VVC is the successor to HEVC and the latest testing by b<>com shows that VVC outperforms HEVC for 8K video by around 41%. Study also concludes that higher frame rates must be considered for 8K.
VVC vs. HEVC
AV1 is gaining traction as a royalty-free video codec but VVC (Versatile Video Coding), also known as H.266, is another a strong contender to supplant the much-maligned HEVC, also known as H.265.
The first TVs with VVC decoding are expected to launch next year so what can we expect to see? According to b<>com's latest testing – highlighted by the 8K Association – VVC can reduce bitrates for 8K video by an average of 41% compared to HEVC in subjective testing, or 26-35% depending on the objective metric used.
- "These results show that the average subjective gain offered by VVC over HEVC for 8K video is around 41%. At the same time, objective improvement ranges from approximately 26% to 35%, depending on the selected objective metric," said Charles Bonnineau, PhD student at IRT b<>com, TDF, and INSA Rennes.
Laboratory environment used for the test, based on ITU-R BT500-13. Photo: b<>com
Higher frame rates required for 8K
However, there are a number of factors that come into play. For 8K video, the industry must consider higher frame rates of 100/120fps, the author noted. Movies and series today are typically shot in 24fps.
The bitrate required for 8K video also varies a lot depending on the scene.
- "For the 'OberbaumSpree' [video clip] motion blur appears on the scene due to a continuous horizontal camera traveling. It shows that higher frame rates, e.g., 100/120fps, must be considered to fully benefit from the 8K resolution. Those curves also show that the bitrate required to reach the source quality using VVC ranges from 11 Mbps to 180 Mbps depending on the sequence," said Charles Bonnineau.
The test compared VVC to HEVC using six video sequences sourced from ITE in Japan and Fraunhofer HHI in Germany. It was not specified which display was used.
In addition, for most tested scenes, a significant visual difference between uncompressed 4K and 8K was observed, the study concluded.
Study: VVC compared to HEVC
The findings were summarized as follows:
- VVC outperforms HEVC for 8K video with around 41% bitrate saving on average for similar visual quality.
- The required bandwidth to convey 8K video at high quality is content-dependent and may vary in the range of 11 Mbps to 180 Mbps with VVC.
- Quality enhancement brought by 8K resolution over 4K is content-dependent: high-quality acquisition sensors are essential, and a high frame rate (>60fps) is necessary for content containing significant motion.
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