QuickTime


QuickTime is an extensible multimedia architecture created by Apple, which supports playing, streaming, encoding, and transcoding a variety of digital media formats. The term QuickTime also refers to the QuickTime Player front-end media player application, which is built-into macOS, and was formerly available for Windows.
QuickTime was created in 1991, when the concept of playing digital video directly on computers was "groundbreaking." QuickTime could embed a number of advanced media types, including panoramic images and Adobe Flash. Over the 1990s, QuickTime became a dominant standard for digital multimedia, as it was integrated into many websites, applications, and video games, and adopted by professional filmmakers. The QuickTime File Format became the basis for the MPEG-4 standard. During its heyday, QuickTime was notably used to create the innovative Myst and Xplora1 video games, and to exclusively distribute movie trailers for several Star Wars movies. QuickTime could support additional codecs through plug-ins, for example with Perian.
As operating systems and browsers gained support for MPEG-4 and subsequent standards like H.264, the need for a cross-platform version of QuickTime diminished, and Apple discontinued the Windows version of QuickTime in 2016. In Mac OS X Snow Leopard, QuickTime 7 was discontinued in favor of QuickTime Player X, which abandoned the aging QuickTime framework in favor of the AVFoundation framework. QuickTime Player X does not support video editing or plug-ins for additional codec support. macOS Catalina dropped support for all 32-bit applications, including the QTKit framework and the old QuickTime 7.
WWW Official Site

Overview

QuickTime is bundled with macOS. QuickTime for Microsoft Windows was downloadable as a standalone installation, and was bundled with Apple's iTunes before iTunes 10.5, but is no longer supported and therefore security vulnerabilities will no longer be patched. Already, at the time of the Windows version's discontinuation, two such zero-day vulnerabilities were identified and publicly disclosed by Trend Micro; consequently, Trend Micro strongly advised users to uninstall the product from Windows systems.
Software development kits for QuickTime are available to the public with an Apple Developer Connection subscription.
It is available free of charge for both macOS operating systems. There are some other free player applications that rely on the QuickTime framework, providing features not available in the basic QuickTime Player. For example, iTunes can export audio in WAV, AIFF, MP3, AAC, and Apple Lossless. In addition, macOS has a simple AppleScript that can be used to play a movie in full-screen mode, but since version 7.2 full-screen viewing is now supported in the non-Pro version.

QuickTime framework

The QuickTime framework provides the following:
The QuickTime framework functioned as a general-purpose multimedia abstraction layer within Apple's operating systems, providing a unified architecture for time-based media. Rather than being limited to a single file format or codec, QuickTime was designed to manage synchronized audio, video, text, and interactive elements through a modular component system. This design allowed media data to be edited non-destructively and referenced externally, which made the framework particularly well suited for professional video editing and multimedia authoring workflows.
  • Encoding and transcoding video and audio from one format to another. Command-line utilities afconvert, avconvert and qtmodernizer are provided with macOS for power users.
  • Decoding video and audio, then sending the decoded stream to the graphics or audio subsystem for playback. In macOS, QuickTime sends video playback to the Quartz Extreme (OpenGL) Compositor.
  • A "component" plug-in architecture for supporting additional 3rd-party codecs.
As of early 2008, the framework hides many older codecs listed below from the user although the option to "Show legacy encoders" exists in QuickTime Preferences to use them. The framework supports the following file types and codecs natively:
Although QuickTime was available on both macOS and Microsoft Windows, the two implementations differed in scope and integration. On macOS, QuickTime was deeply integrated with system graphics, audio, and scripting technologies, and later served as the foundation for higher-level frameworks such as QTKit and AVFoundation. On Windows, QuickTime provided a subset of the API primarily focused on media playback and basic authoring, and relied on technologies such as COM and ActiveX for application integration. Over time, platform divergence and native support for MPEG-4 and H.264 reduced the practical importance of QuickTime as a cross-platform framework.
Due to macOS Mojave being the last version to include support for 32-bit APIs and Apple's plans to drop 32-bit application support in future macOS releases, many codecs will no longer be supported in newer macOS releases, starting with macOS Catalina, which was released on October 7, 2019.
As of Mac OS X Lion, the underlying media framework for QuickTime, QTKit, was deprecated in favor of a newer graphics framework, AVFoundation, and completely discontinued as of macOS Catalina.

