Why mp4 format is given first and then ogg ?

Answer 1

It is a matter of taste. Although it has its logic in that case.

Popularly it is said that OGG has more losses and less compression, the difference is not substantially noticeable for the average user in most cases. But it also offers native support on almost any existing device (since it is open source). On the other hand MP4 is a much more popular format, but if the user does not have the necessary codecs it will not be able to visualize your content (by default some operating systems do not bring support to several formats by their license, and there are many people who they are not interested in downloading them). That is why it is logical to have your file in MP4 and a backup that in this case is OGG, that way your content will always be available. On the downside is the fact that if you have hosted the content on your server this means using a lot of extra space.

Answer 2

because mp4 format is supported by al web browser where as Ogg is not supported by internet explorer, Safari