In general, this disclosure describes techniques for coding video blocks using a color-space conversion process. A video coder, such as a video encoder or a video decoder, may determine whether to use color-space conversion for encoding the video data. In response to determining to use color-space conversion, the video coder may quantize data of a first color component of the video data using a first offset of a first quantization parameter (QP) and quantize data of a second color component of the video data using a second offset of a second QP, wherein the second color component is different than the first color component, and the second QP is different than the first QP. The video coder may further inverse quantize data of the first color component using the first offset and inverse quantize data of the second color component using the second offset.