IOS How to export audio from movie

/* export audio from movie as sound  *.m4a*/
- (void) exportSoundFromMovie:(NSString*) inputVideo outputAudio:(NSString*) outputAudio {
      NSURL*    video_inputFileUrl = [NSURL fileURLWithPath:inputVideo];
      NSURL*    outputFileUrl = [NSURL fileURLWithPath:outputAudio];
      AVURLAsset* videoAsset = [[[AVURLAsset alloc]initWithURL:video_inputFileUrl
                                                                                                      options:nil] autorelease];
    [videoAsset loadValuesAsynchronouslyForKeys:[NSArray arrayWithObject:@"tracks"]  completionHandler:^ {
        //HERE IS THE PROBLEM. THE ARRAY OF TRACKS IS EMPTY FOR SOME REASON.
        AVAssetTrack* audioTrack = [[videoAsset tracksWithMediaType:AVMediaTypeAudio]   objectAtIndex:0];
       
        AVMutableComposition* audioComposition = [AVMutableComposition composition];
        AVMutableCompositionTrack* audioCompositionTrack = [audioComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
        [audioCompositionTrack insertTimeRange:[audioTrack timeRange] ofTrack:audioTrack atTime:CMTimeMake(0, 1) error:nil];
       
AVAssetExportSession *exprortSession = [AVAssetExportSession exportSessionWithAsset:audioComposition presetName:AVAssetExportPresetAppleM4A];
        exprortSession.outputURL = outputFileUrl;
        exprortSession.outputFileType = @"com.apple.m4a-audio";
       
        NSLog(@"exportAsynchronouslyWithCompletionHandler will start");
       
        [exprortSession exportAsynchronouslyWithCompletionHandler: ^(void) {
           
            if (exprortSession.status == AVAssetExportSessionStatusCompleted) {
                NSLog(@"Export success");
            }
            else {
                NSLog(@"Export failed");
            }
        }];
    }];
   
}

Comments

Post a Comment

Popular posts from this blog

Java : Variables Declaring

[1]. Java Variables Variables are containers for storing data values. In Java, there are different types of variables, for example: String - stores text, such as "Hello". String values are surrounded by double quotes int - stores integers (whole numbers), without decimals, such as 123 or -123 float - stores floating point numbers, with decimals, such as 19.99 or -19.99 char - stores single characters, such as 'a' or 'B'. Char values are surrounded by single quotes boolean - stores values with two states: true or false [2]. Declaring (Creating) Variables To create a variable, you must specify the type and assign it a value: Syntax type variable = value ; Where type is one of Java's types (such as int or String), and variable is the name of the variable (such as x or name). The equal sign is used to assign values to the variable. To create a variable that should store text, look at the following example: Example Create a variable called  name  of type  Stri...
Read more

SQL Self JOIN

SQL Self JOIN A self JOIN is a regular join, but the table is joined with itself. Self JOIN Syntax SELECT column_name(s) FROM table1 T1, table1 T2 WHERE condition; T1 and T2 are different table aliases for the same table.
Read more