Is there any software than can convert mp4s into a quality format?

[GoOakland]

I have a ton of mp4s that I would like to be converted into another format. I like mp4s but the only program that can read them is the quicktime player and I HATE how small the window is. I mean sure i can make it "full screen" but then I lose a rediculous amount of quality.

So I need a program that can convert them into a format that can be viewed on a large screen (using WMP or something. I dunno) yet still high in quality. Is that even possible? So far the few programs (I do have to admit though... they were free. I can't expect too much from them I guess) I have tried were not very good. I assume that is because mp4 is designed for mobile devices and thus is smaller. As of right now that is y I think its just not possible to convert into a larger screen AND maintain quality if the source itself is small. But I don't know much about video specs and everything. Any suggestions?

Ideally I would like for it to convert between the vast majority of formats so I can use it for more than just this purpose. I want to get my money's worth.

 

[randomizer]

I'm not a media wizz but a there's few things you need to note:

1) .mp4 is a container. It describes the data within but that data can be encoded in many different formats, such as H.264, XviD and DivX. This means that one MP4 might work on Quicktime but another one might not if you don't have the required codec (Coder-Decoder). The same information can be stored in other containers like .mkv and .avi but it will be stored differently. The program you are using to view the video must support both the container and the video compression standard used.

2) .mp4 is used for low-quality and HD video, since it is just a container.

3) You can't expand the video without losing quality. When downscaling you are either squashing the same amount of data into a smaller area or reducing the amount of redundant data, which is easy. When upscaling you're trying to expand the same amount of data over a larger area and need to interpolate or "estimate" to fill in the gaps. It is the same as using photoshop to upscale an image. A little upscaling can be done without too much loss of quality but large amounts of upscaling makes it very poor quality. The upscaling algorithm used will affect the quality but in the end you will still inevitably have some loss.

The best option would be to find a larger source.