Step II: Configuring AVI Properties
Whenever you save a timeline to a media file, by default it will be saved in a 320 x 240 display size (if it is a video file) and no compression will be used for the audio and the video in the file. However, you can define custom options for saving your timeline in this step of the Wizard.
To let Video Edit Magic Express decide the best AVI Properties for you, click Auto Select. Video Edit Magic Express will scan your files in the timeline and automatically select AVI Properties for optimum quality and size.
Video Dimensions
Video Edit Magic Express gives you the power to save your videos with the original dimensions, or with any imaginable dimensions. You may select to save one of the standard formats or specify custom dimensions.
- By default your timeline is saved as a 320 x 240 pixel (width x height) media file.
- To save with different display dimensions, open the Video Dimensions list and select one.
- To specify custom dimensions for your video, select "Custom" from the Video Dimensions list. This will enable you to specify width and height of the video. If you want to alter the aspect ratio of the video then clear "Lock Aspect Ratio" and then specify width and height of the video.
- Changing the dimensions of the video will affect picture quality. Expanding video can make it look "blocky". Shrinking it too much can lose detail. Changing the aspect ratio (the ratio of width to height) can distort the picture.
Video Compressor and its capabilities
Compressing a media file is usually a good idea as you can drastically reduce the file's size without greatly affecting the quality. By default, the video in your timeline is not compressed when you save it to file. To apply a video compressor: Open the Video Compressor dropdown list to see all the compressors that are available to you. Click on a compressor name to select it. Depending upon the compressor you choose, you may be able to select the Frame Rate, Key Frame Rate, Quality and Predicted Frame Frequency of your media file.
Frame Rate
The Frame Rate of a media file is the number of frames that are displayed in one second. Files with a higher frame rate such as 25, 30 to 60 FPS (Frames Per Second) play smoother than files with lower frame rates such as 10 or 15 FPS. However, lower frame rate media files are much smaller than higher frame rate ones. 15 FPS is the norm that is usually followed for video created for the Web. You may change the Frame Rate of the media file that you are creating from your timeline, by moving the slider until you get the desired frame rate.
Key Frame Rate
Making video files smaller involves "temporal compression". Instead of saving all the information to paint an entire video frame on the screen, the file saves only the difference between this frame and the one before. This works fine if the video is only ever played continuously and in a forward direction, but it makes it hard to seek to a random point, because the video player has to "look back" through the file to find the information needed to reconstruct the current frame.
To alleviate this problem, compressors insert key frames into the sequence at regular intervals. A key frame has all the information needed to paint the entire video without referring to other frames. Frames after a key frame depend on the key frame.
The key frame rate indicates the maximum number of frames you will accept between key frames.
Audio Compressor
By default, the audio in your timeline is not compressed when you save it to file. To apply an audio compressor:
- Open the Audio Compressor dropdown list to see all the compressors that are available to you.
- Click on a compressor name to select it.
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