Choose File > Open and select the file(s). Or drag the file(s) to the application icon.
Fixing an unsynchronized movie by setting the start time offset of the video or the sound track.
Enter the offset time in the Start field, or click "<" ">" button.
The following are the click "<" ">" button options with modifier key.
- Command key: Decrease or increase by 10 time value
- Option key: Decrease or increase by 100 time value
- Control key: Decrease or increase by 1000 time value
- Shift key: Decrease or increase by 1 second
For example: Setting the start time offset to 1 second.
In the aftermath, the stop time is extended. This movie's duration is 1 minute. The movie will be stop before 1 second of the end of the video track.
If you want to change the movie's duration to the end time of the video track, click the "Duration" and choose the video's duration time.
The start time offset cannot be negative. If you want the track to start before the start time of the movie, edit the media time of the 1st Track Segment.
Click the "Advanced" button to show the track segment, and then enter the media time in the Media Time field, or click "<" ">" button.
The Media Time specifies the starting time within the media data.
For example: If the Media Time is set 00:00:01.0804, the media data starts at 00:00:01.0804. It seems like that the start time offset is set to -00:00:01.0804.
The time scale is the number of time units in one second. if the time scale is 600, each unit represents a six-hundredth of a second. MOV/MP4 files has two types of time scales, Movie Time Scale and Media Time Scale. Movie files has one Movie Time Scale. Each media data, stored in the tracks, has one Media Time Scale.
(A): Movie Time Scale
(B): Media Time Scale
In Movie Time Scale units: ➀, ➁, ➂, ➃, ➄
In Media Time Scale units: ➅, ➆
Track segments contain elements of playing-information as the following.
- Duration (in movie time-scale units)
The duration how long to play the media data
- Media Time (in media time-scale units)
The play start time within the media data
Movie players play movies in order of track segments.
When a track has a start time offset, like as Fixing Audio/Video Synchronization 1, an empty segment is inserted at the top of segments.
In the example below the track has two track segments. Movie players play no video on the screen for one second, and then play the video for one hour from 00:00:01.0804 within the media data.
AV Sync Fix cannot add/delete track segments.