As retrieved from Edge RTC capabilities: ```js { clockRate: 90000, kind: "video", maxptime: 0, maxSpatialLayers: 0, maxTemporalLayers: 0, name: "rtx", numChannels: 1, options: {}, parameters: { apt: "107" } } { clockRate: 90000, kind: "video", maxptime: 0, maxSpatialLayers: 0, maxTemporalLayers: 3, name: "X-H264UC", numChannels: 1, options: {}, parameters: { mst-mode: "NI-TC", packetization-mode: "1" }, preferredPayloadType: 122, ptime: 0, rtcpFeedback: [] } ``` The `apt` parameter should be a number. And, AFAIU, also the `packetization-mode`.