Can you recommend a software to sync video and audio?

[digicube]

I have a x264 avi file with no sound and a wav file. Is there a software that will sync and mux these two together without re-encoding the video? The audio can be encoded to other formats such as AAC, AC3.

[JVRaines]

ffmpeg -i video.avi -i audio.wav -map 0:v -map 1:a -c:v copy -c:a aac -b:a 160k output.mp4

[digicube]

I need to sync the audio to the video too, like moving the timeline around.

[davexnet]

It depends on whether it's just an offset problem, or whether it drifts progressively worse ...

[digicube]

It's not an offset problem I just need to put the audio at some point in time in the video like in Adobe Premiere. I'll try Adobe Premiere and see if it won't re-encode.

[JVRaines]

I need to sync the audio to the video too, like moving the timeline around.

ffmpeg -i video.avi -itsoffset secs -i audio.wav -map 0:v -map 1:a -c:v copy -c:a aac -b:a 160k output.mp4

where secs is the number of seconds to delay the audio. Decimals and negative values are permitted.

[digicube]

i don't know the numbers. I have to visually sync people's lips to the works spoken.

[JVRaines]

I guess you're welcome anyway.

[digicube]

Yea. Thanks anyway.

[redwudz]

I've used MPC-HC to determine the sync offset, if that is your problem. Play the video and use the + and - keyboard keypad keys as the video plays.
When you get the audio synced, write down the offset and add it to your encoder/editor program.

But if the sync changes during the playback, then you would need to adjust the length of the audio.
Or if you are unfortunate, you might have a combination of both sync errors.

[digicube]

I tried that before, it's time consuming and have to go through many trial and error. It's better if I can visually see the wave forms and the video and then align them together. I'm currently trying Adobe After Effects but it's a complicated software, so I'm watching some tutorials.

[manono]

It's better if I can visually see the wave forms and the video and then align them together.

I use AviSynth's AudioGraph filter to do just that:

https://forum.videohelp.com/threads/383349-Cropping-the-top-of-frame-in-Handbrake/page4#post2487503

[digicube]

That looks cool. I'll try that if Adobe fails.

[digicube]

Looks like the video and audio are at different frame rates. The video is exactly 18 fps and the audio is slightly under 18 fps. Video duration is 16min 17s and the audio duration is 16min 38s. How do I change the frame rate of the audio so it syncs with the video? I assume Avisynth can do this.

[manono]

Audio doesn't have a framerate. But, yes, audio can be stretched using AviSynth. I do my audio work in Audacity, but AviSynth's TimeStretch command might suit you.

[digicube]

How about if we change the video frame rate to suite the audio's duration time? ChangeFPS() or ConvertFPS() will do? Is this better than TimeStretch?

I will try audacity first and change the speed.

[sneaker]

Neither ChangeFPS() nor ConvertFPS() change video duration, only AssumeFPS() does. But:
- VirtualDub should be able to do that without re-encoding. (AviSynth() implies reencoding)
- matching video to audio duration doesn't always guarantee sync. (only with constant frame rate and lengths of the tracks matching)

[digicube]

Audacity's speed change works. Thanks everyone for the help.