TECHNICAL GUIDE

Automate Subtitle Translation in 2026 — API, CLI & Batch Workflows

By Lisa · Updated March 2026 · 9 min read

To automate subtitle translation, connect to the AdTransPro REST API or install the CLI. Upload video files (or point to a folder for batch jobs), specify target languages, and receive frame-aligned SRT/VTT subtitles in 145+ languages — typically 50% faster than manual workflows. Webhooks notify your pipeline on completion so you can plug directly into CI/CD.

Why Automate Subtitle Translation

Manual subtitle translation is the bottleneck that kills global launch timelines. Industry data shows a single 10-minute video takes an average of 2 hours to subtitle in one language — multiply by 10 markets and you are looking at a week of translator time per asset.

AdTransPro API Setup

Generate an API key from your AdTransPro dashboard under Settings → API Keys. All endpoints use Bearer token auth.

Submit a translation job

curl -X POST https://api.adtranslate.pro/v1/translate \
  -H "Authorization: Bearer $ADTRANS_API_KEY" \
  -F "file=@webinar-en.mp4" \
  -F "source_lang=en" \
  -F "target_langs=es,de,ja,zh-Hans,pt" \
  -F "output_formats=srt" \
  -F "frame_align=true"

# Response
{
  "job_id": "job_abc123",
  "status": "processing",
  "estimated_seconds": 90
}

Poll for completion

curl https://api.adtranslate.pro/v1/jobs/job_abc123 \
  -H "Authorization: Bearer $ADTRANS_API_KEY"

# When status = "completed", download_urls are populated
{
  "job_id": "job_abc123",
  "status": "completed",
  "download_urls": {
    "es": "https://cdn.adtranslate.pro/output/job_abc123/es.srt",
    "de": "https://cdn.adtranslate.pro/output/job_abc123/de.srt",
    "ja": "https://cdn.adtranslate.pro/output/job_abc123/ja.srt"
  }
}

Webhook setup

Instead of polling, register a webhook URL in your dashboard. AdTransPro will POST a payload when each job finishes:

{
  "event": "job.completed",
  "job_id": "job_abc123",
  "source_file": "webinar-en.mp4",
  "download_urls": {
    "es": "https://cdn.adtranslate.pro/output/job_abc123/es.srt",
    "de": "https://cdn.adtranslate.pro/output/job_abc123/de.srt",
    "ja": "https://cdn.adtranslate.pro/output/job_abc123/ja.srt",
    "zh-Hans": "https://cdn.adtranslate.pro/output/job_abc123/zh-Hans.srt",
    "pt": "https://cdn.adtranslate.pro/output/job_abc123/pt.srt"
  }
}

CLI Workflow

The AdTransPro CLI wraps the API into shell-friendly commands — ideal for scripting, cron jobs, and local batch runs.

Install & authenticate

npm install -g adtrans-cli
adtrans login   # opens browser OAuth flow

Translate a single file

adtrans translate ./video.mp4 \
  --target es,de,ja \
  --format srt \
  --out ./subtitles/

Batch-translate a folder

adtrans translate ./videos/ \
  --target es,de,ja,zh-Hans,pt \
  --format srt,vtt \
  --out ./subtitles/ \
  --concurrency 20

The CLI auto-discovers .mp4, .mov, and .webm files in the folder. Use --format to specify one or more output formats (srt, vtt).

Webhook & CI/CD Integration

Plug AdTransPro into your existing deployment pipeline. Below is a GitHub Actions example that translates new video assets on every push to the main branch:

# .github/workflows/translate-subtitles.yml
name: Translate Subtitles
on:
  push:
    branches: [main]
    paths: ["assets/videos/**"]

jobs:
  translate:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Install AdTransPro CLI
        run: npm install -g adtrans-cli

      - name: Authenticate
        run: adtrans login --token ${{ secrets.ADTRANS_API_KEY }}

      - name: Translate new videos
        run: |
          adtrans translate ./assets/videos/ \
            --target es,de,ja,zh-Hans,pt,fr,ko \
            --format srt,vtt \
            --out ./assets/subtitles/ \
            --concurrency 10

      - name: Commit subtitles
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "actions@github.com"
          git add ./assets/subtitles/
          git commit -m "chore: auto-translate subtitles" || true
          git push

Batch Processing at Scale

How does automated translation compare to manual workflows when you are localizing a library of 100 videos?

Automated vs Manual Subtitle Translation

AdTransPro processes 500+ videos concurrently. Time estimate assumes average 5-minute source videos with 5 target languages.

Glossary & Quality Control

Consistency matters — especially for brand names, product terms, and CTAs. AdTransPro supports CSV glossary uploads that lock specific translations across all jobs.

Frequently Asked Questions

Related Reading