What are Video Quality Metrics?
Video Quality Metrics are the parameters used for the quantitative assessment of perceived video degradation following transmission to the client-server.
Video quality metrics have a range of applications - from comparing the quality of different video codecs to measuring the efficacy of each encoding configuration. They are also used to assist in the production of videos and in “live quality of experience (QoE)” monitoring.
Types of Video Quality Metrics
These are the major video quality metrics used for objective evaluation:
- PSNR: It is the most commonly used video quality metric. But it has the lowest predictive value, so the results are inconsistent. Used by major platforms like Netflix and Facebook to compare different codecs and for similar use cases. Overall usage is declining.
- SSIM: Mostly used by technical experts like codec researchers and compression engineers. Usage is declining steadily. However, it has a higher predictive value than PSNR.
- SSIMPlus: Has high functional value and is regarded highly by engineers and users. However, it is a proprietary asset and not easily accessible.
- VMAF: Introduced first by Netflix but then converted into an open-source asset. VMAF is easily accessible and widely used. Designed specifically for evaluating the video quality of streams encoded for multiple-resolution rungs.
Benefits of Video Quality Metrics
- Determining the quantitative value of the quality of an encoded video.
- Providing key KPIs for comparing different video codecs and encoding ladders.
- Determining the viability and productiveness of particular encoding configurations.
- Tracking changes in video quality after deploying different methods of compression and encoding.