A post processing system, method and computer program product content-adaptively transforms MPEG on-demand media streams, including a video optimizer software development kit (SDK); an application layer controlling the SDK interfacing with a mobile device operating and file system. Raw pixel frame buffers are parsed and structured. The buffers are normalizes for processing. Source content is analyzed in an uncompressed format for video patterns and characteristics and parameters are selected in a video codec output format. Estimated are parameters for portions and/or segments of the content. The content is recompressed and optimized in a content-adaptive manner to generate optimized content written into persistent storage of the mobile device, and segments of which are combined with an audio stream and/or a metadata stream information to generate a playable media stream in an ISO base media file format and/or a media file application specific format.