Method for transporting digital media
A networked system is provided for transporting digital media packets, such as audio and video. The network includes network devices interconnected to send and receive packets. Each network device can receive and transmit media signals from media devices. A master clock generates a system time signal that the network devices use, together with a network time protocol to generate a local clock signal synchronised to the system time signal for both rate and offset. The local clock signal governs both the rate and offset of the received or transmitted media signals. The system, which can be implemented using conventional network equipment enables media signals to be transported to meet quality and timing requirements for high quality audio and video reproduction.
1. A processing system configured to transport a media signal over a network comprising:
a network port;
a local clock generator coupled to the network port, the local clock generator configured to synchronize a local clock with a master clock signal received from the network port, and to derive a media clock from the local clock;
a processor coupled to the network port, the processor configured to decode a packetized media signal received from the network port, wherein the media clock directly governs a rate and an offset at which the packetized media signal is decoded; and
wherein the processor outputs the decoded media signal to a media device or software application via the network port.
2. The processing system of claim 1 wherein the processing system is a general purpose computer system.
3. The processing system of claim 1 wherein the packetized media signal includes a timestamp.
4. A processing system of claim 3 wherein the processor determines a playout time for the packetized media signal based on the timestamp.
5. The processing system of claim 1 wherein the packetized media signal is audio.
6. The processing system of claim 1 wherein the packetized media signal is video.
7. The processing system of claim 1 wherein the network port is adapted to be coupled to an Ethernet network.