Digital content is encoded and transmitted in form suitable for presentation in a variety of formats, particularly suited to mobile device environments. In specific embodiments, server-side, independent and integrated architectures are disclosed. In further specific embodiments, techniques for prefix, postfix, interrupted and midway insertions of generic data and multi-media data are disclosed together with techniques for seamlessly handling media duration, whether or not media duration is known. Still further, techniques are disclosed for retaining synchronization among inserted media segments, for reducing startup delay and for traffic smoothing, all as part of systems and techniques for media transcoding.