Differences
This shows you the differences between two versions of the page.
Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
x264_quality [2014/08/17 15:36] beandog |
x264_quality [2014/08/17 15:44] beandog |
||
---|---|---|---|
Line 6: | Line 6: | ||
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. | ||
Line 37: | Line 39: | ||
Here's the formula: | Here's the formula: | ||
<code> | <code> | ||
- | (((1 - [old SSIM]) / (1 - [new SSIM])) - 1) x 100 | + | (((1 - old) / (1 - new)) - 1) * 100 |
</code> | </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> | </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! |