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bluenviron / mediamtx

Ready-to-use SRT / WebRTC / RTSP / RTMP / LL-HLS media server and media proxy that allows to read, publish, proxy, record and playback video and audio streams.
MIT License
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Using net.Buffers.WriteTo send multiple RTP packets to reduce system calls to improve performance #2914

Open Dylan-Ying opened 5 months ago

Dylan-Ying commented 5 months ago

Describe the feature

Description Each RTP packet sent invokes the io.Write function once, and a frame of video generates many RTP packets. From the pprof, it can be observed that RTP transmission consumes a significant amount of CPU resources.

pprof

aler9 commented 2 months ago

Hello, thank you very much for bringing to attention the existence of net.Buffers and the fact that multiple UDP or TCP buffers can be sent with a single call. Using net.Buffers.WriteTo() instead of net.Conn.Write() can surely improve performance in case all RTP packets of a video frames are available in advance, and this happens with the following cases:

However this approach won't bring any benefit when RTP packets are received singularly and sent out as soon as possible, and this happens with:

Therefore: in the future we can add to gortsplib a new method, WritePacketsRTP(pkts []*rtp.Packet), that allows to send out multiple packets at once.