Knowledge Base

ab-av1

2 min read

ab-av1

AV1 video encoding tool with fast VMAF sampling & automatic encoder crf calculation. Uses ffmpeg, svt-av1 & vmaf.

Usage

Command: auto-encode

Automatically determine the best crf to deliver the --min-vmaf and use it to encode a video or image.

Two phases:

  • crf-search to determine the best --crf value
  • ffmpeg to encode using the settings
ab-av1 auto-encode [OPTIONS] -i <INPUT> --preset <PRESET> --min-vmaf <MIN_VMAF>

Interpolated binary search using sample-encode to find the best crf value delivering --min-vmaf & --max-encoded-percent.

Outputs:

  • Best crf value
  • Mean sample VMAF score
  • Predicted full encode size
  • Predicted full encode time
ab-av1 crf-search [OPTIONS] -i <INPUT> --preset <PRESET> --min-vmaf <MIN_VMAF>

Notable options

  • --min-xpsnr <MIN_XPSNR> may be used as an alternative to VMAF.

Command: sample-encode

Encode short video samples of an input using provided crf & preset. This is much quicker than full encode/vmaf run.

Outputs:

  • Mean sample VMAF score
  • Predicted full encode size
  • Predicted full encode time
ab-av1 sample-encode [OPTIONS] -i <INPUT> --crf <CRF> --preset <PRESET>

Notable options

  • --xpsnr specifies calculation of XPSNR score instead of VMAF.

Command: encode

Invoke ffmpeg to encode a video or image.

ab-av1 encode [OPTIONS] -i <INPUT> --crf <CRF> --preset <PRESET>

Command: vmaf

Full VMAF score calculation, distorted file vs reference file. Works with videos and images.

  • Auto sets model version (4k or 1k) according to resolution.
  • Auto sets n_threads to system threads.
  • Auto upscales lower resolution videos to the model.
ab-av1 vmaf --reference <REFERENCE> --distorted <DISTORTED>

Command: xpsnr

Full XPSNR score calculation, distorted file vs reference file. Works with videos and images.

ab-av1 xpsnr --reference <REFERENCE> --distorted <DISTORTED>

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