TweetFollow Us on Twitter

Timeline

Volume Number: 22 (2006)
Issue Number: 2
Column Tag: Programming

QuickTime Toolkit

Timeline

by Tim Monroe

Mapping the Evolution of QuickTime Programming

The QuickTime programming landscape looks pretty good nowadays. In terms of what you can do with QuickTime, the story has never been better. In the nearly 15 years since its introduction in December 1991, QuickTime has gained a truly impressive set of multimedia capabilities. It now provides services for displaying and creating movies, capturing audio and video data, compressing and transcoding media data, broadcasting saved movies and live captured data across a network, displaying and modifying still images, and other tasks too numerous to list here exhaustively. With the recent appearance of QuickTime 7, the QuickTime programming APIs now comprise more than 2500 actively-supported functions.

Introduction

But that of course is only half of the story, and in many ways it is the less interesting half. We would expect this sort of continual feature expansion from any software architecture that has been around for a decade and a half. What is perhaps more interesting is the wealth of tools that we as software developers can use to access those multimedia capabilities. For almost three full years, believe it or not, this QuickTime Toolkit column has focused more or less directly on the issue of how to use various different programming languages and development environments to construct QuickTime applications. We've built applications using a wide variety of alternate languages and IDEs, including Cocoa, REALbasic, Revolution, Visual Basic, AppleScript Studio, Java, Tcl/Tk, and others. From modern object-oriented application frameworks to old-school scripting languages, we've pretty much run the gamut of possibilities for developing applications and tools to create and modify and display QuickTime content.

It would be nice to pause and reflect on these tools and languages and to see how they compare with one another in terms of ease-of-use and feature completeness and extensibility. It would also be nice to run some benchmarks to see if some of these development environments produce particularly more efficient and resource-friendly applications than others. (Java, for instance, has a reputation for being slow; it would be nice to actually test our sample Java-based player application against our other sample applications.) But those reflections will have to wait for some other opportunity, since in this article I want to discuss a somewhat different issue. In particular, I want to look at how QuickTime programming itself has evolved in the years since its introduction. What did it look like in the beginning, and what is its general character now? What sorts of forces have prompted changes in the QuickTime programming model?

I think that this is an interesting set of questions because not every QuickTime developer -- and in fact probably a minority of current QuickTime developers -- has been using QuickTime for a significant portion of those 15 years. In addition, most developers are probably using one or more of the QuickTime-savvy RAD tools or application frameworks. Since none of these tools or frameworks provides access to all the existing QuickTime capabilities, it's likely that some QuickTime developers will need to venture outside the limits of their chosen tools to develop plug-ins or libraries for those tools. And then they land squarely in the realm of those 2500 functions.

MacOS

So let's begin at the beginning. QuickTime was originally released on the Macintosh Operating System (specifically, on MacOS version 6.0.7). Quite sensibly, the original QuickTime APIs were heavily dependent on the data types and structures used by the Macintosh Operating System and the Macintosh User Interface Toolbox. A chunk of memory was typically specified using a Handle data type, and files were typically specified using FSSpec records. Data to be drawn on the screen was accessed using bitmaps drawn into graphics ports and graphics worlds (specified using GrafPtr and GWorldPtr data types). The intention was very clearly that the QuickTime APIs should fit into the existing programming model on Macintosh computers.

At the same time, the QuickTime architects did not hesitate to drive that programming model forward in certain important ways. One of the big departures from existing practices was to make C the language of choice for developing QuickTime applications, in spite of the fact that Pascal still dominated MacOS software development during the time QuickTime was being developed. The original developer CD for QuickTime 1.0 provided 18 sample projects using C but only half that many using Pascal. More importantly, the technical documentation for QuickTime provided all sample code and reference material in C, not Pascal. Indeed, the books Inside Macintosh: QuickTime and Inside Macintosh: QuickTime Components were the very first books in that series to relegate Pascal to the programming summaries at the end of the chapters.