Windows

PictureViewer is a component of QuickTime for Microsoft Windows and the Mac OS 8 and Mac OS 9 operating systems. It is used to view picture files from the still image formats that QuickTime supports. In macOS, it is replaced by Preview.

Irix

A version of QuickTime for the Irix operating system running on SGI hardware with MIPS processors was developed in the mid-1990s but never released.

QuickTime Player

QuickTime Player served as the primary user-facing application for the QuickTime architecture, providing playback and basic media inspection capabilities for QuickTime movies and supported formats. Beyond local playback, the player played a significant role in the distribution of digital video during the 1990s and early 2000s, including interactive CD-ROM titles, embedded web video, and downloadable movie trailers. Its close integration with the QuickTime framework allowed it to act as both a reference implementation and a general-purpose media viewer for end users.

QuickTime 7 Pro

QuickTime Player 7 is limited to only basic playback operations unless a QuickTime Pro license key is purchased from Apple. Until Catalina, Apple's professional applications included a QuickTime Pro license. Pro keys are specific to the major version of QuickTime for which they are purchased and unlock additional features of the QuickTime Player application on macOS or Windows. The Pro key does not require any additional downloads; entering the registration code immediately unlocks the hidden features.
QuickTime 7 is still available for download from Apple, but as of mid-2016, Apple stopped selling registration keys for the Pro version.
Features enabled by the Pro license include, but are not limited to:
  • Editing clips through the cut, copy and paste functions, merging separate audio and video tracks, and freely placing the video tracks on a virtual canvas with the options of cropping and rotation.
  • Saving and exporting to any of the codecs supported by QuickTime. QuickTime 7 includes presets for exporting video to a video-capable iPod, Apple TV, and the iPhone.
  • Saving existing QuickTime movies from the web directly to a hard disk drive. This is often, but not always, either hidden or intentionally blocked in the standard mode. Two options exist for saving movies from a web browser:
  • * Save as source – This option will save the embedded video in its original format.
  • * Save as QuickTime movie – This option will save the embedded video in a.mov file format no matter what the original container is/was.

QuickTime Player X

Mac OS X Snow Leopard includes QuickTime X. QuickTime Player X lacks cut, copy and paste and will only export to four formats, but its limited export feature is free. Users do not have an option to upgrade to a Pro version of QuickTime X, but those who have already purchased QuickTime 7 Pro and are upgrading to Snow Leopard from a previous version of Mac OS X will have QuickTime 7 stored in the Utilities or user defined folder. Otherwise, users will have to install QuickTime 7 from the "Optional Installs" directory of the Snow Leopard DVD after installing the OS.
Mac OS X Lion and later also include QuickTime X. No installer for QuickTime 7 is included with these software packages, but users can download the QuickTime 7 installer from the site. QuickTime X on later versions of macOS support cut, copy and paste functions similarly to the way QuickTime 7 Pro did; the interface has been significantly modified to simplify these operations, however.
On September 24, 2018, Apple ended support for QuickTime 7 and QuickTime Pro, and updated many download and support pages on their website to state that QuickTime 7 "will not be compatible with future macOS releases."

File formats

The native file format for QuickTime video, QuickTime File Format, specifies a multimedia container file that contains one or more tracks, each of which stores a particular type of data: audio, video, effects, or text. Each track either contains a digitally encoded media stream or a data reference to the media stream located in another file. The ability to contain abstract data references for the media data, and the separation of the media data from the media offsets and the track edit lists means that QuickTime is particularly suited for editing, as it is capable of importing and editing in place.
Other file formats that QuickTime supports natively include AIFF, WAV, DV-DIF, MP3, and MPEG program stream. With additional QuickTime Components, it can also support ASF, DivX Media Format, Flash Video, Matroska, Ogg, and many others.

