Multiplex communications – Communication techniques for information carried in plural... – Combining or distributing information via time channels
Reexamination Certificate
1999-01-07
2002-10-29
Ton, Dang (Department: 2732)
Multiplex communications
Communication techniques for information carried in plural...
Combining or distributing information via time channels
C370S437000, C370S468000, C370S537000, C348S465000, C709S217000, C709S236000
Reexamination Certificate
active
06473441
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to streaming video signals and, more particularly, for an apparatus for simultaneously streaming user-specified video files encoded at varying bit rates over a single network .
2. Description of the Related Art
The role of streaming video in local area networks is expected to increase rapidly in the near future. When video that has been compressed using one of the standards of the Moving Pictures Expert Group (MPEG) and stored in a RAID array, or on a digital video (or versatile) disc (DVD), etc., a constant bit rate (or isochronous) stream is created. If a plurality of such streams are to be multiplexed for transmission over a network, as the number of concurrent video streams in a given network segment increases it is essential that each stream be well-behaved in order to maximize network efficiency. Bursty transmission of MPEG video streams in the network will result in congestion and network failure much more quickly than constant bit rate transmission. The more closely the individual data streams are maintained at a constant bit rate, the higher the total aggregate of such streams that can be carried on the network while maintaining a desired quality of service.
The MPEG compression standards are used worldwide for constant bit rate digital video encoding. Decoding of MPEG video relies on the ability to deliver each bit from the encoder to the decoder with a constant delay. This constant bit rate delivery is generally termed Isochronous Streaming. In live broadcasts the encoder is responsible for generating the MPEG bit stream at the proper rate. However, when this information is stored for later playback another mechanism is required to “meter” the data from the storage media to the network connection. Normally, no feedback is provided to the sender by the receiver of MPEG video. The receiver depends on the transmission rate to be both smooth and accurate in order to decode MPEG video properly.
Existing MPEG videos have been encoded at several different rates. Some examples are streams that are 3.282, 3.420, 6.144, and 6.000 megabits per second. Some conventional systems use a handshake protocol to inform the receiving device what is the bit rate of the video stream that will be sent. However, that requires the receiving device to be programmed to use the protocol. Other systems distribute large continuous “chunks” of data that require the receiving device to have enough expensive video memory to buffer the data for smooth display and the ability to determine the appropriate bit rate independently of the rate at which the data is received.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a video streaming device that can output video signals at an average rate within one bit per second of the rate at which the signal was encoded, for a varying signal rates.
It is another object of the present invention to provide a video streaming device that can output signals with different signal rates, each having a jitter of less than one millisecond.
It is a further object of the present invention to provide a video streaming device capable of outputting multiple video signals at varying rates using close to full maximum payload of the network that receives the video signals.
It is yet another object of the present invention to provide a video streaming device capable of outputting video signals to display devices with as little as one or two frames of video memory and without using a handshake protocol.
The above objects can be attained by an apparatus for These together with other objects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.
REFERENCES:
patent: 5561791 (1996-10-01), Mendelson et al.
patent: 5603058 (1997-02-01), Belknap et al.
patent: 5646676 (1997-07-01), Dewkett et al.
patent: 5699362 (1997-12-01), Makam
patent: 5974503 (1999-10-01), Venkatesh et al.
patent: 6181711 (2001-01-01), Zhang et al.
Escient Convergence Corp
Hom Shick
Ton Dang
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