A scalable coding system codes video as a base layer representation and an enhancement layer representation. A base layer coder may code an LDR representation of a source video. A predictor may predict an HDR representation of the source video from the coded base layer data. A comparator may generate prediction residuals which represent a difference between an HDR representation of the source video and the predicted HDR representation of the source video. A quantizer may quantize the residuals down to an LDR representation. An enhancement layer coder may code the LDR residuals. In other scalable coding systems, the enhancement layer coder may code LDR-converted HDR video directly.