When it comes to editing videos, those who are used to working with pictures will hot on some peculiarities as to the picture format, which date back to the analog roots of video technology. Digital video technology partly uses different resolution for the X and the Y axis, which results in "rectangular" pixels. Videos produced by DV cams or video DVDs, as a rule, have a size of 720 x 576 (corresponding to 5 : 4), which, however, does not provide any indication as to the correct aspect ratio of the video image. Other than the video pixels, the aspect ratio is specified as a ratio of 4 : 3 or 16 : 9.
To be able to assess the following examples
on the monitor, you must not use a monitor resolution of 1280 x 1024 pixels.
Choose a resolution which corresponds to the aspect ratio of your monitor,
e.g. this would be 1024 x 768, 1280 x 960 or 1600 x 1200 pixels for a
standard monitor with an aspect ratio of 4 : 3.
Copying the recordings of a video camera onto the hard disk, creates DV files with a picture size of 720 x 576 pixels or 1440 x 1080 pixels for HDV, respectively. Both formats do not feature enough pixels horizontally and must be stretched to the video aspect ratio to be correctly displayed. This is done by entering the aspect ratio in the Video Properties. The following modifications are made thereby:
The slightly egg-shaped wheels and the faces of the dancers show you that both videos are compressed when uncorrected (left), as the computer always assumes that the pixels are square. Only when you stretch the picture on the screen to 4 : 3 or 16:9, will the picture be shown in its correct proportions.
For video DVDs the situation is similar. You have created a screen with the required output format, i.e. 4 : 3 or 16 : 9 for your show. During MPEG-2 creation for DVD, Wings Vioso RX automatically adjusts the aspect ratios using a correction factor of 1.094 based on the standard ITU-R BT.601 for DV/D1 PAL resolution. This way the picture is correctly displayed when played on a DVD player. The steps from the screen in Wings Vioso RX to the TV monitor look as follows:
How the picture is displayed on the TV monitor depends on picture tube and device settings. Unfortunately, the picture is frequently truncated by TV monitors. Information on how to correct this problem can be found at Border for playback on TV screens.
For shows with a different aspect ratio, e.g. based on small format slides with an aspect ratio of 3 : 2, the same screen format with the corresponding aspect ratio is also used for MPEG/DVD creation. This causes black borders in the video for the picture to be displayed without any distortion.