| 摘要 |
An image composed of colour components or channels (e.g. luma and chroma components), each component being composed of one or more colour component portions is encoded/decoded. Information relating to the usability of one or more cross channel prediction methods (S102) in which a portion is dependent on a portion of a different component for encoding is determined or received (e.g. receiving a syntax bit flag at the decoder), for example determining that the current processing load is excessive, decoder delay is too great or a profile limitation exists or decoder capabilities are insufficient. If the method(s) are unusable, a first set of usable methods are provided (S103) which excludes the cross channel prediction method(s) and includes as a replacement at least one intra channel prediction method in which the portion is dependent on another portion of the same component for encoding (S103). If however it is determined that the cross channel prediction method(s) are usable, a second set of usable prediction methods are provided (S104) including the cross channel prediction method(s) to select a prediction method for encoding the portion (S105). Coding/decoding can thus be adapted to network or processing conditions. |
