# US 2014/0153640 A1 · Adaptive single-field/dual-field video encoding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153640 A1 - Document ID: US20140153640A1 - Status: Published application - Kind: A1 - Application number: 13/705,422 - Filed: 2012-12-05 - Published: 2014-06-05 - Earliest claimed: 2012-12-05 - Assignees: ViXS Systems, Inc. - Inventors: Xu Gang Zhao; Ying Li - Web page: https://patentgrep.com/patent/US20140153640A1 ## CPC - H04N 19/112: according to a given display mode, e.g. for interlaced or progressive display mode - H04N 19/149: by estimating the code amount by means of a model, e.g. mathematical model or statistical model - H04N 19/172: the region being a picture, frame or field - H04N 19/124: Quantisation - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A video processing device includes an interface to receive an input video stream and an interface to provide an encoded video stream. The input video stream includes a sequence of frames. Each frame comprises two fields. The video processing device further includes an encoder to encode the input video stream to generate the encoded video stream. The encoder is to dynamically switch between a first encoding mode and a second encoding mode responsive to a variable quantization parameter. In the first encoding mode the encoder is to encode both fields or the complete frame of a corresponding frame of the sequence. In the second encoding mode the encoder is to encode only one field of the two fields of a corresponding frame of the sequence. This approach can achieve a specified low bit rate with reduced quantization effects while keeping the horizontal resolution unchanged. ## Claims ### Claim 1 A method comprising: encoding an input video stream at a video processing device based on a variable quantization parameter to generate an encoded video stream, the input video stream comprising a sequence of frames, each frame comprising two fields, wherein the encoding comprises: encoding only one field of the two fields of each frame of a first subsequence of the sequence of frames for the encoded video stream responsive to the quantization parameter exceeding a first threshold. ### Claim 2 (depends on 1) The method of claim 1, wherein encoding only one of the two fields of each frame of the first subsequence comprises: encoding picture data of a first field of each frame of the first subsequence to generate encoded picture data for inclusion in the encoded video stream; and inserting skip coding information into the encoded video stream in place of encoded picture data for a second field of each frame of the first subsequence. ### Claim 3 (depends on 2) The method of claim 2, further comprising: decoding the encoded video stream, wherein the decoding includes: decoding the encoded picture data to generate a decoded representation of the first field of each frame of the first subsequence; and replicating the decoded representation of the first field of each frame of the as a decoded representation of the second field of the frame. ### Claim 4 (depends on 1) The method of claim 1, wherein the encoding further comprises: encoding both fields of each frame of a second subsequence of the sequence of frames for the encoded video stream responsive to the quantization parameter falling below a second threshold. ### Claim 5 (depends on 4) The method of claim 4, wherein the first threshold and the second threshold are the same threshold. ### Claim 6 (depends on 4) The method of claim 4, wherein the first threshold is greater than the second threshold. ### Claim 7 (depends on 4) The method of claim 4, wherein encoding both fields of each frame comprises encoding both fields using picture adaptive frame field (PAFF) encoding. ### Claim 8 A method of encoding an input video stream, the method comprising: dynamically switching between a first encoding mode and a second encoding mode at a video processing device responsive to a variable quantization parameter, wherein: the input video stream comprises a sequence of frames, each frame comprising two fields; the first encoding mode comprises encoding both fields of a corresponding frame of the sequence; and the second encoding mode comprises encoding only one field of the two fields of a corresponding frame of the sequence. ### Claim 9 (depends on 8) The method of claim 8, wherein dynamically switching between the first encoding mode and the second encoding mode comprises: switching to the second encoding mode at the video processing device responsive to the quantization parameter exceeding a first threshold. ### Claim 10 (depends on 9) The method of claim 9, wherein dynamically switching between the first encoding mode and the second encoding mode further comprises: switching to the first encoding mode at the video processing device responsive to the quantization parameter falling below a second threshold. ### Claim 11 (depends on 8) The method of claim 8, wherein the first encoding mode further comprises selecting between a frame-based encoding sub-mode and a field-based encoding sub-mode for a corresponding frame based on a motion analysis between the two fields of the corresponding frame. ### Claim 12 (depends on 8) The method of claim 8, wherein dynamically switching between the first encoding mode and the second encoding mode comprises delaying a switch between the first encoding mode and the second encoding mode at the video processing device until a specified switch point. ### Claim 13 (depends on 12) The method of claim 12, wherein the specified switch point comprises at least one selected from a group consisting of: a scene boundary; a group of pictures (GOP) boundary; a miniGOP boundary; and a minimum distance condition from a previous switch between the first encoding mode and the second encoding mode. ### Claim 14 (depends on 8) The method of claim 8, further comprising: decreasing the quantization parameter responsive to switching to the second encoding mode. ### Claim 15 A video processing device comprising: an interface to receive an input video stream, the input video stream comprising a sequence of frames, each frame comprising two fields; and an encoder to encode the input video stream to generate an encoded video stream, wherein the encoder is to dynamically switch between a first encoding mode and a second encoding mode responsive to a variable quantization parameter, wherein: in the first encoding mode the encoder is to encode both fields of a corresponding frame of the sequence; and in the second encoding mode the encoder is to encode only one field of the two fields of a corresponding frame of the sequence. ### Claim 16 (depends on 15) The video processing device of claim 15, wherein the encoder is to dynamically switch between the first encoding mode and the second encoding mode by switching to the second encoding mode responsive to the quantization parameter exceeding a first threshold. ### Claim 17 (depends on 16) The video processing device of claim 16, wherein the encoder is to dynamically switch between the first encoding mode and the second encoding mode further by switching to the first encoding mode responsive to the quantization parameter falling below a second threshold. ### Claim 18 (depends on 15) The video processing device of claim 15, wherein in the first encoding mode the encoder further is to select between a frame-based encoding sub-mode and a field-based encoding sub-mode for a corresponding frame based on a motion analysis between the two fields of the corresponding frame. ### Claim 19 (depends on 15) The video processing device of claim 15, wherein the encoder is to delay a switch between the first encoding mode and the second encoding mode until a specified switch point. ### Claim 20 (depends on 15) The video processing device of claim 15, wherein the encoder further is to decrease the quantization parameter responsive to switching to the second encoding mode.