Filters¶

The job-spec filter field is an arbitrary ffmpeg filtergraph string parsed by avfilter_graph_parse2. A filter can be used only if it is enabled in the build — this is the authoritative list of what each profile links.

Lean (all builds)¶

The web-delivery essentials:

null, anull, split, asplit, scale, crop, pad, format, fps, settb, asettb, setsar, setpts, asetpts, trim, atrim, loop, transpose, overlay, concat, xfade, amix, adelay, volume, afade, aresample, aformat, alimiter.

Intermediate (+ over lean)¶

The native filter batch (spec 0017) — all in-tree, LGPL-clean, no external library:

Group	Filters
Video fade	`fade`
Colour / levels	`hue`, `colorbalance`, `curves`, `colorchannelmixer`, `lut`, `lut3d`
Sharpen / blur	`unsharp`, `gblur`, `boxblur`
Compose / grid	`hstack`, `vstack`, `xstack`, `blend`, `tile`
Frame select	`select`, `aselect`, `thumbnail`, `framestep`
GIF quality	`palettegen`, `paletteuse`
Deinterlace	`yadif`, `bwdif`
Keying	`chromakey`, `colorkey`
Geometry	`rotate`, `hflip`, `vflip`, `reverse`, `areverse`
Draw (native)	`drawbox`, `drawgrid`, `vignette`
Audio loudness	`loudnorm`, `dynaudnorm`, `acompressor`, `compand`
Audio EQ / dynamics	`highpass`, `lowpass`, `equalizer`, `atempo`, `aecho`, `silenceremove`, `afftdn`
Channels	`pan`, `channelsplit`, `channelmap`, `join`
Analysis (metadata)	`cropdetect`, `blackdetect`, `signalstats`, `silencedetect`, `ebur128`, `astats`
Text / subtitles (spec 0019)	`drawtext` (freetype + harfbuzz), `subtitles`, `ass` (libass) — burn text/`.srt`/`.ass` onto video

Notes¶

palettegen/paletteuse run as a single-pass split graph — pair them for a good GIF: [0:v]split[a][b];[a]palettegen[p];[b][p]paletteuse[v].
loudnorm resamples to 192 kHz internally; follow it with aresample=<rate> before an encoder that doesn't accept that rate (e.g. AAC).
Analysis filters (cropdetect, blackdetect, silencedetect, ebur128, signalstats, astats, …) surface their measurements as structured output (spec 0017 §Q): the lavfi.* metadata they attach to frames is collected into the process result JSON's analysis array — a time-series of {t, key, value}, deduplicated per key (a stable cropdetect records once; discrete events like silence_start/silence_end each record). Filters that only log by default (ebur128, astats) need their metadata=1 option to populate it. afmpeg exposes it as ProcessResult.Analysis via ParseResult.
eq (a GPL-only level/gamma filter) is not enabled in either variant — reach for curves, colorbalance, or colorchannelmixer for level adjustment instead.
Fonts have no fontconfig — the sandbox has no system fonts. Name the font by path: drawtext=fontfile=/font.ttf:…; for subtitles/ass, point libass at a mounted directory (subtitles=filename=sub.srt:fontsdir=/fonts:force_style='FontName=…'). The libs (freetype/harfbuzz/libass) cross-compile via the meson toolchain of spec 0029.

Full (native)¶

The native-only full profile (0022) adds the heavy HEVC/AV1 encoders (see codecs) but no new filters — the filter set is identical to intermediate.