Seamless digital channel changing

• US 7,523,482 B2
• Filed: 08/13/2002
• Issued: 04/21/2009
• Est. Priority Date: 08/13/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Barrett, Peter T., Baldwin, James A.
• Primary Examiner(s): Miller; John W.
• Assistant Examiner(s): Schnurr; John R.
• Application Number:
  US10/218,675
• Publication Number:
  US 20040034864A1
• Time in Patent Office: 2,443 Days
• Field of Search: 725/38, 725 90- 95, 725118-120, 37524012-24015, 375/240.25, 375/240.26
• US Class Current: 725/120
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/4383 Accessing a communication channel
• CPC Class Codes: H04N 21/6377 directed to server one-way streaming services wherein the source is controlled by the destination H04L65/613
• CPC Class Codes: H04N 21/658 Transmission by the client directed to the server
• CPC Class Codes: H04N 21/8453 by locking or enabling a set of features, e.g. optional functionalities in an executable program

Abstract

Seamless channel changing in a digital-television-based entertainment network can be implemented, for example, by providing an intra frame to a client device upon a change to a new channel even when the broadcast video data is previously compressed on a macroblock basis. In an exemplary implementation, a method includes: receiving a stream of broadcast video data that is encoded on a macroblock basis; continuously decoding the stream of broadcast video data into successive decoded images; and transmitting, responsive to a channel change message received from a client device, an intra frame that has been encoded from a decoded image of the successive decoded images. Other exemplary implementations are described herein.

Claims

1. A system for smoothing channel changing in a digital video environment, the system comprising:

a decoder that receives a digital video stream, the decoder decoding the digital video stream into a plurality of intra macroblocks, and amalgamating the plurality of intra macroblocks to produce a series of uncompressed images over time;

an image holding buffer that accepts uncompressed images of the series of uncompressed images;

an encoder that is capable of receiving at least one uncompressed image from the image holding buffer, the encoder adapted to encode the at least one uncompressed image into an intra frame; and

a channel change message handler that is capable of communicating with the encoder, the channel change message handler adapted to activate the encoder to encode the at least one uncompressed image into the intra frame responsive to receipt of a channel change message from a client device to avoid a waterfall effect.

2. The system as recited in claim 1, further comprising:

a video data distributor that is capable of receiving the intra frame, the video data distributor adapted to transmit the intra frame to the client device.

3. The system as recited in claim 1, further comprising:

a video data distributor that is capable of receiving the intra frame from the encoder, the video data distributor adapted to transmit the intra frame to the client device using a network interface.

4. The system as recited in claim 1, wherein the decoder, the encoder, and the channel change message handler comprise software elements of a data center.

5. The system as recited in claim 1, wherein the decoder and the encoder comprise hardware elements.

6. The system as recited in claim 1, wherein the decoder, the encoder, and the channel change message handler comprise a combination of one or more of hardware, software, and firmware of a server system.

7. An arrangement for smoothing channel changing, the arrangement comprising:

decoding means for decoding a video stream into a plurality of intra macroblocks, and amalgamating the plurality of intra macroblocks over time to produce decoded images;

encoding means for selectively encoding selected ones of the decoded images of the decoding means to produce encoded intra frames; and

handling means for handling channel change messages received from client devices, the handling means configured to cause the encoding means to select for encoding those decoded images of the decoding means that correspond to the channel change messages to avoid a waterfall effect.

8. The arrangement as recited in claim 7, further comprising:

first buffering means for buffering each decoded image of the decoded images of the decoding means during decoding; and

second buffering means for buffering each decoded image of the decoded images of the decoding means after decoding, the second buffering means in communication with the encoding means to facilitate encoding of the selected ones of the decoded images of the decoding means.

9. The arrangement as recited in claim 7, wherein each channel change message of the channel change messages that are received from client devices comprises at least one of a channel change request or a channel change notification.

10. The arrangement as recited in claim 7, wherein the video stream comprises a digital video stream that includes a plurality of sub-streams, each sub-stream of the plurality of sub-streams directed to a macroblock space of an image of the images.

11. The arrangement as recited in claim 10, wherein each sub-stream of the plurality of sub-streams is offset in time with respect to each other sub-stream of the plurality of sub-streams.

12. The arrangement as recited in claim 7, further comprising:

interface means for interfacing with a network, the interface means configured to receive packets via and to transmit packets over the network; and

distribution means for distributing the encoded intra frames to the client devices using the interface means.

