How do I view the progress for converting a Movie with QTKit?

How do I view the progress for converting a Movie with the following QTKit code?

NSDictionary *dict = [NSDictionary 
     dictionaryWithObjectsAndKeys:
     [NSNumber numberWithBool:YES], QTMovieExport, 
     [NSNumber numberWithLong:kQTFileType3GPP], 
     QTMovieExportType, nil];

[[movieView movie] writeToFile:@"/tmp/sample.3gp" 
     withAttributes:dict];

i.e. I want to view the progress of the movie conversion such that I can display it in a progress bar.

Solution

Taken from this site: http://www.mactech.com/articles/mactech/Vol.21/21.08/Threads/index.html

If the movie is very large, this method could take quite a while to complete. During that time, the user would be unable to do anything with the application except move windows around. Not very exciting.

A slightly better solution involves using the movie:shouldContinueOperation:withPhase:atPercent:withAttributes: delegate method. This is a wrapper around QuickTime's movie progress function, which will be used to display a dialog box showing the progress of the export and to allow the user to cancel the operation. Here try this

- (BOOL)movie:(QTMovie *)movie 
      shouldContinueOperation:(NSString *)op 
      withPhase:(QTMovieOperationPhase)phase 
      atPercent:(NSNumber *)percent 
      withAttributes:(NSDictionary *)attributes
{
   OSErr err = noErr;
   NSEvent *event;
   double percentDone = [percent doubleValue] * 100.0;

   switch (phase) {
      case QTMovieOperationBeginPhase:
         // set up the progress panel
         [progressText setStringValue:op];
         [progressBar setDoubleValue:0];

         // show the progress sheet
         [NSApp beginSheet:progressPanel 
            modalForWindow:[movieView window] modalDelegate:nil 
            didEndSelector:nil contextInfo:nil];
         break;
      case QTMovieOperationUpdatePercentPhase:
         // update the percent done
         [progressBar setDoubleValue:percentDone];
         [progressBar display];
         break;
      case QTMovieOperationEndPhase:
         [NSApp endSheet:progressPanel];
         [progressPanel close];
         break;
   }

   // cancel (if requested)
   event = [progressPanel 
         nextEventMatchingMask:NSLeftMouseUpMask 
         untilDate:[NSDate distantPast] 
         inMode:NSDefaultRunLoopMode dequeue:YES];
   if (event && NSPointInRect([event locationInWindow], 
                                          [cancelButton frame])) {
      [cancelButton performClick:self];
      err = userCanceledErr;
   }

   return (err == noErr);
}

Hope this helps.

If you need any help do let me know. let me know if this helped a lil.