ).toEqual({ status: "pass", issues: [] });
  });

  it("warns about what the platform would degrade", () => {
    expect(
      checkExport(
        tiktok,
        measured({
          width: 720,
          height: 1280,
          fps: 60,
          videoKbps: 9500,
          loudness: loudness(-17.26, -0.2),
        }),
      ),
    ).toEqual({
      status: "warn",
      issues: [
        {
          code: "resolution_mismatch",
          width: 1080,
          height: 1920,
          actualWidth: 720,
          actualHeight: 1280,
        },
        { code: "fps_mismatch", maxFps: 30, actualFps: 60 },
        { code: "bitrate_high", maxKbps: 8000, actualKbps: 9500 },
        { code: "loudness_off", targetLufs: -14, actualLufs: -17.3 },
        { code: "true_peak_high", maxDb: -1, actualDb: -0.2 },
      ],
    });
  });

  it("fails what the platform would reject, most severe first", () => {
    const check = checkExport(
      tiktok,
      measured({ codec: "hevc", sizeBytes: 300_456_789, loudness: loudness(-20) }),
    );
    expect(check.status).toBe("fail");
    expect(check.issues).toEqual([
      { code: "file_too_large", maxMb: 287, actualMb: 300.5 },
      { code: "codec_mismatch" },
      { code: "loudness_off", targetLufs: -14, actualLufs: -20 },
    ]);
    expect(checkExport(tiktok, measured({ durationMs: 601_000 })).issues[0]).toEqual({
      code: "too_long",
      maxMs: 600_000,
      actualMs: 601_000,
    });
  });

  it("does not judge the loudness of silent or missing audio, or an unknown frame rate", () => {
    expect(checkExport(tiktok, measured({ loudness: null, fps: 0 })).status).toBe("pass");
    expect(
      checkExport(tiktok, measured({ loudness: loudness(Number.NEGATIVE_INFINITY) })).status,
    ).toBe("pass");
    expect(checkExport(tiktok, measured({ loudness: loudness(-65) })).status).toBe("pass");
  });
});

describe("automatic fixes", () => {
  it("re-encodes an oversized file once at a bitrate scaled from what it averaged", () => {
    expect(sizeFixKbps(tiktok, measured(), 8000)).toBeNull();
    // 330 MB at 4400 kbps average: scale by 287/330 and keep 10% headroom.
    const lower = sizeFixKbps(tiktok, measured({ sizeBytes: 330_000_000, videoKbps: 4400 }), 8000);
    expect(lower).toBe(Math.floor(4400 * (287 / 330) * 0.9));
    // Without a stream bitrate, the file size and length give the average.
    expect(
      sizeFixKbps(
        tiktok,
        measured({ sizeBytes: 330_000_000, videoKbps: undefined, durationMs: 600_000 }),
        8000,
      ),
    ).toBe(Math.floor((4400 - 160) * (287 / 330) * 0.9));
    // Nothing lower is left to try.
    expect(
      sizeFixKbps(tiktok, measured({ sizeBytes: 330_000_000, videoKbps: 200 }), MIN_VIDEO_KBPS),
    ).toBeNull();
  });

  it("re-normalizes audible audio that missed the loudness target by more than the tolerance", () => {
    expect(needsLoudnessFix(tiktok, measured())).toBe(false);
    expect(needsLoudnessFix(tiktok, measured({ loudness: loudness(-16) }))).toBe(false);
    expect(needsLoudnessFix(tiktok, measured({ loudness: loudness(-16.5) }))).toBe(true);
    expect(needsLoudnessFix(tiktok, measured({ loudness: loudness(-10) }))).toBe(true);
    expect(needsLoudnessFix(tiktok, measured({ loudness: null }))).toBe(false);
    expect(needsLoudnessFix(tiktok, measured({ loudness: loudness(-70) }))).toBe(false);
  });
});