Why do so many videos have the sound out of sync? (stream, audio)

[robertpasa]

I've noticed very many times, the sound is out of sync but just a few frames, doesn't match the video. And it's some videos more than others, so it's not my stuff.

To prove I'm not crazy, here are two videos. To me, the first one has the sound exactly right and the second has the sound slightly out of sync. Does it seem out of sync to you? You have to look at the people's lips moving.


https://www.youtube.com/watch?v=ZCPJfasGcp4


https://www.youtube.com/watch?v=mu_pNeqAQ-U

People might say it has to do with the internet being too slow, but why would it be some videos more than others?

[robertpasa]

I just found this nifty sound test. It's synced okay on my device. Hence a lot of videos are not synced right, but why so many?


https://www.youtube.com/watch?v=ucZl6vQ_8Uo

[rjm1cc]

If you are using a USB port you could have a problem with the wiring or the port.

[Peregrine]

It's either the video was just encoded poorly or your computer. That Bangles video plays fine here. Bangles? Really Robert?

[thecoalman]

There can be a lot of reasons especially if the video/audio was originally analog. The video and audio are two separate streams so if the rendered video or audio is little faster or slower then the audio stream it will get out of sync and this can occur anywhere along the process. For short videos not a big problem but a minor out of sync issue gets worse as the video progresses.

FYI this is the reason for clapper you see them use in movie/video production. They have both a visual and audio cue.

[thecoalman]

Originally Posted by Peregrine

That Bangles video plays fine here. Bangles? Really Robert?

Oh come on, don't tell me you don't get a little smile when walk like an Egyptian comes on.

Lita blows them away though, especially this one... My favorite duet of all time.


https://www.youtube.com/watch?v=foGkU6x3eSE

[Peregrine]

Have you heard this?


https://www.youtube.com/watch?v=GMk-8pmTpgU

[robertpasa]

I watched those two videos at another computer at the library - same difference. The Bangles video is only off by a few frames if you look at her mouth closely. You have to look closely.

I found some articles saying it has to do with variable frame rate.

[harry chickpea]

VLC media player has a function where you can adjust that mismatch out for playback.

[thecoalman]

Originally Posted by Peregrine

Have you heard this?


https://www.youtube.com/watch?v=GMk-8pmTpgU

LOL, I've not listened to them but have come across them doing searches.