Reference Picture Resampling (RPR) is a powerful tool that allows improving video coding efficiency of next generation codecs like Versatile Video coding (VVC) or Enhanced Compression Model (ECM). This feature is well...
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ISBN:
(纸本)9781510679344;9781510679351
Reference Picture Resampling (RPR) is a powerful tool that allows improving video coding efficiency of next generation codecs like Versatile Video coding (VVC) or Enhanced Compression Model (ECM). This feature is well designed to support frame changing resolution without inserting an instantaneous decoder refresh (IDR) or intra random access picture (IRAP). Video streaming and low delay scenarios can take advantage of RPR to ensure a smooth frame-based bit-rate adaptation, compared to traditional techniques that can generate bitrate leaps. This paper proposes an encoder method to select the picture resolution change parameters effectively depending on the video signal characteristics. The picture resolution change decision is based on a low complexity neural network, and it is performed before the encoding process without RD-score computations making this approach suitable for real time and low delay implementation. The experiments under Random Access (RA) and All Intra (AI) configurations of the VVC Test Model (VTM-21.1) show that the proposed method can bring luma BD-rate gain improvement of 1.46% and 0.95% respectively compared to the VVC Test Model anchor.
Considering industry needs for further coding efficiency improvements, the Joined Exploration Team on Video (JVET) established by ITU-T and MPEG for standardizing VVC, has developed a new Enhanced Compression Model (E...
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ISBN:
(纸本)9781510654372;9781510654365
Considering industry needs for further coding efficiency improvements, the Joined Exploration Team on Video (JVET) established by ITU-T and MPEG for standardizing VVC, has developed a new Enhanced Compression Model (ECM) based on VVC which is a common area for testing future video coding algorithms. The Versatile Video coding (VVC) supports Reference Picture Resampling (RPR) to change frame resolution without inserting an Instantaneous Decoder Refresh (IDR) or Intra Random Access Picture (IRAP). This feature is particularly well adapted to video streaming and low delay scenarios since it allows seamless frame-based bit-rate adaptation, whereas traditional techniques based on stream switching between coded video chunks at fixed resolution can generate bitrate leaps. ECM implements several new tools that improve the coding efficiency compared to VVC, but some of them were not designed to support RPR. In this paper, we first discuss some necessary adaptations to implement RPR in ECM for these new coding tools. At low bit rate, RPR may improve the coding performance of ECM for luma component, and the coding complexity is reduced. However, RPR may show PSNR drop for chroma component because it performs an additional down-scaling filtering on samples that were already filtered from the original canonical 4:4:4 content to create the 4:2:0 format. Then, in a second part, some modifications of RPR to re-scale luma and chroma differently are proposed. It is shown that it improves ECM efficiency in the context of both super-resolution and low-delay coding use cases.
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