Video data transmission
AssigneeNokia Mobile Phones Ltd.
InventorERKKO LEHTONEN
Life of this patent
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Abstract
A video data transmission system in which a transmission terminal (1) having a colour camera (4) is required to transmit video information to a reception terminal (3) having only a black and white display (7). In order to minimise the transmission bit-rate, during a set-up process the reception terminal (3) sends a “LuminanceOnly” flag to the transmission terminal (1) advising the transmission terminal to send only the luminance component of the video signal generated by the colour camera (4). The chrominance components generated by the camera (4) are either discarded or encoded as null data prior to transmission.
Claims12
A method of transmitting video data from a first to a second terminal over a transmission channel, the method comprising the steps of:
- providing at said first terminal a video signal having luminance (Y) and chrominance components (U,V);
- in the event that chrominance components are not required by the second terminal, transmitting from the second terminal to the first terminal a control message indicating that only the luminance (Y) component of said video signal should be transmitted to the second terminal;
- and
- upon receipt of said control message at the first terminal, transmitting from the first terminal to the second terminal only the luminance component (Y) of the video signal.
A method according to any one of the preceding claims and comprising using a colour video camera to provide said video signal to the first terminal, and providing the transmitted luminance component to a black and white display coupled to the second terminal.
A method according to any one of the preceding claims and comprising transmitting a further control message, from the second to the first terminal, subsequent to the transmission of the first mentioned control message, indicating that the luminance (Y) and chrominance (U,V) components of said video signal should be transmitted to the second terminal.
Apparatus for transmitting video data over a transmission channel (2), the apparatus comprising:
- a first terminal (1) arranged to receive a video signal having luminance (Y) and chrominance components (U,V);
- and
- a second terminal (3) arranged to transmit therefrom, to said first terminal (1), a control message indicating that only the luminance (Y) component of said video signal should be transmitted to the second terminal (3),
- said first terminal (1) being further arranged to transmit to the second terminal only the luminance component (Y) of the video signal, upon receipt of said control message.
A method of transmitting video data between a first and a second terminal over a transmission channel, the method comprising the steps of:
- exchanging flags between the first and second terminals to notify each terminal of the capability of the other terminal to transmit and receive image data with and without chrominance components;
- transmitting video data from the first to the second terminal, and/or vice versa, on the basis of the exchanged flags.
Dependencies are inferred from the claim text.