The Moving Picture: How Powerful a Notebook Do You Need for On-Location Editing and Streaming?
I shoot a lot of live events and have been streaming more and more of them live, streaming the events from one of my Core2Duo-based notebooks-a Hewlett-Packard 8741w and a MacBook Pro. I've used Telestream Wirecast for most events, but all have been single-stream, relatively low-resolution broadcasts, like 480x360 or smaller.
I'm starting to get requests for bigger-screen webcasts, and for multiple-bitrate adaptive streams to optimally serve a broad spectrum of viewers connecting from 3G to 50GB FiOS. Of course, everyone wants to send video to iOS devices these days, so that's typically next on the wish list.
As it turns out, there's a lot going on to more simply accomplish all of these goals. The first relates to repurposing the same compressed video streams so they can be redirected for playback on Flash, iOS devices, or even Silverlight. There are multiple approaches, and all are very cool technologies, with some awesome compression-related buzzwords.
By way of background, 12 months ago, if you wanted to distribute video for Flash consumption on computers, and iPhone playback, you had to encode two separate sets of encoded streams, one for each target. Then, most of the streaming world started using H.264 for live events, and someone realized that the only thing different from a Flash stream and a iOS stream was the file "wrapper." Flash used a Flash (.F4V) or QuickTime (.MOV) or even MPEG-4 wrapper (.MP4), while Apple uses an MPEG-2 wrapper (.M2V). However, the actual encoded bitstream within the wrapper can be the same.
That bright someone came up with the idea of (here comes the jargon) transmuxing a file in one format-say, an H.264 file encoded in QuickTime format-into the .m2v wrapper that can be delivered to iOS devices. The first commercial implementation of this concept, to my knowledge, was by Wowza, whose Wowza Media Server can input a single stream (or set of adaptive streams) and dynamically rewrap them for deployment to a completely different target. So today, if you choose the right live streaming service provider, you can send them one set of streams and serve multiple targets. The provider I use, Powersteam, offers this capability via the Wowza server.
Here's a streaming blast from the past: RealNetworks' Helix server offers the same functionality. In addition, Microsoft's Internet Information Services (IIS) 7 web server with the IIS Live Smooth Streaming can transmux incoming Silverlight streams from their Expression Encoder 4 product to deliver to iPhones. Bottom line is that now you can create one stream, or one set of streams, and serve multiple target platforms.
I know what you're thinking-how can I do that if I'm streaming via a puny 800Kbps-or-less DSL outbound connection? Well, it turns out, there's an app for that as well. Sorenson Media recently launched Squeeze Live. Here's how it works: You upload one live stream to the service, and Squeeze Live produces multiple streams from that file in real time, in the Cloud and formatted as necessary to support iOS, Flash, and other protocols. The product is unique, but it solves such a common problem that it won't be for long.
Which gets us to the question, how powerful a notebook do you need to produce multiple streams, or even a single high-quality stream? Well, that's one of the tests I performed for a recent story I wrote for StreamingMedia.com entitled Live Streaming From a Notebook (http://bit.ly/OzerLive), and the answer depends upon the software program you're using to produce the event.
It turned out that Wirecast was the most efficient of the three product priced under $1,000, and could actually produced three SD streams on either of the Core2Duo-based notebooks identified above. But if you were running the Adobe Flash Media Live Encoder (FMLE), or Microsoft's Expression Encoder (EE4), you couldn't produce the streams without dropping frames. For that, you needed to upgrade to the big dog in the review, the 2.0 GHz i7-based HP Elitebook 8740w, with four cores (eight-with hyperthreading). If you're trying the single stream out approach, and are running FMLE or EE4, you'll need a notebook like the 8740w as well, because the Core2Duo computers just wouldn't cut it.
What about the 8740w for on-location editing? I ran a series of tests in Premiere Pro comparing the 8740w to a six-core Hewlett-Packard Z400 workstation. Based on the number of cores alone, you'd expect the Z400 to be 50% faster. In HDV tests, the notebook actually proved faster, encoding my 104-minute dual camera ballet to MPEG-2 format in 63:51, compared to 70:57 for the Z400. Recalling editor Steve Nathans-Kelly's mandate before I started writing this column ("must ... mention ... DSLRs"), I ran my DLSR test, and found that the 8740w was 274% slower, producing my 21-minute test project in 23:55, compared to 6:24 for the Z400. This stumped me for a bit, then I remembered that the Z400 had 24 GB of memory, and the 8740w only 8GB (with max 16GB). When working with H.264-based formats like footage from the Canon 5D, it's all about memory, not CPU. So if you buy a shiny new notebook for on-location DSLR editing, spend the extra dollars maxing out memory, not buying the fastest CPU.
Jan Ozer (jan at doceo.com) is a frequent contributor to industry magazines and websites on digital video-related topics. He is chief instructor at StreamingLearningCenter.com.