You certainly have to hand it to RealNetworks. Every time it looks like they're about to be Netscaped by Microsoft, they come back with another blockbuster product or feature that solidifies their lead against its northwest neighbor. This time, with RealVideo 9 and the new Helix Server, it's the ability to stream RealVideo, Microsoft Windows Media Video, and QuickTime files from one server, and play them within one player, that present an irresistible combination to any multiformat publisher.
Of course, RealNetworks would rather have everyone use RealVideo and RealAudio, and forget about the other two formats. That's why they keep investing in the quality of their audio/video formats, and the capabilities of their encoding tool, Helix Producer Plus (née RealProducer). At least that's their story, and they're sticking to it.
Here we take a look at Helix Producer Plus, and RealVideo 9, comparing its quality to Apple's new MPEG-4 codec as well as an advance (and very rough) beta version of Microsoft's brand spanking-new Corona codec.
What's Past Is Past
Earlier iterations of RealProducer, like the G2 version, were built at a time when third-party encoding tools were relatively non-existent and all streaming producers were novices. For these reasons, the emphasis was on ease of use, with templates, wizards, and other niceties like pre-compression configuration testing and HTML creation.
With third-party tools now providing the cushy environment for newbie encoders, Real has shifted its focus to create a lean, mean encoding tool for experts, with advanced features that improve performance during live encoding. While we bemoan the loss of certain features—especially HTML creation—we understand that most advanced customers simply don't use them.
What remains is a rather austere, dual-window program with new audio meters on the left. You input video on the left, either a hard disk-based file or content from a live capture device. New in Producer is the ability to accept DV input, which we happily provided via the FireWire port on our Dell Precision M40 laptop.
You select encoding parameters via controls under the window on the right, which displays posted encoded video in near real-time. Happily, Real now scales both windows so that the program fits within one generous full screen; previous versions displayed the actual frame size of the encoded file, zooming the application beyond recognition when encoding 720x480 output.
Other new features include batch processing, reusable job files and audience and server templates and the ability to send both constant bit rate and the higher quality variable bit rate files to a live server. A killer new feature is redundancy, or the ability to send files to one or more locations or one or more broadcast servers simultaneously.
Running Producer Plus is simple. The basic building block is a job. You start each job by choosing your source, either stored file or capture device, and then add destinations for transmitting your video, either disk-based files or live streaming servers.
Each destination can have multiple audiences, each defining the stream parameters for a particular target viewer. As with previous versions of RealProducer, one destination can support multiple bit rates using Real's SureStream technology, which simplifies server-based administration and provides scalability to remote viewers. Here's how it works.
Before encoding, you select the audiences by target connection, e.g., 28.8, 56Kbps, or DSL. During encoding, Producer Plus produces one file with substreams for each target. Before playback, the Helix server queries remote RealOne Players regarding their connection speed, which is the reason you identify your connection during installation. After receiving the answer from the player, Helix sends the appropriate stream.
During playback, the server monitors the connection for reports of lost packets, which occur when the Internet gets congested. When this occurs, the Helix server starts sending data from a lower bit-rate stream to maintain playback smoothness, dropping down to solely audio during severe congestion. Once throughput improves, the Helix server can return to a higher-quality stream, ensuring the best possible-quality experience to each remote user.
Interestingly, a SureStream file can only support one resolution, say 176x132 for low bit rate files, or 320x240 for broadband connections. This is why many streaming publishers like CNN or ESPN have two Real video links, one for modem connections, the other for broadband.
Other basic encoding parameters include high-quality resize and dual-pass encoding, both of which we always engage. You can also designate the appropriate audio codec by choosing between music and voice, and optimize video quality for the sharpest image or smoothest motion.
Advanced encoding options include filters for black level correction and low and high settings for video noise reduction, essentially a blur filter that sacrifices detail. We've typically ignored blur filters in the past, and Real's help file, which encourages producers not to use this filter unless the incoming video is very noisy, convinced us to stay the course. We also noted the inverse telecine capability, but since none of our original footage was film-based, we ignored this as well.