13. The arrangement as recited in claim 12, wherein the network comprises at least one of an Internet protocol (IP)-based network or a digital subscriber line (DSL)-based network.

14. The arrangement as recited in claim 12, wherein the network comprises at least one of a two-way unicast network or a two-way broadcast network.

15. A system for smoothing channel changing in a digital video environment, the system comprising:

one or more memories, the one or more memories including buffering space and electronically-executable instructions;

one or more processors, the one or more processors capable of executing the electronically-executable instructions to perform actions comprising;

decode a video data stream into a plurality of intra macroblocks, and amalgamating the plurality of intra macroblocks into a first uncompressed image;

hold the first uncompressed image in the buffering space while a second uncompressed image is produced by further decoding of the video data stream;

determine whether a channel change message has been received; and

if so, to avoid a waterfall effect, encode the first uncompressed image into an intra frame of video data.

16. The system as recited in claim 15, wherein the one or more memories comprise a first memory and a second memory, the first memory including the buffering space and the second memory including the electronically-executable instructions.

17. The system as recited in claim 16, wherein the first memory comprises at least one dedicated latch, and the second memory comprises shared, general-purpose memory.

18. The system as recited in claim 16, wherein the first memory and the second memory comprise random access memory (RAM).

19. The system as recited in claim 15, wherein the one or more processors comprise at least part of a server computer.

20. The system as recited in claim 15, wherein the system comprises a data center at a headend of a television-based entertainment network.

21. The system as recited in claim 15, further comprising:

one or more network interfaces, the one or more network interfaces capable of interfacing with at least one network and adapted to be controlled by the one or more processors in accordance with the electronically-executable instructions.

22. The system as recited in claim 15, wherein the one or more processors are capable of executing the electronically-executable instructions to perform further actions comprising:

if a channel change message has not been received,

jettison the first uncompressed image from the buffering space; and

hold the second uncompressed image in the buffering space while a third uncompressed image is produced by still further decoding of the video data stream.

23. The system as recited in claim 15, wherein the one or more processors are capable of executing the electronically-executable instructions such that the action to encode the first uncompressed image into an intra frame of video data comprises a further action to:

encode the first uncompressed image into the intra frame of video data in accordance with a Moving Pictures Expert Group (MPEG)-compliant algorithm.

24. The system as recited in claim 15, wherein the one or more processors are capable of executing the electronically-executable instructions such that the action to decode a video data stream into a first uncompressed image comprises a further action to:

decode a plurality of non-intra macroblocks with reference to the plurality of intra macroblocks.

25. One or more electronically-accessible media comprising instructions that, when executed, direct a server to:

continuously decode a plurality of video data streams into a plurality of intra macroblocks, and amalgamate the plurality of intra macroblocks into decoded images, each video data stream of the plurality of video data streams corresponding to a respective channel of a plurality of channels;

periodically provide, based on the decoding of the plurality of video data streams, a plurality of respective decoded images each respective decoded image of the plurality of respective decoded images corresponding to an intra frame of the respective channel of the plurality of channels;

determine whether a channel change message has been received, the channel change message indicating a new channel; and

if a channel change message has been received,

encoding the respective decoded image of the plurality of respective decoded images that corresponds to a respective new channel of the plurality of channels into an encoded intra frame ready for transmission to a client device to avoid a waterfall effect, the respective new channel of the plurality of channels being the indicated new channel from the channel change message.

26. The one or more electronically-accessible media as recited in claim 25, further comprising instructions that, when executed, direct the server to:

receive the channel change message that includes the indicated new channel from a client device.

27. The one or more electronically-accessible media as recited in claim 25, further comprising instructions that, when executed, direct the server to:

if the channel change message has been received from a client device, transmit the encoded intra frame to the client device.

28. The one or more electronically-accessible media as recited in claim 25, wherein a period at which the plurality of respective decoded images is provided equals approximately one-thirtieth ( 1/30) of a second.

29. A method for smoothing channel changing in a video broadcast environment, the method comprising actions of:

decoding a video data stream into a plurality of intra macroblocks, and amalgamating the plurality of intra macroblocks into a first decoded image;

holding the first decoded image during an image frame time slot;

decoding the video data stream into a plurality of intra macroblocks, and amalgamating the plurality of intra macroblocks into a second decoded image;

determining whether a channel change message has been received from a client device during the image frame time slot;

if so, to avoid a waterfall effect,

encoding the first decoded image into an intra frame of video data; and

sending the intra frame of video data to the client device.

