Comment by nomel

Sorry, but it's only apple to oranges if you already know the answer. That answer, explained in the next section, is very clearly intended for someone who didn't already know it:

> This concept of throwing away bits you don't need to save space is called lossy compression. H.264 is a lossy codec - it throws away less important bits and only keeps the important bits.

> PNG is a lossless codec. It means that nothing is thrown away. Bit for bit, the original source image can be recovered from a PNG encoded image.