The Process

Technically, this is divided into two categories: encoding and transcoding. Basically, encoding is the processing of analog or uncompressed digital media into digitally compressed streaming format. Transcoding is converting from one compressed digital format into another.

Encoding:

For most purposes, the encoding process follows two steps:

• Capture from analog to digital.
• Convert/compress into streaming format.

If you are creating streaming files from an analog source, whether it is a live camera feed or from videotape, the first step is to create an uncompressed source file (AVI). This enables you to re-encode the same media until the desired result is achieved, in addition to encoding multiple target delivery rate files. Creating a source file is not always necessary, but for most situations will eliminate the redundancy of recapturing and provide a streamlined workflow. Capturing media is accomplished with an encoding workstation that is configured with audio/video capture cards and appropriate encoding production software. If required, the source file can be edited before entering the conversion/compression phase. The next step is to determine the target delivery rates of the viewing/listening audience. This will determine the settings used to create the streaming file. Utilizing this information, a series of files are created and tested at the target bandwidths, making necessary adjustments until satisfactory results are achieved. The most challenging part of this process is to create low bandwidth files that run the fine line between quality and streamability. High motion clips may require higher frame rate to avoid frame-jitter, but at a sacrifice to overall image quality. On the other hand, a "talking head" clip can utilize a slow frame rate and achieve sharper image quality at the same given delivery rate.