Terminal used in video transmission system

• US 20040264563A1
• Filed: 04/30/2004
• Published: 12/30/2004
• Est. Priority Date: 11/05/2001
• Status: Abandoned Application

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Sato, Masaki, Senga, Satoshi, Komiya, Daisaku, Takeshita, Sachiko, Inoue, Akino, Oka, Toshio
• Application Number:
  US10/494,430
• Publication Number:
  US 20040264563A1
• Time in Patent Office: Days
• US Class Current: 375/240.01
• CPC Class Codes: H04N 21/41407 embedded in a portable device, e.g. video client on a mobile phone, PDA, laptop constructional details of equipment or arrangements specially adapted for portable computer application G06F1/1626; arrangements specially adapted for mobile receivers in broadcast systems H04H20/57
• CPC Class Codes: H04N 21/4402 involving reformatting operations of video signals for household redistribution, storage or real-time display details of conversion of video standards at pixel level H04N7/01; video transcoding H04N19/40; adapting incoming signals to the display format of the display terminal G09G5/005; media handling at the source in data packet switching networks H04L65/764
• CPC Class Codes: H04N 21/44209 Monitoring of downstream path of the transmission network originating from a server, e.g. bandwidth variations of a wireless network arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896
• CPC Class Codes: H04N 21/4788 communicating with other users, e.g. chatting arrangements for providing for computer conferences, e.g. chat rooms, to substation in data switching networks H04L12/1813; distributed application using peer-to-peer [P2P] networks H04L67/104
• CPC Class Codes: H04N 21/6131 involving transmission via a mobile phone network wireless downlink channel access H04W74/006
• CPC Class Codes: H04N 21/643 Communication protocols network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP], H04L65/65
• CPC Class Codes: H04N 21/658 Transmission by the client directed to the server
• CPC Class Codes: H04N 7/14 Systems for two-way working H04N7/12, H04N7/173 take precedence
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 76/30 Connection release

Abstract

Provided is a terminal unit that, even in case video image is suspended by a handover, video reproduction is possible real-time at immediately after an end of the handover. In a video transmission system comprising a wireless LAN accommodated switch for switching over the connection relationship of a terminal unit and an access point, an access point for receiving video data sent from a terminal unit and sending it to another terminal unit, and a terminal unit for receiving video data sent from the access point thereby displaying a video image and carrying out an association establishment or release of a wireless channel to an access point, the terminal unit operates such that, when a calling party releases a wireless channel, the opposite terminal unit determines that the calling party has started a handover and makes an operation to change a video data encoding into an intra-frame encoding.

Claims

1. A terminal unit for sending/receiving video data to/from another terminal unit through an access point an association is established, the terminal unit comprising:

a video data reception status monitoring section for monitoring, packet by packet, a reception status of video data sent from an access point an association is established;

an association establishment status detecting section for detecting a release or association establishment of a wireless channel by the other terminal unit; and

a video data encoding section for encoding video data to be sent to the other terminal unit, under any of an intra-frame encoding or a inter-frame encoding;

whereby the association establishment status detecting section, before the wireless channel is released, instructs the video data encoding section to change the post-release video data encoding for sending to the other terminal unit into an intra-frame encoding, and the other terminal unit to encode the post-release video data under the intra-frame encoding.

2. A terminal unit according to claim 1, wherein the association establishment status detecting section

instructs the video data encoding section to change the video data encoding for sending to the other terminal unit into a inter-frame encoding and the other terminal unit to encode the post-association-establishment video data under the inter-frame encoding, if an association is established with another access point after releasing of the wireless channel.

3. A terminal unit for sending/receiving video data to/from another terminal unit through an access point an association is established, the terminal unit comprising:

a wireless channel releasing section for releasing a wireless channel with an access point an association is established;

a release notifying section for notifying the other terminal unit of a release of a wireless channel;

a wireless channel association establishing section for establishing a new association of a wireless channel with another access point;

an association establishment notifying section for notifying the other terminal unit of an association established with another access point; and

a notification receiving section for receiving a notification from a release notifying section or an association establishing section possessed by the other terminal unit;

whereby the notification receiving section instructs the video data encoding section to encode video data under an intra-frame encoding, when receiving a notification showing a release of a wireless channel.

4. A terminal unit according to claim 3, wherein the notification receiving section further

instructs the video data encoding section to encode video data under a inter-frame encoding, when receiving a notification showing a association established.