Summary

Summary

TV tuner cards and peripherals are becoming ever-more-common features of the PC landscape; Microsoft, in conjunction with Hewlett-Packard, has been working to bring the Media Center to every home. With the advent of the PVR, people have different expectations for their TV viewing. They expect their programs to be recorded invisibly and available instantaneously, and they expect to time-shift their viewing at will, pausing, rewinding, or fast-forwarding TV programs.

What we ve covered in this chapter are the essentials for working with TV tuners and buffered streams, the two core components in a PVR. Truthfully, it takes a lot more than this to create a TiVo-like device. Most of TiVo s magic is in its user interface design, which makes it easy to record and retrieve programming. However, TiVo requires a connection to your home telephone because it dials into its own information service every evening, downloading new program listings and uploading usage information. The home PC, connected to the Internet, has several advantages over TiVo. For example, many PCs are always connected to the Internet, and they have blazingly fast processors with huge supplies of memory. This gives the PC a kind of flexibility that TiVo can t begin to touch.

TiVo can record up to 40 hours of TV programming, which the Stream Buffer Engine could do as well provided it had access to 500 GB of disk space! DV-encoded video files take up lots of disk space and will eat up a computer s capacity quite quickly. We ve already covered how to take a DV-encoded stream and convert it into the much more compact Windows Media format. This is the kind of technique you d need to employ if you were going to design a PC-based TiVo because you could store thousands of hours of television on your computer s hard disk, instead of a few tens of hours. The Windows Media Center PC stores its captured TV programming in MPEG-2 format, which uses from 1 to 3 GB per hour, depending on the quality of the capture. That s one reason the Stream Buffer Engine has been optimized to work with MPEG-2 streams. Whether you choose to use MPEG-2 or Windows Media, you ll find that DirectShow is an incredible foundation for a new generation of TV applications that could make the promise of convergence real.