In preferred embodiments, a system including a transmitter, a receiver, and a serial link, in which the transmitter is configured to transmit video data, embedded-clock auxiliary data (or auxiliary data derived from embedded-clock auxiliary data), and a video clock over the link to the receiver. The transmitter is configured to extract a sample clock from the auxiliary data without use of a phase-locked loop, and to generate time stamp data in response to the sample clock and the video clock. Typically, the auxiliary data are SPDIF (or other) audio data, and the sample clock changes state in response to codes that occur periodically in the audio data. Other aspects of the invention are a transmitter for use in such a system, a time stamp data generation circuit for use in such a transmitter, and a method for generating time stamp data in response to a stream of embedded-clock auxiliary data and a video clock.