Changing the order of AVMutableCompositionTrack segments

Question

I am trying to create a functionality in my app in which the user can "drag and drop" to change the order of the trimmed videos which are already inserted into the an AVMutableComposition track.

I can retrieve the NSArray containing each segment of the track by using the "segments" property, copied this array into another array, made necessary changes to the new array and but cannot assign the new array into the segments array of the AVMutableComposition track.

Any ideas how can I do it?

Any help will be appreciated.

//retrieving the segments array
NSMutableArray *compTracksArr = [[NSMutableArray alloc] initWithArray:compTrack.segments];
//making changes to the order
[compTracksArr replaceObjectAtIndex:0 withObject:[compTracksArr lastObject]];
//assigning changed array to segments array
compTrack.segments = [NSArray arrayWithArray:compTracksArr];

But when I try to get the output by NSLog(), compTrack.segments do not show any changes in its order of components.

score 0 · Answer 1 · answered Nov 18 '14 at 10:43

    /*!
    @method         validateTrackSegments:error:
    @abstract       Tests an array of AVCompositionTrackSegments to determine whether they conform
                    to the timing rules noted above (see the property key @"trackSegments").
    @param          trackSegments
                    The array of AVCompositionTrackSegments to be validated.
    @param          error
                    If validation fais, returns information about the failure.
    @discussion
        The array is tested for suitability for setting as the value of the trackSegments property.
        If a portion of an existing trackSegments array is to be modified, the modification can
        be made via an instance of NSMutableArray, and the resulting array can be tested via
        -validateTrackSegments:error:.
*/
- (BOOL)validateTrackSegments:(NSArray *)trackSegments error:(NSError **)error;

this should give some answers.

Changing the order of AVMutableCompositionTrack segments

1 Answers1