USB camera encoded data stream









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2
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Currently, I am working on a streaming project. I need to grab frames from USB camera and send them over TCP.



To open USB camera video stream I'm using cv::VideoCapture. This allows me to read already decoded frames. According to this question I understood that there is no way to get encoded frame data using cv::VideoCapture and I need to encode each frame again and send it whatever I need using cv::imencode. The problem is that I can encode frames to some specific format listed here, and, in case, I use either .jpg or .png the file size still quite big and on receiving side frame rate very poor.



My question is: Is there any way to get mjpeg or h264 encoded data directly
or maybe you can suggest a better way to encode frames.



OpenCV 3.4.3, camera RICOH THETA V, language C++.



My code:



void Streamer::start()

cv::Mat img;
cv::VideoCapture cap(0);
cap.set(CV_CAP_PROP_FOURCC, CV_FOURCC('H', '2', '6', '4'));

if (!cap.isOpened())
throw std::invalid_argument("No device found.");

std::vector<int> format_params;
format_params.push_back(CV_LOAD_IMAGE_COLOR);
format_params.push_back(CV_IMWRITE_PNG_STRATEGY);

for (;;)

cap.read(img);
cv::imencode(".png", img, buffer_, format_params);

std::string strbuf(buffer_.begin(), buffer_.end());
server_->sendString(socket, strbuf);


cap.release();










share|improve this question



















  • 1




    I think that if you are not going to do any kind of image processing and only stream a video... maybe it is better to use a library/app that does that directly... for example gstreamer or ffmpeg using something like rtsp which in the client side you can connect using videocapture of OpenCV
    – api55
    Nov 7 at 8:48










  • @api55 Thanks for your reply. Yes, in my case I am not doing any image processing. I have now tried to use ffmpeg to stream video using rtp but could not make it work. It would be great if I could use ffmpeg instead.
    – Yevhenii Veretennikov
    Nov 9 at 6:41














up vote
2
down vote

favorite












Currently, I am working on a streaming project. I need to grab frames from USB camera and send them over TCP.



To open USB camera video stream I'm using cv::VideoCapture. This allows me to read already decoded frames. According to this question I understood that there is no way to get encoded frame data using cv::VideoCapture and I need to encode each frame again and send it whatever I need using cv::imencode. The problem is that I can encode frames to some specific format listed here, and, in case, I use either .jpg or .png the file size still quite big and on receiving side frame rate very poor.



My question is: Is there any way to get mjpeg or h264 encoded data directly
or maybe you can suggest a better way to encode frames.



OpenCV 3.4.3, camera RICOH THETA V, language C++.



My code:



void Streamer::start()

cv::Mat img;
cv::VideoCapture cap(0);
cap.set(CV_CAP_PROP_FOURCC, CV_FOURCC('H', '2', '6', '4'));

if (!cap.isOpened())
throw std::invalid_argument("No device found.");

std::vector<int> format_params;
format_params.push_back(CV_LOAD_IMAGE_COLOR);
format_params.push_back(CV_IMWRITE_PNG_STRATEGY);

for (;;)

cap.read(img);
cv::imencode(".png", img, buffer_, format_params);

std::string strbuf(buffer_.begin(), buffer_.end());
server_->sendString(socket, strbuf);


cap.release();










share|improve this question



















  • 1




    I think that if you are not going to do any kind of image processing and only stream a video... maybe it is better to use a library/app that does that directly... for example gstreamer or ffmpeg using something like rtsp which in the client side you can connect using videocapture of OpenCV
    – api55
    Nov 7 at 8:48










  • @api55 Thanks for your reply. Yes, in my case I am not doing any image processing. I have now tried to use ffmpeg to stream video using rtp but could not make it work. It would be great if I could use ffmpeg instead.
    – Yevhenii Veretennikov
    Nov 9 at 6:41












up vote
2
down vote

favorite









up vote
2
down vote

favorite











Currently, I am working on a streaming project. I need to grab frames from USB camera and send them over TCP.



To open USB camera video stream I'm using cv::VideoCapture. This allows me to read already decoded frames. According to this question I understood that there is no way to get encoded frame data using cv::VideoCapture and I need to encode each frame again and send it whatever I need using cv::imencode. The problem is that I can encode frames to some specific format listed here, and, in case, I use either .jpg or .png the file size still quite big and on receiving side frame rate very poor.



My question is: Is there any way to get mjpeg or h264 encoded data directly
or maybe you can suggest a better way to encode frames.



