The Graphics Plugin currently supports two different types of compression and the sending of uncompressed data.

The following options are available:

• No compression (raw)

  • Benefit: No CPU spent on the renderer to compress and no CPU spent on the client to decompress. Usually very good for SD on good networks. Very good on clients with weak CPU and a good network card.

  • Problems: For HD the amount of data is large, and it will typically take longer to transfer over the network than compressed alternatives and it will use a lot of network capacity.

• Portable Network Graphics compression (PNG)

  • Benefit: Compresses graphics very well. On very slow networks this compression will have a very small footprint, which is useful for example over a Digital Subscriber Line (DSL) network, 10Mbit networks or district offices rendering on a renderer in a central office.

  • Problems: Can use a lot of CPU to compress and decompress, which will be a problem on slower computers. Generally outperformed by the other two options and mostly useful for special cases.

• Run-length Encoding compression (RLE)

  • Benefit: Compresses graphics well. Is easy and fast to compress and decompress. Uses a small fraction of the space for a 1080i field compared to no compression so network footprint is quite good. For HD on fairly updated computers it will often perform best. Also does very well on 100Mbit networks. Has special handling that exploits the nature of TV-graphics and NLE graphics which contain bigger open areas, for example lower thirds, over the shoulders, and so on.

  • Problems: Uses CPU on the renderer and the client, so less powerful machines might get better performance with no compression. The smaller amounts of data with SD negates some of the compression benefits, but can often be best for SD too. Might not give much benefit if there are big horizontal gradients.

Lab testing has shown that the general advice above is not always sufficient - only on-site testing can determine what works best for a given network.