QuickTime and MPEG-4

On February 11, 1998, the ISO approved the QuickTime file format as the basis of the MPEG‑4 file format. The MPEG-4 file format specification was created on the basis of the QuickTime format specification published in 2001. The MP4 file format was published in 2001 as the revision of the MPEG-4 Part 1: Systems specification published in 1999. In 2003, the first version of MP4 format was revised and replaced by MPEG-4 Part 14: MP4 file format. The MP4 file format was generalized into the ISO Base Media File Format ISO/IEC 14496-12:2004, which defines a general structure for time-based media files. It in turn is used as the basis for other multimedia file formats.
A list of all registered extensions for ISO Base Media File Format is published on the official registration authority website . This registration authority for code-points in "MP4 Family" files is Apple Computer Inc. and it is named in Annex D in MPEG-4 Part 12.
By 2000, MPEG-4 formats became industry standards, first appearing with support in QuickTime 6 in 2002. Accordingly, the MPEG-4 container is designed to capture, edit, archive, and distribute media, unlike the simple file-as-stream approach of MPEG-1 and MPEG-2.

Profile support

QuickTime 6 added limited support for MPEG-4, specifically encoding and decoding using Simple Profile. Advanced Simple Profile features, like B-frames, were unsupported. QuickTime 7 supports the H.264 encoder and decoder.

Container benefits

Because both MOV and MP4 containers can use the same MPEG-4 codecs, they are mostly interchangeable in a QuickTime-only environment. MP4, being an international standard, has more support. This is especially true on hardware devices, such as the Sony PSP and various DVD players, on the software side, most DirectShow / Video for Windows codec packs include a MP4 parser, but not one for MOV.
In QuickTime Pro's MPEG-4 Export dialog, an option called "Passthrough" allows a clean export to MP4 without affecting the audio or video streams. QuickTime 7 now supports multichannel AAC-LC and HE-AAC audio, for both.MOV and.MP4 containers.

History

Apple released the first version of QuickTime on December 2, 1991, as a multimedia add-on for System 6 and later. The lead developer of QuickTime, Bruce Leak, ran the first public demonstration at the May 1991 Worldwide Developers Conference, where he played Apple's famous 1984 advertisement in a window at 320×240 pixels resolution.

QuickTime 1.x

The original video codecs included:
The first commercial project produced using QuickTime 1.0 was the CD-ROM . The first publicly visible use of QuickTime was Ben & Jerry's interactive factory tour. The Rik and Joe Show was demonstrated onstage at MacWorld in San Francisco when John Sculley announced QuickTime.
Apple released QuickTime 1.5 for Mac OS in the latter part of 1992. This added the SuperMac-developed Cinepak vector-quantization video codec. It could play video at 320×240 resolution at 30 frames per second on a 25 MHz Motorola 68040 CPU. It also added text tracks, which allowed for captioning, lyrics and other potential uses.
Apple contracted San Francisco Canyon Company to port QuickTime to the Windows platform. Version 1.0 of QuickTime for Windows provided only a subset of the full QuickTime API, including only movie playback functions driven through the standard movie controller.
QuickTime 1.6 came out the following year. Version 1.6.2 first incorporated the "QuickTime PowerPlug" which replaced some components with PowerPC-native code when running on PowerPC Macs.

