Netflix/vmaf

libvmaf API does not support `perc*` pool methods

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#818 opened on Feb 1, 2021

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 (3 comments) (0 reactions) (0 assignees)Python (3,829 stars) (700 forks)batch import
help wantedlibvmaf

Description

The libvmaf API used by ffmpeg does not support the perc5, perc10, perc20 pooling methods. Furthermore attempting to pass one of these values will silently fallback to mean as the pooling method due to the implementation in pool_method_map, leading to a confusing user experience (even though the documentation mentions that only min, mean and harmonic_mean are supported).

It would be great to either unify the pooling methods such that perc* works, or to perhaps consider returning an error if an unsupported pooling method is requested.

Contributor guide

Tech stack
pythonc
Domain
apibackend
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic understanding of libvmaf APIFamiliarity with pool method map
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Examine the pool method map in libvmaf to understand how pool methods are currently mapped. Determine if adding percentile based methods (perc5, perc10, perc20) is feasible by implementing a percentile pooling function, or alternatively add an error when an unsupported method is passed. Check existing contributions or comments for additional context. Update documentation to reflect supported pool methods.