[FFmpeg-user] What parameters were set in preset?

[Luke Davis]

On Wed, 20 Aug 2014, Qianliang Zhang wrote:

> You know, while doing x264 encode, -preset can do a good job. Current
> presets in descending order of speed are: ultrafast, superfast, veryfast,
> faster, fast, medium, slow, slower, veryslow, placebo. But what are these
> values stand for? What parameters are used and set in these presets?
>
> Could anybody explain? Appreciate.

>From x264 --fullhelp:

       --preset <string>       Use a preset to select encoding settings [medium]
                                   Overridden by user settings.
                                   - ultrafast:
                                     --no-8x8dct --aq-mode 0 --b-adapt 0
                                     --bframes 0 --no-cabac --no-deblock
                                     --no-mbtree --me dia --no-mixed-refs
                                     --partitions none --rc-lookahead 0 --ref 1
                                     --scenecut 0 --subme 0 --trellis 0
                                     --no-weightb --weightp 0
                                   - superfast:
                                     --no-mbtree --me dia --no-mixed-refs
                                     --partitions i8x8,i4x4 --rc-lookahead 0
                                     --ref 1 --subme 1 --trellis 0 --weightp 1
                                   - veryfast:
                                     --no-mixed-refs --rc-lookahead 10
                                     --ref 1 --subme 2 --trellis 0 --weightp 1
                                   - faster:
                                     --no-mixed-refs --rc-lookahead 20
                                     --ref 2 --subme 4 --weightp 1
                                   - fast:
                                     --rc-lookahead 30 --ref 2 --subme 6
                                     --weightp 1
                                   - medium:
                                     Default settings apply.
                                   - slow:
                                     --b-adapt 2 --direct auto --me umh
                                     --rc-lookahead 50 --ref 5 --subme 8
                                   - slower:
                                     --b-adapt 2 --direct auto --me umh
                                     --partitions all --rc-lookahead 60
                                     --ref 8 --subme 9 --trellis 2
                                   - veryslow:
                                     --b-adapt 2 --bframes 8 --direct auto
                                     --me umh --merange 24 --partitions all
                                     --ref 16 --subme 10 --trellis 2
                                     --rc-lookahead 60
                                   - placebo:
                                     --bframes 16 --b-adapt 2 --direct auto
                                     --slow-firstpass --no-fast-pskip
                                     --me tesa --merange 24 --partitions all
                                     --rc-lookahead 60 --ref 16 --subme 11
                                     --trellis 2