Audio out of sync after rendering

[Johan Lundqvist]

EDIT: This is NOT a rendering problem! When I try to play the movie in RAM preview – I get the same result. Any suggestions?

[Walter Soyka]

Have you installed all the updates for CS6? What format is your audio and video? Is the audio coming from footage? Does it play correctly elsewhere? Can you transcode it to something else?

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
Creative Cow Forum Host: Live & Stage Events

[Jeff Kay]

What format is the Audio? Is it 48K or 44.1k? That difference can cause drift. Is the playback out of sync with the audio waveform? If you start your preview further into the timeline does the audio start at the correct spot (is it drifting only on playback or drifting on the timeline itself)?

If the audio format is not standard and that is what is causing the issue, then transcoding the audio should fix it. Also AE is not the best software to handle audio, so have you considered doing just a video export from AE and laying in the audio in another software?

[Johan Lundqvist]

[Walter Soyka] “Have you installed all the updates for CS6? What format is your audio and video? Is the audio coming from footage? Does it play correctly elsewhere? Can you transcode it to something else?”

Updates are installed. I am using Warp Stablizer for videos shot with my mobile phone (HTC One X). The video is shot in .mp4. Audio is stereo 44.1 and the audio is coming directly from the footage. The audio/video is in sync if I watch the original files in, for example, VLC-player. But it is out of sync after import to After Effects. It’s still out of sync after rendering. I havent tried to transcode it – yet…

[Johan Lundqvist]

[Jeff Kay] “What format is the Audio? Is it 48K or 44.1k? That difference can cause drift. Is the playback out of sync with the audio waveform? If you start your preview further into the timeline does the audio start at the correct spot (is it drifting only on playback or drifting on the timeline itself)?

If the audio format is not standard and that is what is causing the issue, then transcoding the audio should fix it. Also AE is not the best software to handle audio, so have you considered doing just a video export from AE and laying in the audio in another software?”

The audio is 44.1k. It seems like the audio comes more and more out of sync the longer the clip is. It doesnt matter if I start my preview futher into the timeline – the audio doesnt start at the correct spot anyway.

What I want to accomplish in the end is an mkv-file with 2 hours of footage shot with my mobile phone (HTC One X). I am using Warp Stabilizer in After Effects to make the footage look better. Then I use another application to make the acutal .mkv. I am extremely satisfied with Warp Stabilizer!

If I make a lossless .avi-file in After effects – without the sound – and then make a .wav-file (or something) of the sound using another application, how do I put the .avi-file and the .wav-file together in the .mkv?

[Jeff Kay]

Transcode it.

[Ridley Walker]

[Jeff Kay] “Transcode it.

“

That will work. Generally one uses 48kHz audio for video, that’s where your syncing issue originates.

[Walter Soyka]

[Johan Lundqvist] “Updates are installed. I am using Warp Stablizer for videos shot with my mobile phone (HTC One X). The video is shot in .mp4. Audio is stereo 44.1 and the audio is coming directly from the footage. The audio/video is in sync if I watch the original files in, for example, VLC-player. But it is out of sync after import to After Effects. It’s still out of sync after rendering. I havent tried to transcode it – yet…”

The sample rate of the audio should not be the problem. Ae can deal with 44.1 KHz audio and should resample correctly if you are outputting 48 KHz.

I have heard that iPhone video can be variable frame rate (!), wrecking sync. Perhaps your phone has a similar problem.

The solution there is apparently to open in QuickTime Player, Save As, and save out a reference movie. If standard desktop tools aren’t reading the file correctly, perhaps you can use VLC, Handbrake, or ffmpeg/ffmbc to transcode to another format.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
Creative Cow Forum Host: Live & Stage Events

[Johan Lundqvist]

Thanks guys! I transcoded the footage to .mov – and now it works perfectly!