Video transmission system, transmission apparatus, display apparatus, video transmission method, and recording medium

A transmission apparatus that is included in a video transmission system and transmits a video stream, the video transmission system including a display apparatus that is separate from the transmission apparatus, receives the video stream, and displays a video represented by the video stream, and a controller,

• the transmission apparatus comprising:
• an encoder that performs encoding of a first video stream to generate a second video stream, the encoding causing a first bit rate of the first video stream to be a second bit rate lower than or equal to the first bit rate;
• and
• a transmitter that divides the second video stream into a plurality of transmission packets and transmits a plurality of packets including the plurality of transmission packets to the display apparatus via a network, wherein
• the transmission apparatus receives, from the controller, an instruction, which instructs the transmission apparatus to:
• (i) control the encoding performed by the encoder to reduce the second bit rate by a predefined amount or reduce the second bit rate at a transmission rate of a certain proportion;
• and
• (ii) cause the transmitter to transmit a plurality of dummy packets, along with the plurality of transmission packets, to the display apparatus via the network, and
• when transmitting the plurality of dummy packets along with the plurality of transmission packets, the transmitter transmits the plurality of transmission packets with priority over the plurality of dummy packets.

A display apparatus included in a video transmission system, the video transmission system including a transmission apparatus and a controller, the display apparatus being separate from a transmission apparatus, receiving a video stream, and displaying a video represented by the video stream,

• the display apparatus comprising:
• a receiver that receives a plurality of packets including a plurality of transmission packets from the transmission apparatus via a network;
• a decoder that generates a second video stream from the plurality of transmission packets and decodes a video for display from the second video stream;
• a display that displays the video for display;
• and
• a processor configured to determine whether packet loss has occurred, based on the plurality of packets received by the receiver, wherein
• when a determination result of the processor indicates that packet loss has occurred, the display apparatus transmits, to the controller, a first instruction, which instructs the controller to control the encoding performed by the transmission apparatus to reduce a second bit rate, which is a bit rate at which the second video stream is divided into the plurality of transmission packets, by a predefined amount or reduce the second bit rate at a transmission rate of a certain proportion;
• and
• when the determination result indicates that packet loss has not occurred for a predetermined time, the display apparatus:
• transmits, to the controller, a second instruction, which instructs the controller to cause the transmission apparatus to transmit a plurality of dummy packets, along with the plurality of transmission packets, to display apparatus via the network, and
• receives the plurality of transmission packets including (1) the plurality of dummy packets and (2) the plurality of transmission packets transmitted with priority over the plurality of dummy packets.

A video transmission method for a video transmission system, the video transmission system including a transmission apparatus that transmits a video stream, a display apparatus that is separate from the transmission apparatus and that receives the video stream and displays a video represented by the video stream, and a controller, the video transmission method comprising:

• by the transmission apparatus:
• performing encoding of a first video stream to generate a second video stream, the encoding causing a first bit rate of the first video stream to be a second bit rate lower than or equal to the first bit rate;
• and
• dividing the second video stream into a plurality of transmission packets and transmitting a plurality of packets including the plurality of transmission packets to the display apparatus via a network,
• by the display apparatus:
• receiving the plurality of packets;
• generating the second video stream from the plurality of transmission packets and decoding a video for display from the second video stream;
• displaying the video for display;
• and
• determining whether packet loss has occurred, based on the plurality of packets received, and
• by the controller:
• (i) controlling the encoding performed by the transmission apparatus to reduce the second bit rate by a predefined amount or reduce the second bit rate at a transmission rate of a certain proportion, when a determination result of the display apparatus indicates an occurrence of packet loss;
• and
• (ii) causing the transmission apparatus to transmit a plurality of dummy packets, along with the plurality of transmission packets, to the display apparatus via the network, when the determination result indicates that packet loss has not occurred for a predetermined time, wherein
• when transmitting the plurality of dummy packets along with the plurality of transmission packets, the transmission apparatus transmits the plurality of transmission packets with priority over the plurality of dummy packets.