Finding the dimension (height x width) of a MP4 file being uploaded

Question

My ASP.NET / C# web app allows users to upload MP4 files to a database for later display using the HTML5 <video> tag.

What I am looking for is a way (code, component) to determine the on-screen dimension that a given MP4 file will need to properly play. I haven't been able to find anything so far.

Given a MP4 file (as a file upload) - how can I determine the on-screen dimensions of the video contained in it, using C# code? Is there something like MP4 metadata that can be read from the file?

Answer 1

Rather than solving this problem on the server, you can solve it on the client at view time with the HTML5 video element.

$("#video").bind("loadedmetadata", function () {
        var width = this.videoWidth;
        var height = this.videoHeight;
        // ...
});

Using this approach your upload solution can remain untouched.

If storing the dimensions in the database is a requirement, consider finding a way to leverage the video element during the upload process. One approach would be to have a video 'preview' step right after upload that would extract the dimensions with the JavaScript code above and post them as hidden form elements to your server.