Cameras playback troubleshooting

A GUIDE TO RECEIVING RAILCAM LIVE STREAMS FOR THE NON-TECHNICALLY MINDED!

Live streaming problems:- Does your video stream break up, freeze, or go blank?

Would you like this NOT to happen?

Take a few minutes then and read this guide. It has been kept as simple as possible with as little technical content as possible. Now read on …… Streaming can fail at several locations and for several reasons between the image leaving the cam and it arriving at your desktop. Not all of them can be fixed. Let’s start then at the source and work our way back to your PC and take a brief look at the possible issues along the way. You may well find some of this suprising.

THE CAMERA IP cams were never designed to stream high quality, real time footage over the internet. Most cams actually generate 2 or more live streams, a high-res one for watching locally, i.e. on the PC connected directly to the cam, and a low-res stream that can be watched remotely, in real time, over a network or the internet. This is because high-res streaming is difficult and there are a lot of variables to take into consideration. Railcam uses cameras in the opposite manner to that intended by the manufacturer. Why? Because everyone wants to receive high definition images on their desktops. We do it this way because this is what you want. The cams can output these images 24/7 however actually receiving them is a different matter altogether. Sometimes the problem is local to the cam. Like all modern electronics they are subject to outside influences. They often sit in environmentally hostile locations where the temperature can fluctuate between -10C and + 40C. A metal camera body will get far hotter/colder than its ambient surroundings. Try touching a car body that has been sat in the sun all day, then get inside the car with the windows closed and the air-con off. You will not enjoy the experience. The cam has to cope with similar conditions. Cams are sometimes located high up and are buffeted by strong winds, driving rain and snow. Or they freeze in winter. Think about what it is like trying to unfreeze your car door locks and windscreen on a winter’s morning and how cold the inside of the car is. The cam has to cope with similar conditions. On top of all this they are often located close to the tracks and are rattled and vibrated by passing trains, just at the exact time that you want to take a still or watch the stream. Little wonder that they occasionally glitch. When the cam fails there are several things that can be done. An operator from Railcam can electronically send an instruction to the cam to re-set itself. This will cure most common hangs however if the cam is locked to a point where it will not accept remote instructions, this will not work. Most cams have a setting within them that re-sets them automatically at a specified time every day. Sometimes this auto reset will save the day, but it may take several hours before this happens. If the problem is more serious than this then there is nothing that can be done remotely and the camera is effectively “down”.

If the cam has died, if there is a problem with the power supply to the cam (this can be power pack or mains supply related), or a problem with the network connection then it will require someone to physically attend the camera, diagnose the fault and then fix it. Most cameras are hosted by volunteers who have the cam connected to their own home network. If there is a problem with this network, then getting the feed to the Railcam servers is also going to be a problem. Network issues are discussed in more detail below.

THE HOST SITE

Where is the cam located? High up in a domestic property like Camden Junction, in a public business area like Ribblehead Station, up a pole like Farington, at the bottom of a domestic garden like Euxton or on a heritage site like Corfe. No two sites are the same and the networks and connections that they run on are all different. Most are hard wired, (connected directly by a network cable), although one or two run on Wi-Fi due to their remote locations. The difference between hard wired and Wi-Fi is huge. On a hard wired connection it is a “private” direct link to the host router. Wi-Fi can be made private, but is normally a shared resource with anyone else that has a password to access it, sharing the connection. A shared connection is always slower. A Wi-Fi connection is always, always slower than a hard wired one. Once the camera is connected to a network, it is now subject to other network traffic and has to take its place amongst the rest of the data whizzing around the wires. Just about every router on the market runs at two speeds, upstream and downstream. The one most important to most users is the downstream connection as this is the one that brings the data to you. The speed of the connection is usually referred to as bandwidth and is quoted in speeds of bps. What does this mean? Bandwidth. Bps. Bits per second. Gibberish to most people. So let’s use an analogy. Imagine the flow of internet traffic into your home as water flowing through a pipe. If the pipe has a wide diameter, and if the water pressure is high, a lot of water can flow at a high rate in a short space of time. The more water you can receive the higher your bandwidth. In drips per second! But only in theory. Imagine turning on every tap in the house, the shower, the outside hosepipe, flush all the toilets, turn on the shower, set the washing machine and the dishwasher going. How’s your water supply now? By the same principle your bandwidth at any particular connected device depends on outside factors, both internally and externally.

