Edge optimized transrating system
A system and method for bandwidth management by controlling the bit rate of a signal stream in real time according to available link bandwidth. Applications include multiple-channel video data streams over a limited-bandwidth link such as a Digital Subscriber Line. A video signal is transrated at the head end to multiple streams having different bit rates, by a multirating device which sends the multiple streams over a network, along with metadata containing information about the data structure and parameters of the streams. At the network access edge, a demultirating device uses the metadata to select the stream with the highest video quality whose bit rate does not exceed the available bandwidth of the end-user's access link. This scheme provides multiple unicast signals to different end-users in place of a single multicast signal, supports multiple high-definition channels over a limited bandwidth link, and is compatible with standard encryption methods.
1. A device for carrying video data from a video source via a first packet-based network to a video display over a second network, the first network carrying a first video stream in a data format from the video source and a one or more second video stream having a lower bit rate and the data format, translated from the first video stream using a multirater or a transrater, the device comprising:
a receiver for receiving the video streams from the first network;
a selector for selecting one of the first and the second video stream;
a transmitter for transmitting the selected video stream to the second network; and
a single enclosure housing the receiver, the selector, and the transmitter,
wherein the second network is configured to transporting data streams up to a maximum bit rate, and
wherein the selecting of the video stream comprises selecting the video stream associated with the highest bit rate that is lower from the maximum bit rate.
2. The device according to claim 1 , further operative to select the second video stream, and the device further comprising a demultirater for reconstructing the first video stream from the second video stream.
3. The device according to claim 1 , further comprising a multiplexer, and wherein the selecting comprises de-multiplexing of the second video stream.
4. The device according to claim 3 , wherein the multiplexer is a statistical multiplexer, and wherein the selecting comprises statistical de-multiplexing.
5. The device according to claim 1 , further comprising a router, a switch, a multiplexer, or a server.
6. The device according to claim 1 , further comprising a software stored in a tangible data storage medium, and a processor for executing the software.
7. The device according to claim 1 , further comprising a sequencer coupled between the selector and the transmitter for forming a unicast data stream that comprises the selected video stream.
8. The device according to claim 7 , further comprising a cache coupled for buffering the unicast data stream between the sequencer and the transmitter.
9. The device according to claim 1 , wherein the first network is a Metropolitan Area Network (MAN) or a core network, or wherein the first network implements a core layer or an aggregation layer.
10. The device according to claim 1 , wherein the first network uses a medium that is based on, comprises, or uses, an optical fiber.
11. The device according to claim 1 , further comprising an Ethernet interface for connecting to the first network.
12. The device according to claim 11 , wherein the Ethernet interface consists of, comprises, or is compatible with, a Gigabit Ethernet (1 GbE) that is according to, based on, or compatible with, IEEE 802.3-2008 standard.
13. The device according to claim 1 , wherein the second network is an access network or implements an access layer.
14. The device according to claim 13 , wherein the second network uses medium that uses, is based on, or comprises, a twisted wire pair.
15. The device according to claim 14 , wherein the second network uses, is based on, or comprises, a point-to-point connection.
16. The device according to claim 15 , wherein the second network uses, is based on, or comprises, Digital Subscriber Line (xDSL) technology.
17. The device according to claim 16 , wherein the second network uses, is based on, or comprises, Asymmetric Digital Subscriber Line (ADSL) technology.
18. The device according to claim 17 , wherein the second network uses, is based on, or comprises, ADSL2 or ADSL2+ technology.
19. The device according to claim 17 , wherein the ADSL2 or ADSL2+ technology consists of, is based on, is compatible with, or comprises, ITU-T G.992.5 standard.
20. The device according to claim 16 , further comprising a Digital Subscriber Line Access Multiplexer (DSLAM).
21. The device according to claim 1 , wherein the first network further carrying a distinct third video stream in the data format having a lower bit rate and the data format translated using a multirater or a transrater from the first video stream, the device further operative for selecting one out of the first, the second, and the third video stream, and for transmitting the selected video stream over the second network.
22. The device according to claim 1 , wherein the first network further carrying metadata associated with the second video stream, carried as an Out-of-Band ( 00 B) channel or with the second video stream.
23. The device according to claim 22 , further operative for receiving the metadata from the first network and for handling the second video stream responsive to the metadata.
24. The device according to claim 22 , wherein the metadata comprises a video quality level indicator, a consumed bandwidth, a visual noise, spurious edges, a localized motion distortion, Image Structural Similarities (SSIM), Peak-Signal-to-Noise-Ratio (PSNR), a Group of Pictures (GOP) parameter, statistics on moving vectors, macroblock types, or density, relating to the second video stream.
25. The device according to claim 22 , further operative to receive the metadata via the first network, and wherein the selecting one of the first and the second video stream is responsive to the received metadata.
26. The device according to claim 22 , wherein the metadata is indicated by a Packet Identifier (PID).
27. The device according to claim 22 , wherein the metadata comprises the minimum required bandwidth for properly carrying each of the first and second video streams.
28. The device according to claim 1 , further operative to measure or estimate the maximum bit rate.
29. The device according to claim 1 , wherein the second network is operative to be in first and second distinct states, wherein the maximum bit rate is a first bit rate in the first state and a second bit rate in the second state, and wherein the selecting of the video stream comprises selecting the video stream associated with the highest bit rate that is lower from the first bit rate in the first state and the second bit rate in the second state.