rtmp,hls

RTMP(Real-Time Messaging Protocol)

works on top of TCP and uses port number 1935 by default
RTMPS, which is RTMP over a TSL/SSL connection

RTMP,HLS, and WebRTC

What is a Streaming Protocol? Video Streaming Protocol

Video->chunks->transport->reassemble

What is RTMP? RTMP

streaming protocol

low latency streaming

RTMP has taken a new role in live streaming. Ingesting media from the encoder or other source to a video streaming platform.

the most accessible and affordable option since it works with most modern encoders, including many free encoding software.

❗️不兼容很多的视频播放器(not compatible with more modern video players)

✅ very effective in its ingestion role

What is HLS? HLS

developed by Apple from streaming with an HTML5 video player

RTMP delivery to the Adobe Flash player —> HLS delivery to the HTML5 video player

HLS is very secure

produces high-quality steams

supports adaptive bitrate steaming (at the professional broadcasting level)

both delivery(更多场景) and ingest(和编码器encoders的兼容还不太好)

❗️latency of 15-30 seconds (时延比较高)

What is WebRTC? WebRTC

rather than a protocol

was created to support web conferencing and VoIP

make peer-to-peer streaming with real-time latency possible

adaptive bitrate streaming

WebRTC Tutorial

Audience
Prerequisites
Basic Scheme

Media Capture

codec: H.264, iSAC, Opus and VP8

Transportation Layer

Session Management

Browser Compatibility

Trying out WebRTC: apprtc

Comaring RTMP vs. HLS vs. WebRTC

HLS delivery with RTMP ingest. Low latency, ultra-compatibility, affordability

HLS delivery + RTMP ingest

HLS delivery + HLS ingest(编码器支持的少)

WebRTC: more and more popular. 主要的限制：编码器支持的少

professional broadcasting level比较低(不能选择bitrate?)

WebSocket

over HTTP
ws/wss

container format

Design Philosophy

there should be minimal framing It is expected that metadata would be layered on top of WebSocket by the application layer, in the same way that metadata is layered on top of TCP by the application layer (e.g., HTTP).

adds a web origin-based security model for browsers

adds an addressing and protocol naming mechanism to support multiple services on one port and multiple host names on one IP address

layers a framing mechanism on top of TCP to get back to the IP packet mechanism that TCP is built on, but without length limits

includes an additional closing handshake in-band that is designed to work in the presence of proxies and other intermediaries

Security Model

Relationship to TCP and HTTP

Security considerations

Proxy traversal

Establishing a Connection

Subprotocols Using the WebSocket Protocol

references

https://www.tutorialspoint.com/webrtc/webrtc_overview.htm https://en.wikipedia.org/wiki/Dynamic_Adaptive_Streaming_over_HTTP https://www.ibm.com/ibm/history/exhibits/builders/builders_bloch.html https://www.cgl.ucsf.edu/Outreach/pc204/NoSilverBullet.html?spm=ata.21736010.0.0.887316fdudx1ZT https://architecturenotes.co/fallacies-of-distributed-systems/