System for transmitting digital data through a lossy channel

• US 6,412,112 B1
• Filed: 02/08/1999
• Issued: 06/25/2002
• Est. Priority Date: 06/30/1998
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: WebTV Networks Inc. (Microsoft Corporation)
• Inventors: Barrett, Peter T., Wasserman, Steven C., Perlman, Stephen G.
• Primary Examiner(s): Faile, Andrew
• Assistant Examiner(s): Srivastava, Vivek
• Application Number:
  US09/246,275
• Time in Patent Office: 1,233 Days
• Field of Search: 709/717, 348/327, 348/13, 348/12, 348/20, 348/6, 348/906, 348/468, 455/5.1, 455/6.1, 455/6.2, 455/6.3, 455/3.1, 455/3.2, 725/63, 725/64, 725/67, 725/148, 725/143, 725/151, 725/152, 725/39, 725/54, 209/717, 345/329, 375/240.01, 375/240.12
• US Class Current: 725/152
• CPC Class Codes: H04H 20/40 Arrangements for broadcast specially adapted for accumulation-type receivers
• CPC Class Codes: H04H 20/42 Arrangements for resource management
• CPC Class Codes: H04H 20/74 of satellite networks
• CPC Class Codes: H04H 20/91 broadcasting computer programmes
• CPC Class Codes: H04H 20/95 characterised by a specific format, e.g. an encoded audio stream
• CPC Class Codes: H04H 2201/33 via the broadcast channel
• CPC Class Codes: H04H 40/09 Arrangements for receiving desired information automatically according to timetables
• CPC Class Codes: H04H 40/90 specially adapted for satellite broadcast receiving
• CPC Class Codes: H04H 60/72 using electronic programme guides [EPG] focusing on identifying broadcast space time H04H60/39 ; menu type display of EPG in television receivers H04N21/47
• CPC Class Codes: H04H 60/82 the transmission system being the Internet
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/235 Processing of additional data, e.g. scrambling of additional data or processing content descriptors
• CPC Class Codes: H04N 21/23614 Multiplexing of additional data and video streams arrangements for simultaneous broadcast of plural pieces of information H04H20/28
• CPC Class Codes: H04N 21/26241 involving the time of distribution, e.g. the best time of the day for inserting an advertisement or airing a children program
• CPC Class Codes: H04N 21/4143 embedded in a Personal Computer [PC]
• CPC Class Codes: H04N 21/4331 Caching operations, e.g. of an advertisement for later insertion during playback
• CPC Class Codes: H04N 21/4348 Demultiplexing of additional data and video streams
• CPC Class Codes: H04N 21/435 Processing of additional data, e.g. decrypting of additional data, reconstructing software from modules extracted from the transport stream
• CPC Class Codes: H04N 21/4383 Accessing a communication channel
• CPC Class Codes: H04N 21/4622 Retrieving content or additional data from different sources, e.g. from a broadcast channel and the Internet web site content organization and management for information retrieval from the Internet G06F16/958; transmission by internet of broadcast information H04H60/82; stock exchange data over packet-switching network H04L12/1804; push services including data channel over packet-switching network H04L12/1859
• CPC Class Codes: H04N 21/47202 : for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/4782 : Web browsing , e.g. WebTV
• CPC Class Codes: H04N 21/4786 : e-mailing message switching systems, e.g. electronic mail systems H04L51/00
• CPC Class Codes: H04N 21/482 : End-user interface for program selection broadcast systems using EPGs H04H60/72
• CPC Class Codes: H04N 21/6125 : involving transmission via Internet transmission by internet of broadcast information H04H60/82
• CPC Class Codes: H04N 21/6587 : Control parameters, e.g. trick play commands, viewpoint selection
• CPC Class Codes: H04N 7/083 : with signal insertion during the vertical and the horizontal blanking interval , e.g. MAC data signals
• CPC Class Codes: H04N 7/085 : the inserted signal being digital
• CPC Class Codes: H04N 7/088 : the inserted signal being digital
• CPC Class Codes: H04N 7/17327 : with deferred transmission or handling of upstream communications

Abstract

A system for distributing digital data over a video channel to a plurality of remotely located client terminals. The system involves selecting a set of digital data to be distributed and converting it to an intermediate format compatible with video broadcast. The intermediate data is then broadcast over a video channel during a time when no video content is being transmitted so that the intermediate format data takes the place of the video content. The intermediate format data is received at a remotely located client terminal where the set of digital data is recovered.

Claims

1. A method of transmitting digital data through an MPEG compressed video channel, comprising:

providing a set of digital data;

creating a mapping between the digital data in the set of digital data and MPEG run-level codes;

creating an MPEG data stream by converting the set of digital data into MPEG run-level codes using the mapping;

transmitting the MPEG data stream to a remote location;

generating an analog video signal from the MPEG data stream;

digitizing the analog video signal; and

processing the digitized analog video signal to extract the quantity of data.

2. The method of claim 1, wherein the step of processing includes applying a discrete cosine transform to blocks of pixels in the analog video signal to generate frequency coefficient-level pairs and applying an inverse mapping to the frequency coefficients-level pairs to recover the quantity of digital data.