Listing 1 shows what a typical routine to open a movie file might have looked like. It uses the Standard File Package to display the file-opening dialog box to the user, and then it calls OpenMovieFile and NewMovieFromFile to create a Movie identifier for the data in the movie file.

Listing 1: Loading a movie from a file

Movie GetAMovie (void)
{
   OSErr                        myErr; 
   SFTypeList                   myTypes = {MovieFileType, 0, 0, 0}; 
   StandardFileReply            myReply;
   Movie                        myMovie = NULL; 
   short                        myRefNum; 
   short                        myResID = 0; 

   StandardGetFilePreview(NIL, 1, myTypes, &myReply); 

   if (myReply.sfGood) { 
      myErr = OpenMovieFile(&myReply.sfFile, &myRefNum, 
                                          fsRdPerm); 
      if (myErr == noErr) { 
         NewMovieFromFile(&myMovie, myRefNum, &myResID, NULL, 
                                          newMovieActive, NULL); 

         CloseMovieFile(myRefNum); 
      }
   }

   return myMovie; 
}

One interesting thing about this code is that it is almost completely deprecated on current Macintosh computers. The Standard File Package never made the jump from the "classic" MacOS to Mac OS X, and (as we saw in the previous article, "State Property 2" in MacTech, December 2005) the NewMovieFromProperties function is now recommended in place of NewMovieFromFile. After all, the parameters to NewMovieFromFile include oddities like a file reference number and a pointer to a resource ID, which are not standard ways of accessing files or file data on Mac OS X.

It's worth remarking that first QuickTime developer CD also included a small set of HyperCard add-ons, called external commands or XCMDs, that allowed HyperCard developers to access QuickTime functionality in their stacks. This then marks the first integration of QuickTime into what might be called a rapid application development (RAD) tool. There were four XCMD modules:

    (1) The QTMovie XCMD, which could be used to play QuickTime movies in a window or directly onto the screen;

    (2) The QTRecordMovie XCMD, which displayed data from a video digitizer;

    (3) The QTEditMovie XCMD, which supported editing operations on a QuickTime movie;

    (4) The QTPict XCMD, which performed a variety of still image operations, including displaying a picture on a card, compressing pictures, and allowing control over the clipping region of the card window.

(The perceptive reader will notice that, by pure historical accident, one of these XCMDs shares its name with the principal class in the new Cocoa QTKit framework, QTMovie.)

Windows

In the early 1990's, Apple released a version of QuickTime (called "QuickTime for Windows") that provided support for playing QuickTime movies on Windows computers. While it was a significant step forward, this version had some severe limitations. Most importantly, it provided a playback engine only; there was no way to create QuickTime movies on the Windows platform. Also, many of the APIs for playing movies back differed from their Macintosh counterparts. For instance, on the Mac, NewMovieController is declared essentially like this:

MovieController NewMovieController (Movie theMovie, 
                        const Rect *movieRect, long someFlags);

But under QuickTime for Windows, it had this declaration:

MovieController NewMovieController (Movie theMovie, 
                        const LPRECT lprcMovieRect, long someFlags, 
                        HWND hWndParent);

You'll notice that the Windows version took an additional parameter (hWndParent) and that the type of the second parameter was a pointer to the standard Windows rectangle type (RECT), not the Macintosh rectangle type (Rect).

QuickTime 3.0, released in 1998, changed all that. It provided a set of APIs that were virtually identical -- in both parameter lists and feature completeness -- on Macintosh and Windows platforms. It was then possible to write Mac and Windows applications that used the same source code, at least for the QuickTime-specific portions of the application.

The magic provided by the Windows version of QuickTime 3.0 was accomplished principally by a library called the QuickTime Media Layer (or, more briefly, QTML). The QuickTime Media Layer provides an implementation of a number of the parts of the Macintosh Operating System (including the Memory Manager and the File Manager) and the Macintosh User Interface Toolbox (including the Dialog Manager, the Control Manager, the Resource Manager, and the Menu Manager). In other words, QuickTime was ported to Windows mainly by way of transplanting large portions of system software from the MacOS to Windows.

