Got “MMF ENC Queue full” when using 2.4G WiFi for RTSP streaming
“MMF ENC Queue full” appearing only on 2.4 GHz Wi-Fi, suggests a network bandwidth or latency issue. The 2.4 GHz link is slower and more congested, causing encoder output data to queue up. Using 5 GHz or lowering video bitrate/frame rate can prevent the encoder queue from filling.
Answer
Yes, using a 2.4 GHz Wi-Fi connection is likely to cause this warning message when running RTSP streaming–related applications.
Some calibration suggestions:
Switch to 5 GHz Wi-Fi – faster, less interference, more stable throughput.
Lower video bitrate or resolution – reduces encoder output size.
Reduce frame rate – less data per second.
Improve network quality – avoid crowded 2.4 GHz channels.
Check for background traffic – other devices might be saturating the 2.4 GHz band.
Using multi-task structure for application - Wi-Fi and streaming by 2 tasks.
Increase the queue length - using “Video::setQLen(int ch, int len)”.
Refer to the following code for the basic use of “Video::setQLen(int ch, int len)”.
Camera.configVideoChannel(CHANNEL, config);
Camera.videoInit();
rtsp.configVideo(config);
rtsp.begin();
videoStreamer.registerInput(Camera.getStream(CHANNEL));
videoStreamer.registerOutput(rtsp);
if (videoStreamer.begin() != 0) {
Serial.println("StreamIO link start failed");
}
Camera.setQLen(CHANNEL, 30 * 3);
Camera.channelBegin(CHANNEL);