When streaming to Ustream, you can send either a single bitrate or multiple bitrate streams to your Ustream channel ingest point.
Why are multiple bitrates important?
Higher quality (e.g. HD) streams require higher bitrates and greater bandwidth. While some viewers might be on fast connections and are able to watch an HD stream, other viewers will be on slower connections and the live stream or recorded video will pause (rebuffer) frequently for them. When sending only a single bitrate stream, a solution to this is to send a medium-quality stream so that both groups of viewers can watch a stream that is of acceptable quality, but not so high as to cause buffering. The downside of this approach is that the viewers on fast connections aren't getting the best quality, and the viewers on slow connections might still experience some buffering. With multiple bitrate streaming, you don't need to make this compromise and you instead send multiple quality streams so each viewer can watch a stream optimized for their bandwidth. For example, someone on a fast internet connection can view an HD-quality stream while someone on a slower connection can view a lower quality stream without buffering, and someone with a medium-quality connection can view a medium-quality stream.
Ustream Cloud Transcoding
While it is preferable to stream in multiple bitrates, one challenge of multiple bitrate streaming is you need to have a powerful processor to encode multiple streams in parallel, and ample bandwidth to send multiple streams in parallel. In many situations, bandwidth is limited and the encoder is only capable of sending a single stream. This is why we developed the Ustream Cloud Transcoding service. Available with Ustream Pro Broadcasting plans, Ustream's Cloud Transcoding service provides the benefits of multiple bitrate streaming from a single stream ingest. You can send a single high resolution stream, but your viewers can receive multiple streams optimized for their connections. Broadcasters on a Ustream Enterprise plan can enable up to three lower bitrate feeds to be created via Cloud Transcoding in addition to the original, highest quality feed that is passed-through to viewers. Broadcasters on free or Silver level accounts can choose to enable transcoding up to 480p. Users above Silver level Pro Broadcasting can choose up to 720p.
In order to set up Cloud Transcoding for one of your Ustream channels, log in to your account then go to the channel settings tab for the channel you wish to enable. Choose Broadcast settings, then Multi-quality streaming settings. You will see a list of checks that allow you to set what versions of your streams you wish to have transcoded:
Multiple bitrates from external encoders (local transcoding)
Some encoders will allow you to send up to 4 bitrates from your encoder and these will be passed through to the player as you send them. They will be labeled Best, High, Med, Low. Please check the manual for your specific encoder to determine how this can be done. We have included two examples below:
- Sending multiple stream qualities in Wirecast
- Sending multiple stream qualities in Flash Media Live Encoder
Please note that when you send multiple bit rates in this manner, they are not being generated in the cloud- you will need to have the additional bandwidth at your location to successfully send multiple bit rates.
Send a single stream (ideally 720p or 1080p) and on Ustream servers, these are re-encoded into 4 bitrate / resolution streams.
- 720: 1280x720 1500 kbps video 128 Kbps audio
- 480: 854x480 1000 kbps video 128 kbps audio
- 360: 640x360 750 kpbs video 128 kbps audio
- 240: 426x240 500 kpbs video 56kbps audio
- 64k: "Audio Only" 426x240, 6 fps video with 56kbps audio