Aspects of the disclosure provide methods, apparatuses, and non-transitory computer-readable storage mediums for video encoding/decoding. An apparatus includes processing circuitry that decodes prediction information for a current block in a current picture. The prediction information can indicate whether an adaptive color transform (ACT) is enabled for the current block. The processing circuitry determines a maximum transform size based on whether the ACT is enabled for the current block. The processing circuitry can determine whether a subblock transform (SBT) is applied to the current block based at least on the maximum transform size, and perform the SBT on the current block based on the SBT being determined to be applied to the current block. The maximum transform size is determined to be a first maximum transform size when the ACT is disabled for the current block and a second maximum transform size when the ACT is enabled for the current block.