Video Platforms For Handhelds

Firepad, Inc. FireConverter Desktop and FireViewer
FireConverter Desktop is a Windows-only encoding application that converts hypertext, image, and video files into a format optimized for viewing on handheld devices. In combination with FireViewer, FireConverter allows you to convert and HotSync content from the Web, your desktop, or a corporate intranet to your PDA. This is the only toolset that can wirelessly send video files to a Palm handheld and the only one to let you create and view high-definition still images from within the same application.

Firepad has designed its own proprietary video codec, the Firepad Video Format. According to CEO Bill Mitchell, the codec "is designed to allow highly asymmetrical computing time for compression versus decompression, which is consistent with the requirements of handheld devices. In other words, it takes a lot of computing power to compress (as on a server or PC), but little power to decompress (as on a Palm OS PDA)." Firepad claims that there is no limit whatsoever on the frame rate for video playback. However, the most effective frame rate on a fast Palm OS device, such as an m515, is 10fps (frames per second); on a Sony Clié NR70, it is about 12fps.

Regrettably, no audio is currently supported by the Firepad codec. Mitchell says the reason for this is because the current crop of Palm devices does not support high-quality, amplified sound, though he acknowledges that both the Sony Clié and Palm Tungsten models support high-quality audio. "Within a year, we might expect as many as 25 percent of all Palm devices will have decent sound. At that point, we will look at it seriously."

As for future and current MPEG-4 support, the results are mixed. Their video streaming server, FireProducer Enterprise, accepts any MPEG file as input, "assuming that you also have the appropriate QuickTime library installed on the server. Internally, FireProducer decompresses and re-encodes the video stream into FireViewer video format before sending it out over TCP/IP," Mitchell says. What that means for compressionists is that your encoded MPEG-4 (via Apple's QT 6 or Envivio's MPEG-4 toolset) has to be re-encoded first via FireConverter. You then re-distribute your content after the transcode. Mitchell adds, "For non-wireless users that wish to install and view offline video clips on their Palm," Mitchell says, "MPEG-4 video must first be re-encoded into FireViewer format, using the FireConverter desktop program for Windows."

FireProducer Enterprise is a Windows server application that delivers multiple independent, simultaneous streams of live or stored video to multiple Palm OS handheld devices simultaneously. FireProducer Desktop is a Windows application that delivers a single stream of live or stored video to multiple Palm OS handheld devices simultaneously.

Firepad was the first company to develop an application for the encoding and playback of video on a Palm. As such, it is beginning to show its age. The choices that the encoding tool offers are limited. You begin by specifying the color mode (4 or 16 grays; 256 (8-bit) or 16-bit color). The next choice is to select whether the video plays once or repeats. To specify your desired frame rate (dependent upon the device you are encoding for), simply type in the desired number. The skip rate determines the rate of rewind and fast-forward. You choose the size of the .pdb file (the standard video file format for PDAs, like .vob for DVD) by how big you want the file size (in KB) to be. But why encode a file that way? The approach seems backwards. It just makes more sense to specify color depth, frame rate, and aspect ratio, then let the encoder do its job. What's weird is that if you set your max for, say, 2048KB, the encoder may stop encoding when it reaches that size, having only partially encoded the clip.

With Firepad, you have to rescale your source clip from D1 to 160x120 (or whatever size your PDA supports). During testing with Firepad, my source file was a raw AVI with no audio at 160x120, with a frame rate of 29.97fps. My first pass was to encode a movie with 256 colors, a frame rate of 8fps, and a maximum file size of 2048KB. On my Palm m130 (the PDA used in testing all the codecs), the results were fair. The blacks were crushed and the whites were clipped. The colors were washed out and smudged, but that's to be expected at this bit depth.

At 16-bit, the results were far different. The image clarity, naturally, was stunning, but the bit depth and frame rate were too much for my PDA to handle. The frame rate appeared to be a sluggish 2fps, not the 10fps advertised. Since I had set the maximum file size to 3000KB, the encoder was only able to process 25 of the 30 seconds of the source clip.