3ivx is described as 'develops audio/video codecs, and streaming/transcoding components for H.264, MPEG-4, HE-AAC and HLS on Windows, Mac OS X, iOS, Android and Unix/Linux' and is an app in the video & movies category. There are six alternatives to 3ivx for a variety of platforms, including Windows, Linux, Mac, Android and iPhone. The best alternative is FFmpeg, which is both free and Open Source. Other great apps like 3ivx are Video Transcoder, Voukoder, optimizeVideo and AfterCodecs.
FFmpeg is the leading multimedia framework, able to decode, encode, transcode, mux, demux, stream, filter and play pretty much anything that humans and machines have created. It supports the most obscure ancient formats up to the cutting edge.
Video Transcoder is an application which uses the open source program ffmpeg to transcode video files from one format to another. By selecting the video to process, details for the video are provided and the desired settings can be configured.
Voukoder is system wide video- and audio encoding service for Windows that improves your media encoding experience. It supports various encoders (both CPU and GPU based) and also provides a set of post processing filters.
optimizeVideo is just a simple wrapper around ffmpeg, but that saves a lot of guessing. It analyzes the contents of a target video file, and sets the conversion parameters according to Google standards.