Presets and Tuning Options
Presets
Aurora5 has ten predefined presets that optimize the trade-off between encoding speed (encoded frames per second) and compression efficiency (quality per bit in the bitstream). The default preset is medium. It does a reasonably good job of finding the best possible quality without spending excessive CPU cycles looking for the absolute most efficient way to achieve that quality.
When you use faster presets, the encoder takes shortcuts to improve performance at the expense of quality and compression efficiency. When you use slower presets, Aurora5 tests more encoding options, using more computations to achieve the best quality at your selected bit rate (or in the case of –crf rate control, the lowest bit rate at the selected quality).
The presets adjust encoder parameters as shown in the following table. Any parameters below that are specified in your commandline will be changed from the value specified by the preset.
- ultrafast
- superfast
- veryfast
- faster
- fast
- medium
- slow
- slower
- veryslow
- superslow
Tune Options
There are a few tune options available in Aurora5.
| Tune | Effect |
|---|---|
| default | Default configuration, no special optimization |
| screen | Improve encode quality for screen content |
| psnr | Obtain higher PSNR scores and may have some impact on perceptual visual quality |
| ssim | Obtain higher SSIM scores and may have some impact on perceptual visual quality |
| zerolatency | No rc-lookahead, no B-frames |
| game | Under development. |
| vmaf | Under development. |
| movie | Under development. |
| universe | Under development. |