Multimedia Content in the Internet: Synchronization, Processing & Delivery

Introduction5/11/2015

Vasilis Maglaris <maglaris@netmode.ntua.gr>Mary Grammatikou <mary@netmode.ntua.gr>

Dimitris Kalogeras <dkalo@noc.ntua.ge>

www.netmode.ntua.gr

Outline

• Introduction• Video coding (H264, MPEG-4, DivX codecs), description of multimedia

content (metadata standards, RDF, SAML), containers (AVI, MP4, FLV)• Synchronization of multimedia applications (SMIL, HTML5), related tools

(Mozilla Popcorn) and platforms (NETMODE Synchronized eLearning Content – SeLCont)

• Multimedia content delivery in the Internet: Content Delivery Networks CDNs, real time streaming, video on demand servers/clouds, multimedia platforms & video service providers (YouTube, Wowza, Wistia), Massive Open On-Line Courses (MOOCs) - the Coursera business model

• CDN performance analysis and simulation (quality of experience, queuing models), simple video source models, advanced long-term memory models

• Fixed- Mobile Convergence: Multimedia applications in smart phones/tablets, Ultra High Definition TV (4Κ) in optical high-speed networks

Term project (to be agreed with the course coordinator)

What is Video Format?https://library.rice.edu/services/dmc/guides/video/VideoFormatsGuide.pdf

Video formats involve two distinct, and very different technology concepts:

– Containers (sometimes called wrappers)

– Codecs (short for coder/decoder). Codecs are used within a container

What is a Container?http://en.wikipedia.org/wiki/Comparison_of_container_formats

• The container describes the structure of the file: – where the various pieces are stored– how they are interleaved– which codecs are used by which pieces.

• It may specify an audio and/or video codec• It is used to package the video & its components

(audio/metadata) and is identified (usually) by a file extension such as .AVI, .MP4 or .MOV.

Most Common Containershttp://en.wikipedia.org/wiki/Comparison_of_container_formats

• AVI (Audio Video Interleave): a Windows’ standard multimedia container.

• MPEG-‐4 Part 14 (known as .mp4): is the standardized container for MPEG-‐4.

• FLV (Flash Video): the format used to deliver MPEG video through Flash Player.

• MOV: Apple‘s QuickTime container format.

• OGG, OGM & OGV: open-‐standard containers.

• MKV (Mastroska): another open-‐specification container that you've seen if you've ever downloaded anime.

• VOB (DVD Video Object): It's DVD‘s standard container.

• ASF: a Microsoft format designed for WMV and WMA—files can end in .wmv or .asf

What is a Codec?http://en.wikipedia.org/wiki/Comparison_of_video_encoders

A codec (short for "coder/decoder") is a way of encoding audio or video into a stream of bytes. It is the method used to encode the video and is the main determiner of quality.

Methods: Intra-frame (M-JPEG…), Inter-frame (MPEG 2, 4)

Most Common Codecs• MPEG (Moving Pictures Expert Group): three video formats, MPEG 1, 2, and 4.

• MPEG-‐1: Old, supported by everything (at least up to 352x240), reasonably efficient. A good format for the web.

• MPEG-‐2: A version of MPEG-‐1, with better compression. 720x480. Used in HDTV, DVD, and SVCD.

• MPEG-‐4: A family of codecs, some of which are open, others Microsoft proprietary.

• H.264: Most commonly used codecs for videos uploaded to the web. Part 10 of the MPEG-‐4 codec.

• M-JPEG (Motion JPEG): Used by video-capture devices (digital cameras, IP cameras, webcams), non-linear video editing systems, QuickTime.

• WMV (Windows Media Video): A collection of Microsoft proprietary video codecs. Since version 7, it has used a special version of MPEG4.

• RM (RealMedia): a closed codec developed by Real Networks for streaming video and audio.

• DivX: in early versions, essentially an ASF (incomplete early MPEG-‐4) codecinside an AVI container; DivX 4 and later are a more full MPEG-‐4

Container - Codec

A container is the file itself while codec is its content.

• Most container formats can hold many codecs. For example a .MOV container can hold almost any kind of codec data.

• The same goes for .MP4 and even .AVI files can hold a wide variety of codecs as their contents. In no way does the container decide the quality or features of the video itself, that is up to the codec.

• The proper way to describe video is to indicate both: .MOV file containing H.264 data; .AVI file containing DivX data.

Container – Codechttp://www.w3.org/2008/03/video-on-the-web#%2811%29

File Size & Qualityhttp://www.dr-lex.be/info-stuff/videocalc.html

• Frames per Second (FPS): the standard is 29.97; increasing the FPS allows for more images per second thus a smoother image; decreasing the FPS will make the video a bit choppy and not nearly as smooth.

• Bitrate: number of bits that are transmitted over a set length of time. Your overall bitrate is a combination of your video stream, audio stream & metadata in your file with the majority coming from your video stream. The higher the bit rate, the better the quality, the bigger the size.

• Resolution: number of pixels present in the images of the video. This determines whether your video is standard definition or high definition. The higher the resolution, the clearer the image, the bigger the file.

• Video File: depends on resolution, FPS, length– Compressed H.264: 1920x1080 / 23,98 Frame Rate / 1h length ~ 34GB

– Uncompressed, Clean HDMI: 1920x1080 / 23,98 Frame Rate / 1h length ~ 500GB

Trends & Analysis 2013 – 2018http://www.netmode.ntua.gr/courses/postgraduate/video_communications/2014/VNI_Hyperconnectivity_WP.pdf

• Every second, nearly a million minutes of video content will cross the network by 2018.

• Globally, IP video traffic will be 79 percent of all IP traffic (both business and consumer) by 2018, up from 66 percent in 2013.

• Internet video to TV grew 35 percent in 2013. It will continue to grow at a rapid pace, increasing fourfold by 2018.

• Consumer VoD traffic will double by 2018. The amount of VoD traffic in 2018 will be equivalent to 6 billion DVDs per month.

• Content delivery network traffic will deliver over half of all Internet video traffic by 2018. By 2018, 67 percent of all Internet video traffic will cross content delivery networks, up from 53 percent in 2013.

• Fixed broadband speeds will nearly triple by 2018 (FTTH access, Wi-Fi Hotspots)

• IP Video accelerates IP traffic growth (but upstream/downstream asymmetry seems to persist, due to Clouds and CDNs)

• Other factors: expected IPv6 growth; pricing and user quota imposed by Service Providers; migration from offline to online (clouds); from multicast to unicast; Ultra HD demand (4K); growth of Internet-of-Everything (M2M)

Global Consumer Internet Video

4K Video Traffic

Increasing Video Definition

• By 2018, more than 20% of connected flat-panel TV sets will be 4K

References

• Video Formats Guide [pdf]:– https://library.rice.edu/services/dmc/guides/video/VideoFormatsGuide.pdf

• Wikipedia: – http://en.wikipedia.org/wiki/Comparison_of_container_formats

– http://en.wikipedia.org/wiki/Comparison_of_video_encoders

• The Zettabyte Era: Trends & Analysis (Cisco White Paper)– http://www.netmode.ntua.gr/courses/postgraduate/video_communications/2014/V

NI_Hyperconnectivity_WP.pdf

• Video on the Web: – http://www.w3.org/2008/03/video-on-the-web#%281%29

• Video size calculators:– http://www.digitalrebellion.com/webapps/video_calc.html

– http://www.dr-lex.be/info-stuff/videocalc.html