Category Archives: H.264

Understanding Video Traffic Interference

Understanding Video Traffic Interference

Here is a great discussion on network traffic and video over IP.

By Phil Hippensteel On November 28, 2012

Dear Professor Phil,
At lunch several of us were discussing our new videoconferencing deployment. A debate developed. Some of the group said UDP traffic such as VoIP would be the most likely to interfere with the videoconferencing traffic because it gets high priority, just like the video. Others argued that traffic from TCP data applications would be more of a problem because of their socalled “bursty” nature. Who is correct? Terrance, Canton, OH

Terrance,

Both will cause problems but for very different reasons. The group arguing that VoIP will cause problems is assuming some things. First, to interfere with the video, the voice traffic must be on the same VLAN as the video traffic. Often it is not. Second, if the VoIP and video traffic are on the same physical LAN and have the same priority settings, the VoIP must be using enough of the bandwidth that it constrains the bandwidth available to the video conferencing devices. With good design, this should never happen. So, to summarize this side of the argument, VoIP can interfere with videoconferencing, but only if the network design is inadequate.
On the other hand, TCP traffic such as database applications and web traffic can have unpredictable effects on video conferencing traffic. The burstiness of TCP applications is virtually uncontrollable. It’s the way that TCP protocol works. So, when TCP traffic and video share a physical network, TCP has a tendency to grab all of the bandwidth it can. In addition, the TCP algorithm groups the packets in blocks of packets that can vary in size which is dependent on network conditions and application design. The resulting bursty nature of the traffic increases variation in delivery relative to time, or jitter. If the jitter becomes excessive, the jitter buffers can’t compensate and packets are dropped. This means that it is important to separate video conferencing traffic from data applications using VLANs or completely separate networks.
In addition to all of these facts, my experience has taught me that the group arguing that TCP traffic is more of a problem is indeed correct.

Phil Hippensteel, Ph.D., has spent more than forty years in higher education and now teaches for Penn State Harrisburg.

Posted in DIRAC, H.264, JPEG2000, MPEG-2, Video Networking - Enterprise IPTV, Video Streaming - Webcasting | Tagged , , | Leave a comment

Things to Consider When Building an IP Video Application

Creating Your Content
The core of an IP Video solution is encoding. Encoders come in all shapes and sizes and with varying degrees of reliability, functionality, and scalability. Some encoders are re-purposed computers with capture cards while others are purpose-built network appliances that have serving technology.  Determining the best compression format must also be addressed.  However, your general requirements and budget will likely make the choice for you.

Managing and Securing Your Content

IP Video is a powerful tool, capable of communicating to anyone, anywhere. That doesn’t mean you want your message in the hands of everyone. Being able to manage and secure your IP video solution is crucial to creating an effective viewing experience while protecting your content from prying eyes. Continue reading

Posted in Applications - Industries, Broadcast, Government and Military, H.264, IPTV, JPEG2000, MPEG-2 Basic Training, Professional AV - Pro AV, Sports, Video Networking - Enterprise IPTV, Video Streaming - Webcasting | Tagged , , , , , , , , , | Leave a comment

IPTV and the Spanning Tree Process

By Phil Hippensteel

IPTVDear Professor Phil,

We’re using IPTV at our school and have discovered a situation that we don’t understand. The video is delivered over a group of Ethernet switches. When we investigate the individual links, we find some links carry large amounts of traffic, while others transport no traffic at all. Can you offer a possible explanation?
Barry, Alexandria, VA

Barry,

A very likely explanation is that the switches have a loop circuit within them and the spanning tree process has automatically disabled a link. That’s not bad. In fact, it is a very necessary requirement.

IPTVThe spanning tree algorithm is used with Ethernet switches to routinely remove loop circuits. If these loops weren’t removed, a single IP packet carrying video could loop endlessly while consuming valuable bandwidth. To understand essentially how spanning tree works, look at the diagram of a hypothetical network of switches. The simple hexagon with a diagonal has three loops in it: A-D-E-F-A, A-D-C-B-A, and A-B-C-D-E-F-A.

The spanning tree algorithm picks a switch, say B, to be the root of a tree that will be formed. A series of spanning tree messages is sent over the links starting from the root switch, B. These messages allow the switches to discover that a loop exists. For example, in our drawing, switch E received messages from both F and D. Therefore, E disables the link to one of them, say the one to D. In the same manner, C chooses to disable its link to D. After these two operations, the loops are eliminated and the entire structure forms a tree. Now every switch is connected to every other switch through exactly one path. Occasionally, technicians disable the spanning tree operation to reduce traffic, but that is almost always a bad idea.

Phil Hippensteel, Ph.D., has spent more than forty years in higher education and now teaches at Penn State Harrisburg.

Posted in Applications - Industries, Broadcast, Education, FAQ, Government and Military, H.264, IPTV, MPEG-4 H.264, Professional AV - Pro AV, Sports, Video Compression, Video Networking - Enterprise IPTV, Video Streaming - Webcasting | Tagged , , , , , , , , , | Leave a comment

Video Over IP Solutions – NAB Preview Video 3

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To webcasting solutions such as the Minicaster or VidBlaster.  No matter what your webcasting needs are these two solutions employ the technology to efficiently and effective broadcast over the internet to a diverse range of audiences.

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Stay tuned for more VidOvation informational videos…

Posted in Applications - Industries, Broadcast, H.264, NAB Show, News, NHL - National Hockey League, Professional AV - Pro AV, Trade Shows, Video Compression, Video Networking - Enterprise IPTV, VidOvation Video Report and Newsletter | Tagged , , , , , , , , | Leave a comment

NAB Preview Video 1: The VidOvation Difference Newsletter

Check out why VidOvation is becoming one of the most requested solutions providers.

VidOvation realizes every need is different and we specialize in finding superior products to match some of the most demanding needs. Call today or stop by our NAB booth to experience the VidOvation difference. Visit our NAB Booth # SU11012. Register for a FREE Exhibits Only Pass with VIP Code LV2863. Continue reading

Posted in H.264, NAB Show, News, Trade Shows, Video Networking - Enterprise IPTV, Video Streaming - Webcasting, VidOvation Video Report and Newsletter | Tagged , , , , , , , , | Leave a comment