100fps: How to deinterlace Video the right way. Examples, Tricks, Comparisons

Should you resize before or after deinterlacing by Bob'ing?

If you make a 50fps movie out of a 25fps movie (bobbing) then the movie will be half the height as explained on the main page "How to deinterlace".

There are 3 ways how you can handle this:


1) Leave it and resize the movie during play.
2) During encoding: Reduce the width, the height stays

Drawback: You lose half of the width information. Movie becomes unsharper.

Benefit 1: Filesize is less, PC needs less power to decode it.

Benefit 2: You don't need a special player and don't need PC power to resize the movie.

3) Increase the height, the width stays.

Drawback 1: You bloat the filesize to about 140%-160% (which is still about 25%-35% smaller than DivX 4, when you use DivX 5 Professional).

Drawback 2: Because your PC now has to decode double the rate, the movie can become unplayable. You need a very fast computer to be fast enough. Resizing during play is much less processor power consuming than decoding double the rate.

Benefit 1: You don't need special players, that can resize unproportionally during play. You can use any player, as long as the PC is fast enough.

Benefit 2: The quality is about 200%. The picture is more clear and more sharp.

Benefit 3: Compression artefacts are less visible. When you resize during play, the encoded artefacts are resized also. There is another way to get Benefit 3: Use a better compression method (higher DivX quantizer). But even if you use DivX 100% quality you won't be get a quality as high as resizing up before encoding. Did you ever hear conversations with salesclerks telling you that digital zoom is not needed? Well, it's not true with the same reason.

Benefit 4: The resizing is different (=more accurate) than on-the-fly-resizing. Thus the resizing itself can make the frame look better or worse.

Here is the big version of "relex_smooth.avi" from the main page. This time unchanged 720x576 (7.3 MB). Be warned, you won't be able to watch it, unless your computer is much more faster than my AMD 1900+, which decodes it stuttering, or unless you have a very fast graphics card. My AMD 1900+ even can't decode 720x528 fluidly (=height and width are multiples of 16). So be warned. And yes, I tried Xvid, and Xvid's decoding is slower and the quality is worse than DivX 5.0.2 Professional.

Here is the big version of "inmyhand_smooth", but as unchanged 720x576 (8.1 MB). Be warned here, too.

Here is the big version (and this time deinterlaced with method 4b) of Britney's dance performance as unchanged 520x560 (8.8 MB). Be warned here, too.

Please see this comparison of resulting filesizes with the mentioned methods above.


100fps: How to deinterlace Video the right way. Examples, Tricks, Comparisons