Introduction to Streaming Video

Transcription

1 Introduction to Streaming Video Eric Smith Assistant Director Information Security & Networking Bucknell University AIM: ejsxj1100

2 What is Streaming Video? Goal: to replicate typical TV broadcasts. Transmission of digital audio and video across a data network. Playback begins immediately (almost after buffering). A copy of the content is not readily obtained by the client.

3 Challenges TV is easy: Everyone has the same Channel 3. In streaming video, you have to address diverse: >> Operating Systems >> Bandwidth >> Browsers >> Media Players >> Media Codecs >> Users

4 A Shopper s Guide to Streaming Video HTTP: File Download Streaming Media Servers Hybrids Multicast

5 HTTP Streaming : File Download.AVI (.MOV, etc.) file on a webserver File is saved to the client s hard drive Client plays the downloaded file

6 HTTP Streaming : File Download Easy Just put the AVI on your webserver. Client machine must download entire file before playback begins No control over the playback experience. Client keeps a full copy of the media file.

7 HTTP Streaming : Demo Click on Demo 1 Copy AVI to webserver Test with audience

8 A Shopper s Guide to Streaming Video HTTP: File Download Streaming Media Servers Hybrids Multicast

9 Streaming Media Servers Windows Media (QuickTime / Real / Flash / etc...) Each client s connection is negotiated with the server on an individual basis Automatically adjusts quality based on bandwidth Able to stream live events You already own the software: Included as part of Window Server 2003/2008

10 Streaming Media Servers Windows Media Services Files to be streamed must be in a compatible WMV format Clients must use a compatible version of WMP/VLC Mac / Linux users are problematic*

11 Streaming Media Servers: Demo Windows Media Services Convert source video to WMV Create publishing point Test with audience

12 Convert source video to WMV using FFMPEG: ffmpeg.mplayerhq.hu ffmpeg b 2000k -i /uploads/startrektos-thelightsofzetar-clip.avi -acodec wmav2 TrekClip.wmv

13 Convert source video to WMV using Windows Media Encoder

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18 Create publishing point (Windows 2003 Server)

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24 A Shopper s Guide to Streaming Video HTTP: File Download True Streaming Hybrids AKA Progressive Download Multicast

25 HTTP Streaming Hybrids FLV file on a webserver Playback begins ~ immediately Excess data cached to local disk

26 HTTP Streaming Hybrids Played Downloaded

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30 FFmpeg version SVN-rUNKNOWN, Copyright (c) Fabrice Bellard, et al. Input #0, avi, from '/uploads/startrektos-thelightsofzetar-clip.avi': Duration: 00:00:32.5, start: , bitrate: 1178 kb/s Stream #0.0: Video: msmpeg4, yuv420p, 512x384, fps(r) Stream #0.1: Audio: mp3, Hz, stereo, 32 kb/s Output #0, flv, to 'StarTrekTOS-TheLightsOfZetar-Clip.avi flv': Stream #0.0: Video: flv, yuv420p, 512x384, q=2-31, 700 kb/s, fps(c) Stream #0.1: Audio: mp3, Hz, stereo, 0 kb/s Stream mapping: Stream #0.0 -> #0.0 Stream #0.1 -> #0.1 Press [q] to stop encoding A few seconds later video:3060kb audio:255kb global headers:0kb muxing overhead %

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32 streamdemo.bucknell.edu >> Watch Test with audience

33 Approaches to Streaming Video HTTP: File Download True Streaming Hybrids Multicast

34 Multicast Video Single AV stream sent to a multicast IP address e.g.: Clients join the multicast group Stream is duplicated and distributed by the network

35 Multicast: Digital CATV Equipment MPEG2 Encoder Set-Top Box (STB)

36 BUTV: Bucknell University s Digital Cable TV Subscription CATV Foreign Language & Special Events Bucknell Local CATV Company

37 BUTV: Bucknell University s Digital Cable TV D&E Communications Datacenter State College, PA

38 Multicast Video: Pros and Cons High bandwidth, broadcast-quality streams Very efficient use of network bandwidth Requires multicast-aware routers and switches Inefficient for single-viewer applications Disastrous to wireless networks Does not work across the Internet

39 The Institutional Repository (IR) Audience Patron location is not fixed local versus remote. No control over clients hardware or software. >> Present both high and low bandwidth options. >> Include tools to help the user decide which option to use. >> Use an operating system-agnostic stream.

40 Just one solution for your IR streamdemo.bucknell.edu Archival Video In IR FLV Transcoder Streaming Flash Video

41 Streaming versus Archival Formats Totally Incompatible! DVD Format: 1 Hour MPEG2, 720x480x30fps ~ 2 gigabytes = 16 gigabits (8bits=1byte) 1 MB DSL: ~ 4.5 hours to download DV: ~ 13 gigabytes per hour 720x480x30fps What to do? Store archival video in the IR; provide a link to the streaming version

42 100% Free / Open Source Solution Encode using FFMPEG under MediaUbuntu JW Flash FLV Player

43 Complete control over the user experience Custom Skins

44 Complete control over the user experience Equalizer Display Playlists

45 Tons of nerd knobs

46 IR Tie-In Demo using ac.uk s DSpace

47 IR Tie-In Demo: streamdemo.bucknell.edu

48 Streaming Video: Internet Bandwidth Issues 200Mb Internet Streaming Server 320x240 30FPS stream ~500k per client Max of 200 clients assuming 50% load [n]

49 The tubes are full: Akamai* to the rescue 34,000 Servers 70 Countries 900 Networks Bucknell hosts 5 Akamai servers * Amazon S3, Limelight, and others

50 The tubes are full: Akamai to the rescue 34,000 Servers 70 Countries 900 Networks Bucknell hosts 5 Akamai servers

51 The tubes are full: Akamai to the rescue 34,000 Servers 70 Countries 900 Networks Bucknell hosts 5 Akamai servers

52 Akamai and Streaming Video Content is served by the closest Akamai server. All major ISPs host Akamai cache servers.

53 Akamai Streaming Video: Case Study Patron connecting from a Remote Cable Modem Streaming directly to Bucknell: 41ms Latency 24 Router Hops Streaming through Akamai: 10 ms Latency 7 Router Hops

54 Akamai Demo streamdemo.bucknell.edu/demos >> Demo 3 Be sure to look at the HTML source! Try this and let me know what your system shows! C:\>nslookup sas-origin.onstreammedia.com Non-authoritative answer: Name: a907.g.akamai.net Addresses: , Look up the IP Address at How close is it? Report back via chat

55 Thank you for your attention. Questions? References and Resources: VLC: VirtualDub: FFMPEG: sourceforge.net/projects/ffmpeg Ububtu: Medibuntu: SWFObject: Akamai: PSKL:

56 Appendix A: Tools: VirtualDub

57 Appendix B: Archival Formats & Key Frames