# Stream video from Raspberry Pi with OpenCV

**URL:** <https://discuss.bluerobotics.com/t/stream-video-from-raspberry-pi-with-opencv/13904>\
**Category:** Cameras\
**Created:** [March 15, 2023, 1:23am UTC](https://discuss.bluerobotics.com/t/stream-video-from-raspberry-pi-with-opencv/13904 "2023-03-15T01:23:07Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![leone24](https://avatars.discourse-cdn.com/v4/letter/l/e0b2c6/32.png) [@leone24](https://discuss.bluerobotics.com/u/leone24)\
**Post date:** [March 15, 2023, 1:23am UTC](https://discuss.bluerobotics.com/t/stream-video-from-raspberry-pi-with-opencv/13904/1 "2023-03-15T01:23:07Z")

</div>

Hello,  
I am trying to stream my Raspberry Pi camera video modified using OpenCV to the ground station with the following code:

```python
import cv2
import numpy as np

def send():
    cap_send = cv2.VideoCapture(0)
    out_send = cv2.VideoWriter('appsrc ! video/x-raw ! videoconvert ! x264enc ! rtph264pay ! udpsink host=192.168.2.1 port=5600',cv2.CAP_GSTREAMER,0, 30, (1920,1080), True)

    if not cap_send.isOpened():
        print('Error openning in')
        exit(0)
    if not out_send.isOpened():
        print("Error openning out")

    while True:
        ret,frame = cap_send.read()

        if not ret:
            print('empty frame')
            break

        out_send.write(frame)
        print(frame)
        pass

    cap_send.release()
    out_send.release()

send()

```

However, when QGroundControl automatically detects the stream it shows me a green page with no frames changing the view.  
I have verified that the frames are correctly recorded by the OpenCV.

```plaintext
gst-launch-1.0 -v udpsrc port=5600 ! application/x-rtp,media=(string)video,clock-rate=(int)90000,encoding-name=(string)H264,payload=(int)96 ! rtph264depay ! decodebin ! videoconvert ! autovideosink

