Multi-point motion picture encoding and decoding apparatus

• US 5,790,179 A
• Filed: 09/27/1996
• Issued: 08/04/1998
• Est. Priority Date: 12/21/1993
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Shibata, Koichi, Kinoshita, Taizo
• Primary Examiner(s): Powell, Mark R.
• Assistant Examiner(s): GRANT, CHRISTOPHER C
• Application Number:
  US08/722,796
• Time in Patent Office: 676 Days
• Field of Search: 348/15, 348/14, 348/16, 348/17, 348/18, 348/6, 348/7, 348/8, 348/9, 348/10, 348/11, 348/12, 348/13, 348/563, 348/564, 348/565, 348/567, 455/4.1, 455/4.2, 455/5.1, 455/6.1, 455/6.2, 455/6.3
• US Class Current: 348/14.09
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/423 characterised by memory arrangements H04N19/433 takes precedence
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/2365 Multiplexing of several video streams
• CPC Class Codes: H04N 21/4347 Demultiplexing of several video streams
• CPC Class Codes: H04N 7/15 Conference systems
• CPC Class Codes: H04N 7/152 Multipoint control units therefor
• CPC Class Codes: Y10S 370/902 Packet switching

Abstract

A multi-point video conference system includes a plurality of terminals and a network. Each terminal includes a coder to code and to packetize at least a motion picture in a block unit and a multi-point video decoder to sequentially receive and to decode packets sent from decoders at other points. The decoder includes a video processor to process video information in a time sharing manner, a channel selection controller to decide a transmission source of a received packet according to information of the packet and to notify the source to the video processor, a shared frame memory to store therein video information from the plural terminals, and a display frame memory to output therefrom the video information in a synchronous fashion.

Claims

1. A terminal for displaying a plurality of video images on a display screen, comprising:

a receiver for receiving video data packets from a plurality of video sources in a time sharing manner, each of said video data packets including coded video information for representing a partial image contained within one of a plurality of blocks constituting a video frame, attribute information for indicating at least a location of a block corresponding thereto within the video frame and identification information of the video source;

a decoder connected to said receiver for decoding the coded video information extracted from each of said video data packets and for outputting a partial image corresponding to one of said blocks in the video frame;

a set of frame memories for assembling partial images into video frames, each of said frame memories having a plurality of image areas located in a predetermined layout defined therein, a set of said image areas each located at a same location within respective said frame memories being associated with a same video source with respect to each other;

a recorder for writing each partial image derived from said decoder into one of said image areas within one of said frame memories which is specified in accordance with the identification information extracted from a video data packet related to the partial image and a utilization status of said image areas; and

a selector for selectively outputting contents of said frame memories on a display screen by changing over said frame memories depending upon a display position on the display screen thereby to present a plurality of video frames at a plurality of image areas on the display screen.

2. A terminal as claimed in claim 1, further comprising:

a memory for keeping therein status information for each of said image areas, said recorder operating by referencing said memory so as to write said partial image into one of said set of image areas which is specified by the identification information and as indicated in a status available for a write operation by said status information, and said selector operating by referencing said memory so as to selectively output the contents of one of said image areas which is indicated by said status information in an output waiting status or in an output execution status.

3. A terminal as claimed in claim 1, wherein said decoder comprises a memory for storing said coded video information for each video source until an amount of the coded video information sufficient to produce one partial image is prepared in the decoder.

4. A terminal as claimed in claim 1, wherein said receiver means is connected so as to receive said video data packets transmitted from at least one remote terminal through a communication network.

5. A terminal as claimed in claim 1, wherein said decoder comprises an extra-frame reproducer for producing partial images from first coded video information coded through an intra-frame encoding, and an inter-frame reproducer for producing partial images from second coded video information coded through an inter-frame encoding.

