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Version: 5.0 (Stable) ✅

RTMP PK HTTP

There are two major methods to deliver video over internet, Live and WebRTC.

  • Live streaming: HLS, RTMP and HTTP-FLV for entertainment.
  • WebRTC: RTC, for communication.

Ignore other delivery protocol, which is not used on internet:

  • UDP: Private protocols, realtime protocol, latence in ms.
  • P2P: FlashP2P of Adobe, others are private protocol. Large latence, in minutes.
  • RTSP: Private protocol not for internet.

And the protocol base on HTTP:

  • HTTP progressive: Ancient protocol, not used now.
  • HTTP stream: Support seek in query string, for instance, http://x/x.mp4?start=x.
  • HLS: The HLS is developed by Apple. Both Apple and Android support it.
  • HDS: The HLS like developed by Adobe, shit.
  • DASH: The HLS like developed by some companies, not used in China.

Compare the delivery methods on internet:

  • HLS: Apple HLS, for both live and vod.
  • HTTP: HTTP stream, private http stream, for vod.
  • RTMP: Adobe RTMP, for live stream.

RTMP

The RTMP is stream protocol, good for:

  • Realtime: RTMP latency can be 0.8-3s.
  • DRM: RTMPE/RTMPS encrypt protocol.
  • Stable for PC flash.
  • Server input: The actual industrial standard for encoder to output to server is RTMP.
  • Fault Tolerance: The RTMP edge-origin can support fault tolerance for stream protocol.
  • Monitor: The stream protocol can be monitored.

RTMP is bad for:

  • Complex: RTMP is more complex than HTTP, especially the edge.
  • Hard to cache: Must use edge to cache.

HTTP

The HTTP stream is the vod stream used for some video website:

HTTP is delivery files, good for:

  • High performance: There are lots of good HTTP server, such as nginx, squid, traffic server.
  • No small piece of file: The large file is good than pieces of file for HTTP cache.
  • Firewall traverse: Almost all firewall never block the HTTP protocol.

HTTP is bad for:

  • Large lantency: The http stream atleast N10s latency.
  • Player does not support: Only PC flash can play http stream. Mobile platform does not support http stream.

HLS

HLS is the open standard of Apple. HLS is supported by Android3+.

HLS is good for:

  • High performance: Same to HTTP stream.
  • Firewall traverse: Same to HTTP stream.
  • Mobile Platform standard: Apple IOS/OSX, Android and PC/flash support HLS.

HLS is bad for:

  • Large lantency: The http stream atleast N10s latency.
  • Pieces of file: CDN does not like small file.

Use Scenario

See HTTP and RTMP

I recomment to use these delivery protocols in:

  • Encoder always output RTMP for internet server.
  • Server always accept RTMP from encoder.
  • The cluster use RTMP as internal delivery protocol.
  • The low latency application on PC: Use flash to play RTMP.
  • Application without low latency required: RTMP or HLS.
  • The vod stream on PC: Use HLS or HTTP stream.
  • Apple IOS/OSX: Always use HLS. Or use library to play RTMP, like https://www.vitamio.org
  • Android: Always use HLS. Or use library to play RTMP.

Winlin 2014.11