Pcaptix extracts SIP signaling and RTP media from .pcap / .pcapng captures, decodes the audio, and measures per-stream quality with both perceptual (Sevana MOS) and network-estimated (R-factor → Network MOS) models. Available as a web app for quick triage and as a native desktop app (Qt6, Linux AppImage / Windows installer) for captures that don’t fit a browser workflow.
Built on Sevana’s vq_pcap engine.
What it measures
- SIP + RTP extraction from
.pcap/.pcapng, linking streams to dialogs by SSRC / Call-ID. Standalone streams are analyzed on their own. - Per-codec decoding (G.711 A-law/μ-law, G.729, Opus, and others identified via SDP or payload type).
- Dual MOS per stream alongside R-factor, jitter avg/max/min, delay, packet loss, and illegal-packet counters.
- 680 ms quality timeline with per-interval R-factor and impairment labels (clipping, echo, noise). CSV export.
- Event markers on the waveform: RFC 2833 DTMF, packet-loss positions, impairments; re-INVITE and SIP message markers on call-level audio.
- Call-flow ladder diagram with auto-discovered UAs and proxies, colour-coded by method and response class.
Cross-stream statistics
Every analysis runs an aggregate pass across all streams in the capture to answer “which network conditions are actually hurting quality here, and by how much?” — correlations, regression, and LASSO feature selection, with the depth scaled to the sample size. Optional per-subnet grouping (IPv4 / IPv6) reruns the same pipeline for each source subnet, so you can see whether one segment is dominated by loss while another is hurt by jitter.
Optional LLM
An opt-in LLM client explains streams, calls, or statistical findings in plain English. Large reports (> 100 KB) switch to a tool-augmented RAG workflow with per-entity fetch functions. Endpoint, model, and prompts are user-configurable — default is Sevana-hosted; any OpenAI-compatible backend (including local) works.
Desktop vs. Web
Same engine, different deployment:
- Pcaptix Web — zero-install, browser-based. Good for small-to-medium captures, demos, and sharing.
- Pcaptix Desktop — for cases the browser can’t serve: no upload, no size ceiling, no timeouts. Parsing, decoding, MOS, statistics, and (if used) the LLM endpoint all run locally. Appropriate for captures containing regulated or confidential traffic.
Both expose the same views — call flow, stream detail, dual MOS, timeline, waveform, DTMF / impairment markers, audio playback, PDF and CSV export.
Install
- Windows x64: pcaptix-windows-x64-setup.exe
- Linux x86_64: pcaptix-x86_64.AppImage
Tested on Windows 10+, Ubuntu 20.04+ / Debian 11+ and compatible distributions.
Contact us for commercial licensing or an online demo. The desktop build above is freely downloadable.
