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
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.