QuickTime 2.x

Apple released QuickTime 2.0 for System Software 7 in June 1994—the only version never released for free. It added support for music tracks, which contained the equivalent of MIDI data and which could drive a sound-synthesis engine built into QuickTime itself, or any external MIDI-compatible hardware, thereby producing sounds using only small amounts of movie data.
Following Bruce Leak's departure to Web TV, the leadership of the QuickTime team was taken over by Peter Hoddie.
QuickTime 2.0 for Windows appeared in November 1994 under the leadership of Paul Charlton. As part of the development effort for cross-platform QuickTime, Charlton, along with ace individual contributor Michael Kellner and a small highly effective team including Keith Gurganus, ported a subset of the Macintosh Toolbox to Intel and other platforms as the enabling infrastructure for the QuickTime Media Layer which was first demonstrated at the Apple Worldwide Developers Conference in May 1996. The QTML later became the foundation for the Carbon API which allowed legacy Macintosh applications to run on the Darwin kernel in Mac OS X.
The next versions, 2.1 and 2.5, reverted to the previous model of giving QuickTime away for free. They improved the music support and added sprite tracks which allowed the creation of complex animations with the addition of little more than the static sprite images to the size of the movie. QuickTime 2.5 also fully integrated QuickTime VR 2.0.1 into QuickTime as a QuickTime extension. On January 16, 1997, Apple released the QuickTime MPEG Extension as an add-on to QuickTime 2.5, which added software MPEG-1 playback capabilities to QuickTime.

Lawsuit against San Francisco Canyon

In 1994, Apple filed suit against software developer San Francisco Canyon for intellectual property infringement and breach of contract. Apple alleged that San Francisco Canyon had helped develop Video for Windows using several hundred lines of unlicensed QuickTime source code. They were contracted by Intel to help make Video for Windows better use system resources on Intel processors, which was subsequently unilaterally removed. Microsoft and Intel were added to the lawsuit in 1995. The suit ended in a settlement in 1997.

QuickTime 3.x

The release of QuickTime 3.0 for Mac OS on March 30, 1998, introduced the now-standard revenue model of releasing the software for free, but with additional features of the Apple-provided MoviePlayer application that end-users could only unlock by buying a QuickTime Pro license code. Since the "Pro" features were the same as the existing features in QuickTime 2.5, any previous user of QuickTime could continue to use an older version of the central MoviePlayer application for the remaining lifespan of Mac OS to 2002, indeed, since these additional features were limited to MoviePlayer, any other QuickTime-compatible application remained unaffected.
QuickTime 3.0 added support for graphics importer components that could read images from GIF, JPEG, TIFF, and other file formats, and video output components which served primarily to export movie data via FireWire. Apple also licensed several third-party technologies for inclusion in QuickTime 3.0, including the Sorenson Video codec for advanced video compression, the QDesign Music codec for substantial audio compression, and the complete Roland Sound Canvas instrument set and GS Format extensions for improved playback of MIDI music files. It also added video effects which programmers could apply in real-time to video tracks. Some of these effects would even respond to mouse clicks by the user, as part of the new movie interaction support.

QuickTime interactive

During the development cycle for QuickTime 3.0, part of the engineering team was working on a more advanced version of QuickTime to be known as QuickTime interactive or QTi. Although similar in concept to the wired movies feature released as part of QuickTime 3.0, QuickTime interactive was much more ambitious. It allowed any QuickTime movie to be a fully interactive and programmable container for media. A special track type was added that contained an interpreter for a custom programming language based on 68000 assembly language. This supported a comprehensive user interaction model for mouse and keyboard event handling based in part on the AML language from the Apple Media Tool.
The QuickTime interactive movie was to have been the playback format for the next generation of HyperCard authoring tool. Both the QuickTime interactive and the HyperCard 3.0 projects were canceled in order to concentrate engineering resources on streaming support for QuickTime 4.0, and the projects were never released to the public.

