A video encoding method of performing scalable encoding on input video includes: determining a total number of layers of the scalable encoding to be less than or equal to a maximum layer count determined according to a frame rate; and performing the scalable encoding on the input video to generate a bitstream, using the determined total number of layers.

A video encoding method of performing scalable encoding on input video includes: determining a total number of layers of the scalable encoding to be less than or equal to a maximum layer count determined according to a frame rate; and performing the scalable encoding on the input video to generate a bitstream, using the determined total number of layers.

A video decoder may be configured to output layers of video data according to layers specified in an output layer set mode as well as based on the actual layers received in an access unit. Accordingly, the video coder may be configured to output layers actually received rather than restart a video bitstream in situations where the layers actually received do not match the layers specified in the output layer set mode. In another example, a video encoder may disable inter prediction when the sub-picture ID of a sub-picture in a currently coded picture does not match the sub-picture ID of a sub-picture in a reference picture.

A video decoder may be configured to output layers of video data according to layers specified in an output layer set mode as well as based on the actual layers received in an access unit. Accordingly, the video coder may be configured to output layers actually received rather than restart a video bitstream in situations where the layers actually received do not match the layers specified in the output layer set mode. In another example, a video encoder may disable inter prediction when the sub-picture ID of a sub-picture in a currently coded picture does not match the sub-picture ID of a sub-picture in a reference picture.

A method by which a decoding device decodes an image, according to the present document, comprises the steps of: acquiring image information including decoded picture buffer (DPB) parameter information and an output layer set (OLS) DPB parameter index for a target OLS; deriving the DPB parameter information about the target OLS on the basis of the OLS DPB parameter index; updating a DPB on the basis of the DPB parameter information about the target OLS; and decoding the current picture on the basis of the updated DPB.

A method by which a decoding device decodes an image, according to the present document, comprises the steps of: acquiring image information including decoded picture buffer (DPB) parameter information and an output layer set (OLS) DPB parameter index for a target OLS; deriving the DPB parameter information about the target OLS on the basis of the OLS DPB parameter index; updating a DPB on the basis of the DPB parameter information about the target OLS; and decoding the current picture on the basis of the updated DPB.

Systems, apparatuses, and methods for utilizing different modulation coding schemes (MCSs) for different components of a video stream are disclosed. A system includes a transmitter sending a video stream over a wireless link to a receiver. The transmitter splits the video stream into low, medium, and high quality components, and then the transmitter modulates the different components using different MCS's. For example, the transmitter modulates the low quality component using a lower, robust MCS level to increase the likelihood that this component is received. Also, the medium quality component is modulated using a medium MCS level and the high frequency component is modulated using a higher MCS level. If only the low quality component is received by the receiver, then the receiver reconstructs and displays a low quality video frame from this component, which avoids a glitch in the display of the video stream.

Systems, apparatuses, and methods for utilizing different modulation coding schemes (MCSs) for different components of a video stream are disclosed. A system includes a transmitter sending a video stream over a wireless link to a receiver. The transmitter splits the video stream into low, medium, and high quality components, and then the transmitter modulates the different components using different MCS's. For example, the transmitter modulates the low quality component using a lower, robust MCS level to increase the likelihood that this component is received. Also, the medium quality component is modulated using a medium MCS level and the high frequency component is modulated using a higher MCS level. If only the low quality component is received by the receiver, then the receiver reconstructs and displays a low quality video frame from this component, which avoids a glitch in the display of the video stream.

The present disclosure discloses a video encoding and decoding method, apparatus and system, where the video encoding method includes: determining an independently decodable view in a to-be-encoded picture according to a configuration file corresponding to the video; dividing the picture into at least two tiles, where an area corresponding to one or more tiles that cover the independently decodable view is an independently decodable area; generating an auxiliary message corresponding to the picture, where the auxiliary message includes a location identifier of the independently decodable area; and encoding all tiles included in the picture to form an encoded video bitstream, where the encoded video bitstream includes the auxiliary message. Decoding this encoded video bitstream can lower a requirement for performance of a decoder and improve decoding efficiency.

Techniques and tools for encoding enhancement layer video with quantization that varies spatially and/or between color channels are presented, along with corresponding decoding techniques and tools. For example, an encoding tool determines whether quantization varies spatially over a picture, and the tool also determines whether quantization varies between color channels in the picture. The tool signals quantization parameters for macroblocks in the picture in an encoded bit stream. In some implementations, to signal the quantization parameters, the tool predicts the quantization parameters, and the quantization parameters are signaled with reference to the predicted quantization parameters. A decoding tool receives the encoded bit stream, predicts the quantization parameters, and uses the signaled information to determine the quantization parameters for the macroblocks of the enhancement layer video. The decoding tool performs inverse quantization that can vary spatially and/or between color channels.