Thank you all. Looks like the -flags low_delay made the largest difference from my previous command line. It's not quite as instantaneous as mjpeg but much lower latency at 30hz (200-300ms). So mostly in the client application (FFPLAY) playing the stream, not the stream generator (OAK POE). ie:
ffplay -flags low_delay -fflags nobuffer -strict experimental udp://0.0.0.0:9922
Much appreciated.
Reducing the bitrate did not help. Doing mjpeg, which is a ton more data, has no latency so I don't suspect the bytearray either ( using exact same code path for mjoeg).
I can check the queue size and see if that has any impact when using h264 or h265.
Did you have any luck in getting reduced latency? Running into the same issue, even running a basic UDP stream on the camera directly.
Hello! I've been looking through and tweaking the samples, but so far I can't seem to get below about 1s in straming video latency when attempting to stream video from the camera to an RTP receiver.
I'm using the Python RTSP streamer as a starting place but then I just take the data and do the following to send a UDP video stream without using Gstreamer. I initialized the encoder with the following args:
videnc.setDefaultProfilePreset(FPS, dai.VideoEncoderProperties.Profile.H264_MAIN)
videnc.setNumBFrames(0)
videnc.setBitrateKbps(4000)And send the data with:
with dai.Device(pipeline, device_info) as device:
seqNum = 0
sock = socket.socket(socket.AF_INET, # Internet
socket.SOCK_DGRAM) # UDP
encoded = device.getOutputQueue("encoded", maxSize=30, blocking=True)
print("Setup finished")
while True:
data = encoded.get().getData()
dataToSend = len(data)
startPos = 0
while startPos < dataToSend:
dataLeft = dataToSend - startPos
toSend = min_of_two(1400, dataLeft)
endPos = startPos + toSend
buffer = bytearray()
buffer.extend(data[startPos:endPos])
print(f"Sending {len(buffer)} / {dataLeft} {startPos} {endPos}")
startPos = endPos
sock.sendto(buffer, ("192.168.0.73", 9922))Ive then played it by using ffplay on the receiver computer:
ffplay -fflags nobuffer -i udp://0.0.0.0:9922
The video looks fine, but the 1s delay is there.
Are there any other items to tweak here? I have tried the H264 encoder with no better results.
Thanks in advance! Would love to have any other samples of direct RTP/UDP streaming if anyone has managed to get low latency video.
Just a quick mention that I also ran this code directly on the oak camera by using the script interpreter there and did not have any better performance.