Design and Implementation for Chroma Extensions Video Coding Based on AVS2 Platform
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摘要: 色度扩展视频编码是当前视频编码领域的一个热点研究课题。该文提出基于AVS2平台的色度扩展视频帧内编码的实现方案。仿444/422编码方案通过将输入图像中的色度分量下采样后,使用原有的420方式进行编码,以实现444/422编码。进一步,该文将帧内预测及环路滤波等编码模块无缝扩展到相应的444/422格式,实现444/422帧内预测编码。实验结果表明,对444格式和422格式序列,在高码率的情况下444/422帧内预测编码与仿444/422编码相比,U/V平均BD-rate的减少分别为31.44%/31.72%和18.85%/19.3%,而Y分量平均BD-rate的增加仅为0.5%。其中422色度帧内预测过程的算法优化减少Y/U/V BD-rate最高可达5.66%。与HEVC RExt编码相比,在低码率时,444/422帧内预测编码取得了更好或相近的编码性能。Abstract: Chroma extensions video coding is a hot topic in the field of video coding. Chroma extensions video coding scheme based on AVS2 platform is proposed. The most direct solution is pseudo444/422 coding. In this method, chroma component in the input image is down sampled by averaging adjacent samples. The core coding modules are still 420 coding. Further, this paper seamlessly extends intra prediction and loop filter to the 444/422 chroma format to implement 444/422 intra prediction coding. The experimental results show that compared with pseudo444/422 coding, in the case of high bit rate, the average U/V BD-rate saving is 31.44%/31.72% and 18.85%/19.30% for 444 and 422 test sequences respectively, with negligible increase of Y BD-rate (0.5% on average). The modification of the 422 chroma intra prediction algorithm achieves up to 5.66% Y/U/V BD-rate reduction. 444/422 intra prediction coding provides similar or better coding performance than HEVC RExt coding at low bitrates.
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Key words:
- Chroma extensions video coding /
- Chroma subsampling /
- AVS2 /
- Intra prediction
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表 1 8个测试序列
序号 序列名 短名 分辨率 比特数/样点 帧率 1 iceAerial_3840×2160_444(422)_10 bit ARL 3840×2160 10 30 2 iceRiver_3840×2160_444(422)_10 bit RVR 3840×2160 10 30 3 iceRock_3840×2160_444(422)_10 bit RCK 3840×2160 10 30 4 iceRock2_3840×2160_444(422)_10 bit RK2 3840×2160 10 30 5 Bubbles_4096×2160_24_10bit_444(422) BBE10b 4096×2160 10 24 6 Traffic_2560×1600_30_10 bit_444(422)_crop TFC10b 2560×1600 10 30 7 Bubbles_4096×2160_24_12 bit_444(422) BBE12b 4096×2160 12 24 8 Traffic_2560×1600_30_12 bit_444(422)_crop TFC12b 2560×1600 12 30 表 2 两组测试QP
传统QP组 超高质量QP组 P444/422及IP444/422编码器,
10-bit序列41, 48, 54, 61 14, 21, 28, 34 P444/422及IP444/422编码器,
12-bit序列57, 64, 70, 77 30, 37, 44, 50 HM16.6编码器 22, 27, 32, 37 2, 7, 12, 17 表 3 IP444/422与P444/422实验结果比较(%)