For existing Macintosh developers, this scheme had some profound benefits. First and foremost, this greatly reduced the need to learn the intricacies of a new operating system. To display the standard Windows file-selection dialog box to elicit a movie file from the user, a developer could just use the familiar StandardGetFile function that he or she had been using all along on MacOS. And custom application icons, sounds, and fonts could be stored in resources, just as they are with MacOS applications. And existing QuickTime code could, as noted above, simply be recompiled for Windows applications. (Indeed, the code in Listing 1 would still compile and link just fine on Windows computers.)

But for Windows developers, this scheme was less than optimal. It required working with unfamiliar data types, like Handle and FSSpec and GrafPtr, and also working with command-line tools to create resources or add them to application files. A better solution, which Apple and several third-party developers pursued, was to develop Component Object Model (COM) plug-ins that support QuickTime APIs in Windows applications. One type of COM object is an ActiveX control, which can display a user interface and process events directed at that interface. The developer can then support QuickTime in a COM-aware application (for instance, one developed using Visual Basic) by using an appropriate ActiveX control. For instance, Listing 2 shows some Visual Basic code to handle the Open menu item in the File menu.

Listing 2: Handling the Open menu item

Private Sub FileOpen_Click()
   Dim openDial As New DialogWindow
   On Error GoTo bail

   openDial.CommonDialog1.Filter = "All Files (*.*)|*.*|Movie Files (*.mov)|*.mov|Flash Files 
      (*.swf)|*.swf"
   openDial.CommonDialog1.FilterIndex = 2
   openDial.CommonDialog1.Flags = 4

   ' hide the "Read Only" check box
   openDial.CommonDialog1.CancelError = True
   openDial.CommonDialog1.ShowOpen

   OpenFile (openDial.CommonDialog1.FileName)
   Unload openDial
   Exit Sub

bail:

   ' the user pressed the Cancel button

   Unload openDial
   Exit Sub
End Sub

The FileOpen_Click handler uses standard Visual Basic methods, except for the application defined OpenFile method, shown in Listing 3.

Listing 3: Opening a movie file

Sub OpenFile(fileNm As String)
   Dim movieWind As New MovieWindow

   If Len(fileNm) = 0 Then
      movieWind.Caption = "Untitled"
   Else
      movieWind.Caption = BaseName(fileNm)
      movieWind.QTActiveXPlugin1.SetURL (fileNm)
   End If

   movieWind.Show
End Sub

It's important to note that a QuickTime-savvy ActiveX control does not so much remove the dependence on QTML as hide it. That is to say, although the Visual Basic developer doesn't need to know about MacOS data types, the person who wrote the ActiveX control does. And even the VB developer might need to know about MacOS data types when using the declare statement to reference external procedures in the QTML library. This would happen if the developer needs to access QuickTime functionality that was not implemented in whichever ActiveX control he or she is using.

Mac OS X

QuickTime's migration from MacOS to Mac OS X is remarkably similar in spirit to its migration from MacOS to Windows. Once again, a software layer was added to support the Macintosh Operating System and User Interface Toolbox managers that originated on MacOS and which are used extensively throughout the QuickTime source code. Mac OS X is a UNIX-based operating system and provides no more native support for QuickTime than does Windows. In this case, the implementation of the Macintosh Operating System and Toolbox managers is provided by a library called Carbon. The only real difference between QTML and Carbon is that Carbon has evolved more swiftly than QTML. For instance, as mentioned earlier, the Standard File Package has long since been deprecated on Macintosh computers, having been replaced by the Navigation Services (which supports longer filenames and alternate text encoding schemes such as Unicode).