DOWNSTREAM

Let’s start internally. What is using your bandwidth? How many of these do you have running when trying to watch cams? Netflix? The biggest bandwidth hog of them all. Any other smart TV streaming service? Your phone or tablet via Wi-Fi or even hard wired? Do other member of your household have a pc and are they using it on-line? Is anyone playing an on-line game? Windows update? Anti-virus update? Bit torrent or any other p2p file sharing programme? Skype? Any device that needs an internet connection is using your bandwidth. Then ask yourself this. How many cams do I want to watch at once? Every camera has its own stream. Every camera uses bandwidth. Also ask yourself; how many diagrams do I want to watch? Every diagram generates its own stream. Whilst this is minimal compared to a cam feed it is still using bandwidth. Can your bandwidth supply all this or do you need to turn some taps off? What speed do you connect to your router at? Assuming that your pc and router are correctly configured take a look at your network cables. If your network cable has got “Cat 6” printed on it you probably have the best you can achieve. If your network cable has got “Cat 5” printed on it then this is also probably a pretty good connection. Avoid Wi-Fi as this will feel like swimming in treacle but without the sweetness. Not recommended. How do you connect to the internet? Fibre optic is best. Cable Broadband/IDSN can be hit and miss as this is a shared connection with the rest of your street and can be slow at peak times. Which is usually just when you want to use it. If using broadband get the best connection you can and complain loudly to your supplier if they fail to deliver. How powerful is your PC? Try this. Open a media player that will allow several instances to run at once. Something like VLC. Or open media player, quick time player, and divx player all at the same time. Now try to play a different video from your hard disk on each player at the same time. If your PC is not powerful enough to do this without lag/chop/synch issues then it is unlikely to be powerful enough to run multiple cam streams regardless of your bandwidth. If your PC has deficiencies in connection speed, ram, hard disk speed, hard disk storage space, connection speed or video card speed you need to think twice about how many streams it can cope with. Even if the windows are closed or minimised they are still connected.

UPSTREAM All the issues listed above also apply to the upstream flow. This is at the local sites where the cams are located. On top of all of the above, they also have to transmit the live stream to Railcam. As stated earlier, routers run at different speeds upstream than they do downstream. The reason for this is simple. Most users simply request data from the internet by clicking a hyperlink, e.g. clicking on the “CREWE 1” camera link. This sends a very short string of data to the server and it then transmits the data back to you. The amount of data going up is normally quite minimal whilst that coming down can be very big indeed. Hence upstream speeds are usually quite slow. Fortunately they are normally big enough to allow a cam feed to go out at full speed. Again though, it all depends on what other data the host site is transmitting. Bit torrent will severely affect the data flow, as will anything else that transmits a large amount of data or holds a high bandwidth connection open. Remember, these flows are coming from volunteer sites. No-one is paid for hosting. Everyone wants to use their own connection as they see fit. Don’t expect miracles!

THE INTERNET

The speed of the internet is not fixed. It transmits data by means of cutting information into small manageable pieces and then throwing them out onto the network. The individual packets use the fastest routes possible to reach the destination and are then re-assembled by the receiving host. This is true whether you are receiving, emails, images, web pages or live streams. It is similar to the road network, in that large items can be split, individually packaged, placed in different vehicles, delivered by different routes, and then reassembled at the other end. The network itself takes care of all this however bottlenecks can and do occur. Imagine closing a section of a busy motorway. All the local “A” and “B” roads soak up the traffic and everything slows to a crawl. Everyone going through this bottleneck arrives at their destinations late, and/or out of sequence. This exactly what happens with the internet. You can have the fastest connection in the world, but if there is a bottle neck between you and the source, your connection suffers. You don’t know where the problem is, there is nothing you can do about it. All you can do is complain that CREWE 1 has gone choppy. Whilst someone else thousands of miles away receives it perfectly because their signal is routed down the VSNL Transatlantic Cable but yours is trying to get through a server in Birmingham which has just suffered an outage because a JCB has just chopped the optical cable whilst digging up a collapsed sewer under the Ring Road…..

RAILCAM Whilst all of the above is taking place, Railcam have to try and deliver the streams to those that wish to view them. The streams arrive at Railcam HQ where they are re-transmitted out to the world in multiple formats, one connection for every user, every camera feed, every diagram feed, every chatroom message, every still image, and every posted hyperlink. The bandwidth used by Railcam is huge. Everything is monitored and tweaked for maximum efficiency. The feed from network rail is decoded, restructured so that it can work with the diagrams, and colour coded so that it looks pretty. The cameras all take auto stills as the trains pass the cams and they are published on-line for download. There is a lot happening. And it happens 24/7/365. In short, it’s a modern miracle that anything ever reaches anyone. So please be nice to the ops when a cam fails to deliver an image for a few seconds.

SUMMARY The cams and feeds are as reliable as we can make them. We accept that they can fail for a number of reasons however most of them are beyond Railcams control. Those that we can fix we do, as quickly as possible, as soon as we see them, or as soon as they are reported. Ensure that you have done everything possible at your end of the connection to receive the best signal possible and structure your expectations as to what is possible with your current Device, ISP and the world at large!

Enjoy………………