Http streaming
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HTTP streaming technologies like HDS and HLS are better than plain file delivery or RTMP for video streaming. They support features like multibitrate streaming, live streaming, and buffering of content. HDS is fully implemented in Flash and allows control over playback, while HLS is optimized for iOS and Android but with less client control. MPEG-DASH is a new standard but not fully implemented yet. In summary, HDS and HLS are the best choices for video streaming currently.
Http streaming
- 1. HTTP STREAMING HDS & HLS
- 2. Plain file delivery + Simple & fast (nginx) + Easy to collect logs + Excelent buffer support (possible to buffer whole file) - No multibitrate - No live streaming - Awfull seeking (almost impossible with mp4) - Traffic overusage with seeks and transparent caching proxies
- 3. RTMP (pros) + Live event streaming + Proper seek support ± Bitrate switch (only manual)
- 4. RTMP (cons) - No buffering (primitive content protection) - Firewall blocking - Hard clustering (almost impossible to proxy file rtmp access) - Impossible to do automatic multibitrate - Non cacheable by intermediate proxies
- 5. Design problems of RTMP Persistent TCP connection Non-HTTP port and protocol Two players that require logic sync: on client and on server
- 6. HTTP Streaming Don’t miss with pseudostreaming Adobe HDS, Apple HLS, Microsoft Smooth MPEG-DASH Content is delivered in chunks according to manifest Live streaming is done by reloading changing manifest
- 7. Multibitrate implementation Client downloads several chunks via HTTP It knows their duration from manifest If download takes more than duration, lower bitrate is chosen If download is faster than next bitrate, upper bitrate is chosen
- 8. Adobe HDS Fully implemented in flash player libraries, can be rewritten to any needs NetStream.appendBytes mp4/flv chunks are delivered timeshift multibitrate chunk skipping (on slow channels) buffering of whole file possible
- 9. Apple HLS Implemented inside iOS, Android or firmware Almost no control of video from client-side Multibitrate No full-file buffering Very high container overhead (15-30%)
- 10. Microsoft SmoothStreaming Silverlight is going to die Nothing interesting in fact Almost the same as HDS: manifest and mp4 chunks
- 11. MPEG-DASH Some not-implemented not-designed standard Will be interesting in mid-2013
- 12. Videostreaming File serving (http pseudostreaming) is bad for long files RTMP is bad for everything HDS/HLS is choice of 2012-2014