A core technical objective of iSize is to find the optimal way to preprocess (or precode – in our nomenclature) any input video into a (typically) smaller pixel stream, such that any video encoder can achieve the best video quality at a given bitrate, or save the maximum amount of bits for a given perceptual quality level. We are especially interested in this problem given that perceptual quality can now be measured with advanced perceptual quality metrics from the literature, e.g., using the fusion of multiple quality metrics (akin to VMAF of Netflix) or via other advanced metrics.

We present here seven Full HD (FHD) test video sequences from Xiph.org, encoded via our platform at BitSave.tech. They have been chosen to represent a wide variety of content with rapid/irregular motion, rich texture details, and camera motion/zoom. Each sequence was compressed with the HEVC encoder at 5mbps, 8.5mbps and 14mbps, with and without the use of the iSize deep precoder for perceptual optimization. The examples illustrate

  • the noticeable perceptual quality improvement brought by the iSize precoder at the same bitrate (iSize+HEVC at 5mbps versus HEVC at 5mbps),
  • comparable or higher quality at 40% lower bitrate than the HEVC encoder (iSize+HEVC at 5mbps versus HEVC at 8.5mbps, and iSize+HEVC at 8.5mbps versus HEVC at 14mbps).

The full details of our encoding and viewing tests are discussed in the associated article in our news page. Each of the sequences below presents the video in two halves (since we want to show two concurrent videos in 1080p resolution, we can only show the half side of each video at any given viewing). The full set of videos can be downloaded via this link for independent inspection of the HEVC bitstream playback of each case.

aspen_1080p30_i5_c5_lhs
iSize+HEVC at 5mbps (VMAF:94.2) versus HEVC at 5mbps (VMAF:85.6)

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iSize+HEVC at 5mbps (VMAF:94.2) versus HEVC at 8.5mbps (VMAF:90.7)

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iSize+HEVC at 8.5mbps (VMAF:98.6) versus HEVC at 14mbps (VMAF:94)

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controlled_burn_1080p30_i5_c5_lhs
iSize+HEVC at 5mbps (VMAF:99.4) versus HEVC at 5mbps (VMAF:91.2)

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iSize+HEVC at 5mbps (VMAF:99.4) versus HEVC at 8.5mbps (VMAF:94.1)

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iSize+HEVC at 8.5mbps (VMAF:100) versus HEVC at 14mbps (VMAF:96.1)

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crowd_run_1080p50_i5_c5_lhs
iSize+HEVC at 5mbps (VMAF:76.5) versus HEVC at 5mbps (VMAF:67.8)

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iSize+HEVC at 5mbps (VMAF:76.5) versus HEVC at 8.5mbps (VMAF:79.9)

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iSize+HEVC at 8.5mbps (VMAF:89.5) versus HEVC at 14mbps (VMAF:89.3)

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old_town_cross_1080p50_i5_c5_lhs
iSize+HEVC at 5mbps (VMAF:100) versus HEVC at 5mbps (VMAF:92.5)

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iSize+HEVC at 5mbps (VMAF:100) versus HEVC at 8.5mbps (VMAF:93.6)

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iSize+HEVC at 8.5mbps (VMAF:100) versus HEVC at 14mbps (VMAF:94.2)

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rush_field_cuts_1080p30_i5_c5_lhs
iSize+HEVC at 5mbps (VMAF:98.6) versus HEVC at 5mbps (VMAF:88.8)

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iSize+HEVC at 5mbps (VMAF:98.6) versus HEVC at 8.5mbps (VMAF:94.1)

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iSize+HEVC at 8.5mbps (VMAF:100) versus HEVC at 14mbps (VMAF:96.6)

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touchdown_pass_1080p30_i5_c5_lhs
iSize+HEVC at 5mbps (VMAF:100) versus HEVC at 5mbps (VMAF:96)

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iSize+HEVC at 5mbps (VMAF:100) versus HEVC at 8.5mbps (VMAF:97.4)

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iSize+HEVC at 8.5mbps (VMAF:100) versus HEVC at 14mbps (VMAF:98.1)

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tractor_1080p25_i5_c5_lhs
iSize+HEVC at 5mbps (VMAF:100) versus HEVC at 5mbps (VMAF:99.3)

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iSize+HEVC at 5mbps (VMAF:100) versus HEVC at 8.5mbps (VMAF:99.7)

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iSize+HEVC at 8.5mbps (VMAF:100) versus HEVC at 14mbps (VMAF:99.8)

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