从python中的opencv编写Gstreamer管道 [英] Write in Gstreamer pipeline from opencv in python

问题描述

我正在尝试使用gstreamer从opencv流式传输一些图像，但管道出现了一些问题.我是gstreamer和opencv的新手.我在树莓派3上使用gstreamer为python3编译了opencv 3.2.我有一个与raspivid一起使用的bash脚本

I'm trying to stream some images form opencv using gstreamer and I got ome issues with the pipeline. I'm new to gstreamer and opencv in general. I compiled opencv 3.2 with gstreamer for python3 on a raspberry pi 3. I have a little bash script that I use with raspivid

raspivid -fps 25 -h 720 -w 1080 -vf -n -t 0 -b 2000000 -o - | gst-launch-1.0 -v fdsrc ! h264parse ! rtph264pay config-interval=1 pt=96 ! gdppay ! tcpserversink host=192.168.1.27 port=5000

我想转换此管道，以便从opencv中使用它，并将算法处理的图像输入其中.我进行了一些研究，发现可以将videoWriter与appsrc一起使用，而不是fdsrc，但出现以下错误

I wanted to translate this pipeline in order to use it from opencv and feed into it images that my algorithm manipulates. I did some research and figured that I can use videoWriter with appsrc instead of fdsrc but I get the following error

GStreamer Plugin: Embedded video playback halted; module appsrc0 reported: Internal data flow error.

顺便说一下，我想出的python脚本如下 导入cv2

The python script that I came up with is the following by the way import cv2

cap = cv2.VideoCapture(0)


# Define the codec and create VideoWriter object
fourcc = cv2.VideoWriter_fourcc(*'MJPG')
out = cv2.VideoWriter('appsrc  ! h264parse ! '
                      'rtph264pay config-interval=1 pt=96 ! '
                      'gdppay ! tcpserversink host=192.168.1.27 port=5000 ',
                      fourcc, 20.0, (640, 480))

while cap.isOpened():
    ret, frame = cap.read()
    if ret:
        frame = cv2.flip(frame, 0)

        # write the flipped frame
        out.write(frame)

        if cv2.waitKey(1) & 0xFF == ord('q'):
            break
    else:
        break

# Release everything if job is finished
cap.release()
out.release()
cv2.destroyAllWindows()

管道中是否有任何错误?我不明白这个错误.我已经有一个可以从bash管道读取的Python客户端，从延迟角度和消耗资源的角度来看，结果都非常好.

Is there any error in the pipeline? I don't understand the error. I already have a Python client that can read from the bash pipeline and the result are pretty good from the latency perspective and consumed resources .

推荐答案

我遇到了解决方案，希望对其他遇到相同问题的人有所帮助. 管道布置错误，需要视频转换. 另一方面，延迟是非常相关的，但是将speed.preset设置为ultrafast可以解决此问题，即使那里没有太多压缩，这也是一个很好的折衷方案.这是我的解决方法.

I came across the solution and I hope this helps other people that come across the same issue. The pipeline was mistakenly arranged and videoconvert was needed. On the other hand the latency was quite relevant but setting speed.preset to ultrafast solved the issue even if there's not much of compression going on there, it was a good compromise. Here's my solution.

import cv2

cap = cv2.VideoCapture(0)

framerate = 25.0

out = cv2.VideoWriter('appsrc ! videoconvert ! '
                      'x264enc noise-reduction=10000 speed-preset=ultrafast tune=zerolatency ! '
                      'rtph264pay config-interval=1 pt=96 !'
                      'tcpserversink host=192.168.1.27 port=5000 sync=false',
                      0, framerate, (640, 480))

while cap.isOpened():
    ret, frame = cap.read()
    if ret:

        out.write(frame)

        if cv2.waitKey(1) & 0xFF == ord('q'):
            break
    else:
        break

# Release everything if job is finished
cap.release()
out.release()

这篇关于从python中的opencv编写Gstreamer管道的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！