2014-09-12
The high quality adaptive multi-bitrate is a new key technology of PowerSmart for network videos after the ones Like MVC-3D encoding, Super De-interlace, low bandwidth optimization for iphone, multi-bitrate parallel encoding, Internet flow control, automatic loudness balance, and dynamic definition optimization, etc.
Based on this technology, the system is able to automatically select the proper code rate for live broadcast according to the different terminal decoding capacities and real-time network bandwidth of different users. Compared to the single code-rate or manual selection of code rate for live broadcast, it promotes greatly the user experience.
Implementation of adaptive multi-biterate requires the encoder’s capability of multi-channel video streaming output. In the meantime, frame alignment of videos with different code rates and timestamps must be available, or there will be a lot of defects during the transitions, such as:
1)During the switch between different bitrates, there are often pauses and delays caused by buffering.
2)Video rebounding, a video with duration of twenty minutes usually takes 40 minutes to play due to rebounding.
3)Simple alignment of timestamps, while scene detection and dynamic B frames are not available, so that the image quality is terrible.
CNTV is the first user to apply this technology to network live broadcasts of TV channels. Since March, the test of adaptive multi-bitrate live broadcast of CCTV News Channel has begun. Up to now, the official launch of program over the Internet proved a successful process. Viewers testified excellent experience, which greatly improved the click rate of the live broadcast channels of CNTV.
Notes on Interface: The red circle on the upper corner indicates the current bitrate for live broadcast.
Click the red circle area, a blue dialogue box pops up. In the blue dialogue box, there are a few bitrates of live broadcast available for selection. If watching at a certain fixed code rate, please select one code rate you need. If trying self-adaptation, please select the option of auto in the blue dialogue box.
The progress bar below red allows you to watch time shifting video playback during live broadcast. The duration of time shifting ranges over one hour.
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