Monitor and Video Aspect are different things - both must be known and honoured to fill as much of the screen surface without distorting the picture too much. ZapDvb together with MPlayer offers full support for cropping and scaling the picture for an optimal result for a given monitor.
Historically this could be 4:3 which gives the ratio between horizontal and vertical size (size, not the number of pixels). Pixels are not necessarily squares! Another good choice for computer work is a ratio of 5:4 (for text processing!). A Video display intended for TV use would preferably have a 15:9 ratio (a compromise) or for Movie watching better a 16:9 ratio. So we end up with 4 common monitor aspects:
If you do not inform your player about the Monitor Aspect the Picture will get distorted. Eventually the player can try to make an estimate from your X11 configuration.
Historically a 4:3 ratio was used and the film image was not distorted. The movie industry kept the physical 4:3 ratio for film but later used anamorphic lenses to distort the image. They ended up with many different aspect ratios.
TV broadcast was always anamorphic (don't panic you player know about and usually does the correct scaling), but the DVB broadcast standard supports two different ratios:
Not really. The information is not sufficient to support clipping/scaling to obtain an optimal result for a given monitor (it's 2 bits only). For a good result you can take any of the following actions:
...
...