Re: Problems using QTKit to create 24 fps movie

QuickTime uses integers for time.

Check the movie time scale and make sure it's divisible by 24 -- IIRC 
the default is 600.

Try setting the movie timeScale to 600 and using:

QTTime duration = QTMakeTime(25, 600); /* 25 = 600/24 */

This should give you exactly 24fps

HTH,

-Steve

At 10:13 AM -0500 3/8/12, Marshall Houskeeper wrote:
> I am trying to use QTKit to export a 24 fps movie.  However, when I 
> open the movie in QuickTime Player or other applications the movie 
> has a frame rate of 25 fps.
>
> Is there a known bug with exporting 24 fps movies using QTKit or am 
> I doing something wrong?
>
> Note: I see the problem in both 10.6.8 and 10.7.3.
>
> Below is a slightly modified version of  the createMovie method in 
> the Apple sample program WritableFileDemo that shows the problem:
>
> - (IBAction)createMovie:(id)sender
> {
>         QTMovie *movie = nil;
>         NSImage *image = nil;
>         NSDictionary *attrs = nil;
>         SInt32 i;
>
>
>
> 	attrs = [NSDictionary dictionaryWithObject:@"jpeg" 
> forKey:QTAddImageCodecType];
>
>
>
> 	NSTimeInterval	mFrameInterval = 1.0 / 24.0;	// set frame 
> rate to 24 fps
>         QTTime duration = QTMakeTimeWithTimeInterval(mFrameInterval);
>
> 	movie = [[QTMovie alloc] initToWritableFile:@"/tmp/newMovie" 
> error:NULL];
>
>
>
>         for ( i = 0; i < 100; i++)
>         {
>                 image = [NSImage imageNamed:@"A"];
> 		[movie addImage:image forDuration:duration 
> withAttributes:attrs];
>
>                 image = [NSImage imageNamed:@"B"];
> 		[movie addImage:image forDuration:duration 
> withAttributes:attrs];
>
>                 image = [NSImage imageNamed:@"C"];
> 		[movie addImage:image forDuration:duration 
> withAttributes:attrs];
>         }
>
>
>
>         [movie updateMovieFile];
>
>
>
>         [movieView setMovie:movie];
>         [sender setEnabled:NO];
> }
>
>  _______________________________________________
> Do not post admin requests to the list. They will be ignored.
> QuickTime-API mailing list      ([EMAIL PROTECTED])
> Help/Unsubscribe/Update your Subscription:
> https://lists.apple.com/mailman/options/quicktime-api/sgs-lists%40codewell.com
>
> This email sent to [EMAIL PROTECTED]

_______________________________________________
Do not post admin requests to the list. They will be ignored.
QuickTime-API mailing list      ([EMAIL PROTECTED])
Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/quicktime-api/alexiscircle%40gmail.com

This email sent to [EMAIL PROTECTED]