A method for enabling playback of a video signal at a decoder comprising: selecting a level of quality for playback of the signal at the decoder; retrieving reconstruction data from a repository; transmitting the retrieved reconstruction data to a decoder, the decoder configured to reconstruct renditions of a signal based on the transmitted reconstruction data; and during the transmitting, varying a level of quality of the reconstruction data retrieved and transmitted to the decoder, wherein the method is characterized in that: the retrieved reconstruction data is encoded in accordance with a hierarchy including multiple levels of quality, the levels of quality being defined in association with different image resolutions, wherein the retrieved reconstruction data at a given level indicates how to reconstruct a rendition of the signal at a given level of quality, wherein the retrieved reconstruction data comprises at least residual data for a frame of the video signal indicating adjustments to be made during upsampling the rendition of signal at a first level of quality into the rendition of the signal at a next higher level of quality, wherein each frame of the video signal is divided into a plurality of tiles, and the retrieved reconstruction data for a frame of the video signal comprises a sequence of reconstruction data (A1-T1, A2-T1,..., A8-T1) for each tile of the plurality of tiles, wherein each sequence of reconstruction data comprises data to reconstruct a particular tile in the plurality of tiles and comprises reconstruction data for each of a plurality of levels up to the selected level of quality, and wherein the sequences of reconstruction data for the plurality of tiles are decodable in parallel on a set of multiple processors, and each sequence of reconstruction data is assignable to a separate processor in the set of multiple processors to reconstruct a rendition of picture elements of the video signal for a corresponding tile, the renditions for the plurality of tiles being combined to produce an overall rendition of the video signal for playback. selecting a level of quality for playback of the signal at the decoder; retrieving reconstruction data from a repository; transmitting the retrieved reconstruction data to a decoder, the decoder configured to reconstruct renditions of a signal based on the transmitted reconstruction data; and during the transmitting, varying a level of quality of the reconstruction data retrieved and transmitted to the decoder, wherein the method is characterized in that: the retrieved reconstruction data is encoded in accordance with a hierarchy including multiple levels of quality, the levels of quality being defined in association with different image resolutions, wherein the retrieved reconstruction data at a given level indicates how to reconstruct a rendition of the signal at a given level of quality, wherein the retrieved reconstruction data comprises at least residual data for a frame of the video signal indicating adjustments to be made during upsampling the rendition of signal at a first level of quality into the rendition of the signal at a next higher level of quality, wherein each frame of the video signal is divided into a plurality of tiles, and the retrieved reconstruction data for a frame of the video signal comprises a sequence of reconstruction data (A1-T1, A2-T1,..., A8-T1) for each tile of the plurality of tiles, wherein each sequence of reconstruction data comprises data to reconstruct a particular tile in the plurality of tiles and comprises reconstruction data for each of a plurality of levels up to the selected level of quality, and wherein the sequences of reconstruction data for the plurality of tiles are decodable in parallel on a set of multiple processors, and each sequence of reconstruction data is assignable to a separate processor in the set of multiple processors to reconstruct a rendition of picture elements of the video signal for a corresponding tile, the renditions for the plurality of tiles being combined to produce an overall rendition of the video signal for playback. the retrieved reconstruction data is encoded in accordance with a hierarchy including multiple levels of quality, the levels of quality being defined in association with different image resolutions, wherein the retrieved reconstruction data at a given level indicates how to reconstruct a rendition of the signal at a given level of quality, wherein the retrieved reconstruction data comprises at least residual data for a frame of the video signal indicating adjustments to be made during upsampling the rendition of signal at a first level of quality into the rendition of the signal at a next higher level of quality, wherein each frame of the video signal is divided into a plurality of tiles, and the retrieved reconstruction data for a frame of the video signal comprises a sequence of reconstruction data (A1-T1, A2-T1,..., A8-T1) for each tile of the plurality of tiles, wherein each sequence of reconstruction data comprises data to reconstruct a particular tile in the plurality of tiles and comprises reconstruction data for each of a plurality of levels up to the selected level of quality, and wherein the sequences of reconstruction data for the plurality of tiles are decodable in parallel on a set of multiple processors, and each sequence of reconstruction data is assignable to a separate processor in the set of multiple processors to reconstruct a rendition of picture elements of the video signal for a corresponding tile, the renditions for the plurality of tiles being combined to produce an overall rendition of the video signal for playback.