KR20150103789A - Contents prefetch scheme based on ip multicast for seamless screen switching - Google Patents

Abstract

Disclosed is a contents prefetch method based on an IP multicast for a seamless screen switching. An N screen system is composed of a smart phone, a content server, an N screen support smart device, and a sensor. A set-top box buffers image content data by transmitting the image content data to a screen switching candidate device to perform the seamless screen switching.

Description

TECHNICAL FIELD [0001] The present invention relates to an IP multicast-based content pre-

The following embodiments are directed to techniques for seamless switching of screens.

The N-Screen service, derived from AT & T's 3-Screen Play Service, allows users to seamlessly access the same content or service anytime, anywhere, on any device. The 3-screen enables users to use multimedia contents in mobile, TV and PC environments. Currently, various display devices such as tablets and game consoles have been added to the service, which has been redefined as an expanded N-screen service.

The N-Screen service is a smart-time killer service that provides various contents and services to various wired and wireless devices owned by individuals as broadcasting services are bidirectionally, converged, personalized, and intelligent.

As the number of devices capable of playing back content is increasing, users are increasingly demanding to play back the same content that they own on various devices or share with others.

It is essential to develop computing technology that can provide real-time video service through interfacing interface between smart devices, content streaming and related shared services, and cross-screen.

A key element of the N-Screen service is a platform that mediates the same content or services across multiple devices. To this end, it is essential to have an interface with a content provider, a synchronization technology between display devices, and a cloud technology capable of providing contents to various devices.

IP multicast is a one-to-many communication technology through the IP infrastructure on the network. By transmitting the same data to all people participating in a specific group with one Internet address, the network bandwidth is efficiently used by transmitting the packet only once from the content provider. Therefore, when a plurality of receivers connect to a specific server at a time It is possible to reduce server traffic experienced when receiving large-capacity multimedia contents.

IP multicast includes Internet Group Management Protocol (IGMP), so that a host can join or leave a multicast group and manage group membership information. In other words, the multicast transmission scheme is a transmission scheme that effectively prevents the waste of network resources due to the redundant data transmission and efficiently assures real-time collaborative work without imposing burden on the information that does not require the information.

OMA (Open Mobile Alliance) is a mobile content exchange (SCE) that supports the use of content without disruption in various devices by sharing the right to use content after domain configuration between home devices. SRM (Secure Removable Memory) is proposed to support seamless use of content on media [3].

Apple has launched a variety of screen line-ups for its N-Screen strategy by launching Apple TV. Apple offers a variety of screens ranging from iPods, iPhones, iPads, Macintosh PCs and iTVs to all of these display devices with MobileMe, a service that allows users to synchronize all their content on all screens [4] .

SKT has launched an 'N-Screen' service called 'Hoppin' that enables users to watch content on mobile devices, PCs and TVs. Hoppin service is characterized in that a smartphone in which a content is stored in a terminal dedicated to a service of a Hoppin service connected to a TV is physically connected and a smartphone is set up as a set-top box to provide a content streaming service [5].

KT has released 'Playy' service that supports N-Screen service without a dedicated terminal. Using the cloud service of the company, it is possible to enjoy the contents continuously by maintaining the reproduction point even if the contents are moved to the other display device by using the streaming or the file downloading method.

In the case of multicast, it is possible to solve the network efficiency degradation caused by a single sender transmitting the same data to multiple receivers redundantly. There are mainly streaming media (audio / video, live internet lectures), shared data applications (video conferencing), and interactive games (multiplayer games). And as the spread of smart devices grows, the use of such applications increases in wireless networks, and multicast usage is required. Multicast-based content delivery provides better quality of service to multiple devices without requiring additional load on the server.

In the conventional inter-display-device interworking technique, a user physically connects display devices to use the N-screen service or receives streaming data from a server in a continuous manner from a specific portion of contents.

In case of a physical connection between the devices, it is troublesome to connect the device so that the actual screen switching occurs after the user requests the N-screen service, the time of the physical connection action of the user, latency time in the execution of the corresponding service application, Occurs.

The seamless connection of the content provided by the existing N-screen service means that the playback frame information of the content being used is transmitted to another display device so that the content is played back accurately from the next frame of the frame that has been played back, Can be easily reproduced without complicated procedures, and real-time screen switching service between devices can not be provided.

When a large amount of multimedia contents is received from a cloud server, the delay time due to screen switching may become longer due to the buffering time.

In the Open Mobile Alliance (OMA), in order to reduce the screen switching time, the same content was previously stored for each display device, and the screen switching was performed quickly by synchronizing only the playback time. This allows for seamless screen switching, but the use of storage space is inefficient because the user may not use the content previously downloaded.

The existing N-Screen service is not smooth streaming of content, so playback stops in the midst of content playback, and sound and image quality deteriorate. Which is inconvenient for users. The inconvenience that the nature of the N-screen service is not fully realized is an obstacle to the spread and development of the N-screen.

The existing N - Screen service selects nearby devices that are highly likely to switch screens for continuous content playback and delivers some content to these devices. This may result in degradation of network efficiency and transmission delay caused by duplicating one and the same content to multiple recipients. In addition, there is a disadvantage in that the content server transmits the content without considering the resolution supported by the display of each device, and the transmission speed is also slow because the content is not transcoded.

The purpose of the following embodiments is to perform seamless screen switching.

According to the following embodiments, a screen switching technique is provided.

According to the following embodiments, it is possible to perform seamless screen switching.

1 is a diagram illustrating an embodiment of receiving content according to resolution of each device.
2 is a flowchart of an IP multicast-based content prefetch technique for seamless switching.

FIG. 1 shows an example of receiving content according to a resolution of a device through a device configuration and a multicast technique for selecting a context-based screen transition candidate device proposed in the present invention. The N screen system consists of a smart phone, a content server, a smart device with N screen, and a sensor. Each smart device and sensor has an intelligence module.

If a user who has a smartphone appears in the AP recognition range, it transmits its own IP address to a content server that does not know the existence of the smartphone. If the user passes near the sensor installed in every place in the house, And notifies the movement of the user to the position of the nearby smart device through the broadcast message of the position. The smart device that receives the message via the home location requests the IP address of the smart phone to the content server, and receives the IP address of the smart phone to connect with the smart phone. It informs the smartphone that it is a smart device having a possibility of conversion and requests to register itself in the device list. The smart phone sends the smart device that has transmitted the message to the content server to request the transmission, and each smart device requests the router to join the multicast group.

The set-top box transmits the image content data to the screen switching candidate device so that the screen switching can be performed without interruption.

1 is a diagram illustrating an embodiment of receiving content according to resolution of each device.
2 is a flowchart of an IP multicast-based content prefetch technique for seamless switching.

Claims (1)

Screen switching technique.

Images