There are quite a few factors impacting the data size of the guides. Which in turn affect load times and bandwidth usage.
We created a guide with nine steps in it – all to be played back in 800x600 pixels. All except the last one is about 15 seconds long and show how to open the control panel, devices and printers and then change the default printer.
- A reference step – screen resolution 1024x768, shrinked to 800x600, no audio
- Recorded in 800x600 (no stretch). No audio.
- Recorded in 800x600 (no stretch). Mid-quality audio
- Recorded in 1024x768. Low quality audio.
- Recorded in 1024x768. Mid-quality audio
- Recorded in 1024x768. High quality audio
- Recorded in 1024x768. No audio. Windows Aero Transparent Glass.
- Recorded in 1024x768. No audio. Windows Aero without Transparent Glass.
- A longer step - recorded in 1024x768. No audio.
The guide was published both to Rich Media and Flash:
Sizes
The following table shows the data size of the steps in the two test guides:
Step | RichMedia | Flash | Length | Comment |
1 | 265 450 | 453 929 | 15 | 1024x768, shrinked to 800x600, no audio |
2 | 291 318 | 367 993 | 15 | Recorded in 800x600. No audio. |
3 | 367 894 | 422 945 | 15 | Recorded in 800x600. Mid-quality audio |
4 | 302 936 | 501 857 | 15 | Recorded in 1024x768. Low quality audio. |
5 | 341 487 | 520 291 | 15 | Recorded in 1024x768. Mid-quality audio |
6 | 359 837 | 542 829 | 15 | Recorded in 1024x768. High quality audio |
7 | 848 959 | 1 168 815 | 15 | Recorded in 1024x768. No audio. Windows Aero Transparent Glass. |
8 | 836 771 | 1 186 451 | 15 | Recorded in 1024x768. No audio. Windows Aero without Transparent Glass. |
9 | 429 697 | 775 640 | 28 | A longer step - recorded in 1024x768. No audio. |
Observations
Total data size. The Rich Media guide is 31% smaller than the Flash one. Using Rich Media is a quick way to save bandwidth. Conclusion: Rich Media guides are smaller.
Audio (medium quality) adds 26 % of size to Rich Media Guides and 15 % to Flash guides. Conclusion: Audio adds 15-25%.
Audio quality does not affect data size too much. Starting from medium - using low quality audio decreases the size with 11 % for Rich Media guides and 3.5% for flash. Using high-quality audio adds 2 % for both Rich Media and Flash guides. Conclusion: Audio quality has no great effect.
Recording vs. playback size ratio affects the size of the movies very differently for Rich Media and Flash guides. In the case of Rich Media Guides, using1024x768 recording size instead of 800x600 for a 800x600 playback step the step increases 1 % in size. Doing the same for flash increases the size with 19 %. Conclusion: Stretching adds approx. 20% to flash guides.
Windows Transparent Glass and Windows Aero implicates less compression on the recorded media as it does not contain the same repetition of screen elements. For Rich Media guides the size increases with 220 % when Transparent Glass / Windows Aero is activated. For Flash guides the ratio is 150%. Conclusion: Do not create guides using the Transparent Glass / Aero effect as this increases guide size tremendously.
In general - guides are about 15 to 30 kBytes per second.