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qcpostprod
qcpostprod
Participant
April 14, 2026

Encoding a file using H.264 in MP4 format causes the audio and video to become out of sync.

  • April 14, 2026
  • 1 reply
  • 65 views

When I use Media Encoder to transcode a video—for example, Apple ProRes 422 HQ with Linear PCM audio—After Effects and Premiere create a delay of about one frame between the audio and the video, which is very annoying. This problem only occurs when I set the output settings to MP4 H.264 with AAC audio.

 

As I need to deliver an MP4 H.264 file with AAC as the audio codec to my client, I have no choice but to use other video transcoding software. And in that case, I don’t have any issues with the audio and video being out of sync; the audio is exactly the same as in the source Apple ProRes file.

Is this a bug or have I configured the settings incorrectly?

I have attached my ME output preset along with a screenshot of the delay caused by the encoding .

 

Thanks.

    1 reply

    EckiAME
    Community Manager
    EckiAMECommunity Manager
    Community Manager
    April 20, 2026

    What are your specs (OS, CPU, GPU, memory)? Can you provide a small sample for me to investigate? I can send you the instructions via private message in this forum.

    qcpostprod
    qcpostprodAuthor
    Participant
    April 20, 2026

    Thanks for your feedback. Yes I can send you all the infos you need in PM.
     

    Here’s some infos :

     

    M4 14” MacBook Pro (2024) - 24 GB RAM - macOS Tahoe 26.4.1

    Adobe Media Encoder, After Effects, Premiere 26.2

     

    Also tested with other devices like Mac Studios on macOS 15 Sequoia, ME 25, and Windows configs from colleagues. Always the same problem.

     

    You’ll also find some new tests and sample files. My source is an Apple ProRes file which I use to create the social deliverables for my clients (they absolutely want MP4 H.264 with AAC audio)

     

    Thanks for your time and help

    EckiAME
    Community Manager
    EckiAMECommunity Manager
    Community Manager
    April 20, 2026

    Would you be able to share a full project?

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