Zac Gaetano
16ae17d2a1
Adds Alloc(), the ephemeral loopback UDP port grabber the subsystem uses to pick the RTP port it will hand to FFmpeg and then re-bind with core/webrtc.NewSourceOn. Covered by a 100x rebind test. Adds BuildArgs(), which emits the -f rtp output fragments (video on the passed port, audio on port+1) with copy codecs by default and an H.264 baseline / libopus re-encode leg when ForceTranscode is set. Covered by three unit tests.
31 lines
1.1 KiB
Go
31 lines
1.1 KiB
Go
// Package webrtc is the datarhei Core subsystem that turns WebRTC into
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// a first-class output alongside RTMP, SRT, and HLS. It owns the WHEP
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// HTTP handler, wires FFmpeg's RTP output into per-process Pion
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// Sources, and tracks active peer connections.
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//
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// See docs/design/2026-04-17-datarhei-dragon-fork-m2-webrtc-core-integration.md
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// for the full design.
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package webrtc
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import (
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"fmt"
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"net"
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)
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// Alloc binds :0 on loopback UDPv4, records the port the kernel assigned,
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// closes the socket, and returns the port number.
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//
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// The caller is expected to re-bind that exact port via
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// core/webrtc.NewSourceOn immediately. There is a microsecond-sized race
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// window where another process on the host could grab the port; if that
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// happens, the caller's rebind will fail and the error should be
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// propagated. In practice this is rare enough that a retry loop would be
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// unnecessary churn.
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func Alloc() (int, error) {
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c, err := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 0})
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if err != nil {
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return 0, fmt.Errorf("webrtc: portalloc: %w", err)
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}
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defer c.Close()
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return c.LocalAddr().(*net.UDPAddr).Port, nil
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}
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