Budget Internet streaming
May 1, 2010 12:00 PM, By Sid Guel
A Colorado broadcaster targets Apple devices.
Figure 1. The KCXP-LP off-air signal is first encoded in three formats: Adobe Flash, Microsoft
Silverlight and M3U8 for smart phones. It is delivered to a local ISP and then a CDN, which
feeds multiple carriers and the Internet.
Select figure to enlarge.
As broadcasters look for new ways to increase audience and revenue, sending video to mobile receivers looks attractive. Mobile device data traffic is growing at a compounded annual growth rate of 268 percent. These factors encouraged one Colorado broadcaster to begin broadcasting a live media stream to the Internet and to smart phones. On Dec. 14, 2009, KCXP-LP (TV Aspen Network) became the first local TV station to broadcast 24/7 to the Apple iPhone.
The initial goal was to broadcast the station's OTA signal live, or semi-live, to the Internet and smart phones. Live streaming to the Internet has been around for several years and is an established technology. Broadcasting to a smart phone, however, is newer and more complex.
The business model
Some broadcasters continue to question the business model of broadcasting live to the Internet or to smart phones, and perhaps for good reason. The revenue and audience gains are unclear. Even so, Marcos Rodriguez, the station's owner and general manager, decided to give the technology a try.
With less than $30,000, Rodriguez acquired the needed hardware and software to create an H.264 IP transport stream for smart phone M3U8 protocols and a variety of VC-1 file formats for live Internet streaming.
The monthly ISP and CDN service fees are currently around $1500. Even if costs increase as more users begin accessing the content, Rodriguez sees his overall investment as remarkably small.
The project team
Rodriguez hired Wayne Brenengen of Waymo Engineering to direct the project. Additional IT consulting support came from Devon Vaughn of the CDN company Liquid Broadcast and Kathy McVey of the ISP Everwave (a TV Aspen Network sister company). Inlet Technologies provided hardware and software. The system's basic block diagram is shown in Figure 1.
The media output format
The network delivers a variety of resolution levels for smart phones and live Internet streaming. The two most common formats are Microsoft's Silverlight Smooth and Adobe's Flash. Each format has advantages, but the choice of which to use is left to the viewer.
TV Aspen Network delivers two types of resolution levels of M3U8 for smart phones. Because the iPhone normally connects using a 3G-GSM cellular network, the signal must be supplied in a compatible transport format. When the smart phone is connected to the Internet via Wi-Fi, a higher-resolution M3U8 stream is available for smart phone viewing.
Why Apple?
The design team researched the marketplace and chose Apple's iPhones and iPads over other smart phones and mobile broadcast technologies for one significant reason: More than 60 percent of all Internet data traffic going to smart phones is going to iPhones, iPod Touches and iPads.
The iPhone's M3U8 file format is unique in the sense that it is actually a playlist of video segments that are about 10 seconds long. The M3U8 format requires video stream packets to be cut up into segments that are played out in sequence on the iPhone. To the viewer, the sequential playlist of video segments appears as a continuous video stream.
The encoder
The IP encoder handles SD-SDI video and analog audio, converting the stream into multiple IP streaming formats. Being able to output several formats simultaneously is a workflow benefit.
The ISP
Specifying and configuring an ISP network for live video streaming is critical. The network relies on a dedicated dual-T1 link, which is separate from the station's business network. The configuration includes two T1 lines and an exclusive T1 router to handle the encode stream going to the CDN provider. This keeps other traffic off the network and avoids congestion. The network's cost is about $1000 per month.
The CDN
The CDN provider is in Fort Collins, CO. While there were several CDN companies available, the team selected a local vendor for more personal attention. The station sends a 3Mb/s stream from Aspen to Denver. From Denver, the CDN contracts with other carriers to transport the stream to Dallas, where the live stream can be accessed by national and international users.
The biggest challenge
There are a number of issues that must be addressed when broadcasting to any smart phone. They include bandwidth optimization, production workflow, the ISP and the CDN. Other issues that have to be considered include the type of compression to use and any resulting latency. The biggest challenge turned out to be balancing data rate against optimal video imaging.
Other mobile platforms
There are other mobile platforms. The Open Mobile Video Coalition (OMVC) just released a paper supporting the ATSC-M/H standard. Even so, waiting for other mobile broadcast technologies and standards to roll out was not feasible for the TV Aspen Network. Team leaders thought other technologies were still being tested and had an unclear future. In addition, the team thought that the ATSC system was too expensive for its application.
The end result
At the end of this project, TV Aspen Network had a spectacular video stream for website and smart phone M3U8 access. The 1.4Mb/s Flash stream can be viewed at media.tvaspen.mobi/flashhi/index.html. The Silverlight stream can be found at media.tvaspen.mobi/smooth/index.html. For those with Apple devices, the link can be found at media.tvaspen.mobi/iPhone/stream1.m3u8.
The bottom line
There are large companies working to develop new technology standards for broadcasting to mobile devices. Public acceptance of this technology, however, is not yet clear. The Apple smart phone and Internet streaming applications are off-the-shelf technologies that exist today. There are numerous CDN and encoding companies that can provide cost-effective solutions for smaller stations. As TV Aspen Network is discovering, new ideas can work with proper planning — even if it requires breaking new ground.
Sid Guel is the president and founder of Broadcast Automation Consulting.
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