Software rate control

Two-pass video encoding with CPU software encoders

Use classic two-pass H.264 and H.265 encoding when predictable bitrate allocation matters more than raw hardware speed.

Classic two-pass encoding belongs to software encoders. Convertrilo routes two-pass H.264 and H.265 jobs to CPU encoders so the requested behavior matches the real FFmpeg command.

Try in dashboardAPI integration guideEstimate pricing
Request classic two-passfeature
await client.onDemandEncode({
  sourceUrl: "https://example.com/master.mp4",
  codec: "h264",
  resolution: "1080p",
  preset: "slow",
  bitrateTier: "medium",
  passes: 2,
  optimize: "none"
});

Use software encoders for true classic two-pass behavior.

Avoid silently pretending hardware encoders are classic two-pass.

Improve bitrate allocation for constrained file-size targets.

Keep VMAF and two-pass semantics separate.

How it works

Encoding behavior that maps to the real worker path

These capability pages describe concrete job behavior: payload fields, worker choices, FFmpeg execution, and terminal output handling.

  1. Step 1

    Submit a job with passes set to 2 and optimize set to none.

  2. Step 2

    The worker chooses libx264 or libx265 instead of a hardware encoder.

  3. Step 3

    FFmpeg runs the first analysis pass to create passlog data.

  4. Step 4

    FFmpeg runs the second pass and uploads the completed output.

Truthful encoder selection

Two-pass requests select CPU software encoders because hardware encoders do not provide the same classic passlog workflow.

H.264 and H.265 support

Use libx264 for broad compatibility or libx265 when smaller HEVC outputs fit your playback targets.

Best for constrained outputs

Two-pass is useful when you need steadier bitrate allocation for uploads, archives, and delivery caps.

Feature questions

Why does two-pass use CPU instead of hardware?

Classic two-pass relies on software encoder passlog behavior. Hardware encoders may expose their own multipass modes, but they are not the same contract.

Should every job use two-pass?

No. Use one-pass hardware for speed, VMAF for quality-targeted optimization, and two-pass software when bitrate allocation is the priority.

Does two-pass cost more?

Two-pass uses more compute time than one-pass encoding, so pricing estimates and reserved credits reflect the requested pass count.

Related capability pages

VMAF video encodingUse VMAF-guided sample encoding to choose a better quality target before the final video encode, without manually testing bitrate settings.Hardware video encodingRun video encoding on real hardware encoder families where available, with honest fallback behavior and per-job encoder reporting.Priority video encodingSubmit high-priority video jobs through the API or dashboard when customers pay for faster queue placement.S3 video encodingEncode videos from S3-compatible sources and write completed outputs back to customer-owned S3-compatible buckets.Video encoding APICreate video encoding jobs from your backend with API keys, idempotency, metadata, priority queues, webhooks, and storage destinations you control.Video encoding CLIAutomate video compression from terminals, deployment jobs, content pipelines, and scheduled scripts with a Convertrilo CLI workflow.

Start with a real estimate

Choose your codec, resolution, FPS, bitrate, quality, and optimization settings. Convertrilo shows the NEU estimate before credits are reserved, and failed jobs release reserved credits back to your balance.

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