In a method for adaptive synchronization of a data sink device to a data source device coupled by a USB, data is received and stored in a buffer of the sink device at an average data rate representative of the data rate of the source device. A data level for the buffer is determined based on input packet size and output packet size. An accumulated data level for the buffer is compared with a threshold level. A clock frequency for the sink device is corrected when the accumulated data level exceeds the threshold level.