6. A terminal for displaying a plurality of video images on a display screen comprising:

a packet supplier for sequentially supplying video data packets each of which includes coded video information related to one of a plurality of blocks constituting a video frame, attribute information for indicating a location of a block corresponding thereto within the video frame and identification information of a video source;

a decoder connected so as to receive said video data packets for decoding the coded video information extracted from each of said video data packets to output a partial image;

a set of frame memories for assembling partial images into video frames;

a memory for storing control information for indicating a status of each of a plurality of video areas defined within each of said frame memories in a predetermined layout and correlation between the video areas and video sources;

a recorder for writing the partial image output from said decoder into one of said video areas within one of said frame memories specified by the control information in the memory and the identification information extracted from the video data packet related to the partial image; and

a selector for selectively outputting the contents of said frame memories on a display screen by changing over said frame memories depending upon a status of said video areas thereby to present a plurality of video frames at a plurality of video areas on the display screen.

7. A terminal as claimed in claim 6, wherein said decoder comprises a buffer memory for storing said coded video information for each video source until an amount of the coded video information necessary to produce one partial image is prepared in said decoder.

8. A terminal as claimed in claim 6, wherein said packet supplier for sequentially supplying said video data packets is connected so as to receive video data packets transmitted from at least one remote terminal through a communication network.

9. A terminal as claimed in claim 6, wherein said decoder comprises an intra-frame reproducer for producing partial images from first coded video information coded through an intra-frame encoding, and an inter-frame reproducer means for producing partial images from second coded video information coded through an inter-frame encoding.

10. A multi-point video conference system, comprising:

a network;

a plurality of terminals interconnected via said network, with each terminal comprising;

a camera for capturing a video image;

a coding and packeting arrangement for coding and packetizing said video images into video data packets;

a receiver for receiving video data packets from other ones of said terminals in a time sharing manner, each of said video data packets including coded video information for representing a partial image contained within one of a plurality of blocks constituting a video frame, attribute information for indicating at least a location of a block corresponding thereto within the video frame and identification information of a terminal source;

a decoder connected to said receiver means for decoding the coded video information extracted from each of said video data packets and for outputting a partial image corresponding to one of said blocks in the video frame;

a set of frame memories for assembling partial images into video frames, each of said frame memories having a plurality of window areas located in a predetermined layout defined therein, a set of said window areas each located at a same location within respective said frame memories being associated with a same terminal source with respect to each other;

a recorder for writing each partial image derived from said decoder into one of said window areas within one of said frame memories which is specified in accordance with the identification information extracted from a video data packet related to the partial image and a utilization status of said window areas; and

a selector for selectively outputting contents of said frame memories on a display screen by changing over said frame memories depending upon a display position on the display screen thereby to present a plurality of video frames at a plurality of window areas on the display screen.

11. A video conference system as claimed in claim 10, further comprising:

a memory for keeping therein status information for each of said window areas, said recorder operating by referencing said memory so as to write said partial image into one of said set of window areas which is specified by the identification information and as indicated in a status available for a write operation by said status information, and said selector operating by referencing said memory so as to selectively output the contents of one of said window areas which is indicated by said status information in an output waiting status or in an output execution status.

12. A video conference system as claimed in claim 10, wherein said decoder comprises a memory for storing said coded video information for each terminal source until an amount of the coded video information sufficient to produce one partial image is prepared in the decoder.

13. A video conference system as claimed in claim 10, further comprising a transmitter for transmitting said video data packets to at least one remote terminal through said network.

14. A video conference system as claimed in claim 10, wherein said decoder comprises an intra-frame reproducer for producing partial images from first coded video information coded through an intra-frame encoding, and an inter-framed reproducer for producing partial images from second coded video information coded through an inter-frame encoding.

15. A multi-point video conference system, comprising:

a network;

a plurality of terminals interconnected via said network, with each terminal comprising;

a camera for capturing a video image;

a coding and packeting arrangement for coding and packetizing said video images into video data packets;

a sequencer for sequentially supplying said video data packets each of which includes coded video information related to one of a plurality of blocks constituting a video frame, attribute information for indicating a location of a block corresponding thereto within the video frame and identification information of a terminal source;

a decoder connected so as to receive said video data packets from other ones of said terminals for decoding the coded video information extracted from each of said video data packets to output a partial image;

a set of frame memories for assembling partial images into video frames;

a memory for storing control information for indicating a status of each of a plurality of video areas defined within each of said frame memories in a predetermined layout and correlation between the video areas and terminal sources;

a recorder for writing the partial image output from said decoder into one of said video areas within one of said frame memories specified by the control information in the memory and the identification information extracted from the video data packet related to the partial image; and

a selector for selectively outputting the contents of said frame memories on a display screen by changing over said frame memories depending upon a status of said video areas thereby to present a plurality of video frames at a plurality of video areas on the display screen.

