Search form

AWS Elemental Blog

Video Processing Perspectives

How Does Quality-Defined Variable Bitrate (QVBR) Control Improve Video Quality?

How Does Quality-Defined Variable Bitrate (QVBR) Control Improve Video Quality?

Quality-defined variable bitrate (QVBR) control is a new rate control mode designed to deliver consistently high-quality video viewing experiences that keep your audiences coming back for more, and your budget under control – saving you up to 50% on storage and delivery costs in the process.

If you’re interested in learning how QBVR works, watch our on-demand webcast for a detailed explanation of the technological and business benefits. You can watch the QVBR webcast here.

In the meantime, this short, visual summary illustrates how QVBR improves video quality when compared to constant bitrate and variable bitrate modes:

Figure 1: How constant bitrate affects video quality

  • Using bits when not needed, because you've already met video quality requirements
  • Not having enough bits when needed, resulting in lower video quality
  • Different types of content require different bitrate choices
  • Operator must take a best-guess approach when selecting the bitrate

Figure 2: How variable bitrate affects video quality

  • Encoder uses as many bits as required to hit average bitrate, even if not needed for video quality
  • Operator needs to pick the average bitrate per asset
  • Selecting average to peak ratio is not straightforward
  • Different settings needed for different content types
  • Can’t get to optimal bit savings unless you encode multiple times and iterate to get lowest bitrate required by asset

Figure 3: How quality-defined variable bitrate control benefits video quality

  • Bitrate control that automatically adjusts to different kinds of content and scenes
  • Encoder automatically adjusts actual quantization
  • Built on statistics developed for perceptual encoding such as AQ, MD, and RC
  • Save bits when quality level is reached (don't use what you don't need)
  • Use more bits to maintain quality level for complex scenes get

At the 2018 NAB Show, NewBay Media’s Video Edge magazine honored QVBR with a best in show award. AWS Elemental is pleased to be recognized, but what’s most gratifying is knowing our customers are using QVBR to address complex but very common operational problems in ways that save them time and money. You can get more info about the specific video quality problems QVBR solves, its advantages, and its simple set up and operation here: What is Quality-Defined Variable Bitrate (QVBR)?