MPEG video transcoding to a fine-granular scalable format

The principle for elastic storage of compressed multimedia content has been introduced. It is based on the combination of a random-access storage medium and a bit rate scaling method. When the storage medium is full, the bit rate of the content that has been previously stored is reduced allowing additional content to be stored. For compressed video, the bit rate can be reduced thanks to well known bit rate transcoding techniques. However, these techniques suffer from complexity problems in the scope of elastic storage application and do not present good performance in terms of resulting picture quality because transcoding is applied several times on the same video. An alternative technique referred to as transcoding to a SNR scalable format is introduced in this paper. Based on the fine granular scalability (FGS) proposed in the MPEG-4 standard, it has been adapted to our transcoding problem. Compared to the bit rate transcoding approach, the proposed solution presents better resulting picture quality and does not suffer from complexity problems when bit rate reduction of multiple streams is required.