Compression Considerations

As we already mentioned, we don't recommend the usage of AVI files (both raw and re-compressed), unless you are advanced video programmer and know how to deal with issues like available CODECs, CODEC installation, etc. AVI files (especially raw AVIs) tend to be MUCH larger, compared to WMV files. So, unless you really know what to do with the AVIs, leave this property to its default value. The WMV files the control creates can be played with MS Windows Media Player and several other players. For more information on WMF in general, please visit www.windowsmedia.com.

The default values for the video files will allow you to create streams for low quality, low bandwidth (dial-up) users and for medium quality, medium broadband users. You can alter any of the properties to achieve better quality or lower bandwidth usage.

The default values for both video streams are:

What values should I use?

This really depends on what you need to achieve. The resulting file size (in KBytes) can be calculated (approximately) by using the following formula:

size = (ASFAU_Bitrate + ASFVID_Bitrate + 5) * video_length_in_seconds / 10

If you want to keep the file size small, you'll generally have to keep the ASFAU_Bitrate and ASFVID_Bitrate property values low. If you do that, you'll need to keep the ASFVID_Width, ASFVID_Height and ASFVID_FPS property values low too. This means smaller video with lower quality. On the other hand, if you (and your visitors) can handle bigger files, you can increase those values and get a larger, smoother video.

For your audio tracks, you can use any of the following combinations:

Important: Please note, that if you don't use one of the combinations above, the control WILL NOT compress and upload the video. Make sure, your parameters fit one of the lines in the table above.

For your video parameter, you can use the following guidelines:

Using the table above and the formula at the top of this page, you can also project the average filesize. Don't forget, that your visitors will have to upload this file over their existing internet connection. So even if they are able to capture and encode a 30 minutes clip at 250Kbit/s., uploading it over a dial-up connection will take... approximately 4 hours!!!