Microsoft Expression Encoder 4, Adobe Flash Live Media Encoder
Apr 1, 2011 4:24 PM, by Jan Ozer
If you’re looking for inexpensive alternatives for on-location streaming, you should consider the software-only approach, particularly if you’ve got a powerful i7-based notebook available. In a previous article, I reviewed Telestream Wirecast Pro, which is a very full-featured program capable of multiple camera switching, titling and other production features, as well as live encoding. In this review, I’ll look at two other software programs for live encoding, Microsoft’s Expression Encoder 4 and Adobe Flash Live Media Encoder.
The two programs perform very different functions, so I’ll cover that first. Briefly, as the name suggests, the Flash Live Media Encoder is a cross-platform application that can encode files for streaming via a Flash-streaming server, both in single file configurations and for adaptive streaming. In contrast, Expression Encoder 4 can produce both on demand and live files. In live applications, you can push single or multiple files to a Windows Media Services publishing point for live Windows Media or Silverlight streaming, or for conversion to an MPEG-2 transport stream for single or multiple file delivery to Apple iOS devices. So, you’ll need for creating Flash-compatible streams, and Microsoft for serving video to either Windows Media or Silverlight players or for re-muxing for iOS devices.
I tested both programs on an HP EliteBook 8740w notebook configured with a 2.00GHz Intel i7CPU, running a 64-bit version of Windows 7 Professional with 8GB of RAM. I performed two basic tests; multiple file encoding from SD source connected via FireWire and a single file HD test captured via a BlackMagic Decklink card connected to the notebooks Express Card slot. Specifically, with SD input, I tested the CPU requirements for producing three streams; 320x240 at 300kbps, 480x360 at 500kbps, and 640x480 at 800kbps, all with 64kbps mono audio. For HD, I tested by producing an 848x480 stream at 1.5mbps, again with 64kbps audio.
Adobe Flash Media Live Encoder
The Adobe Flash Media Live Encoder (FMLE) can encode up to three streams in either VP6 or H.264 format, with Nellymoser and MP3 audio encoding built in, and AAC audio compression available from MainConcept for $180. The interface is very straightforward, with input/output preview windows on top, input controls on the lower left, and output controls on the lower right.
The basic building block of an event is a profile, and individual profiles save all input and output settings. You can program operation in the office, tell the operator which profile to load when in the field, and all configuration options should be set. In addition to running the program from the user interface, you can drive it via command line for easy system integration and automation.
FMLE is designed to work with any DirectShow compliant capture device on Windows (and QuickTime on the Mac), and Adobe’s device compatibility matrix page lists a good mix of webcams, capture cards from ViewCast, Digital Rapids, Epiphan, and Blackmagic as well as plain old DV input. Note that FMLE is not compatible with HDV input via FireWire however; you’ll need a separate capture device.
After choosing your audio and video inputs, you configure your streams. Adobe includes nine presets with the program, five single file and four multiple file in both VP6 and MP4 format. You can encode up to three streams simultaneously, with options for setting the data rate and output size for each stream and cropping and deinterlacing controls for the video input as a whole. With H.264, you can also choose the Baseline or Main Profile (Baseline is the default), and set the Level and key frame interval. With VP6, you can choose key frame interval, the desired balance between frame quality and data rate, elect to apply noise reduction, and choose whether to dedicate the computer to live encoding or reserve CPU cycles for other programs.
Via controls available on the lower right side of the program, you can output to a Flash Media or compatible server, store the streams to hard disk, or both. For my tests, I connected to a Flash Media Server-compatible Wowza server provided by PowerStream, a Detroit-based Content Delivery Network. After inputting the server address and stream name, you can click Connect to test the connection, a nice feel-good option before actually going live. Once you’re ready, click Start, and you’re live.
Once you start streaming, FMLE flips the interface over to Encoding mode, where you can check the current and average bit rate of your encoded streams, the bandwidth and buffer state for your primary and backup outbound streams, and determine if you’re dropping frames. On the i7-based HP Elitebook, the Flash Live Media Encoder produced the three SD files using about 50 percent CPU utilization, which should be plenty of headroom for a live event. CPU utilization when producing the single 848x480 HD stream was slightly higher at 53 percent, which again should be fine for on-location streaming.
One of the irritations of working with FMLE is that you can’t play the video files that it archives to disk without first converting them to a watchable format via a downloadable Windows-only command line utility. That’s because the files are created in fragments that are appropriate for streaming, rather than disk-based watching. Once I converted the files and was able to play them, I found the quality quite good, which isn’t surprising since Adobe uses the high-quality Main Concept H.264 codec.
Given the performance and price, the Adobe Flash Media Live Encoder is definitely worth a look if you’re looking to produce Flash-compatible streams for notebook-based on-location streaming.
- Microsoft Windows XP or higher
- 1024x768 screen resolution with 32-bit video card
- Microsoft DirectX End-User Runtime version 9.0c
- For H.264 and AAC support: Flash Media Live Encoder 2.5 required
- Intel 933MHz or faster processor
- 256MB of RAM (1GB recommended)
- 40MB of available hard-disk space (excludes archived FLV and F4V files)
- Microsoft DirectShow compatible video capture device
- For H.264 and AAC support: Intel Core 2 Duo 1.67GHz required (Intel Core 2 Duo 3GHz recommended)
- For multiple output streams, minimum Intel Core 2 Duo 3GHz and 2GB of RAM required (quad- or 8-core machine with 3GB of RAM recommended)