sudo apt install x264 x265 libx264-dev libx265-dev
sudo apt-get install ubuntu-restricted-extras
sudo apt-get install libavcodec54 libav-tools ffmpeg
Saturday 29 January 2022
Tuesday 25 January 2022
How to use the rotatedRect in opencv c++?
#include <iostream>
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
int main(int argc, char* argv){
cv::Mat src = cv::imread("../tony.jpg");
// rect is the RotatedRect (I got it from a contour...)
cv::RotatedRect rect(cv::Point2f(453, 127), cv::Size(230,140), 45);
// matrices we'll use
cv::Mat M, rotated, cropped;
// get angle and size from the bounding box
float angle = rect.angle;
cv::Size rect_size = rect.size;
if (rect.angle < -45.) {
angle += 90.0;
cv::swap(rect_size.width, rect_size.height);
}
// get the rotation matrix
M = cv::getRotationMatrix2D(rect.center, angle, 1.0);
// perform the affine transformation
cv::warpAffine(src, rotated, M, src.size(), cv::INTER_CUBIC);
// crop the resulting image
cv::getRectSubPix(rotated, rect_size, rect.center, cropped);
cv::imshow("cropped", cropped);
cv::waitKey(0);
return 0;
}
ref: https://gist.github.com/steven2358/ba153c642fe2bb1e47485962df07c730
https://ffmpeg.org/ffmpeg-all.html#Video-Options
FFmpeg cheat sheet
A list of useful commands for the ffmpeg command line tool.
Download FFmpeg: https://www.ffmpeg.org/download.html
Full documentation: https://www.ffmpeg.org/ffmpeg.html
Basic conversion
ffmpeg -i in.mp4 out.avi
Remux an MKV file into MP4
ffmpeg -i in.mkv -c:v copy -c:a copy out.mp4
High-quality encoding
Use the crf (Constant Rate Factor) parameter
to control the output quality. The lower crf, the higher the quality
(range: 0-51). The default value is 23, and visually lossless
compression corresponds to -crf 18. Use the preset parameter to control the speed of the compression process. Additional info: https://trac.ffmpeg.org/wiki/Encode/H.264
ffmpeg -i in.mp4 -preset slower -crf 18 out.mp4
Trimming
Without re-encoding:
ffmpeg -ss [start] -i in.mp4 -t [duration] -c copy out.mp4
-ssspecifies the start time, e.g.00:01:23.000or83(in seconds)-tspecifies the duration of the clip (same format).- Recent
ffmpegalso has a flag to supply the end time with-to. -ccopy copies the first video, audio, and subtitle bitstream from the input to the output file without re-encoding them. This won't harm the quality and make the command run within seconds.
With re-encoding:
If you leave out the -c copy option, ffmpeg
will automatically re-encode the output video and audio according to
the format you chose. For high quality video and audio, read the x264 Encoding Guide and the AAC Encoding Guide, respectively.
For example:
ffmpeg -ss [start] -i in.mp4 -t [duration] -c:v libx264 -c:a aac -strict experimental -b:a 128k out.mp4
Mux video and audio from another video
To copy the video from in0.mp4 and audio from in1.mp4:
ffmpeg -i in0.mp4 -i in1.mp4 -c copy -map 0:0 -map 1:1 -shortest out.mp4
- With -c copy the streams will be
stream copied, not re-encoded, so there will be no quality loss. If you want to re-encode, see FFmpeg Wiki: H.264 Encoding Guide. - The
-shortestoption will cause the output duration to match the duration of the shortest input stream. - See the
-mapoption documentation for more info.
Concat demuxer
First, make a text file.
file 'in1.mp4'
file 'in2.mp4'
file 'in3.mp4'
file 'in4.mp4'
Then, run ffmpeg:
ffmpeg -f concat -i list.txt -c copy out.mp4
Delay audio/video
Delay video by 3.84 seconds:
ffmpeg -i in.mp4 -itsoffset 3.84 -i in.mp4 -map 1:v -map 0:a -vcodec copy -acodec copy out.mp4
Delay audio by 3.84 seconds:
ffmpeg -i in.mp4 -itsoffset 3.84 -i in.mp4 -map 0:v -map 1:a -vcodec copy -acodec copy out.mp4
Burn subtitles
Use the libass library (make sure your ffmpeg install has the library in the configuration --enable-libass).
