Imported from golusoris/golusoris (media/av/AGENTS.md). Install upstream with npx skills add golusoris/golusoris --skill av. Copyright stays with the author.

Agent guide — media/av/

Audio/video probing + transcoding backed by FFmpeg via go-astiav (CGO). Direct-import constructors — no fx wiring; apps build a Prober / Transcoder and share them.

API

p, err := av.NewProber(av.Options{})            // LogLevel default "warning"
info, err := p.Probe(ctx, "video.mp4")          // MediaInfo: Format, Duration, Streams[]

t, err := av.NewTranscoder(av.Options{})
err = t.Transcode(ctx, "in.mp4", "out.webm", av.TranscodeOptions{
    VideoCodec: "vp9", AudioCodec: "opus",      // empty codec = stream copy
})

MediaInfo.Streams holds StreamInfo (codec, dims, frame rate, channels, sample rate, bit rate, duration) per audio/video/subtitle stream.

Why go-astiav

• Thin, low-level binding straight onto the FFmpeg C API (libav*), giving full codec/format reach without shelling out to an ffmpeg binary or its parsing fragility.

Notes

• CGO-gated, own go.mod sub-module. Shipped constructors are stubs returning ErrCGORequired; activate per the package doc (drop //go:build ignore from impl_astiav.go, go get github.com/asticode/go-astiav, go mod tidy).
• Requires FFmpeg shared libs: libavcodec-dev + friends (apt) / ffmpeg (brew).
• Probe/Transcode take file paths, not byte slices — stage uploads to disk (or a temp file) first.