Scintilla wrote:The point is that you didn't have to add the black borders -- a widescreen resolution like 640x352 is fine. Black borders waste bits.
Actually, the idea that borders waste bits is a common misconception. They can waste bits sometimes, but not all times. There will only be a noticable difference when the borders fall in the middle of a macroblock. When going from 352>480, you add 64 pixels on both the top and bottom, which is an even multiple of 16. This means that the black border falls precisely on a seperate macroblock from the video data. Thus you get a bunch of pure black macroblocks, which encode extremely well, such that any difference in quality or filesize is completely negligible. The time when they WOULD effect things adversely, is if they didn't fall right on the mod16 border. For instance, if he had made his video at say, 640x360, and then added borders. In this case, you would have 2 rows of macroblocks in which part of the block contains video data, and the other part of the block contains black data. This solid line between the video and the black is difficult to compress, and can waste a bit of bits. By aligning your borders to the macroblocks though, you can nullify this disadvantage.