---
title: "Runway (Runway Dev API) Alpha channel support on /v1/video_to_hdr: 2026-09-11 | Harbyn"
description: "Runway (Runway Dev API) Alpha channel support on /v1/video_to_hdr, announced Sep 11, 2026."
canonical: "https://harbyn.com/changes/runway/2026-09-11-alpha-channel-support-on-v1-video-to-hdr"
last-updated: 2026-10-02
---

# Runway (Runway Dev API) Alpha channel support on /v1/video\_to\_hdr

Markdown version of <https://harbyn.com/changes/runway/2026-09-11-alpha-channel-support-on-v1-video-to-hdr>.

Behavior change - Runway (Runway Dev API). low severity. In effect.

Ruby now preserves source-video alpha on /v1/video\_to\_hdr without a request parameter. The EXR deliveries write alpha as the A channel; hdr\_prores is delivered as ProRes 4444 regardless of proresProfile. Alpha passes through unchanged and is not premultiplied. hdr10 and hlg still deliver video without alpha. Pricing is unchanged.

## Facts

| Fact | Value |
| --- | --- |
| Vendor | [Runway (Runway Dev API)](https://harbyn.com/vendors/runway.md) |
| Kind | Behavior change |
| Severity | low |
| Status | In effect |
| Announced | Sep 11, 2026 |
| Added to Harbyn | Oct 2, 2026 |
| Lead time | No dated deadline |
| Symbols | `hdr_exr_sequence`, `hdr_exr_acescg_sequence_1_3`, `hdr_exr_acescg_sequence_2_0`, `hdr_prores` |
| Review | Reviewed by a person, extracted by a model |

## Find it in your code

```sh
npx harbyn scan
```

This change names no identifier the scanner can match line by line, so the scan tells you whether your repository uses Runway (Runway Dev API), from its packages and API hosts. Nothing leaves your machine.

## Sources

Where this event comes from: the page we read, when we read it, and the hash of that snapshot.

- <https://docs.dev.runwayml.com/api-details/api_changelog.md> (changelog, fetched 2026-10-02 22:20 UTC, sha256 `ad20c1e9353f74a167dfb12692d8212f5cdf01dd25df96db51e00b716c76d5b7`)

## Related changes

### More from Runway (Runway Dev API)

- [Ruby ACEScg sequences are now referenced to the source](https://harbyn.com/changes/runway/2026-09-12-ruby-acescg-sequences-are-now-referenced-to-the-source.md) (Behavior change, announced Sep 12, 2026)

### Changes at other vendors

- [Amazon Selling Partner API: ORDER\_CHANGE notifications add PreFulfillmentStatusChange for Amazon Autos](https://harbyn.com/changes/amazon-sp-api/2026-10-14-sp-api-updates-new-listings-items-api-ivp-values-in-eu5-jp-and-ca-stores-oct-3.md) (effective Oct 28, 2026)
- [BigCommerce: 301 redirects will apply only to storefront channels](https://harbyn.com/changes/bigcommerce/2026-10-07-301-redirects-now-apply-to-storefront-channels-only.md) (effective Nov 10, 2026)
- [GitHub: Secret scanning audit log business field changes to enterprise slug](https://harbyn.com/changes/github/2026-10-20-updates-to-github-secret-scanning-7.md) (effective Nov 12, 2026)
- [Jira / Atlassian Cloud: New IP address ranges in use from January 1, 2027](https://harbyn.com/changes/atlassian-jira/2026-10-16-atlassian-cloud-adds-new-ip-address-ranges.md) (effective Jan 1, 2027)

[All upcoming deadlines](https://harbyn.com/deadlines.md)