Emit: Internet Broadcasting with HTTP Live Streaming

Transcript

1. Internet Broadcasting: HTTP Live Streaming Ray Hilton @rayh Emit Media emit.com Monday, 13 May 13
2. This isn’t about Cocoa WARNING: Monday, 13 May 13
3. It is Apple-ish Monday, 13 May 13
4. Community Radio • FM & AM well are established • DAB+ is rolling out, but only to ~30 metro • No sector-wide internet streaming solution - smaller stations are precluded • FM/AM/DAB need special hardware - Internet streaming available to any internet connected device Monday, 13 May 13
5. Emit Media • We are @rayh and @jurgen • A startup with revenue! • Attempting to build a scalable broadcast platform for the internet • Born out of PBS, but now working with 3RRR, 3MBS, 2FBI, 4ZZZ and more • v1.0 has been running for a few years Monday, 13 May 13
6. Problem • Traditional streaming is expensive and hard to scale (RTSP, etc) • We have no money, and neither do our clients - prefer upfront costs to ongoing • Continuous/Live broadcasts aren’t the norm for existing services • Many devices and codecs to support Monday, 13 May 13
7. Approach • Pick one or two well supported codecs (mp3 and AAC) • Pick one streaming tech (HLS) • Design for failure • Aim to scale out rather than up Monday, 13 May 13
8. Stack • Ruby / Sinatra / Resque / Redis • RESTful APIs • Static HTML5/JS front-end(s) • S3 + CloudFront for distribution • ElasticSearch • MySQL (RDS) • EC2 Cluster (3 x c1.medium + others) Monday, 13 May 13
9. HLS Apple HTTP Live Streaming Monday, 13 May 13
10. RESTful Streaming Monday, 13 May 13
11. How does it work • Segmenter takes audio stream and chops it into short (10-30s) segments • Segments are uploaded to your CDN • Playlist (m3u8) file generated with references to new segments • Client polls playlist file to check for new segments Monday, 13 May 13
12. We scale this S3/CloudFront In-studio appliance Monday, 13 May 13
13. Server is dumb Monday, 13 May 13
14. dumb == cheap(er) Monday, 13 May 13
15. Server is stateless Monday, 13 May 13
16. stateless == scalable Monday, 13 May 13
17. Great for iOS • Apple have requirements about how you stream content (prefer HLS, include audio-only 3G friendly bitrate) • AVPlayer et al support HLS out-of-the-box • Manifest file lists playlists for each bitrate and codec - client can choose to up/downgrade stream based on network conditions • Just HTTP, works well with proxies, firewalls, front-end caches, etc Monday, 13 May 13
18. Other Benefits • Use S3 & CloudFront for all client interaction • Scaling costs are a function of broadcasters, not listeners • Fault tolerant - worst case, playlist doesn’t get updated, or segments are lost • Event streaming (rewindable live streams) • PVR-style, pause live streams Monday, 13 May 13
19. Drawbacks • Not entirely live, lag-time is the segment size + processing overhead • Transcode to all desired bitrates ahead of time, even if they aren’t used • Transcoding segments to avoid lossy encoding ‘gaps’ is tricky • HA segmenter is problematic Monday, 13 May 13
20. Future • Reporting, billing tools • Reusable html5 player for stations • Update PBS and Dial apps • Commercial possibilities • Big (Meta)data - Elasticsearch • Video Streaming • Raspberry Pi - Cheap, in-studio appliance Monday, 13 May 13
21. Call for help • We need volunteers to help our effort (coding, design, promotion) • Anyone with deep ffmpeg, libfdk_aac, mpegts and adts knowledge? • Investment / Funding to grow the project and pursue commercial options Monday, 13 May 13
22. Questions? Follow @rayh emit.com | ray.sh Monday, 13 May 13