Making a RTSP Server out of a Raspberry PI in 15 minutes or less

Recently, I was performing some video analytics against a new Reolink PoE camera.  Nice new camera, BUT it struggled with OpenCV, namely, I was getting the following type of errors:

[h264 @ 0xafb9ec0] left block unavailable for requested intra4x4 mode -1
[h264 @ 0xafb9ec0] error while decoding MB 0 28, bytestream 11378
[h264 @ 0xafb9500] error while decoding MB 38 19, bytestream -26
[h264 @ 0xafb9500] left block unavailable for requested intra4x4 mode -1
[h264 @ 0xafb9500] error while decoding MB 0 28, bytestream 694
[h264 @ 0xafb9500] error while decoding MB 15 22, bytestream -18
[h264 @ 0xafb9ec0] error while decoding MB 30 19, bytestream -10
[h264 @ 0xafb9500] error while decoding MB 48 19, bytestream -26
[h264 @ 0xafb9080] error while decoding MB 10 20, bytestream -10
[h264 @ 0xafb9a00] left block unavailable for requested intra4x4 mode -1
[h264 @ 0xafb9a00] error while decoding MB 0 24, bytestream 842
[h264 @ 0xafb9ec0] error while decoding MB 59 29, bytestream -20
[h264 @ 0xafb9ec0] left block unavailable for requested intra4x4 mode -1
[h264 @ 0xafb9ec0] error while decoding MB 0 26, bytestream 620
[h264 @ 0xafb9a00] error while decoding MB 42 23, bytestream -22
[h264 @ 0xafb9ec0] error while decoding MB 46 21, bytestream -32
[h264 @ 0xafb9080] left block unavailable for requested intra4x4 mode -1
[h264 @ 0xafb9080] error while decoding MB 0 20, bytestream 902
[h264 @ 0xafb9500] left block unavailable for requested intra4x4 mode -1
[h264 @ 0xafb9500] error while decoding MB 0 22, bytestream 608
[h264 @ 0xafb9500] error while decoding MB 38 19, bytestream -28

Because the processing I needed to do was sub second, I could not rely on the sporadic errors and as such had to find a different solution.  [Note, the RTSP server on Pi still produces some error, but no where near as many as the Reolink did.  Also, I did open a ticket with Reolink and they could not solve the issue.  :(]

I set out to see if I could easily convert a raspberry pi + camera to do the job.

While I could have used most any USB camera, I chose to use the Pi camera, just because I already had it (and no use for it).

Install Process:

1. install Raspbian Stretch on the device (~6 minutes using Raspbian Lite)

2. log into the system and switch user to root

su root

3. update the system and install git and cmake

apt update && apt install git cmake

4. download the source for v412rtspserver

git clone https://github.com/mpromonet/v4l2rtspserver.git

5. make and install the code (~5 minutes)

cd v4l2rtspserver && cmake . && make && make install

6. add the following command to your /etc/rc.local

v4l2rtspserver /dev/video0 &

7. in VLC, open network stream to:  rtsp://{IPAddressOfYourPI}:8554/unicast

You should see something similar to below:

From a performance perspective, there is very little CPU or memory used, as shown below, meaning this could easily run on a PI Zero:

Note, not all cameras support the H264, as discussed here: https://github.com/mpromonet/v4l2rtspserver/issues/88

 

 

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