QuickTime 4.x

Apple released QuickTime 4.0 on June 8, 1999 for Mac OS 7.5.5 through 8.6 and Windows 95, Windows 98, and Windows NT. Three minor updates followed.
It introduced features that most users now consider basic:
  • Graphics exporter components, which could write some of the same formats that the previously introduced importers could read.
  • Support for the QDesign Music 2 and MPEG-1 Layer 3 audio.
  • QuickTime 4 was the first version to support streaming. It was accompanied by the release of the free QuickTime Streaming Server version 1.0.
  • QuickTime 4 Player introduced brushed metal to the Macintosh user interface.
On December 17, 1999, Apple provided QuickTime 4.1, this version's first major update. Two minor versions followed. The most notable improvements in the 4.1.x family were:

QuickTime 5.x

QuickTime 5 was one of the shortest-lived versions of QuickTime, released in April 2001 and superseded by QuickTime 6 a little over a year later. This version was the last to have greater capabilities under Mac OS 9 than under Mac OS X, and the last version of QuickTime to support Mac OS versions 7.5.5 through 8.5.1 on a PowerPC Mac and Windows 95. Version 5.0 was initially only released for Mac OS and Mac OS X on April 14, 2001, and version 5.0.1 followed shortly thereafter on April 23, 2001, supporting the classic Mac OS, Mac OS X, and Windows. Three more updates to QuickTime 5 were released over its short lifespan.
QuickTime 5 delivered the following enhancements:
  • MPEG-1 playback for Windows, and updated MPEG-1 Layer 3 audio support for all systems.
  • Sorenson Video 3 playback and export.
  • Realtime rendering of effects & transitions in DV files, including enhancements to DV rendering, multiprocessor support, and Altivec enhancements for PowerPC G4 systems.
  • Flash 4 playback and export.
  • A new QuickTime VR engine, adding support for cubic VR panoramas.

QuickTime 6.x

On July 15, 2002, Apple released QuickTime 6.0, providing the following features:
QuickTime 6 was initially available for Mac OS 8.6 – 9.x, Mac OS X, and Windows 98, Me, 2000, and XP. Development of QuickTime 6 for Mac OS slowed considerably in early 2003, after the release of Mac OS X v10.2 in August 2002. QuickTime 6 for Mac OS continued on the 6.0.x path, eventually stopping with version 6.0.3.
QuickTime 6.1 & 6.1.1 for Mac OS X v10.1 and Mac OS X v10.2 and QuickTime 6.1 for Windows offered ISO-Compliant MPEG-4 file creation and fixed the vulnerability.
Apple released QuickTime 6.2 exclusively for Mac OS X on April 29, 2003, to provide support for iTunes 4, which allowed AAC encoding for songs in the iTunes library.
On June 3, 2003, Apple released QuickTime 6.3, delivering the following:
  • Support for 3GPP, including 3G Text, video, and audio.
  • Support for the.3gp,.amr, and.sdv file formats via separate component.
QuickTime 6.4, released on October 16, 2003, for Mac OS X v10.2, Mac OS X v10.3, and Windows, added the following:
On December 18, 2003, Apple released QuickTime 6.5, supporting the same systems as version 6.4. Versions 6.5.1 and 6.5.2 followed on April 28, 2004, and October 27, 2004. These versions would be the last to support Windows 98 and Me. The 6.5 family added the following features:
QuickTime 6.5.3 was released on October 12, 2005, for Mac OS X v10.2.8 after the release of QuickTime 7.0, fixing a number of security issues.