3. The method of claim 1, wherein the mapping utilizes only low frequency coefficients.

4. The method of claim 3, wherein the mapping utilizes less than 10 levels for each frequency coefficient.

5. In a system using lossy compression to distribute digital data, a method for losslessly distributing digital data over a video channel of the system to a plurality of remotely located client terminals, the method comprising the acts of:

providing a set of digital data to be distributed;

encoding the set of digital data in an MPEG formatted data stream compatible with a video broadcast of the system, wherein the set of digital data is inserted after a lossy compression step of the system;

broadcasting the MPEG formatted data stream over the video channel at a predetermined time of the day when no video content is being transmitted over the video channel so that the MPEG formatted stream in which the set of digital data is encoded takes the place of the video content;

receiving the MPEG formatted data stream at the remotely located client terminals; and

recovering the set of digital data from the received intermediate format data by performing the acts of;

creating an analog video signal from the MPEG formatted data stream;

digitizing the analog video signal; and

extracting the set of digital data from the digitized video signal.

6. The method of claim 5, further comprising saving at least a portion of the set of digital data at the client terminals.

7. The method of claim 6, further comprising displaying information to a user of one of the client terminals, the displayed information corresponding to the saved portion of the set of digital data.

8. The method of claim 7 wherein the set of digital data is chosen from the group consisting of:

an electronic programming guide, software, advertisements, web pages and news.

9. The method of claim 5, wherein the act of broadcasting includes transmitting the MPEG formatted data stream over a digital satellite system.

10. The method of claim 9, wherein the act of encoding includes mapping the set of digital data into only low frequency components in the MPEG formatted data stream.

11. The method of claim 5, wherein a preselected number of bits of data from the set of digital data are encoded in each MPEG block of the MPEG formatted data stream.

12. The method of claim 5, further including configuring the client terminal to begin receiving the MPEG formatted data stream at a predetermined time and wherein the act of broadcasting begins at the predetermined time.

13. The method of claim 5, wherein the act of encoding includes the act of creating a mapping between MPEG run-level codes for pixel blocks and digital data bit patterns of predetermined bit length and applying the mapping to pieces of the digital data of the predetermined bit length.

14. The method of claim 13, wherein the act of creating a mapping includes selecting only a subset of coefficients and levels from all possible MPEG coefficients and levels to use in mapping digital data bit patterns.

15. The method of claim 14, wherein the mapping uses only a subset of the possible coefficient and level combinations within the subset of selected coefficients and levels.

16. A method of transmitting digital data over a channel, where all data transmitted over the channel is decompressed at a receiver using MPEG decompression, the method comprising:

encoding data to be transmitted in a form suitable for transmission over the channel by performing at least the steps of;

obtaining a quantity of digital data to be transmitted over the channel;

dividing the digital data into data blocks; and

encoding each of the data blocks in a sequence of Huffman codes corresponding to an MPEG pixel block, the encoded sequence being suitable for decoding upon reception at the receiver;

receiving the encoded data by the receiver and using an MPEG decompressor to decompress the received data and produce an analog video signal;

digitizing the analog video signal to identify portions of the analog video signal corresponding to MPEG pixel blocks;

determining MPEG coefficients and levels from the MPEG pixel blocks; and

recovering the encoded data by decoding the MPEG coefficients and levels.

17. A method of distributing digital data over a video channel to a plurality of remotely located client terminals, comprising:

providing a set of digital data to be distributed;

converting the set of digital data to an intermediate format data compatible with a video broadcast;

mapping the set of digital data into only low frequency components in the intermediate format data;

broadcasting the intermediate format data over the video channel at a predetermined time of the day when no video content is being transmitted over the video channel so that the intermediate format data takes the place of the video content, wherein the intermediate format data is an MPEG formatted data stream;

transmitting the intermediate format data over a digital satellite system;

receiving the intermediate format data at the remotely located client terminals;

recovering the set of digital data from the received intermediate format;

creating an analog video signal of the intermediate format data; and

digitizing the analog video signal and extracting the set of digital data from the digitized video signal.

18. In a client system included in a video broadcast system that also includes a plurality of other client systems, a method of extracting from a video channel a set of digital data that has been encoded and broadcast to the client system in an MPEG format, the method comprising the acts of:

receiving a video channel from the video broadcast system, wherein the video channel includes an MPEG formatted data stream in which a set of digital data has been encoded;

decoding the MPEG formatted data stream to obtain an analog video signal from the MPEG formatted data stream;

digitizing the analog video signal to obtain pixel data; and

extracting the set of digital data from the pixel data by performing the acts of;

dividing the pixel data into pixel blocks; and

using the frequency coefficients and levels associated with the pixel blocks to recover the set of digital data that has been encoded in the MPEG formatted data stream.

19. The method of claim 18, wherein the act of extracting the set of digital data is conducted by further performing the act of applying a discrete cosine transformation on the pixel blocks.

20. The method of claim 18, wherein the video broadcast system comprises a digital satellite system and the video channel is received by the client system from the digital satellite system.

21. The method of claim 18, wherein the act of dividing the pixel data into data blocks comprises the act of locating boundaries between the pixel blocks using pattern recognition.

22. The method of claim 18, wherein the act of dividing the pixel data into data blocks comprises the act of locating a boundary between the pixel blocks by measuring a predetermined time in the digital pixel data with respect to a left edge of a screen associated with the client system.

23. The method of claim 18, wherein the act of using the frequency coefficients and levels associated with the pixel blocks to recover the set of digital data comprises the act of using the frequency coefficients and levels to access a codebook having indices that represent portions of the set of digital data.