序列名 QP=14, 21, 28, 34 or 30, 37, 44, 50 QP=41, 48, 54, 61 or 57, 64, 70, 77 Y U V Y U V YUV444 ARL –0.59 –71.07 –47.01 0.08 –4.42 –2.31 RVR –0.21 –25.13 –39.49 0.43 4.49 1.36 RCK 0.18 –16.67 –14.77 0.43 7.47 7.88 RK2 0.21 –27.59 –18.88 0.43 2.29 0.51 BBE10b 0.17 –48.05 –38.37 0.13 –22.79 –15.33 TFC10b 1.85 –27.33 –55.52 0.53 –6.05 –9.89 BBE12b 0.24 –28.43 –18.69 –0.14 –15.12 –8.67 TFC12b 2.12 –7.27 –21.05 0.12 –3.76 –5.52 444平均 0.50 –31.44 –31.72 0.25 –4.74 –4.00 YUV422 ARL 0.08 –32.45 –21.12 5.45 –3.48 –1.82 RVR 0.58 –18.22 –29.51 3.58 4.79 1.99 RCK 0.65 –11.52 –9.44 3.94 8.96 8.74 RK2 0.71 –21.95 –13.92 3.89 1.92 1.75 BBE10b 0.06 –19.36 –18.34 1.27 –2.63 –0.68 TFC10b 0.81 –21.35 –38.49 3.46 –2.43 –5.66 BBE12b 0.43 –8.77 –6.16 0.18 –2.98 –1.37 TFC12b 0.90 –17.14 –17.42 0.30 –1.69 –2.81 422平均 平均 0.53 –18.85 –19.30 2.76 0.31 0.02 表 4 IP444/422编码与HM16.6实验结果比较(%)
序列名 QP=14, 21, 28, 34 or 30, 37, 44, 50 QP=41, 48, 54, 61 or 57, 64, 70, 77 Y U V Cpsnr Y U V Cpsnr YUV444 ARL –8.91 71.73 65.46 –2.32 –13.07 64.85 58.25 –5.98 RVR –8.66 87.33 117.26 –1.61 –6.25 100.29 97.44 –0.39 RCK –6.27 65.96 68.14 –3.26 –9.45 41.87 40.87 –6.92 RK2 –6.60 78.85 82.33 –3.04 –8.97 41.30 36.70 –6.84 BBE10b –21.38 144.38 100.00 1.08 –34.36 99.20 101.21 –14.43 TFC10b –33.59 100.00 100.00 71.28 –20.12 83.45 68.89 –8.13 BBE12b –20.58 100.00 100.00 12.25 –25.99 138.27 125.42 –2.67 TFC12b –32.97 100.00 100.00 66.38 –12.85 84.05 81.61 –1.69 444平均 –17.37 93.53 91.65 17.60 –16.38 81.66 76.30 –5.88 YUV422 ARL –5.32 11.11 12.37 –3.01 –6.08 7.18 5.96 –4.22 RVR –5.67 26.32 37.23 –1.82 –2.27 13.82 17.62 –0.31 RCK –3.18 25.05 24.41 –1.45 –4.34 3.84 2.76 –3.69 RK2 –3.10 29.96 29.46 –1.01 –3.66 1.06 –4.21 –3.51 BBE10b –11.98 23.52 23.79 –3.75 –16.58 18.07 25.56 –9.42 TFC10b –16.17 100.00 77.21 23.00 –6.84 18.05 14.23 –2.53 BBE12b –10.98 49.59 54.40 2.84 –7.30 31.64 36.23 0.66 TFC12b –15.42 100.00 126.25 22.01 –2.16 20.82 21.55 1.66 422平均 平均 –8.98 45.69 48.14 4.60 –6.15 14.31 14.96 –2.67 表 5 422格式色度帧内预测修改的实验结果(%)
序列名 QP=14, 21, 28, 34 or 30, 37, 44, 50 QP=41, 48, 54, 61 or 57, 64, 70, 77 Y U V Y U V ARL –1.68 –1.61 –1.73% –3.24 –3.02 –2.73 RVR –1.96 –1.01 –1.91 –2.91 –2.41 –2.48 RCK –1.57 –0.17 0.08 –2.82 –5.30 –5.66 RK2 –1.43 –1.22 0.09 –2.40 –2.50 –2.74 BBE10b –0.86 –0.82 –0.70 –2.48 –3.53 –3.37 TFC10b –1.05 –2.60 –1.25 –1.71 –2.60 –1.22 BBE12b –0.80 –2.54 –2.19 –5.44 –2.13 –0.77 TFC12b –1.14 –3.70 –4.47 –2.90 –2.20 –1.58 平均 –1.31 –1.71 –1.51 –2.99 –2.96 –2.57 -
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