```

But still, the result is the when I use the following gstreamer pipeline in the receiving end, yielding the following output.

```plaintext
Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
/GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:src: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264, payload=(int)96
/GstPipeline:pipeline0/GstRtpH264Depay:rtph264depay0.GstPad:sink: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264, payload=(int)96
/GstPipeline:pipeline0/GstRtpH264Depay:rtph264depay0.GstPad:src: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, codec_data=(buffer)01f40028ffe1001f67f40028919b280f0044fc4e02d40404050000030001000003003c8f18319601000668ebec448440, level=(string)4, profile=(string)high-4:4:4
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink.GstProxyPad:proxypad0: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, codec_data=(buffer)01f40028ffe1001f67f40028919b280f0044fc4e02d40404050000030001000003003c8f18319601000668ebec448440, level=(string)4, profile=(string)high-4:4:4
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, codec_data=(buffer)01f40028ffe1001f67f40028919b280f0044fc4e02d40404050000030001000003003c8f18319601000668ebec448440, level=(string)4, profile=(string)high-4:4:4
Redistribute latency...
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstH264Parse:h264parse0.GstPad:src: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, codec_data=(buffer)01f40028ffe1001f67f40028919b280f0044fc4e02d40404050000030001000003003c8f18319601000668ebec448440, level=(string)4, profile=(string)high-4:4:4, pixel-aspect-ratio=(fraction)1/1, width=(int)1920, height=(int)1080, framerate=(fraction)30/1, coded-picture-structure=(string)frame, chroma-format=(string)4:4:4, bit-depth-luma=(uint)8, bit-depth-chroma=(uint)8, colorimetry=(string)bt709, parsed=(boolean)true
Redistribute latency...
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/avdec_h264:avdec_h264-0.GstPad:sink: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, codec_data=(buffer)01f40028ffe1001f67f40028919b280f0044fc4e02d40404050000030001000003003c8f18319601000668ebec448440, level=(string)4, profile=(string)high-4:4:4, pixel-aspect-ratio=(fraction)1/1, width=(int)1920, height=(int)1080, framerate=(fraction)30/1, coded-picture-structure=(string)frame, chroma-format=(string)4:4:4, bit-depth-luma=(uint)8, bit-depth-chroma=(uint)8, colorimetry=(string)bt709, parsed=(boolean)true
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstCapsFilter:capsfilter1.GstPad:src: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, codec_data=(buffer)01f40028ffe1001f67f40028919b280f0044fc4e02d40404050000030001000003003c8f18319601000668ebec448440, level=(string)4, profile=(string)high-4:4:4, pixel-aspect-ratio=(fraction)1/1, width=(int)1920, height=(int)1080, framerate=(fraction)30/1, coded-picture-structure=(string)frame, chroma-format=(string)4:4:4, bit-depth-luma=(uint)8, bit-depth-chroma=(uint)8, colorimetry=(string)bt709, parsed=(boolean)true
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstCapsFilter:capsfilter1.GstPad:sink: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, codec_data=(buffer)01f40028ffe1001f67f40028919b280f0044fc4e02d40404050000030001000003003c8f18319601000668ebec448440, level=(string)4, profile=(string)high-4:4:4, pixel-aspect-ratio=(fraction)1/1, width=(int)1920, height=(int)1080, framerate=(fraction)30/1, coded-picture-structure=(string)frame, chroma-format=(string)4:4:4, bit-depth-luma=(uint)8, bit-depth-chroma=(uint)8, colorimetry=(string)bt709, parsed=(boolean)true
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstH264Parse:h264parse0.GstPad:sink: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, codec_data=(buffer)01f40028ffe1001f67f40028919b280f0044fc4e02d40404050000030001000003003c8f18319601000668ebec448440, level=(string)4, profile=(string)high-4:4:4
Redistribute latency...
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:sink: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, codec_data=(buffer)01f40028ffe1001f67f40028919b280f0044fc4e02d40404050000030001000003003c8f18319601000668ebec448440, level=(string)4, profile=(string)high-4:4:4
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, codec_data=(buffer)01f40028ffe1001f67f40028919b280f0044fc4e02d40404050000030001000003003c8f18319601000668ebec448440, level=(string)4, profile=(string)high-4:4:4
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/avdec_h264:avdec_h264-0.GstPad:src: caps = video/x-raw, format=(string)Y444, width=(int)1920, height=(int)1080, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1, chroma-site=(string)mpeg2, colorimetry=(string)bt709, framerate=(fraction)30/1
/GstPipeline:pipeline0/GstVideoConvert:videoconvert0.GstPad:src: caps = video/x-raw, width=(int)1920, height=(int)1080, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, format=(string)YV12, colorimetry=(string)bt709
/GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0.GstGhostPad:sink.GstProxyPad:proxypad1: caps = video/x-raw, width=(int)1920, height=(int)1080, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, format=(string)YV12, colorimetry=(string)bt709
/GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0/GstXvImageSink:autovideosink0-actual-sink-xvimage.GstPad:sink: caps = video/x-raw, width=(int)1920, height=(int)1080, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, format=(string)YV12, colorimetry=(string)bt709
/GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0.GstGhostPad:sink: caps = video/x-raw, width=(int)1920, height=(int)1080, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, format=(string)YV12, colorimetry=(string)bt709
/GstPipeline:pipeline0/GstVideoConvert:videoconvert0.GstPad:sink: caps = video/x-raw, format=(string)Y444, width=(int)1920, height=(int)1080, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1, chroma-site=(string)mpeg2, colorimetry=(string)bt709, framerate=(fraction)30/1
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstDecodePad:src_0.GstProxyPad:proxypad2: caps = video/x-raw, format=(string)Y444, width=(int)1920, height=(int)1080, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1, chroma-site=(string)mpeg2, colorimetry=(string)bt709, framerate=(fraction)30/1
Redistribute latency...
Redistribute latency...
WARNING: from element /GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0/GstXvImageSink:autovideosink0-actual-sink-xvimage: Pipeline construction is invalid, please add queues.
Additional debug info:
../gstreamer/subprojects/gstreamer/libs/gst/base/gstbasesink.c(1249): gst_base_sink_query_latency (): /GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0/GstXvImageSink:autovideosink0-actual-sink-xvimage:
Not enough buffering available for the processing deadline of 0:00:00.015000000, add enough queues to buffer 0:00:00.015000000 additional data. Shortening processing latency to 0:00:00.000000000.
WARNING: from element /GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0/GstXvImageSink:autovideosink0-actual-sink-xvimage: Pipeline construction is invalid, please add queues.
Additional debug info:
../gstreamer/subprojects/gstreamer/libs/gst/base/gstbasesink.c(1249): gst_base_sink_query_latency (): /GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0/GstXvImageSink:autovideosink0-actual-sink-xvimage:
Not enough buffering available for the processing deadline of 0:00:00.015000000, add enough queues to buffer 0:00:00.015000000 additional data. Shortening processing latency to 0:00:00.000000000.
ERROR: from element /GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0/GstXvImageSink:autovideosink0-actual-sink-xvimage: Output window was closed
Additional debug info:
../gstreamer/subprojects/gst-plugins-base/sys/xvimage/xvimagesink.c(586): gst_xv_image_sink_handle_xevents (): /GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0/GstXvImageSink:autovideosink0-actual-sink-xvimage
Execution ended after 0:00:13.277670659
Setting pipeline to NULL ...
Freeing pipeline ...

```

---

<div class="post-metadata">

**Author:** ![clyde](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/clyde/32/8563_2.png) [@clyde](https://discuss.bluerobotics.com/u/clyde)\
**Post date:** [March 18, 2023, 2:53am UTC](https://discuss.bluerobotics.com/t/stream-video-from-raspberry-pi-with-opencv/13904/2 "2023-03-18T02:53:31Z")

</div>

The key warning message is “Pipeline construction is invalid, please add queues”. It appears that the h264 decoder is a bit slower than expected and frames are getting dropped. Try adding a queue between rtph264depay and decodebin: “rtph264depay ! queue ! decodebin”. You can also try adding a queue between decodebin and videoconvert.

---

<div class="post-metadata">

**Author:** ![judahwo](https://avatars.discourse-cdn.com/v4/letter/j/77aa72/32.png) [@judahwo](https://discuss.bluerobotics.com/u/judahwo)\
**Post date:** [February 27, 2024, 5:06pm UTC](https://discuss.bluerobotics.com/t/stream-video-from-raspberry-pi-with-opencv/13904/3 "2024-02-27T17:06:09Z")

</div>

Were you able to solve this? We are tying to do something similar.