First convert the subtitles to .ass format:
ffmpeg -i sub.srt sub.ass
Then add them using a video filter:
ffmpeg -i in.mp4 -vf ass=sub.ass out.mp4
Extract the frames from a video
To extract all frames from between 1 and 5 seconds, and also between 11 and 15 seconds:
ffmpeg -i in.mp4 -vf select='between(t,1,5)+between(t,11,15)' -vsync 0 out%d.png
To extract one frame per second only:
ffmpeg -i in.mp4 -fps=1 -vsync 0 out%d.png
Rotate a video
Rotate 90 clockwise:
ffmpeg -i in.mov -vf "transpose=1" out.mov
For the transpose parameter you can pass:
0 = 90CounterCLockwise and Vertical Flip (default)
1 = 90Clockwise
2 = 90CounterClockwise
3 = 90Clockwise and Vertical Flip
Use -vf "transpose=2,transpose=2" for 180 degrees.
Download "Transport Stream" video streams
- Locate the playlist file, e.g. using Chrome > F12 > Network > Filter: m3u8
- Download and concatenate the video fragments:
ffmpeg -i "path_to_playlist.m3u8" -c copy -bsf:a aac_adtstoasc out.mp4
If you get a "Protocol 'https not on whitelist 'file,crypto'!" error, add the protocol_whitelist option:
ffmpeg -protocol_whitelist "file,http,https,tcp,tls" -i "path_to_playlist.m3u8" -c copy -bsf:a aac_adtstoasc out.mp4
Mute some of the audio
To replace the first 90 seconds of audio with silence:
ffmpeg -i in.mp4 -vcodec copy -af "volume=enable='lte(t,90)':volume=0" out.mp4
To replace all audio between 1'20" and 1'30" with silence:
ffmpeg -i in.mp4 -vcodec copy -af "volume=enable='between(t,80,90)':volume=0" out.mp4
Deinterlace
Deinterlacing using "yet another deinterlacing filter".
ffmpeg -i in.mp4 -vf yadif out.mp4
Create a video slideshow from images
Parameters: -r marks the image framerate (inverse time of each image); -vf fps=25 marks the true framerate of the output.
ffmpeg -r 1/5 -i img%03d.png -c:v libx264 -vf fps=25 -pix_fmt yuv420p out.mp4
Extract images from a video
- Extract all frames:
ffmpeg -i input.mp4 thumb%04d.jpg -hide_banner - Extract a frame each second:
ffmpeg -i input.mp4 -vf fps=1 thumb%04d.jpg -hide_banner - Extract only one frame:
ffmpeg -i input.mp4 -ss 00:00:10.000 -vframes 1 thumb.jpg
Metadata: Change the title
ffmpeg -i in.mp4 -map_metadata -1 -metadata title="My Title" -c:v copy -c:a copy out.mp4
Sunday 23 January 2022
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5: version `Qt_5.15' not found (required by /home/justin/.local/lib/python3.8/site-packages/PyQt5/QtCore.abi3.so)
ls /usr/lib/x86_64-linux-gnu/libQt5Core*
pip uninstall pyqt5
conda list qt
conda install pyqt==5.9.2
Wednesday 19 January 2022
How to make a simple OpenCV C++ program CMakeLists.txt?
cmake_minimum_required(VERSION 3.10)
project(main)
set(CMAKE_PREFIX_PATH /data/opencv-4.4.0/distribute/)
find_package(OpenCV REQUIRED)
include_directories(/data/opencv-4.4.0/distribute/include)
link_directories(/data/opencv-4.4.0/distribute/lib)
add_executable(main main.cpp)
target_link_libraries(main opencv_core opencv_imgproc opencv_highgui opencv_videoio)
Friday 14 January 2022
How to calculate the module time in C++ OpenCV?
method1:
double t = (double)cv::getTickCount();
bool status = weightedMovingVariance(frame, output, count);
t = ((double)cv::getTickCount() - t)/cv::getTickFrequency();
std::cout << "Times passed in seconds: " << t << std::endl;
method2:
cv::TickMeter tm;
tm.start();
// do something ...
tm.stop();
std::cout << "Total time: " << tm.getTimeSec() << std::endl;
Wednesday 12 January 2022
How to run spawn using a bash script?