OpenCV 3.4.3, camera RICOH THETA V, language C++.



My code:



void Streamer::start()

cv::Mat img;
cv::VideoCapture cap(0);
cap.set(CV_CAP_PROP_FOURCC, CV_FOURCC('H', '2', '6', '4'));

if (!cap.isOpened())
throw std::invalid_argument("No device found.");

std::vector<int> format_params;
format_params.push_back(CV_LOAD_IMAGE_COLOR);
format_params.push_back(CV_IMWRITE_PNG_STRATEGY);

for (;;)

cap.read(img);
cv::imencode(".png", img, buffer_, format_params);

std::string strbuf(buffer_.begin(), buffer_.end());
server_->sendString(socket, strbuf);


cap.release();










share|improve this question















Currently, I am working on a streaming project. I need to grab frames from USB camera and send them over TCP.



To open USB camera video stream I'm using cv::VideoCapture. This allows me to read already decoded frames. According to this question I understood that there is no way to get encoded frame data using cv::VideoCapture and I need to encode each frame again and send it whatever I need using cv::imencode. The problem is that I can encode frames to some specific format listed here, and, in case, I use either .jpg or .png the file size still quite big and on receiving side frame rate very poor.



My question is: Is there any way to get mjpeg or h264 encoded data directly
or maybe you can suggest a better way to encode frames.



OpenCV 3.4.3, camera RICOH THETA V, language C++.



My code:



void Streamer::start()

cv::Mat img;
cv::VideoCapture cap(0);
cap.set(CV_CAP_PROP_FOURCC, CV_FOURCC('H', '2', '6', '4'));

if (!cap.isOpened())
throw std::invalid_argument("No device found.");

std::vector<int> format_params;
format_params.push_back(CV_LOAD_IMAGE_COLOR);
format_params.push_back(CV_IMWRITE_PNG_STRATEGY);

for (;;)

cap.read(img);
cv::imencode(".png", img, buffer_, format_params);

std::string strbuf(buffer_.begin(), buffer_.end());
server_->sendString(socket, strbuf);


cap.release();







c++ opencv stream encode






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edited Nov 11 at 12:34









Zoe

10.7k73575




10.7k73575










asked Nov 7 at 6:31









Yevhenii Veretennikov

1113




1113







  • 1




    I think that if you are not going to do any kind of image processing and only stream a video... maybe it is better to use a library/app that does that directly... for example gstreamer or ffmpeg using something like rtsp which in the client side you can connect using videocapture of OpenCV
    – api55
    Nov 7 at 8:48










  • @api55 Thanks for your reply. Yes, in my case I am not doing any image processing. I have now tried to use ffmpeg to stream video using rtp but could not make it work. It would be great if I could use ffmpeg instead.
    – Yevhenii Veretennikov
    Nov 9 at 6:41












  • 1




    I think that if you are not going to do any kind of image processing and only stream a video... maybe it is better to use a library/app that does that directly... for example gstreamer or ffmpeg using something like rtsp which in the client side you can connect using videocapture of OpenCV
    – api55
    Nov 7 at 8:48










  • @api55 Thanks for your reply. Yes, in my case I am not doing any image processing. I have now tried to use ffmpeg to stream video using rtp but could not make it work. It would be great if I could use ffmpeg instead.
    – Yevhenii Veretennikov
    Nov 9 at 6:41







1




1




I think that if you are not going to do any kind of image processing and only stream a video... maybe it is better to use a library/app that does that directly... for example gstreamer or ffmpeg using something like rtsp which in the client side you can connect using videocapture of OpenCV
– api55
Nov 7 at 8:48




I think that if you are not going to do any kind of image processing and only stream a video... maybe it is better to use a library/app that does that directly... for example gstreamer or ffmpeg using something like rtsp which in the client side you can connect using videocapture of OpenCV
– api55
Nov 7 at 8:48












@api55 Thanks for your reply. Yes, in my case I am not doing any image processing. I have now tried to use ffmpeg to stream video using rtp but could not make it work. It would be great if I could use ffmpeg instead.
– Yevhenii Veretennikov
Nov 9 at 6:41




@api55 Thanks for your reply. Yes, in my case I am not doing any image processing. I have now tried to use ffmpeg to stream video using rtp but could not make it work. It would be great if I could use ffmpeg instead.
– Yevhenii Veretennikov
Nov 9 at 6:41

















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