Differences
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x264_quality [2014/08/17 15:34] beandog created |
x264_quality [2014/08/17 15:44] beandog |
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| Use SSIM or PSNR to gauge differences between encoding settings. | Use SSIM or PSNR to gauge differences between encoding settings. | ||
| + | |||
| + | ==== SSIM ==== | ||
| When comparing two values, here is the formula to discern what percentage amount something has improved. | When comparing two values, here is the formula to discern what percentage amount something has improved. | ||
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| x264 [info]: SSIM Mean Y:0.9751283 (16.043db) | x264 [info]: SSIM Mean Y:0.9751283 (16.043db) | ||
| </code> | </code> | ||
| + | |||
| + | Here's the formula: | ||
| + | <code> | ||
| + | (((1 - old) / (1 - new)) - 1) * 100 | ||
| + | </code> | ||
| + | |||
| + | Here's a simpler visualization: | ||
| + | |||
| + | <code> | ||
| + | 1 - 0.9613678 = 0.0386322 | ||
| + | 1 - 0.9751283 = 0.0248717 | ||
| + | 0.0386322 / 0.0248717 = 1.55325932686547361057 | ||
| + | 1.55325932686547361057 - 1 = 0.55325932686547361057 | ||
| + | 0.55325932686547361057 * 100 = 55.325932686547361057 | ||
| + | </code> | ||
| + | |||
| + | Rounding it out to an integer, would be 55, for a result of 55%. So when encoding this particular video at double the bitrate, the SSIM increases by 55%. Not bad! | ||
