Audio Tracks

The Audio tab lets you view, add, update, replace, and remove audio tracks associated with your asset. Use it to manage multiple languages, alternate mixes, or updated audio sources.

Uplynk encodes audio using HE-AAC at a 48 kHz sample rate, compatible with all standard playback and delivery formats. Some older assets created with legacy Slicers may use different sample rates, but the platform fully supports them.

Field Definitions


Description	A user-defined label for the audio track (e.g., Spanish Mix, Director Commentary).
Language	A two- or three-letter ISO-639 language code such as en, es, spa, fra. Uplynk accepts both ISO-639-1 and ISO-639-2/3 codes.
Dolby	Enabling Dolby creates new Dolby-encoded audio subtracks derived from the audio you upload: Dolby 5.1 (surround). Dolby 2.0 (stereo). These appear as separate Dolby indicators in the Audio table.
AC3 Pass-Through	Enabling AC3 Pass-Through preserves existing Dolby audio in your source file without re-encoding it. If your uploaded audio contains Dolby Digital (AC3) or Dolby Digital+ (EAC3), including streams with Atmos metadata, Uplynk will: Keep that Dolby audio exactly as-is. Make it available as a Dolby Pass-through subtrack. If the source audio has no Dolby, the toggle has no effect.
URL	A link to the audio file you want to upload or replace. When replacing a track, providing a new URL fully overwrites the existing audio for that track. If you provide a URL to a video, Uplynk strips the audio from that video and adds it to your asset.

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Important Note

Replacing audio permanently removes the old audio.

Track 0 cannot be replaced.

Only the last audio track in the list can be deleted.

Adding a New Audio Track

Open the Audio tab.
Select + Audio.
Enter the Description and Language.
(Optional) Enable Dolby and/or AC3 Pass-Through.
Provide a URL to your audio/video file.
Select Create.

The new track appears once processing completes. If something goes wrong (invalid URL, unsupported format), an error message explains the issue.

Updating Track Information

You can update the Description and Language of an existing audio track.

Select a track row.
Edit the metadata.
Select Update.

Changes appear immediately.

Replacing an Audio Track

Use replacement when you want to overwrite an existing track with new audio.

Select a track.
Provide a new URL.
(Optional) Enable Dolby and/or AC3 Pass-Through.
Select Update.

Deleting an Audio Track

Select the trash can icon for an eligible track.
Confirm the deletion.
The track is removed.

FAQ

When should I use the Dolby option?

Use Dolby when you want to generate new high-quality Dolby audio:

Your source audio does not contain Dolby, but you want Dolby output.
You want to guarantee a consistent set of Dolby 5.1 + 2.0 tracks.
You want Uplynk to encode your stereo or surround audio into Dolby formats.
You are targeting devices or distribution partners that expect Dolby renditions.

When should I use the AC3 Pass-Through option?

Use AC3 Pass-Through when you want to keep your original Dolby track untouched:

Your source file already contains high-quality Dolby audio.
You want to avoid re-encoding to preserve fidelity.
You want the original AC3/EAC3 delivered exactly as provided.
You want to maintain Atmos metadata that may be lost if re-encoded.

Can I use both Dolby and AC3 Pass-Through together?

Yes. You can enable:

Dolby only
AC3 Pass-Through only
Both at the same time

When both are enabled:

Uplynk creates new Dolby versions (5.1 & 2.0)
AND passes through the original Dolby audio if present

When should I use both Dolby and AC3 Pass-Through together?

Use both when:

You want to preserve your original Dolby audio and
You also want Uplynk to generate Dolby 5.1 + 2.0 encodes for maximum compatibility.