30. The method as recited in claim 29, the method further comprising actions of:

if not,

holding the second decoded image during a subsequent image frame time slot; and

decoding the video data stream into a third decoded image.

31. The method as recited in claim 29, the method further comprising an action of:

receiving the channel change message from the client device, the channel change message including an indication of a new channel.

32. The method as recited in claim 29, the method further comprising an action of:

receiving the video data stream from a broadcast center, the video data stream comprising a digitally-encoded stream of video data that has been encoded on a macroblock basis.

33. The method as recited in claim 29, wherein the method is performed at a headend of a television-based entertainment network.

34. The method as recited in claim 29, wherein the action of decoding the video data stream into a second decoded image is performed during the image frame time slot.

35. The method as recited in claim 29, wherein the second decoded image immediately follows the first decoded image.

36. One or more electronically-accessible media comprising electronically-executable instructions that, when executed, direct one or more electronic systems to perform the method as recited in claim 29.

37. A method for a client device for smoothing channel changing, the method comprising actions of:

receiving a video data stream comprising a digitally-encoded stream of video data that has been encoded on a macroblock basis;

receiving a channel change input from a user, the channel change input ordering a change to a new channel;

sending a channel change message responsive to the channel change input, the channel change message including an indication of the new channel;

to avoid a waterfall effect, receiving an intra frame of broadcast video data for the new channel at least as a result of the action of sending the channel change message; and

receiving a plurality of macroblocks of broadcast video data for the new channel at least as a result of the action of receiving the channel change input from the user, the plurality of macroblocks of broadcast video data being decodable with reference to the intra frame of broadcast video data.

38. The method for a client device as recited in claim 37, the method further comprising actions of:

decoding the intra fame of broadcast video data; and

decoding the plurality of macroblocks of broadcast video data with reference to the intra frame of broadcast video data.

39. One or more electronically-accessible media comprising electronically-executable instructions that, when executed, direct a client device to perform the method as recited in claim 37.

40. A method for one or more nodes of a television-based entertainment network, the method comprising actions of:

receiving a stream of broadcast video data that is encoded on a macroblock basis for a particular channel;

continuously decoding the stream of broadcast video data into successive decoded images for a particular channel;

receiving a channel change massage from a client device, the channel change message indicating a new channel that corresponds to the particular channel; and

responsive to the channel change message receive from the client device;

transmitting towards the client device an intra frame that has been encoded from a decoded image of the successive decoded images, the intra frame comprising a complete frame that may be decoded by the client device without reference to any other frame or to macroblocks, thereby allowing the client device

to avoid a waterfall effect upon changing to the new channel; and

transmitting toward the client device the stream of broadcast video data that is encoded on a mcroblock bases.

41. The method for one or more nodes as recited in claim 40, the method comprising a further action of:

encoding the decoded image of the successive decoded images into the intra frame.

42. The method for one or more nodes as recited in claim 40, wherein the channel change message comprises at least one of a channel change request or a channel change notification.

43. The method for one or more nodes as recited in claim 40, wherein the intra frame covers an entire screen that is associated with the client device.

44. One or more electronically-accessible media comprising electronically-executable instructions that, when executed, direct one or more nodes to perform the method as recited in claim 40.

45. A system that is capable of smoothing channel changing in a video broadcast environment, the system comprising:

a receiver to receive a message that relates to a change to a new channel from a client device;

a decoder to decode a broadcast video stream into a plurality of intra macroblocks, and amalgamating the plurality of intra macroblocks into decoded images;

an encoder that is capable of encoding at least one of the decoded images into a complete frame; and

a transmitter that is capable of transmitting the complete frame to the client device;

wherein to avoid a waterfall effect the transmitter transmits the complete frame for the new channel responsive to receipt of the message that relates to the change to the new channel from the client device.

46. The system as recited in claim 45, wherein the system comprises an upstream node of a cable or satellite network.

47. The system as recited in claim 45, wherein the encoder is capable of encoding in accordance with a Moving Pictures Expert Group (MPEG)-compliant scheme.

48. The system as recited in claim 45, wherein the complete frame may be decoded by the client device without reference to any other frame.

49. The system as recited in claim 45, wherein the encoder encodes the at least one of the decoded images into the complete frame responsive to receipt of the message that relates to the change to the new channel from the client device.

50. The system as recited in claim 45, wherein the broadcast video stream is comprised of a plurality of sub-streams, each sub-stream of the plurality of sub-streams corresponding to a macroblock.