The move to Mac OS X has prompted two additional sorts of changes to QuickTime APIs, above and beyond the changes required for it to keep pace with enhancements in the Carbon library. First, a reasonably extensive Cocoa framework, QTKit, was developed to replace the existing QuickTime-related classes, NSMovie and NSMovieView. We investigated QTKit in several recent articles (MacTech, May, June, and July 2005) and saw that we can develop full-featured Cocoa applications with only minimal need to venture outside of the methods it provides. And venturing outside of Cocoa is easy, because Objective-C is a superset of ANSI C. This means that we can easily call Carbon APIs within our Cocoa code. For example, Listing 4 shows a method for setting the magnification level of a Flash movie opened using QTKit. Notice that we call GetMovieIndTrackType to find the first Flash track in the movie, and then we call GetTrackMedia, GetMediaHandler, and FlashMediaSetZoom to set the zoom level of that track.

Listing 4: Setting the zoom level of a Flash movie

- (void)setZoom:(float)zoomPct
{
   Track flashTrack = NULL;
   Media flashMedia = NULL;
   MediaHandler flashHandler = NULL;
   
   flashTrack = GetMovieIndTrackType([self quickTimeMovie], 
                        1, FlashMediaType, movieTrackMediaType | 
                        movieTrackEnabledOnly);
   if (flashTrack) {
      flashMedia = GetTrackMedia(flashTrack);
   flashHandler = GetMediaHandler(flashMedia);
      FlashMediaSetZoom(flashHandler, zoomPct);
   }
}

The second principal way in which Mac OS X has affected QuickTime, on the API level, is the adoption within QuickTime of Core Foundation data types. Core Foundation is a procedural C framework that is modeled on the object-oriented Foundation framework in Cocoa. It provides, among other things, some very nice collection classes (such as arrays and dictionaries) and Unicode-compatible strings. QuickTime 6.4 introduced, for instance, several functions for creating data references from Core Foundation data types like CFString and CFURL, including these:

QTNewDataReferenceFromFullPathCFString
QTNewDataReferenceFromURLCFString
QTNewDataReferenceWithDirectoryCFString

And we saw in an earlier article ("State Property" in MacTech, November 2005) that the QuickTime property function QTGetMoviePropertyInfo can return reference-counted Core Foundation objects that need to be released (by calling CFRelease). Interestingly enough, these Core Foundation data types and functions are supported now on Windows as well as on Mac OS X.

Conclusion

So where do we stand here in early 2006? The good news is that Apple and third-party developers have invested considerable resources into making sure that the major programming tools and development environments support some level of QuickTime movie playback and editing. Moreover, the QuickTime APIs have kept pace with changes in the Carbon library and have expanded to provided support for Cocoa and Core Foundation programming paradigms.

The bad news, if there is any, is that some important parts of QuickTime are still accessible only using functions and data types are arose on MacOS, a now-deprecated operating system. It would be nice to never have to allocate another Handle object. We aren't quite there yet. But surely some day we will be.


Tim Monroe is a member of the QuickTime engineering team at Apple. You can contact him at monroe@mactech.com. The views expressed here are not necessarily shared by his employer.

 
AAPL
$102.23
Apple Inc.
+2.47
MSFT
$44.61
Microsoft Corpora
+0.53
GOOG
$520.91
Google Inc.
+0.07

MacTech Search:
Community Search:

Software Updates via MacUpdate

NTFS 12.0.39 - Provides full read and wr...
Paragon NTFS breaks down the barriers between Windows and OS X. Paragon NTFS effectively solves the communication problems between the Mac system and NTFS, providing full read and write access to... Read more
RestoreMeNot 2.0.3 - Disable window rest...
RestoreMeNot provides a simple way to disable the window restoration for individual applications so that you can fine-tune this behavior to suit your needs. Please note that RestoreMeNot is designed... Read more
Macgo Blu-ray Player 2.10.9.1750 - Blu-r...
Macgo Mac Blu-ray Player can bring you the most unforgettable Blu-ray experience on your Mac. Overview Macgo Mac Blu-ray Player can satisfy just about every need you could possibly have in a Blu-ray... Read more
Apple iOS 8.1 - The latest version of Ap...
The latest version of iOS can be downloaded through iTunes. Apple iOS 8 comes with big updates to apps you use every day, like Messages and Photos. A whole new way to share content with your family.... Read more
TechTool Pro 7.0.5 - Hard drive and syst...
TechTool Pro is now 7, and this is the most advanced version of the acclaimed Macintosh troubleshooting utility created in its 20-year history. Micromat has redeveloped TechTool Pro 7 to be fully 64... Read more
PDFKey Pro 4.0.2 - Edit and print passwo...
PDFKey Pro can unlock PDF documents protected for printing and copying when you've forgotten your password. It can now also protect your PDF files with a password to prevent unauthorized access and/... Read more
Yasu 2.9.1 - System maintenance app; per...
Yasu was originally created with System Administrators who service large groups of workstations in mind, Yasu (Yet Another System Utility) was made to do a specific group of maintenance tasks... Read more
Hazel 3.3 - Create rules for organizing...
Hazel is your personal housekeeper, organizing and cleaning folders based on rules you define. Hazel can also manage your trash and uninstall your applications. Organize your files using a... Read more
Autopano Giga 3.7 - Stitch multiple imag...
Autopano Giga allows you to stitch 2, 20, or 2,000 images. Version 3.0 integrates impressive new features that will definitely make you adopt Autopano Pro or Autopano Giga: Choose between 9... Read more
MenuMeters 1.8 - CPU, memory, disk, and...
MenuMeters is a set of CPU, memory, disk, and network monitoring tools for Mac OS X. Although there are numerous other programs which do the same thing, none had quite the feature set I was looking... Read more

Latest Forum Discussions

See All

Clips Review
Clips Review By Jennifer Allen on October 21st, 2014 Our Rating: :: CONVENIENT PASTINGUniversal App - Designed for iPhone and iPad Making copying and pasting more powerful than usual, Clips is a great way to move stuff around.   | Read more »
MonSense Review
MonSense Review By Jennifer Allen on October 21st, 2014 Our Rating: :: ORGANIZED FINANCESiPhone App - Designed for the iPhone, compatible with the iPad Organize your finances with the quick and easy to use, MonSense.   | Read more »
This Week at 148Apps: October 13-17, 201...
Expert App Reviewers   So little time and so very many apps. What’s a poor iPhone/iPad lover to do? Fortunately, 148Apps is here to give you the rundown on the latest and greatest releases. And we even have a tremendous back catalog of reviews; just... | Read more »
Angry Birds Transformers Review
Angry Birds Transformers Review By Jennifer Allen on October 20th, 2014 Our Rating: :: TRANSFORMED BIRDSUniversal App - Designed for iPhone and iPad Transformed in a way you wouldn’t expect, Angry Birds Transformers is a quite... | Read more »
GAMEVIL Announces the Upcoming Launch of...
GAMEVIL Announces the Upcoming Launch of Mark of the Dragon Posted by Jessica Fisher on October 20th, 2014 [ permalink ] Mark of the Dragon, by GAMEVIL, put | Read more »
Interview With the Angry Birds Transform...
Angry Birds Transformers recently transformed and rolled out worldwide. This run-and-gun title is a hit with young Transformers fans, but the ample references to classic Transformers fandom has also earned it a place in the hearts of long-time... | Read more »
Hail to the King: Deathbat Review
Hail to the King: Deathbat Review By Rob Thomas on October 20th, 2014 Our Rating: :: SO FAR AWAYUniversal App - Designed for iPhone and iPad Hail to the King: Deathbat may feel like “Coming Home” for Avenged Sevenfold’s faithful,... | Read more »
Find Free Food on Campus with Ypay
Find Free Food on Campus with Ypay Posted by Jessica Fisher on October 20th, 2014 [ permalink ] iPhone App - Designed for the iPhone, compatible with the iPad | Read more »
Strung Along Review
Strung Along Review By Jordan Minor on October 20th, 2014 Our Rating: :: GOT NO STRINGSUniversal App - Designed for iPhone and iPad A cool gimmick and a great art style keep Strung Along from completely falling apart.   | Read more »
P2P file transferring app Send Anywhere...
File sharing services like Dropbox have security issues. Email attachments can be problematic when it comes to sharing large files. USB dongles don’t fit into your phone. Send Anywhere, a peer-to-peer file transferring application, solves all of... | Read more »