So our initial tests focused on the quality Producer's scaling and de-interlacing capabilities. By way of background, over the years, many producers have resisted both scaling and de-interlacing in tools like Real Producer, for fear that low-quality filters might introduce artifacts into the compressed video. Instead, they scaled and de-interlaced in Adobe Premiere, or other similar editor, which employ sophisticated algorithms to ensure a high-quality result. The obvious price was another step in the workflow, and the need to render an intermediate file from Premiere for subsequent reloading into the encoder and compression.
So we were eager to see whether Producer Plus could scale and de-interlace without producing artifacts. To test this, we encoded two files to similar parameters, one starting with the original DV footage, the other using a file that had been scaled and de-interlaced in Adobe Premiere. The results were virtually identical, meaning that Producer Plus had passed with flying colors. We should note, however, that Producer Plus has no editing capabilities whatsoever, not even mark in or out, so you may need quick trip to Premiere to capture and trim your clips anyway.
Our next test was to see how Producer Plus would handle these scaling activities in real time, once again using FireWire input on our Dell Precision notebook, running a 1.2gHz Pentium IV processor with 512MB RAM and Windows 2000. Here we found that files encoded to 34Kbps at 176x132 resolution were clearly inferior to files produced from HDD-based files of the same DV footage, even those encoded in a single pass.
More significantly, on files encoded at 320x240 resolution, we frequently experienced audio distortion. Specifically, the audio became much faster than video and finished long before the video finished playing. Using Windows 2000's Task Manager, we soon saw why—at the higher resolutions, Helix Producer Plus was consuming 100% of the Precision's CPU resources, and probably needed a faster machine to encode without distortion.
So we moved to Winnov's XtremeEngine EZ, a standalone encoding engine running a 1.6gHz Pentium IV processor with internal capture hardware that performs scaling and de-interlacing. In this configuration, we had no problem encoding 320x240 streams at data rates as high as 1Mbps, with quality commensurate with the data rate.
The take away is that while Producer Plus can produce excellent quality from disk-based files, real-time encoding quality will drop without dedicated capture hardware. In addition, without capture hardware, more serious problems, such as the loss of audio synchronization, can also occur at higher bandwidths during live captures from DV.
These results are hardly shocking; after all, scaling, de-interlacing and encoding are complex tasks. For real-time streaming, a hardware capture board or appliance like the XtremeEngine EZ is clearly the preferred approach.
Producer Plus Versus The World
Now that these preliminaries are over, let's move to the main event. In this corner, RealVideo 9; in the other corner, Microsoft's new Corona technology (Windows Media Technologies 9), Apple's new MPEG-4, and Sorenson Video 3. Let's get ready to rumble.
The stars were aligned in our favor, and towards the end of our Helix Producer Plus review, we received an advanced look at Microsoft's new Corona technology and Windows Media Video 9. We quickly fired up some test compressions and loaded the results on side-by-side displays on our identical Dell Precision 530 workstations running 3Dlabs Wildcat III 6110 graphics cards and 18-inch flat-panel displays.
At lower bit rates—28.8, 56—Real exhibited both better quality and more detail than Microsoft, which looked comparatively more faded and fuzzy. However, Microsoft clearly dropped fewer frames while encoding, especially during high-motion sequences, producing much smoother video at these lower rates. For talking head videos, Real is definitely preferable, though producers of higher-motion clips may prefer Microsoft.
At about 100Kbps, Real appeared to catch up to Microsoft's frame rate, while retaining its advantages in color quality and detail. Real's lead narrowed at 200 and 500Kbps, but was still the clear winner.
To be fair to Microsoft, we tested the first release candidate, and subsequent versions may have boosted quality. With both codecs, however, we encoded with default settings when available, changing only the target data rates to achieve comparable file sizes. We produced variable bit rate files using two-pass encoding, with no filtering or black level correction.
For the record, at all tested data rates, both Real and Microsoft proved clearly superior to Apple's MPEG-4 codec and Sorenson Vision 3, which generally comes into its own at about 750Kbps and higher.
On the Real Side
The streaming media market has moved well past the point where the technology with the best quality wins. As we said up front, the strongest feature of Real's new Helix technology is the fact that the server can stream Real, Windows Media, and QuickTime file types, and runs on eleven platforms, compared to Microsoft's one.
Still, it's good to know that if you pick Real, you'll be rewarded with very competitive video quality at the low end, and the best we've seen at higher bit rates. RealVideo 9 is an awesome codec, and Helix Producer Plus is quite the capable tool for encoding these files.