I read https://github.com/opencv/opencv/wiki/Tengine-based-acceleration.
And, I found that the following description.
In this case the Tengine should be separately downloaded from github, tengine-opencv
branch:
GitHub - OAID/Tengine at tengine-opencv
Does the latest OpenCV(4.5.3) currently support Tengine(tengine-opencv
branch) only?
I found that Tengine is downloaded when I does not specify the path of Tengine.
https://github.com/opencv/opencv/blob/4.5.3/3rdparty/libtengine/tengine.cmake#L34-L47
SET(OCV_TENGINE_FILENAME "${TENGINE_COMMIT_VERSION}.zip")#name
SET(OCV_TENGINE_URL "https://github.com/OAID/Tengine/archive/") #url
SET(tengine_md5sum 23f61ebb1dd419f1207d8876496289c5) #md5sum
ocv_download(FILENAME ${OCV_TENGINE_FILENAME}
HASH ${tengine_md5sum}
URL
"${OPENCV_TENGINE_URL}"
"$ENV{OPENCV_TENGINE_URL}"
"${OCV_TENGINE_URL}"
DESTINATION_DIR "${OCV_TENGINE_DIR}"
ID TENGINE
STATUS res
UNPACK RELATIVE_URL)