QuickTime 7.x

Initially released on April 29, 2005, in conjunction with Mac OS X v10.4, QuickTime 7.0 featured the following:
After a couple of preview Windows releases, Apple released 7.0.2 as the first stable release on September 7, 2005, for Windows 2000 and Windows XP. Version 7.0.4, released on January 10, 2006, was the first universal binary version. But it suffered numerous bugs, including a buffer overrun, which is more problematic to most users.
Apple dropped support for Windows 2000 with the release of QuickTime 7.2 on July 11, 2007. The last version available for Windows 2000, 7.1.6, contains numerous security vulnerabilities. References to this version have been removed from the QuickTime site, but it can be downloaded from Apple's support section. Apple has not indicated that they will be providing any further security updates for older versions. QuickTime 7.2 is the first version for Windows Vista.
Apple dropped support for Flash content in QuickTime 7.3, breaking content that relied on Flash for interactivity, or animation tracks. Security concerns seem to be part of the decision. Flash flv files can still be played in QuickTime if the free Perian plugin is added.
In QuickTime 7.3, a processor that supports SSE is required. QuickTime 7.4 does not require SSE. Unlike versions 7.2 and 7.3, QuickTime 7.4 cannot be installed on Windows XP without service packs or with Service Pack 1/1A installed.
QuickTime 7.5 was released on June 10, 2008. QuickTime 7.5.5 was released on September 9, 2008, which requires Mac OS X v10.4 or higher, dropping 10.3 support. QuickTime 7.6 was released on January 21, 2009. QuickTime 7.7 was released on August 3, 2011.
QuickTime 7.6.6 is available for OS X, 10.6.3 Snow Leopard until 10.14 Mojave, as 10.15 Catalina will only support 64-bit applications. There is a 7.7 release of QuickTime 7 for OS X, but it is only for Leopard 10.5.
QuickTime 7.7.6 is the last release for Windows XP Service Pack 2 or 3.
QuickTime 7.7.9 is the last Windows release of QuickTime. Apple stopped supporting QuickTime on Windows afterwards.
Safari 12, released on September 17, 2018, for macOS Sierra and macOS High Sierra, which drops support for NPAPI plug-ins dropped its support for QuickTime 7's web plugin. On September 24, 2018, Apple dropped support for the macOS version of QuickTime 7. This effectively marked the end of the technology in Apple's codec and web development.
Starting with macOS Catalina, QuickTime 7 applications, image, audio and video codecs will no longer be compatible with macOS or supported by Apple.

QuickTime X

QuickTime X was initially demonstrated at WWDC on June 8, 2009, and shipped with Mac OS X v10.6.
It includes visual chapters, conversion, sharing to YouTube, video editing, capture of video and audio streams, screen recording, GPU acceleration, and live streaming.
But it removed support for various widely used formats, in particular the omission of MIDI caused significant inconvenience and trouble to many musicians and their potential audiences.
In addition, a screen recorder is featured which records whatever is on the screen. However it is not possible to capture certain Digital rights management protected content. This includes iTunes/Apple TV video purchases, or any content protected by Apple's FairPlay DRM technology. While Safari uses FairPlay, Google Chrome and Firefox use Widevine for DRM, whose content is not protected from QuickTime screen capturing.
The reason for the jump in numbering from 7 to 10 was to indicate a similar break with the previous versions of the product that Mac OS X indicated. QuickTime X is fundamentally different from previous versions, in that it is provided as a Cocoa framework and breaks compatibility with the previous QuickTime 7 C-based APIs that were previously used. QuickTime X was completely rewritten to implement modern audio video codecs in 64-bit. QuickTime X is a combination of two technologies: QuickTime Kit Framework and QuickTime X Player. QTKit is used by QuickTime player to display media. QuickTime X does not implement all of the functionality of the previous QuickTime as well as some of the codecs. When QuickTime X attempts to operate with a 32-bit codec or perform an operation not supported by QuickTime X, it will start a 32-bit helper process to perform the requested operation. The website Ars Technica revealed that QuickTime X uses QuickTime 7.x via QTKit to run older codecs that have not made the transition to 64-bit.
QuickTime X does not support.SRT subtitle files. It has been suggested using the program Subler to interleave the MP4 and SRT files will fix this oversight, which can be downloaded at Bitbucket.
QuickTime 7 may still be required to support older formats on Snow Leopard such as QTVR, interactive QuickTime movies, and MIDI files. In such cases, a compatible version of QuickTime 7 is included on Snow Leopard installation disc and may be installed side-by-side with QuickTime X. Users who have a Pro license for QuickTime 7 can then activate their license.
A Snow Leopard compatible version of QuickTime 7 may also be downloaded from Apple Support website.
The software got an increment with the release of Mavericks, and as of August 2018, the current version is v10.5. It contains more sharing options, more export options. It also includes a new way of fast forwarding through a video and mouse support for scrolling.
Starting with macOS Catalina, Apple only provides QuickTime X, as QuickTime 7 was never updated to 64-bit, affecting many applications, image, audio, and video formats utilizing QuickTime 7, and compatibility with these codecs in QuickTime X.

