Transcoding is the ability to adapt digital files so that content can be viewed on different playback devices. Working like an interpreter, a transcoder translates files to a suitable format for the end user. The translations are built upon complicated algorithmic computations and require significant processing resources.
Transcoding servers and services reformat material that would otherwise have to be developed separately for different platforms. They are commonly used for adapting content for mobile devices or serving video. There are a number of different ways that transcoding can take place but the overall process remains the same. The source format is translated into a raw intermediate format and then re-translated into a format the end user's device recognizes.
In one example, the original material is analyzed by a program that creates a separate version containing annotations. The annotations include information that will instruct the reformatting process. When a request for the file is sent to the hosting server, the server submits the annotated version to an authoring application. The material is reformatted there and sent on to a proxy server. The proxy server accesses information about device preferences and adapts the material as needed before delivering it to the end user.
There are two main options for those who want to automate the reformatting of content: using a transcoding server product or using a transcoding service. Transcoding services are application service providers (ASPs) that take responsibility for the entire process and deliver the reformatted content from legacy material.