Spatial Scalable Video Coding using Non-Scalable Video CODEC

An apparatus for encoding a sequence of source video frames into a scalable video bit-stream where the scalable video bit-stream comprises a base layer bit-stream and an enhancement layer bit-stream, the apparatus comprising a preprocessor and an encoding unit, wherein:

• for an individual video frame in the sequence of source video frames, the preprocessor is configured to downscale said individual video frame by a pre-determined scale factor m, m being an integer at least 2, to yield a downscaled video frame having a resolution reduced by m times in each of x- and y-directions when compared to said individual video frame's resolution;
• the encoding unit is configured to execute a pre-determined video encoding algorithm to encode the downscaled video frame such that image information of the downscaled video frame is incorporated into the base layer bit-stream;
• the encoding unit is configured to execute a decoding algorithm corresponding to the pre-determined video encoding algorithm in order to decode the base layer bit-stream that has incorporated the image information of the downscaled video frame, and in order to reconstruct the downscaled video frame from the base layer bit-stream, thereby yielding a decoded base video frame which is the downscaled video frame as reconstructed;
• the preprocessor is configured to up-scale the decoded base video frame by a scale factor of m to yield an up-scaled decoded base video frame having a resolution that is the resolution of said individual video frame;
• the preprocessor is configured to subtract said individual video frame by the up-scaled decoded base video frame to yield a residual frame;
• the preprocessor is configured to divide the residual frame into N equal-size, non-overlapping residual sub-frames, N=m2, wherein each of the N residual sub-frames has a resolution that is the downscaled video frame's resolution;
• and
• the encoding unit is configured to execute the pre-determined video encoding algorithm to encode each of the N residual sub-frames such that image information in said each of the N residual sub-frames is incorporated into the enhancement layer bit-stream;
• whereby the encoding unit reuses the pre-determined video encoding algorithm to encode the N residual sub-frames as also employed in encoding the downscaled video frame so that the base layer bit-stream and the enhancement layer bit-stream are generable by using only one non-scalable encoding algorithm, allowing both of such bit-streams to be decodable by employing only one non-scalable decoding algorithm.