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Dmitry Kurtaev
8e0c0dc347
Optimize FFmpeg VideoCapture with swscale threads option #27755 ### Pull Request Readiness Checklist resolves https://github.com/opencv/opencv/issues/21969 * Switch to `sws_scale_from` for `libswscale >= 6.4.100` (FFmpeg >= 5.0) * Use new context init API with threads option (`libswscale >= 8.12.100`: https://github.com/FFmpeg/FFmpeg/commit/2a091d4f2ee1e367d05a6bbbe96b204257cbda87) * Replicate `sws_getCachedContext` with threads option for `libswscale < 8.12.100` 1 hour mp4 video every frame reading | HW | sws_scale | sws_scale_frame + 16 threads | sws_scale_frame + 24 threads (#cpus) | |---|---|---|---| | Intel Core i9-12900 CPU | 45.1 sec | 25.4 sec (x1.77) | 30 sec (x1.50) | | NVIDIA GPU 4090 | 232 sec | 89.4 sec (x2.59) | 77 sec (x3.01) | ``` import time import numpy as np import os import cv2 as cv # os.environ["OPENCV_FFMPEG_CAPTURE_OPTIONS"] = "hwaccel;cuvid|video_codec;h264_cuvid|vsync;0" start = time.time() video = "test.mp4" cap = cv.VideoCapture(video, cv.CAP_FFMPEG) while True: has_frame, frame = cap.read() if not has_frame: break print(time.time() - start) ``` See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request - [x] I agree to contribute to the project under Apache 2 License. - [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV - [x] The PR is proposed to the proper branch - [x] There is a reference to the original bug report and related work - [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable Patch to opencv_extra has the same branch name. - [x] The feature is well documented and sample code can be built with the project CMake
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