Bug Report / API Defect: Scripted Export Queue Fails Silently with HEVC (H.265) Presets

There is a critical bug in the Premiere Pro / Media Encoder API (app.encoder) where attempting to programmatically queue a sequence using an HEVC (H.265) preset fails entirely. While the API seamlessly processes H.264, ProRes, and WAV presets, passing an HEVC preset results in a silent failure—Media Encoder simply drops the request without adding the item to the queue or returning an error code.

Scope of Impact

This is not an isolated plugin issue. This API defect completely breaks the core functionality of major industry-standard automation extensions, including:

• Excalibur (by Knights of the Editing Table)

• RenderSegments

• Blinkl.io

Any workflow or custom JSX script utilizing the Adobe API to automate exports to HEVC is currently non-functional.

The Inefficient Workaround

Currently, editors are forced to use a highly disruptive workaround:

1. Trigger the scripted export using an H.264 or ProRes preset to successfully force the item into the Media Encoder queue.

2. Manually select the queued items inside Media Encoder.

3. Manually re-assign the desired HEVC preset to all items.

For high-volume editors handling dozens of social media clips, localized versions, or review cuts daily, this manual intervention completely defeats the purpose of investing in automation tools.

Steps to Reproduce (For Adobe Engineers)

1. Create a custom export preset using the HEVC (H.265) format in Media Encoder.

2. Use a CEP/ExtendScript workflow to programmatically queue an active sequence via app.encoder.encodeSequence(), passing the path of the HEVC preset.

3. Observe Media Encoder: The application registers a command, but the queue remains empty. No error is thrown in the console.

4. Repeat the exact same script using an H.264 preset path: The sequence queues instantly and perfectly.

Requested Action

Adobe Engineering needs to investigate the backend handling of the encodeSequence method specifically when interfacing with the HEVC encoder wrapper. The API should treat HEVC presets with the exact same reliability as H.264 and ProRes.

If you use automation extensions and have been frustrated by your HEVC queues failing, please upvote and comment with the extension you use to bring visibility to the Adobe API team!