Transcoding

a short explaination

There are a vast number of file formats in the digital world and it is possible to convert almost all of them from one format to another.

AUTEUR are specialists – but there are dangers – and it would be irresponsible of us to guarantee quality because there can be loss in certain circumstances.

For example, “Excell Productions” has produced a wonderful video and they have come to Auteur to have the DVD made. It is then Encoded (from tape in real time) to MPEG2 and the sound is converted to an AIFF file. The DVD is produced and everybody is pleased with the result.

It is then decided that they want to stream the video, but horror upon horrors – the master tape has been lost. So now we have to Transcode the MPEG2 video files to the Sorenson 3 codec and the AIFF files to the QDesign Audio codec. Although time consuming the result will still be satisfactory because the Sorenson codec will be throwing information away to make the video streamable. (ie. It produces a smaller file with less data and therefore reduced quality), similarly the Audio codec.

Three months later “Excell” phone up and say they want to use a section of the video on a CD business card and because the budget is tight could they use the same files as were used in the streamed video?

The Auteur answer is “yes” – but it’ll look horrible because the Sorenson files will have to be Transcoded again to a multiplexed MPEG1 file and the quality will deteriorate very significantly.

In conclusion, Transcoding always involves some loss of quality but provided the master file is good, the output should be excellent.