Eclipsa Audio on a feature-length film

[AntPradZT]

Hello,
As part of the release of a film on YouTube, we were hoping to take advantage of Eclipsa Audio in order to use the film’s Atmos mix. Since there are no tools to directly convert an ADM Atmos into Eclipsa, I therefore used the Eclipsa Audio plug-ins on a Pro Tools session.
Because the ADM contained far too many objects, and since Eclipsa is limited to a maximum of 28 channels, I decided to export the original version in 7.1.4, then two additional versions in 7.1 for two foreign languages so that the total would be 28 channels (Base Enhanced profile). When I realized that YouTube does not allow language selection in Eclipsa Audio (Mix Presentation choice), I then decided to put only the original version in 7.1.4 into Eclipsa Audio (Simple profile).
On a 5-minute excerpt, it worked successfully. When Pro Tools reaches the end of the export (the useless MP3), the progress bar remains at 100% while the Eclipsa plug-in generates the audio (IAMF) as well as the video with this audio encapsulated (MP4). However, on the full film (1h10min), the Eclipsa plug-in does nothing (except the wav stems if that option is checked).
I have tried in several studios, all Mac Studio machines with M2 Ultra and 192 GB of RAM, with several terabytes free on the SSD, but without success. I thought the plug-in might be overloaded, so I unchecked the wav stems and video export in order to try generating only the IAMF Eclipsa audio, but that doesn’t work either. It seems impossible to export the film in Eclipsa Audio!
Could you please help me? Thank you very much in advance,
Antoine Pradalet

[jwcullen]

Can you try again on the latest release, v1.2.1 beta?

This version should perform much better on long files.

[AntPradZT]

Hello Joseph, A huge thank you for letting me know, it worked indeed! However, I’m now facing another issue. The film is 1h05min long, and this time it successfully generated the .iamf and .mp4 files without any problem. So, I tried 3 different versions to test on YouTube: one with only 7.1.4 at 128 kbps per channel, another similar one but with an additional “Mix presentation” including stereo (without binaural) as a fallback, and a third one like the first but with 7.1.4 only at 96 kbps per channel. YouTube accepted the videos, they play fine and the audio is audible, but there’s no trace of IAMF when I analyze the stream with yt-dlp—no warning about an unreadable codec type like IAMF as I’ve seen before. It feels like YouTube is downmixing my 7.1.4 to stereo and removing the original. Is that possible? How can I prevent this? A huge thanks in advance for your help! Le ven. 26 sept. 2025 à 01:32, Joseph Cullen ***@***.***> a écrit :

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*jwcullen* left a comment (google/eclipsa-audio-plugin#46) <#46 (comment)> Can you try again on the latest release (v1.2.1 beta)? This version should perform much better on long files. — Reply to this email directly, view it on GitHub <#46 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/A3IDLL6642QN4CUTQRT7K3L3UR3PLAVCNFSM6AAAAACGRPKV6GVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTGMZWGIZTGNZZHA> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[AntPradZT]

[AntPradZT]

Apart from TV mode on the latest Samsung TVs — which, as far as I know, aren’t even on sale yet — it’s impossible to experience this properly on YouTube. I also have no way of testing it other than in stereo downmix in my studio. VLC 4 Beta does decode IAMF, but it only outputs stereo, with no option to choose between stereo downmix / discrete 7.1.4 / binaural decoding (with or without head-tracking). That would be fantastic. In addition, it doesn’t display the different “Mix Presentations” (such as multiple languages, or in my case a stereo fallback).

I don’t know if this might be useful for your tests, but here are the downloadable files I used for the YouTube upload (original and English versions, either video.mp4 or audio.iamf). They were created with the latest version of the Eclipsa plug-ins in Pro Tools, so I assume they fully comply with the IAMF spec. It’s a sci-fi space opera film that makes full use of 7.1.4.

https://mab.to/t/zvQvEf7NXiN/eu1