Aspects of the disclosure provide an apparatus that includes interface circuitry and processing circuitry. The interface circuitry is configured to receive signals carrying metadata for visual track composition from multiple visual tracks. The visual track composition includes alpha compositing, and can include spatial compositing and background compositing. The processing circuitry is configured to parse the metadata to extract configuration information for the visual track composition. Further, the processing circuitry receives a first sample from a first visual track and a second sample from a second visual track, and combines the first sample with the second sample to generate a composite sample based on the configuration information for the visual track composition.