This evening I recorded a five minute introduction for my Technology 4 Teacher’s class this week, since I’ll be absent and a guest presenter / professor will be leading my class on Wednesday. I recorded this video using QuickTime Player 7 on my MacBook Pro and a USB 2.0 Hue Webcam. There was a slight audio and video sync delay in my original recorded movie, but when I uploaded the unedited video to YouTube the sync problem was even more pronounced. (Several seconds delay.) This was unacceptable, so I used MPEG Streamclip (free) to export the video as a MP4 and re-uploaded to YouTube. This video version is MUCH better in terms of audio sync. It’s still there, but not nearly as pronouced as my first attempt.

These are the specs on the first version of this movie I recorded directly with QuickTime Player 7 and my USB webcam:

My original video file today, created with QuickTime Player 7

These are the specs of the second version, which I converted before uploading using MPEG Streamclip:

Movie properties for my exported video this evening, using MPEG Streamclip

I see differences in the data rates and sizes for these videos, but everything else looks very similar. Looking at YouTube’s video codec guidelines, nothing is jumping out at me that would explain the differences in YouTube’s transcoding of these video versions this evening.

I need to get my built-in iSight camera fixed on my Macbook, because I’m sure the initial audio sync problem was caused by the slower USB webcam I used. I’m mystified why the first uploaded video had a MORE pronounced audio sync problem on YouTube, however. Have you seen these types of audio sync problems with videos you’ve recorded and uploaded to YouTube? Any suggestions or theories as to why I had these problems tonight?

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