Audio video alignment test video does here is flash a white square for one frame with a 10ms length beep 520ms or 13 frames before the flash, then does this again 480ms or 12 frames before the flash, repeating until the beep and flash happen simultaneously and continue until the beep is 520ms or 13 frames after the flash. In theory, when this video is played back, where the beep and flash occur simultaneously, the info at the bottom of the screen reveals how much the audio is behind or ahead, as shown in the example to the right.
MP4 file Specifications:
Video: 720 x 576 @ 25fps
H264 Video -- Default settings
AAC audio -- 56kbps
Source:
[ Ссылка ]
![](https://i.ytimg.com/vi/52134vY0SNU/mqdefault.jpg)