Exploring Flash Player support for HD video and audio

by David Hassoun

The next major step in the video revolution is here. Flash Player 9 Update is taking a step into the high-definition (HD) video realm in a major way by adding MPEG-4 video to its already impressive ranks of video support. MPEG-4 utilizes crisp, powerful H.264 encoding and is an industry standard for video, which includes high-definition (HD) delivery. It is also the standard for HD content online and on devices such as your home television.

To pair with the excellent visual power of H.264 encoded video, Flash Player 9 Update also supports HE-AAC audio, which is the higher quality successor to MP3. Advanced Audio Coding (AAC) is a high-efficiency (HE) and high-fidelity (HiFi), low-bandwidth audio codec that can be used with or without video.

These codecs allow users to stream high-quality video at low bit rates. In addition, this update to Flash Player makes it possible to leverage tools that are standard across the industry, such as Adobe Premiere, Adobe After Effects, Adobe Soundbooth, and Adobe Audition — and even such non-Adobe technology as Apple Final Cut Pro — to create and deliver compelling video content. Future updates are even being planned for Adobe Creative Suite 3 (CS3) to enhance end-to-end H.264 content development and distribution. The future is looking very bright indeed.

The new video and audio capabilities are available in the beta release of Flash Player 9 Update 3 (version, code-named "Moviestar," and will be included in the upcoming release of Adobe® AIR™ 1.0. Both platforms will have the ability to stream from the next generation of Flash Media Server, due to release early next year. The new Adobe Media Player, a powerful new Adobe AIR application, will also support H.264, HE-AAC, and encrypted video content using the new Flash Media Rights Management Server from Adobe.

So does this new Flash Player support for MPEG-4 and H.264 mean that it will replace the On2 VP6 codec? Absolutely not. The addition of H.264 gives developers greater choice to select the technology that best meets their needs. The current implementation of H.264 does have some limitations, such as lack of support for alpha channel and the inability to embed video into a SWF file. On2 VP6 is a solid, high-quality choice for Flash-based video projects. The On2 VP6 codec is also clear of any licensing issues that may arise with MPEG-LA. (Licensing information can be found on the MPEG LA and Via Licensing sites.) The On2 VP6 codec will remain a consistent and viable option for media delivery — see the On2 VP6 technology white paper (PDF, 140K) for more information. The added support for H.264 simply means that there are now more options and wider spread compatibility for high quality and HD video.

This article takes a look at the new codecs and file types supported in Flash Player "Moviestar." In the article I'll show you how to import both H.264 video and AAC audio into Flash, examine how to use hardware acceleration with the new Flash Player Update, and provide instructions on how to import the metadata included with MPEG-4 files.

Installing Flash Player 9 Update beta

Currently there isn't an installer for the standalone player used by the Flash IDE, so you'll have to do all your testing for H.264 and AAC players in the browser. The final release of this Flash Player update is included as an updater for Flash CS3 Professional.

In the meantime, however, here are the instructions to install the Flash Player 9 Update (beta) in your browser:

  1. Uninstall your previous version of the Flash Player. TechNote 14157 provides instructions to download and run the uninstaller for your system.
  2. After downloading the appropriate Adobe Flash Player uninstaller, close all programs that use Flash Player. Otherwise, previous versions of Flash Player will not uninstall.
  3. If you are on a Mac, uncompress and run the uninstaller to remove older versions.

    If you are on Windows, open up a command prompt window by selecting the Run option on the Windows menu and entering cmd.

    Navigate to the directory where you downloaded the uninstaller. If your DOS commands are rusty, remember that the change directory command is cd.

    Run the uninstaller with the command uninstall_flash_player.exe /clean.
  4. All users: Download and run the Flash Player 9 Update prerelease installer from Adobe Labs.

Understanding H.264 and AAC compression

This section provides information on the H.264 video spec guidelines and AAC/AAC+ compression. You will learn what is technically supported in H.264, what standard HD video dimensions are, how H.264 is a container format — and what that means — some basic information on what AAC/AAC+ has to offer, as well as some basic encoding resources.

MPEG-4 H.264

MPEG-4 (Motion Pictures Expert Group) H.264 is an international standard for video compression recognized by the International Organization for Standardization (ISO). H.264 is also known as "MPEG-4 Part 10" or AVC (Advanced Video Coding).

What does that mean? First, it means that when you encode your video for H.264, you're not just encoding it for Flash Player; video can be played back using other software like Apple iTunes or your iPod, or on Sony PlayStation Portable (PSP). With the new hardware scaling and multithreading support of Flash Player, you can now play back video at any resolution and bit rate, including the ultimate high-definition 1080p — as long as the system supports it (see Figure 1).

Screen resolutions

Figure 1: Screen resolutions and bit rates available with the current video standards

MPEG-4 containers

The MPEG-4 standard also describes a container format, which means that one file can contain several different types of data, stored as tracks. The overall file synchronizes and interleaves the data. So the video or audio in an MPEG-4 container can also be accompanied by metadata, cover art, subtitles, and other textual or visual data that can potentially be extracted by Flash Player. The container can also include multiple video and audio tracks too, but Flash Player will only play back one of each right now and ignores the rest.


Audio files encoded in an MPEG-4 container can now be used in Flash Player if they use the AAC (Advanced Audio Coding) codec. The AAC codec is a lossy compression scheme for audio that has been used since MPEG-2, but has been updated for MPEG-4. It should be familiar to most people, since all music sold from iTunes uses AAC. For you technical folks, it is much higher quality because it can support capture up to 96kHz and can support up to 48 channels and backwards prediction. AAC achieves higher audio quality than MP3 files and maintains similar or lower file sizes. AAC+ or HE-AAC (High Efficiency AAC) is the AAC codec with the addition of parametric stereo and spectral band replication that has been optimized to provide high-quality audio at a low bit rates for applications such as streaming audio. Now you can take advantage of this file format through Flash Player by bringing in MPEG-4 files with AAC encoded audio.

Video encoding

With the H.264 update to the Flash Player, video encoding has now been standardized across the entire video ecosystem, including the Adobe Creative Suite 3 family. Tools such as Adobe Premiere and After Effects can now be used to deliver content without using additional plug-ins.

Part of adopting H.264 is leveraging the massive number of solutions on the market. The following is a list of some of the companies that provide industry standard tools for encoding video in the supported format for the new Flash Player 9 Update:

Supported file formats

Flash Player 9 Update plays files derived from the standard MPEG-4 container format that contain H.264 video and/or HE-AAC audio, such as MP4, M4A, MOV, MP4V, 3GP, and 3G2. One thing to note is that protected MP4 files, such as those downloaded from iTunes or digitally encrypted by FairPlay, are not supported.

A more comprehensive version of this article appears in the Adobe Developer Connection and includes information on importing H.264 video and M4A audio using the NetStream object, extracting metadata from MPEG-4 files, and using hardware scaling with full-screen video.

Visit the Flash Player Developer Center

David Hassoun is the founder of RealEyes Media, LLC, a digital media firm based in Colorado that focuses on interactive motion media and advanced Flash and Flex platform applications.