Creating software that uses QuickTime

QuickTime was widely used as a development platform for multimedia software throughout the 1990s and 2000s. Its APIs allowed developers to build applications that handled synchronized time-based media without requiring direct management of codec details or hardware acceleration. This made QuickTime a common foundation for professional video editing tools, interactive multimedia titles, and early web-based media applications. Over time, Apple transitioned development away from the original QuickTime APIs toward AVFoundation and related frameworks, reflecting broader changes in media standards and system architecture.

QuickTime X

QuickTime X previously provided the QTKit Framework on Mac OS 10.6 until 10.14.
Since the release of macOS 10.15, AVKit and AVFoundation are used instead.

Previous versions

QuickTime consists of two major subsystems: the Movie Toolbox and the Image Compression Manager. The Movie Toolbox consists of a general API for handling time-based data, while the Image Compression Manager provides services for dealing with compressed raster data as produced by video and photo codecs.
Developers can use the QuickTime software development kit to develop multimedia applications for Mac or Windows with the C programming language or with the Java programming language, or, under Windows, using COM/ActiveX from a language supporting this.
The COM/ActiveX option was introduced as part of QuickTime 7 for Windows and is intended for programmers who want to build standalone Windows applications using high-level QuickTime movie playback and control with some import, export, and editing capabilities. This is considerably easier than mastering the original QuickTime C API.
QuickTime 7 for Mac introduced the QuickTime Kit, a developer framework that is intended to replace previous APIs for Cocoa developers. This framework is for Mac only, and exists as Objective-C abstractions around a subset of the C interface. Mac OS X v10.5 extends QTKit to full 64-bit support. The QTKit allows multiplexing between QuickTime X and QuickTime 7 behind the scenes so that the user need not worry about which version of QuickTime they need to use.

Bugs and vulnerabilities

QuickTime 7.4 was found to disable Adobe's video compositing program, After Effects. This was due to the DRM built into version 7.4 since it allowed movie rentals from iTunes. QuickTime 7.4.1 resolved this issue.
Versions 4.0 through 7.3 contained a buffer overflow bug which could compromise the security of a PC using either the QuickTime Streaming Media client, or the QuickTime player itself. The bug was fixed in version 7.3.1.
QuickTime 7.5.5 and earlier are known to have a list of significant vulnerabilities that allow a remote attacker to execute arbitrary code or cause a denial of service on a targeted system. The list includes six types of buffer overflow, data conversion, signed vs. unsigned integer mismatch, and uninitialized memory pointer.
QuickTime 7.6 has been found to disable Mac users' ability to play certain games, such as Civilization IV and The Sims 2. There are fixes available from the publisher, Aspyr.
QuickTime 7 lacks support for H.264 Sample Aspect Ratio. QuickTime X does not have this limitation, but many Apple products still use the older QuickTime 7 engine. iTunes previously utilized QuickTime 7, but as of October 2019, iTunes no longer utilizes the older QuickTime 7 engine.
QuickTime 7.7.x on Windows fails to encode H.264 on multi-core systems with more than approximately 20 threads, e.g. HP Z820 with 2× 8-core CPUs. A suggested solution is to disable hyper-threading/limit CPU cores. Encoding speed and stability depends on the scaling of the player window.
On April 14, 2016, Christopher Budd of Trend Micro announced that Apple has ceased all security patching of QuickTime for Windows, and called attention to two Zero Day Initiative advisories, ZDI-16-241 and ZDI-16-242, issued by Trend Micro's subsidiary TippingPoint on that same day. Also on that same day, the United States Computer Emergency Readiness Team issued alert TA16-105A, encapsulating Budd's announcement and the Zero Day Initiative advisories. Apple responded with a statement that QuickTime 7 for Windows is no longer supported by Apple.