(Beaverton, Oregon - June 30, 2015)
isovideo announces their joint paper titled
“HEVC/AVC Coding Results of Noise-reduced 4:2:0 and 4:4:4 HDR/WCG Video”
was presented at the 21st Joint Collaborative Team on Video Coding (JCT-VC)
meeting, 2015.
In addition, bitstreams were played at the meeting on a SIM2 professional
HDR monitor in order to show the gains provided by this highly accurate, quality-optimized processing.
As the media entertainment industry rapidly adopts HDR/WCG video,
one of the challenges is to reduce noise in HDR content,
in order to further reduce HEVC/AVC bitrate, while maintaining sufficient detail, sharpness and contrast.
A total of 9 challenging video clips, selected in the HDR Call for Evidence (CfE) study,
were then noise reduced by isovideo's proprietary game-changer-award winning Viarte prior to HEVC/AVC encoding,
in order to provide a visual comparison with the same clips coded without noise reduction.
For each of the test clips, both HEVC CQP (Constant Qp 444 and 420)
and CRF 444 (Constant Rate Factor) runs, as well as AVC CRF 420 runs were performed.
Detailed comparisons of original vs denoised, and HEVC vs AVC were given as graphs of PSNR vs log-bitrate.
Our analysis of the CQP runs show that denoised compressed versions of the sequences gain significantly
on PSNR at a give bitrate, and bitrate reduction at a given PSNR. For example,
for the three noisiest clips, bitrate reductions of about 13x, 8x, and 5x,
respectively at 47db PSNR were achieved. The other three relative noisy clips also see about 3x
reduction at 47db PSNR. On the other hand, for a given bitrate, denoised compressed versions gain
significant PSNR. For examples, the three noisiest clips at 3Mbps gained about 5db, 3db and 3.5db PSNR, respectively.
The comparison of HEVC vs AVC (CRF results) runs show that for the noisiest three clips,
denoised AVC has PSNR/size gains over HEVC originals above about 2Mbps (43db), 3Mbps (40db),
and 3Mbps (44db). At higher bit rates, this advantage extends to 4db, 4db, and 3.5db respectively.
Alternatively, bitrate reductions by about 7x, 3x, and 2.5x respectively occur at 47db.
The significance of the results is that the denoise gains easily exceed what
one may expect for moving to a next generation encoder. For example, the three noisiest
clips show about two encoder generations of gain around 42-46db.
It has been demonstrated that isovideo's high quality MC noise reduction processing prior to HEVC/AVC
encoding can be very effective in reducing bitrates and/or increasing PSNR,
while also providing an enhanced immersive viewing experience, both for conventional and HDR video streams.
For more information about the paper, please follow link here.
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