Production and Capture Considerations

If you’re not intent on live streaming, but wish to capture a live switching session, you would likely record at full resolution using the Record button (rather than Stream). The high quality captured files can then be used later in a DDR, or perhaps be transferred to another computer (even on a different platform) for external processing or editing.

You can always convert these files to a streaming file format if you later decide you’d like to supply them for on demand Internet viewing. This lets you retain best quality right through to final output. When you eventually encode for streaming, you can choose settings that best suit the intended audience and streaming environment. At the very least, if (perhaps to save conversion time) you capture video for web distribution, it’s best to capture it at least at the size that you intend for final output. This helps ensure satisfactory video quality for your viewers. When video is compressed (as it invariably is for web viewing) you can lose important detail.

Other Parameters

Other variables to keep in mind when you’re creating video for the web are contrast and motion. During video encoding for web distribution, a fair amount of video information and detail can be lost. For this reason, good lighting of your source video is essential.

Also, web streaming doesn’t handle detail, transitions and motion all that well: So your best shots should be close up, and without a lot of movement. Too, audio from cameras and camcorders is rarely as good as that from external microphones. You should at least use a clip-on lavaliere microphone, if not a directional or shotgun microphone to be sure you record only the audio you really want. Finally, for high quality streaming, consider using a 720p session, even when your cameras may be SD and interlaced (there is no particular benefit to working in SD when your goal is a smaller streaming output.

On Demand or Live Streaming

Not all streaming is live streaming. The difference is similar to watching a television program you previously recorded at a time convenient for you versus watching a live event. On demand streams are stored on a server (often supplied by an external service provider), ready to be transmitted whenever a viewer wishes. Live streams are available at the time they are broadcast, such as during a live concert or event.

Bandwidth Considerations

You’ll often hear the term ‘bitrate’ in connection with streaming. This expression refers to data throughput per second (generally measured in Kilobits per second, or Kbps.) You could think of this as being like water flowing through a hose. You control the ‘faucet’, because you get to choose the streaming Profile setting in the system’s Configuration panels. However, you don’t own the ‘hose’ – or, at least, not the entire hose.

Once the stream leaves your immediate environment, even if you can supply good throughput locally, bandwidth may be constricted elsewhere along the transmission path. The level of Internet traffic can impose limits, but another major factor is the sort of connections your viewing audience may have. Consider an example scenario: Even though you know that most of your audience is going to connect to your program using (relatively slow) wireless devices, you use a very high outgoing bitrate – thinking that this will surely be enough to fill the need. The fact is, though, a high bitrate actually ensures their experience will be poor. The client player tries to play at the specified bitrate, but (in this example) the wireless bottleneck impedes flow. It is as if you connected a fire hose on your end, giving them a suitable high capacity nozzle for their end – but in the last stage of flow, the stream must pass through a small garden hose. Sadly, the stream will be quite insufficient, and output from the ‘nozzle’ (the client player) will falter badly.

For reliable performance, try to ensure the potential upload bandwidth from your system to the net is around twice the bitrate you choose. You can broadcast at a rate closer to your actual ceiling, but reliable performance cherishes headroom.
Also consider the expected download abilities of your viewers. Ideally, a safety margin 1.5 times the stream’s bitrate is desirable. This may mean you need to consider using a lower resolution, or lower framerate for your stream. Doing this when required will generally deliver a smooth result, and is the recommended course.
See Speed Tests in section Diagnostics and Troubleshooting.

Streaming Media Providers

Using a commercial streaming media provider (Content Delivery Network, CDN) bypasses otherwise high-bandwidth requirements for the encoding computer. When you have made arrangements for a streaming media provider to distribute your stream, the encoder only needs enough bandwidth to get a single a/v stream to the provider. All end users connect to the provider to view the stream.

Most streaming providers have access to massive bandwidth (and often, with very little notice, they can scale up your allotment to meet a temporary need.) Since your local bandwidth is really only used for uploading a single stream, you can send a high quality stream, secure in the knowledge that it will not degrade as soon as a second viewer attempts to see it.