One, to solve the problem that QuickTime recording screen can not bring sound:
Use the QuickTime screen under Mac
Soundflower->audio Setup->soundflower (2ch), the right mouse button, in the pop-up menu, "Use this device for sound input" and "Use this device for sound output" are dimmed.
At this point we can no longer hear the sound of the Mac, but can record a recording screen with a sound through QuickTime.
You need to set it up before the QuickTime recording screen:
After recording, in order to hear the sound, you need to restore the sound, through the Mac's system preferences and sound. Change the output back to the built-in speakers and change the input back to the built-in microphone.
Reference: http://jingyan.baidu.com/article/6dad5075100507a123e36efc.html
Second, if you need to upload video to Youku, do not use imovie for editing and export, imovie exported video upload Youku will produce a sound and screen out of sync, but if you directly to the QuickTime recorded video to Youku, There is no problem with the sound and the picture not syncing. The reason for guessing might be that QuickTime recorded a video frame rate of 60fps (see the properties of the. mov file under Windows System for its frame rate), and the video frame rate that imovie exported will be reduced to 30fps. So it's a good idea to simply crop the video from QuickTime and upload the Youku (don't use imovie for video stitching or more complex edits), the video does not merge and there is no big deal, build an album on Youku to aggregate the video clips.
Considerations for using QuickTime recording screen and uploading Youku under Mac