AOM CTC¶

AOM has specified vmaf to be the standard implementation metrics tool according to the AOM common test conditions (CTC).

Metrics¶

The versioned --aom_ctc preset registers the metrics below with the options the AOM CTC specifies. Each version adds to or changes the one before it (see the version history).

Metric	Registered as	Options set by the preset
VMAF	model `vmaf_v0.6.1` (output `vmaf`)	pinned, from v1.0
VMAF NEG	model `vmaf_v0.6.1neg` (output `vmaf_neg`)	pinned, from v1.0
PSNR, APSNR	`psnr`	`reduced_hbd_peak=true`, `enable_apsnr=true`, `min_sse=0.5`
SSIM	`float_ssim`	`enable_db=true`, `clip_db=true`; `scale=1` from v7.0
MS-SSIM	`float_ms_ssim`	`enable_db=true`, `clip_db=true`
CIEDE-2000	`ciede`	none
PSNR-HVS	`psnr_hvs`	none
CAMBI	`cambi`	none, from v3.0

The two models are pinned to the v0.6.1 family regardless of the default model of the build.

Usage¶

Basic usage of the tool is described in the vmaf README. Use the versioned --aom_ctc presets to register and configure all metrics according to the AOM CTC. Basic AOM CTC usage is as follows:

./build/tools/vmaf \
    --reference reference.y4m \
    --distorted distorted.y4m \
    --aom_ctc v1.0 \
    --output output.xml

There are also a few optional command-line settings you may find useful.

Use --threads to set the thread count to be used for multi-threaded computation. This will decrease the overall latency.
If you prefer a JSON log over the default XML log, use the --json flag.

Output¶

XML and JSON logging formats provide per-frame metrics, pooled metrics, and aggregate metrics.

AOM CTC Version History¶

Version	Date	Change	libvmaf release
`--aom_ctc v1.0`	2020-12-22	Initial CTC release; `--aom_ctc proposed` deprecated.	v2.1.0
`--aom_ctc v1.0` (revised)	2021-01-13	Fix for lossless comparisons; dB clipping for PSNR, APSNR, SSIM and MS-SSIM according to the AOM CTC.	v2.1.1
`--aom_ctc v2.0`	not recorded	Same metric set as v1.0.	v2.2.1
`--aom_ctc v3.0`	2022-04-05	Add CAMBI.	v2.3.1
`--aom_ctc v4.0`	not recorded	Identical to v3.0.	not recorded
`--aom_ctc v5.0`	not recorded	Identical to v4.0.	not recorded
`--aom_ctc v6.0`	2023-12-07	Support bit depth conversion for Y4M inputs.	v3.0.0
`--aom_ctc v7.0`	fork addition	Replace the SSIM entry with `float_ssim` at `scale=1`, still with dB clipping.	none (added in this fork)

Precompiled static binaries of the upstream releases are attached to the release pages linked above.