Lossy Compressed Image Formats Study

Mozilla Corporation, October 2013
Original: http://people.mozilla.org/~josh/lossy_compressed_image_study_october_2013/

Update by Dominik Homberger, November 2013
Now with VP8, VP9 and actually WebP Snapshot (Nov 2013)

Introduction

This study compares the compression performance of four different image formats: JPEG, JPEG XR, WebP, and HEVC-MSP, VP8, VP9 and actually WebP from git.

Quality Comparison Algorithms

Image Sets

  1. Lenna: Widely used Lenna image, a 512x512 PNG.

Methodology

The same from the link: http://people.mozilla.org/~josh/lossy_compressed_image_study_october_2013/

Additional software for this study:

Results from Nov 2013 (Raw Data)

The following Excel (.xlsx) files contain the full results for this study. These can be opened with MS Excel or LibreOffice 4.1.x.

Change over JPEG Quality Range at Equivalent Y-SSIM

The goal for this section is to visualize file size ratios, where JPEG is always 1.0, over a range of JPEG qualities. File sizes are recorded at equivalent Y-SSIM values. In each graph, the Y axis represents file size ratios. The X axis represents a range of JPEG quality values. There is one graph for each image set.

Graph 1: Lenna.png, Y-SSIM quality metric, lower is better

Change over JPEG Quality Range at Equivalent RGB-SSIM

The goal for this section is to visualize file size ratios, where JPEG is always 1.0, over a range of JPEG qualities. File sizes are recorded at equivalent RGB-SSIM values. In each graph, the Y axis represents file size ratios. The X axis represents a range of JPEG quality values. There is one graph for each image set.

Graph 1: Lenna.png, RGB-SSIM quality metric, lower is better

Change over JPEG Quality Range at Equivalent IW-SSIM

The goal for this section is to visualize file size ratios, where JPEG is always 1.0, over a range of JPEG qualities. File sizes are recorded at equivalent IW-SSIM values. In each graph, the Y axis represents file size ratios. The X axis represents a range of JPEG quality values. There is one graph for each image set.

Graph 1: Lenna.png, IW-SSIM quality metric, lower is better

Change over JPEG Quality Range at Equivalent PSNR-HVS-M

The goal for this section is to visualize file size ratios, where JPEG is always 1.0, over a range of JPEG qualities. File sizes are recorded at equivalent PSNR-HVS-M values. In each graph, the Y axis represents file size ratios. The X axis represents a range of JPEG quality values. There is one graph for each image set.

Graph 1: Lenna.png, PSNR-HVS-M quality metric, lower is better

Bibliography and Relevant Reading

  1. WebP Compression Study, Draft 0.1. May 18, 2011. Google.
  2. HD View: JPEG XR updates. May 30, 2013. Matt Uyttendaele (Microsoft).
  3. Structural similarity. Wikipedia.
  4. The SSIM Index for Image Quality Assessment.
  5. IW-SSIM: Information Content Weighted Structural Similarity Index for Image Quality Assessment.
  6. Nikolay Ponomarenko homepage - PSNR-HVS-M download page.

Contributors