Price Scanner via MacPrices.net

Strong iPhone, Mac And App Store Sales Drive...
Apple on Monday announced financial results for its fiscal 2014 fourth quarter ended September 27, 2014. The Company posted quarterly revenue of $42.1 billion and quarterly net profit of $8.5 billion... Read more
Apple Posts How-To For OS X Recovery
OS X 10.7 Lion and later include OS X Recovery. This feature includes all of the tools you need to reinstall OS X, repair your disk, and even restore from a Time Machine backup. OS X Recovery... Read more
Mac OS X Versions (Builds) Supported By Vario...
Apple Support has posted a handy resource explaining which Mac OS X versions (builds) originally shipped with or are available for your computer via retail discs, downloads, or Software Update. Apple... Read more
Deals on 2011 13-inch MacBook Airs, from $649
Daily Steals has the Mid-2011 13″ 1.7GHz i5 MacBook Air (4GB/128GB) available for $699 with a 90 day warranty. The Mid-2011 13″ 1.7GHz i5 MacBook Air (4GB/128GB SSD) is available for $649 at Other... Read more
2013 15-inch 2.0GHz Retina MacBook Pro availa...
B&H Photo has leftover previous-generation 15″ 2.0GHz Retina MacBook Pros now available for $1599 including free shipping plus NY sales tax only. Their price is $400 off original MSRP. B&H... Read more
Updated iPad Prices
We’ve updated our iPad Air Price Tracker and our iPad mini Price Tracker with the latest information on prices and availability from Apple and other resellers, including the new iPad Air 2 and the... Read more
Apple Pay Available to Millions of Visa Cardh...
Visa Inc. brings secure, convenient payments to iPad Air 2 and iPad mini 3as well as iPhone 6 and 6 Plus. Starting October 20th, eligible Visa cardholders in the U.S. will be able to use Apple Pay,... Read more
Textkraft Pocket – the missing TextEdit for i...
infovole GmbH has announced the release and immediate availability of Textkraft Pocket 1.0, a professional text editor and note taking app for Apple’s iPhone. In March 2014 rumors were all about... Read more
C Spire to offer iPad Air 2 and iPad mini 3,...
C Spire on Friday announced that it will offer iPad Air 2 and iPad mini 3, both with Wi-Fi + Cellular, on its 4G+ LTE network in the coming weeks. C Spire will offer the new iPads with a range of... Read more
Belkin Announces Full Line of Keyboards and C...
Belkin International has unveiled a new lineup of keyboard cases and accessories for Apple’s newest iPads, featuring three QODE keyboards and a collection of thin, lightweight folios for both the... Read more

Jobs Board

Project Manager / Business Analyst, WW *Appl...
…a senior project manager / business analyst to work within our Worldwide Apple Fulfillment Operations and the Business Process Re-engineering team. This role will work Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Position Opening at *Apple* - Apple (United...
…customers purchase our products, you're the one who helps them get more out of their new Apple technology. Your day in the Apple Store is filled with a range of Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** At the Apple Store, you connect business professionals and entrepreneurs with the tools they need in order to put Apple solutions to work in their Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** The Apple Store is a retail environment like no other - uniquely focused on delivering amazing customer experiences. As an Expert, you introduce people Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.