The first question that I have for you is what type of video are you interested in compressing, there are different types of videos that can be played on HTML5 compliant browsers.
The most popular format for web video is the mp4 format, and it looks like when a standard is finally decided that will probably be the format that wins over the standardization wars. mp4 has some pretty good compression already built into the video formatting when it is created and if you want to have high quality video you probably would not want to compress the videos much more than a standard mp4 video format.
If you insist on compressing the videos there are few tools that are available, I used Sorenson Squeeze for many years as I was building my training library of videos for my students, but after realizing that the higher compression ratios were costing to much in quality I went back to the standard mp4 formats. Sorenson is also quite pricey and the upgrades are pretty expensive also.
I have been doing on-line video for almost 10 years and I will help you if I can, just let me know some specifics on what you are looking for.
What do you mean by standard. I am not certain what you are getting at. Is your audience only for the android systems?
As far as display of the video in a cam or gallery, that would depend on your application and the amount of content on the short cut screen. If there is text, you would obviously not want to use a gallery, title screens would be hard to read.
Yes we are targeting only mobile users at the moment. Standard means to say compressor for any format of videos. Data will be huge and displayed one by one. So I think it does not matter what is the data source or where it comes from.