Video communication method having refresh function of coding sequence and terminal devices thereof
First Claim
1. A video communication method for performing communication of coded video information between a sending terminal and a receiving terminal connected to each other via a network, the video communication method comprising the steps of:
- converting, in the sending terminal, successive video frames into respective coded video frames according to a coding sequence, the coding sequence being periodically repeated and including a first coding mode wherein an initial video frame of the successive video frames is converted into an INTRA frame representative of only the initial video frame, and a second coding mode wherein remaining video frames of the successive video frames are converted into respective INTER frames each representative of a difference between a respective one of the successive video frames and a preceding one of the successive video frames;
transmitting, in the sending terminal, the coded video frames to the receiving terminal via the network;
detecting, in the receiving terminal, whether any portion of the transmitted coded video frames has been lost in transmission;
transmitting, in the receiving terminal, to the sending terminal via the network, a refresh request requesting the sending terminal to refresh a current coding sequence when it is detected that a portion of the transmitted coded video frames has been lost in transmission; and
refreshing, in the sending terminal, in response to the transmitted refresh request, a current coding sequence by interrupting the current coding sequence and beginning a new coding sequence, thereby causing a next coded video frame transmitted to the receiving terminal via the network to be an INTRA frame.
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Accused Products
Abstract
In a video communication system including a sending terminal and a receiving terminal connected via a packet switching network, a receiving terminal which has detected loss of a video packet sets a video output into a freeze status and transmits a refresh request command to the sending terminal. Upon receiving the refresh request command, the sending terminal requests a video coder unit to execute refreshing and transmits a series of video packets beginning from an INTRA frame. Upon receiving a packet of the INTRA frame, the receiving terminal releases the freeze status and restarts video information decoding.
192 Citations
21 Claims
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1. A video communication method for performing communication of coded video information between a sending terminal and a receiving terminal connected to each other via a network, the video communication method comprising the steps of:
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converting, in the sending terminal, successive video frames into respective coded video frames according to a coding sequence, the coding sequence being periodically repeated and including a first coding mode wherein an initial video frame of the successive video frames is converted into an INTRA frame representative of only the initial video frame, and a second coding mode wherein remaining video frames of the successive video frames are converted into respective INTER frames each representative of a difference between a respective one of the successive video frames and a preceding one of the successive video frames; transmitting, in the sending terminal, the coded video frames to the receiving terminal via the network; detecting, in the receiving terminal, whether any portion of the transmitted coded video frames has been lost in transmission; transmitting, in the receiving terminal, to the sending terminal via the network, a refresh request requesting the sending terminal to refresh a current coding sequence when it is detected that a portion of the transmitted coded video frames has been lost in transmission; and refreshing, in the sending terminal, in response to the transmitted refresh request, a current coding sequence by interrupting the current coding sequence and beginning a new coding sequence, thereby causing a next coded video frame transmitted to the receiving terminal via the network to be an INTRA frame. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A video communication method for performing communication of coded video information between a sending terminal and a plurality of receiving terminals connected to each other via a network, the video communication method comprising the steps of:
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converting, in the sending terminal, successive video frames into respective coded video frames according to a coding sequence, the coding sequence being periodically repeated and including a first coding mode wherein an initial video frame of the successive video frames is converted into an INTRA frame representative of only the initial video frame, and a second coding mode wherein remaining video frames of the successive video frames are converted into respective INTER frames each representative of a difference between a respective one of the successive video frames and a preceding one of the successive video frames; transmitting, in the sending terminal, the coded video frames to the receiving terminals via the network; detecting, in each of the receiving terminals, whether any portion of the transmitted coded video frames has been lost in transmission; transmitting, in each of the receiving terminals, to the sending terminal via the network, a refresh request requesting the sending terminal to refresh a current coding sequence when it is detected that a portion of the transmitted coded video frames has been lost in transmission; monitoring, in the sending terminal, a time interval which has elapsed since a refresh request was last received in the sending terminal; disregarding, in the sending terminal, a refresh request which has just been received in the sending terminal, if the time interval which has elapsed since a refresh request was last received in the sending terminal is less than a predetermined time interval; and refreshing, in the sending terminal, in response to the refresh request which has just been received in the sending terminal, a current coding sequence by interrupting the current coding sequence and beginning a new coding sequence, thereby causing a next coded video frame transmitted to the receiving terminals via the network to be an INTRA frame, if the time interval which has elapsed since a refresh request was last received in the sending terminal is not less than the predetermined time interval. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A receiving terminal for receiving coded video information from a sending terminal via a network, the receiving terminal comprising:
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receiving means for receiving, from the network, coded video frames transmitted to the network by the sending terminal, the sending terminal having generated the coded video frames by converting successive video frames into respective ones of the coded video frames according to a coding sequence, the coding sequence being periodically repeated and including a first coding mode wherein an initial video frame of the successive video frames is converted into an INTRA frame representative of only the initial video frame, and a second coding mode wherein remaining video frames of the successive video frames are converted into respective INTER frames each representative of a difference between a respective one of the successive video frames and a preceding one of the successive video frames; decoding means for decoding the received coded video frames; detecting means for detecting, based on the received coded video frames, whether any portion of the transmitted coded video frames has been lost in transmission; and transmitting means for transmitting, to the network, a refresh request requesting the sending terminal to refresh a current coding sequence when the detecting means detects that a portion of the transmitted coded video frames has been lost in transmission, the refresh request causing the sending terminal to refresh a current coding sequence by interrupting the current coding sequence and beginning a new coding sequence, thereby causing a next coded video frame transmitted to the network to be an INTRA frame. - View Dependent Claims (21)
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Specification