/data/build/main1.sh &
P1=$!
/data/build/main2.sh &
P2=$!
wait $P1 $P2
Friday 7 January 2022
triton - how to set the batch size: dynamic versus predefined
predefined:-
name: "kps"
platform: "tensorrt_plan"
max_batch_size: 16
dynamic_batching {
preferred_batch_size: [ 1,2,4,8,16 ]
max_queue_delay_microseconds: 50
}
instance_group [
{
count: 16
kind: KIND_GPU
gpus: [ 0 ]
}
]
input [
{
name: "input"
data_type: TYPE_FP32
format: FORMAT_NCHW
dims: [ 3, 64, 64 ]
reshape { shape: [ 3, 64, 64 ] }
}
]
output [
{
name: "output1"
data_type: TYPE_FP32
dims: [ 1]
},
{
name: "output2"
data_type: TYPE_INT32
dims: [ 1 ]
},
{
name: "output3"
data_type: TYPE_FP32
dims: [ 8,64 ]
}
]
version_policy: { all { } }
dynamic:-
platform: "tensorrt_plan"
max_batch_size: 0
instance_group [
{
count: 16
kind: KIND_GPU
gpus: [ 0 ]
}
]
input [
{
name: "images"
data_type: TYPE_FP32
dims: [ -1,3, 640, 640]
}
]
output [
{
name: "524"
data_type: TYPE_FP32
dims: [ -1,3,80,80, 7 ]
},
{
name: "585"
data_type: TYPE_FP32
dims: [ -1,3,40,40, 7 ]
},
{
name: "646"
data_type: TYPE_FP32
dims: [ -1,3,20,20, 7 ]
},
{
name: "output"
data_type: TYPE_FP32
dims: [ -1, 25200, 7 ]
}
]
~
~
~
~
Tuesday 4 January 2022
cmake of VisionWorks
cmake_minimum_required(VERSION 3.10)
#set the project name and version
project(render)
find_package(OpenCV REQUIRED)
find_package(CUDA 10.2 REQUIRED)
set(WITH_CUDA ON)
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -pthread")
include_directories(${OpenCV_INCLUDE_DIRS})
add_executable(main main_nvgstcamera_capture.cpp)
target_include_directories(main PUBLIC
-I/usr/local/cuda-10.2/targets/aarch64-linux/include
/usr/share/visionworks/sources/nvxio/include
/usr/share/visionworks/sources/nvxio/src/
/usr/share/visionworks/sources/nvxio/src/NVX/
/usr/share/visionworks/sources/3rdparty/opengl
/usr/share/visionworks/sources/3rdparty/glfw3/include
/usr/share/visionworks/sources/3rdparty/freetype/include
/usr/share/visionworks/sources/3rdparty/eigen
)
target_link_libraries(main
-L$(PKG_CONFIG_SYSROOT_DIR)/usr/lib
/usr/share/visionworks/sources/libs/aarch64/linux/release/libovx.a
/usr/share/visionworks/sources/3rdparty/freetype/libs/libfreetype.a
/usr/share/visionworks/sources/3rdparty/glfw3/libs/libglfw3.a
/usr/lib/aarch64-linux-gnu/tegra-egl/libGLESv2_nvidia.so.2
-L/usr/lib/aarch64-linux-gnu
-lEGL
-lXrandr
-lXi
-lXxf86vm
-lX11
-lgstpbutils-1.0
-lgstaudio-1.0
-lgstvideo-1.0
-lgstapp-1.0
-lgstbase-1.0
-lgstreamer-1.0
-lgobject-2.0
-lglib-2.0
/usr/lib/aarch64-linux-gnu/tegra/libcuda.so
-L/usr/local/cuda-10.2/targets/aarch64-linux/lib
-lcudart
-lvisionworks
${OpenCV_LIBS}
)
Saturday 1 January 2022
how to loop a string array in c++?
#include "iostream"
#include "string.h"
using namespace std;
int main()
{
string strNames[] = { "Name1", "Name2", "Name3", "Name4", "Name5", "Name6"};
for each(string name in strNames)
{
printf("%s\n", name.c_str());
}
return 0;
}
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