US 11,716,475 B2
Image processing device and method of pre-processing images of a video stream before encoding
Fredrik Pihl, Lund (SE); and Mattias Pettersson, Lund (SE)
Assigned to AXIS AB, Lund (SE)
Filed by Axis AB, Lund (SE)
Filed on Oct. 13, 2021, as Appl. No. 17/499,887.
Claims priority of application No. 20202951 (EP), filed on Oct. 21, 2020.
Prior Publication US 2022/0124339 A1, Apr. 21, 2022
Int. Cl. H04N 19/132 (2014.01); H04N 19/146 (2014.01); H04N 19/172 (2014.01); H04N 19/59 (2014.01)
CPC H04N 19/132 (2014.11) [H04N 19/146 (2014.11); H04N 19/172 (2014.11); H04N 19/59 (2014.11)] 15 Claims
OG exemplary drawing
 
1. A method of pre-processing images of a video stream before encoding the video stream, the method comprising:
at predetermined intervals, obtaining images of the video stream, wherein the obtained images have a first resolution;
at the predetermined intervals, determining a bitrate of the video stream as encoded for a current interval, wherein the bitrate is determined for images of the video stream obtained in a previous interval;
at the predetermined intervals, determining a second resolution for the current interval based on the determined bitrate of the video stream as encoded for the current interval, wherein if the determined bitrate of the video stream as encoded for the current interval has increased compared to a previous interval, the second resolution is decreased for the current interval, and if the determined bitrate of the video stream as encoded for the current interval has decreased compared to a previous interval, the second resolution is increased for the current interval;
during the predetermined intervals, sub sampling the obtained images to intermediate images having the second resolution for the current interval lower than the first resolution and lower than a third resolution; and
during the predetermined intervals, upsampling the intermediate images to output images having the third resolution, wherein the third resolution is the same for all images of the video stream.