WO2007036833A2

WO2007036833A2 - Method and apparatus for pausing a live transmission

Info

Publication number: WO2007036833A2
Application number: PCT/IB2006/053343
Authority: WO
Inventors: Srinivas Gutta; Mauro Barbieri
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2005-09-30
Filing date: 2006-09-18
Publication date: 2007-04-05
Also published as: WO2007036833A3

Abstract

Live transmission data, such as a live audio-visual program, is received and output, e.g. on as a television, step 205. If the user pauses the live transmission, the live data which continues to be received is stored in a memory, step 207. The audio visual features are extracted, step 209 and these are used to generate a summary, step 215 so that the user can view the summary to eliminate the time lag in returning to view the live program.

Description

Method and apparatus for pausing a live transmission

FIELD OF THE INVENTION

The present invention relates to rendering of live transmission data, e.g. broadcast or multicast data. In particular, it relates to recordal and playback of a live audiovisual program or live audio program which has been paused.

BACKGROUND OF THE INVENTION

Personal Video Recorder (PVR) based devices have become increasingly popular and there are now many devices available in the market. A few examples of these devices include the TiVo PVR from TiVo Inc., Sonic Blue from Panasonic, etc. One specific advantage other than having the ability to digitally record audio-visual programs, is the ability to pause live audio-visual programs.

During the course of watching the program, if the user temporarily has to attend to other things, then the user depresses a pause button thereby, the audio-visual live program is effectively paused. The PVR system then records the program from the moment the pause button is depressed. On return, the user has two options, either to watch the program that has been saved onto the PVR, that is to continue watching the program from the moment it was paused, or resume watching the program at the current time. If the user chooses the first option, then there is a lag time. This lag time could be quite irritating especially if the user is watching a live program such as a sporting event.

SUMMARY OF THE INVENTION

Therefore, it is desirable to provide a system which enables live broadcast data such as an audio-visual program to be paused, which eliminates the lag time inherent in existing video recorder systems such as PVRs. This is achieved by an aspect of the present invention which comprises a method of providing a service to a client, the client receiving live transmission data, the method comprising the steps of: enabling the client to submit a first command to indicate a start of a pause and to submit a second command to indicate an end of the pause; and upon receipt of the second command enabling the client to receive a summary of the live transmission data, said summary representing a time period which at least includes the pause. The method may be performed, for example, by a service provider or by software used on an electronic device. The method may comprise the step of providing the live transmission data to the client, but this is not required. This is also achieved by another aspect of the present invention which comprises a device for reproducing a live transmission, the device comprising: means for enabling a user to submit a first command to indicate a start of a pause and to submit a second command to indicate an end of the pause; and means for providing the user with a summary of the live transmission data upon receipt of the second command, said summary representing a time period which at least includes the pause.

The summary may be effectively generated using conventional methods. In the preferred embodiment, the summary is generated by extracting features from the received live multicast data and deriving the summary from the extracted features. The features may be extracted as part of the summary generation process if the live transmission data has been stored. In an alternative embodiment, only the extracted features are stored, while the live transmission data is not.

The summary may be generated of said received live transmission data from substantially the point at which the live transmission is paused, i.e. no summary will be generated for the part already seen by the viewer. Alternatively, the summary may be generated of said received live transmission data from substantially the start of said live transmission.

The summary may be generated of said received live transmission data up to the point when output of the live transmission data is resumed.

Alternatively, the summary may be generated of said received live transmission data up to the point when said second command is received.

Rendering of said summary may be started upon receipt of said second command.

Rendering of said received live transmission data may be resumed upon completion of rendering said summary. In the preferred embodiment, the user, on returning to view the live transmission, may have 3 options. Namely, continue to view the live transmission as it is received, view the live transmission from the point the transmission was paused in a time- shifted manner as in conventional recorder or view the summary. In viewing the summary, there will be a delay before the user resumes viewing the live transmission as it is received, therefore it would be preferable to continue generation of the summary up to the point when rendering of the live transmission is resumed.

In case that the video summary comprises still images (e.g. key- frames) simultaneously displayed as one poster/table of content, a certain amount of time may be necessary to allow the user to view it. During this time, incoming data may still be stored and analysed to generate new key- frames that are displayed over the previous ones until the user decides to switch to live incoming data.

BRIEF DESCRIPTION OF DRAWINGS For a more complete understanding of the present invention, reference is made to the following description taken in conjunction with the accompanying drawings, in which:

Figure 1 is a schematic block diagram of the apparatus according to a preferred embodiment of the present invention; and

Figure 2 is a flow diagram of the steps of the method according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to Figure 1, the video recorder or Personal Video Recorder (PVR) 100 comprises a receiver 101 for receiving incoming transmission data (for example incoming broadcast data, such as a live audio-visual program). The receiver 101 includes a first switch 103 and a second switch 105. The first and second switches 103, 105 are connected in series and each have a first position and a second position. The first switch 103 is connected to the input of the receiver 101 and hence the input of the PVR 100 and the second switch is connected to a rendering device 107, such as a television or the like. The first and second positions of the first and second switches 103, 105 define two paths. The first path connects the input of the receiver 101 and PVR 100 to the rendering device 107. The second path connects the input of a memory device 109 to the input of the receiver 101 and PVR 100 and the output of the memory device 109 to the rendering device 107. In the second path, the input of the receiver 101 and PVR 100 is also connected to a feature extractor 111. The output of the feature extractor 111 and memory 109 are connected to a summary generator 113. The output of the summary generator 113 is connected to the rendering device 107 via a third switch 115. The third switch 115 has an open position and a closed position. The receiver 101 may be designed to receive data of different formats. The data can be of any type, such as video broadcast, audio broadcast, Internet streaming, including streaming from one server to one client (for example video on demand), and peer- to-peer etc. Depending on the type of content, the rendering device 107 may include a demultiplexer, decoder, etc. The memory 109 may, for example, comprise a hard-disk drive, optical disk, etc. The feature extractor 111 has an associated memory (not shown here) which may, for example, comprise a RAM.

