Selecting a Flash 8 video encoder
Selecting a Flash 8 video encoder
Flash video is the new JPEG! The release of Flash 8 signaled a milestone for Flash. With this version, Flash matured into a truly competitive platform for delivering web video. New benefits include quality/file size improvement and support for true 8-bit, alpha-channel transparency. The new Flash 8 video format makes it possible to deploy Flash video at about half the bit rate as Flash 7 video without losing any quality. You can also look at the equation from a different angle: With Flash 8, you can deliver video of much higher quality than Flash 7 without increasing the bit rate of your videos.
Either way you look at it, the improved video codec (compressor/decompressor) helps you deliver a better video experience to your users. Just ask ABC or NBC. In 2006 both companies chose Flash as the best platform for their broadband video streaming needs. The near ubiquity of Flash Player and the fast adoption rate of new versions make Flash the best choice for large- and small-scale web video deployment. There are now more choices among encoding tools than ever before to compress your video into the new format.
Before I discuss Flash 8 video encoding and delivery, here’s a brief history lesson and Flash video primer. Before the FLV Flash video format hit the scene, clever Flash designers simulated video by placing sequences of images on the Flash timeline. That method is inefficient because each frame of video is compressed as a unique JPG image. True video codecs attain smaller file sizes by using interframe compression. This means that each frame is compared with recently played frames to determine what areas of the image have changed. Only the parts of the image that require updating are recompressed, while parts of the image that haven’t changed substantially are simply repeated. Macromedia released the FLV interframe Flash video format with Flash MX and Flash Player 6. The codec, called Sorenson Spark, was based on the H.263 international video compression standard. A basic version of Spark shipped with Flash MX, and users who wanted superior quality turned to third-party encoding software made by Sorenson or Wildform to convert their videos to the early FLV format.
Flash video compression can be done in one or two passes and with constant or variable bit rate (CBR/VBR). Sorenson and Wildform achieved higher quality at a given bit rate by providing two-pass VBR encoding. When you apply two-pass and VBR options while encoding, the software takes a first pass over the entire length of a clip, inspecting it for parts that would be more difficult than others to encode. On the second pass, the software applies what it learned during the first pass and adjusts how much of the designated bit rate it will use for each frame of the clip. Hard-to-encode frames get extra bits to ensure that they look great, and the budget is balanced by taking away bits from easy-to-encode frames without sacrificing their quality. In the end, the file size is the same as a one-pass encode but the data is more wisely allocated than if the video had been encoded with a constant bit rate.
Along came Flash MX Professional 2004 and the bundled video exporter, allowing video professionals to use their favorite editing software and other video utilities like Apple QuickTime to export two-pass VBR Flash video, and narrowing the quality gap between what could be achieved with OEM encoding tools from Macromedia and third-party encoding tools. (As a quick aside, it also included a second video codec, the Screen Recording Codec, which provides lossless compression.) The Screen Recording Codec is optimized for video captures of the activity on your computer monitor. Flash Player 8 still plays FLVs encoded to this format but the Flash 8 Video Encoder from Adobe no longer can encode to this format, so don’t toss your old installation disks if you want to convert video to the Flash Screen Recording Codec format. The FLV specifications indicate that the FLV format has the built-in ability to display an updated Screen Recording Codec (Screen Codec 2), but there aren’t currently any encoders that write the new format.
With the release of Flash 8, the quality gap between the bundled Adobe Flash Video Encoder and third-party options has been closed even further; Adobe now provides a one-pass CBR solution with Flash Professional 8, and one-pass results are excellent with the new On2 VP6 video codec. However, those who insist on the highest possible quality may still want to consider third-party solutions that offer two-pass VBR encoding.
In this article I compare the different Flash 8 video encoding software to help you determine if you need to upgrade from the encoder that ships with Flash 8 and, if so, which third-party solution is right for you. Many of the features I discuss apply to Flash 7 video as well as Flash 8 video, but this article focuses on what you can achieve with third-party encoding software for Flash 8 video. While comparable versions of all three solutions are available on the Mac OS platform, I did my testing on a Windows XP machine. All the encoding software is upgraded regularly, so please use this article as a guideline only and download the latest trial versions to try out the features yourself. Canopus and Autodesk also make software that can encode Flash video, but at the time of this writing neither package is compatible with the On2 Exporter; when they are able to encode two-pass VBR Flash 8 video, they will be reviewed as well.
Note: All quoted prices are standard retail prices in U.S. dollars and were accurate at the time this article was posted. Needless to say, prices and version numbers may change by the time you read this.