IRTCCustomVideoTrack

virtual StatusCode pushVideoFrame(int stmtype, unsigned char* buf, int buf_len, int frmtype, long ts) = 0;

// 推送 H264 关键帧
IRTCCustomVideoTrack* track = nullptr;
engine->getCustomVideoTrack("my_custom_track", &track);
track->pushVideoFrame(0x1b, frameData, frameSize, 1, timestamp);