16. A terminal system as claimed in claim 15, wherein said decoder comprises a buffer memory for storing said coded video information for each video source until an amount of the coded video information necessary to produce one partial image is prepared in said decoder.

17. A terminal system as claimed in claim 15, wherein said sequencer for sequentially supplying said video data packets is connected so as to receive video data packets transmitted from at least one remote terminal through said network.

18. A terminal system as claimed in claim 15, wherein said decoder comprises a means for producing partial images from first coded video information coded through an intra-frame encoding, and a means for producing partial images from second coded video information coded through an inter-frame encoding.

19. A method of displaying a plurality of video images on a display screen, comprising the steps of:

receiving video data packets from a plurality of video sources in a time sharing manner, each of said video data packets including coded video information for representing a partial image contained within one of a plurality of blocks constituting a video frame, attribute information for indicating at least a location of a block corresponding thereto within the video frame and identification information of the video source;

decoding the coded video information extracted from each of said video data packets and outputting a partial image corresponding to one of said blocks in the video frame;

assembling partial images into video frames in a set of frame memories, each of said frame memories having a plurality of image areas located in a predetermined layout defined therein, a set of said image areas each located at a same location within respective said frame memories being associated with a same video source with respect to each other;

writing each partial image derived from said decoding step into one of said image areas within one of said frame memories which is specified in accordance with the identification information extracted from a video data packet related to the partial image and a utilization status of said image areas; and

selectively outputting contents of said frame memories on a display screen by changing over said frame memories depending upon a display position on the display screen thereby to present a plurality of video frames at a plurality of image areas on the display screen.

20. A method as claimed in claim 19, comprising the further steps of:

storing status information for each of said image areas, referencing stored said status information so as to write said partial image into one of said set of image areas which is specified by the identification information and as indicated in a status available for a write operation by said status information, wherein said selectively outputting step references stored said status information so as to selectively output the contents of one of said image areas which is indicated by said status information in an output waiting status or in an output execution status.

21. A method as claimed in claim 19, wherein said decoding step includes the substep of storing said coded video information for each video source until an amount of the coded video information sufficient to produce one partial image is prepared.

22. A method as claimed in claim 19, wherein in said receiving step, said video data packets are received after being transmitted from at least one remote terminal through a communication network.

23. A method as claimed in claim 19, wherein said decoding step includes alternative substeps of producing partial images from first coded video information coded through an intra-frame encoding, and producing partial images from second coded video information coded through an inter-frame encoding.

24. A method of displaying a plurality of video images on a display screen, comprising the steps of:

sequentially supplying video data packets each of which includes coded video information related to one of a plurality of blocks constituting a video frame, attribute information for indicating a location of a block corresponding thereto within the video frame and identification information of a video source;

receiving said video data packets for decoding the coded video information extracted from each of said video data packets to output a partial image;

assembling partial images into video frames using a set of frame memories;

storing control information for indicating a status of each of a plurality of video areas defined within each of said frame memories in a predetermined layout and correlation between the video areas and video sources;

writing the partial image output from said receiving step into one of video areas within one of said frame memories specified by the control information and the identification information extracted from the video data packet related to the partial image; and

selectively outputting the contents of said frame memories on a display screen by changing over said frame memories depending upon a status of said video areas thereby to present a plurality of video frames at a plurality of video areas on the display screen.

25. A method as claimed in claim 24, wherein said receiving step includes storing said coded video information for each video source in a buffer memory until an amount of the coded video information necessary to produce one partial image is prepared.

26. A method as claimed in claim 24, wherein in said sequentially supplying step, said video data packets are transmitted from at least one remote terminal through a communication network.

27. A method as claimed in claim 24, wherein said receiving step includes alternative substeps of producing partial images from first coded video information coded through an intra-frame encoding, and producing partial images from second coded video information coded through an inter-frame encoding.