This isn't so much a mikrotik topic, but they are involved.

To clarify, this topic isn't about Rapid Spanning Tree (RSTP) but the video standard RTSP (Real Time Streaming Protocol)!

The scenario is the following:
I'm currently building a new house and I want to follow the build, create a timelapse and just be able to remotely monitor the site while I'm at work, etc. I hooked up some camera's that I can remotely view. For software I either use Genius Vision or VLC but used extensively in local configurations.

These camera's are Chinese Ti DM368 5 Megapixel camera's which I own 30 or 40 of and they have served me very well during various occasions. I hooked it up to a neighbor's internet connection where I have a POE switch, a Hex Lite, a 2TB disk and a Raspberry Pi2. I built this setup at home and tested it for several weeks before moving it to the remote site. Initially I wanted to push the RTSP stream through a VPN to my home (PPTP). And while testing this all worked great locally.

So I hooked it up at the remote site and checked it locally and all was working fine. VPN established and traffic seemed to flow through and locally I could access the camera's and view the RTSP stream without any issues. The problem started when I wanted to access there camera's remotely using RTSP.

For some reason, RTSP seems to be allergic to be transferred through the internet. I would be able to get some pictures on the stream, but it would keep breaking up or not give me any picture at all. While I could clearly see the data stream coming in locally. Very odd.

I tried all kind of things but everything in my PPTP connection and setup seemed to be working perfectly. Pings to the remote devices would be accurate and very stable, never dropping a packet. And both routerboards on both sides tell me everything is great. The VPN also stays stable for weeks without issue and there is plenty of bandwidth available to handle everything.

After more testing I noticed something weird. At night.... everything worked great, no dropped frames or video that wasn't working at all. All great! Looking at the JPEG's I pull out of the camera they are a lot bigger during the day then during the night so it's probably the extra information for color and detail during the day and night that is the difference. But WHY does my stream break??

I have no clue what is going on here. Currently I'm running RTSP forced over TCP which gives me some pictures which breaks down a lot during the day but at least I get some images, but I want to understand what is going on here. I can't explain it. For RTSP, I set it to a constant bandwidth, usage during the day or night should be similar, but then why is there so much corruption and error's during the day remotely, but when opening the same stream locally, there is no issue whatsoever.

Again, the camera's are working great. While opening the same stream locally, all of this works great! I have also tried doing it directly through the modem with port mappings, same result. So it's not limited to Mikrotik, just RTSP over the internet it seems?

Data throughput over the internet seems to be constant during the day or night, just during the day I have corruption and not during the night. :S Raising the bitrate also worsens the effect and lowering lessens the problem but nowhere to a workable level. I've included 2 images. One is the traffic of the Pi2 downloading 2 JPEG's (2 camera's) each minute. And the other is the internet out of the mikrotik to the internet providing me with the video signal at my home.

I'm wondering if anyone ever has a similar result or who can explain what is going on and maybe how to fix it? I'm at a loss to why this is happening.