Sony AVCHD .MTS AC-3 audio doesn't work on Premiere Pro?

[AntDX316]

Sony AVCHD .MTS AC-3 audio doesn't work on Premiere Pro?

I needed to use it as .mp4 was going to be too big for the 64GB I have on it.

VLC player works perfectly, but Windows Media Player doesn't. Adobe Premiere doesn't see the Audio. Even converting to Adobe ProRes 422 doesn't work the audio either and neither does .mp4 with AAC Audio Format Export. 😔

[Peru Bob]

See here:

https://community.adobe.com/t5/premiere-pro-discussions/premiere-pro-2025-version-25-0-0-doesn-t-acc...

and here:

https://www.majorgeeks.com/files/details/dolby_ac_3ac_4_installer.html

[R Neil Haugen]

Windows 11 doesn't support AC3 audio ... so you have to add the audio codec to your computer, and there are several ways to get a free download. There's also several posts on this forum about getting that installed.

Search for AC3 audio codec ... that will bring up several.

This is listed in one post ...

https://www.free-codecs.com/download/ac3_filter.htm

[RjL190365]

The issue is not Adobe. It's Windows. You see, Adobe since version 2018 has restricted AC-3 codec support only to native OS support, which meant that Adobe can no longer include an AC-3 decoder or encoder in its video programs. Windows 11 previously supported the AC-3 codec for playbach until that support was removed beginning with the 24H2 feature update (only for clean installations of such newer feature update versions). Thus, if your Windows 11 PC was a fresh installation of 24H2 or 25H2, you get absolutely no AC-3 support at system level. Hence the need for the workaround mentioned above.

And VLC detects the AC-3 audio because it incorporates a "free-to-use" component of the AC-3 decoder, which is then partially reverse-engineered by the ffmpeg people to mimic the behavior of the actual Dolby Digital decoder and then restricted only for use in VLC and cannot be utilized by any other program. (Both Handbrake and Shutter Encoder also do this, as well because they, like VLC, use ffmpeg for both decoding and encoding media.) As a result, VLC (and Handbrake and Shutter Encoder as well) cannot use the trademarked Dolby Digital logo.

[RjL190365]

By the way, if you used Adobe's Media Encoder to transcode that video to ProRes 422 or mp4, the export will come out with a completely blank audio track because Media Encoder has the exact same AC-3 support restriction as Premiere Pro itself.

[Sumeet Kumar Choubey]

Hi AntDX316,

I hope the suggestions provided by the experts were helpful. You mentioned that the transcoded ProRes 422 or MP4 doesn't work. Could you please let us know the app you used for transcoding?

Thanks,

Sumeet