The operation of the PVR 100 of figure 1 is illustrated in the flow chart diagram of figure 2. During normal mode of operation, the first and second switches 103, 105 are in their respective first positions and the third switch is in its open position such that the input of the receiver 101 is connected to the receiving device 107. In this way the user views the live broadcast as it is received, step 205. When the user has to leave watching the live broadcast (or live program) for one reason or other, he depresses the pause button, step 203, which may be located on the device itself or on an associated remote control device. Upon detection of receipt of a pause command, the first switch 103 switches to its second position such that the input of the receiver 101 is connected to the memory 109 and the feature extractor 111. The audio-visual live program is recorded and stored in memory 109, step 207. The low, mid and high level audio-visual features of the live program are extracted by the feature extractor 111, step 209, using a known algorithm such as shot cut detection, overlaid text detection, motion activity extraction, etc. as, for example, disclosed in Dimitrova N. et al., "Applications of Video-Content Analysis and Retrieval", IEEE Multimedia 2002, pp. 42 - 55, volume 9, Issue 3, 2002. Features are stored in the associated memory of the extractor 111 along with any additional information that is available (e.g. closed captions), step 211. This process continues whilst the pause mode of operation is activated. If the user depresses a summary button, step 213, the summary generator 113 generates a summary of the stored live program using the extracted features stored in the associated memory of the extractor 111, step 215. The third switch switches to its closed position so that the summary can be forwarded and output by the rendering device 107, step 217. Once the summary has been viewed, the PVR switches to its normal mode of operation, step 219, and forwards the incoming data (live audio-visual program) to the rendering device 107.

If the summary button is not depressed, step 213, and the pause button is depressed, step 221. The second switch 105 switches to its second position and the PVR continues the live program from the moment the pause has activated by playing back the live program stored in the memory 109 in a time-shifted manner on the rendering device 107, step 223.

On returning to view the program, the user may request to view the live program from that moment and skip the paused portion of the program. This is achieved by the first and second switches returning to their respective first positions and the third switch returning to its open position.

Any summarization algorithm known from the state-of-the-art can be used to produce the video summary, for example, selection of key- frames, video highlights, video skim, etc.). An overview of summarization types and methods are disclosed in Barbieri M., Agnihotri L., Dimitrova N., "Video Summarization: Methods and Landscape", Proc. of SPIE Int. Conf. on Internet Multimedia Management Systems IV, ITCom 2003, Orlando, FL, USA, 7-11 September 2003. While outputting the summary, incoming data can still be stored, analysed and included in the summary so that when the summary is finished the user has caught up with the live broadcast and can then continue to view it in real time In case that the video summary comprises still images (e.g. key- frames) simultaneously displayed as one poster/table of content, a certain amount of time is necessary to allow the user to view it. During this time, incoming data is still stored and analysed to generate new key- frames that are displayed over the previous ones until the user decides to switch to live incoming data, by pressing again the summary button. Therefore, the summarization algorithm may continue to summarize the live broadcast until viewing of the live broadcast is resumed to allow time for the user to view the summary. The user may then choose to view the summary in full or may elect to resume viewing the live broadcast at any time.

Although a preferred embodiment of the present invention has been illustrated in the accompanying drawings and described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiment disclosed, but is capable of numerous modifications without departing from the scope of the invention as set out in the following claims. For example, instead of requiring a user to press a special summary button, a summary may be rendered automatically when the user presses the pause button while the live transmission is in a pause state. In this case, the summary functionality replaces a time- shift functionality.

Claims

1. A method of providing a service to a client, the client receiving live transmission data, the method comprising the steps of: enabling the client to submit a first command to indicate a start of a pause and to submit a second command to indicate an end of the pause; and upon receipt of the second command enabling the client to receive a summary of the live transmission data, said summary representing a time period which at least includes the pause.

2. A method according to claim 1, further comprising the steps of: extracting features from said received live transmission data; deriving said summary from said extracted features; and providing said summary to the client.

3. A method according to claim 1 or 2, wherein the summary is generated of said received live transmission data from substantially the point at which the live transmission is paused.

4. A method according to any of claims 1 or 2, wherein the summary is generated of said received live transmission data from substantially the start of said live transmission.

5. A method according to any one of claims 1 to 4, wherein the summary is generated of said received live transmission data up to the point when output of the live transmission data is resumed.

6. A method according to any one of claims 1 to 4, wherein the summary is generated of said received live transmission data up to the point when said second command is received.

7. A method according to any one of the preceding claims, further comprising the step of enabling rendering of said summary to be started upon receipt of said second command.

8. A method according to any one of the preceding claims, further comprising the step of enabling rendering of said live transmission to be resumed upon completion of rendering said summary.

9. A method according to any one of the preceding claims, wherein said summary comprises still images.

10. A device for reproducing a live transmission, the device comprising: means for enabling a user to submit a first command to indicate a start of a pause and to submit a second command to indicate an end of the pause; and means for providing the user with a summary of the live transmission data upon receipt of the second command, said summary representing a time period which at least includes the pause.

11. A device according to claim 10, further comprising: an extractor for extracting features from said received live transmission data; and a processor for deriving the summary from said extracted features.

12. A computer program product comprising a plurality of program code portions for carrying out the method according to any one of claim 1 to 9.