X is Microsoft's favourite letter at the moment, with ActiveX and DirectX both providing improvements in PC sound. Martin Walker explains all.
There are now so many software 'technologies' emerging from the doors of Microsoft that it can get very confusing. What exactly are the differences between ActiveX, ActiveMovie, ActiveX Streaming, DirectX, DirectSound and DirectSound3D? One of the main problems is that Microsoft have a tendency to change their mind about names: originally, the Microsoft technology used by PC Audio plug‑ins was called Quartz, but this was renamed ActiveMovie. The names are synonymous, and the program is a subset of ActiveX technology, which is itself now largely associated with adding functions to Internet web site pages.
ActiveMovie was originally designed by Microsoft as a media‑streaming architecture for Windows, and was intended to replace Video for Windows. Rather than making you wait for a complete audio or animated graphics file to be processed before it can be auditioned, 'streaming' was designed to work in real time, processing a stream of smaller packets of data, each of which could be heard or seen before the next arrived. This also allowed synchronisation between video and audio to be maintained, as long as the user's system was fast enough. However, since ActiveMovie had a standard set of underlying interfaces for both audio and video, it proved an ideal way to create plug‑in applications that would work with any host program that supported ActiveMovie.
What creates confusion is that Microsoft have another technology called ActiveX Streaming Format (ASF), which was specifically created for Internet use — when you're downloading video or audio over the Net, ASF streaming allows the synchronisation of audio with page loading. For instance, audio processed in Sound Forge can be saved in ASF format for real‑time audio use on the Internet.
When version 4.0a of Sound Forge was released, its incorporation of ActiveMovie technology not only allowed third‑party plug‑ins to be added, but also achieved real‑time operation for many of them by using its streaming. However, it was the Native Power Pack from Waves that really made people sit up and take notice. For the first time, plug‑ins originally created for high‑end Mac use, with added DSP farms (extra processing modules to take much of the load from the main processor) could run without any additional hardware. A further carrot arrived shortly after this, when Steinberg announced that the next version of WaveLab (version 1.6) would also be compatible with ActiveMovie. Cakewalk's Pro Audio version 6 was also upgraded in the same way. Once plug‑in manufacturers realised that they simultaneously had access to owners of Sound Forge, WaveLab, Cakewalk and the forthcoming Cubase VST as well, allocating development time to PC versions became much more feasible; with a much bigger potential market, prices could also be more competitive, resulting in even better sales.
The Direct Approach
DirectX technology is something different again. It's primarily a set of application program interfaces (APIs) that sit between hardware and applications. Until its arrival, it was difficult for Windows games to compete with their console equivalents for speed, especially as dedicated drivers needed to be written for each different piece of audio and video hardware. Since there are so many graphics accelerator cards and soundcards in the market, what Microsoft have done is remove the need for each game developer to write individual software drivers. The APIs sit between the hardware and the application, so that all the developer needs to do is use standard calls to the DirectX layer, to send audio or graphic data to any make of hardware that has DirectX drivers. This transparent approach should result in many more sound and graphics cards being fully supported.
There are several components in the DirectX system for graphics, including DirectDraw (for normal 2D graphics), and Direct3D (for fast 3D rendering), but the two components that will be more of interest to musicians are DirectSound and DirectSound3D. DirectSound was written primarily for low‑latency mixing of sound, as well as some giving volume, pan, and frequency control, so that multiple channels of sound can be quickly mixed down to emerge as a single stereo channel. Latency is the time delay that occurs between your sending the data and your hearing it through the soundcard; including the DirectX drivers as part of Windows 95 minimises this time delay. Once again, streaming is involved, and Microsoft estimate that up to 32 simultaneous audio streams can be sent to a DirectSound audio system if it uses the PCI buss, without grabbing too much of its total bandwidth.
Although DirectX 3.0a has been out for some time (see Figure 1 on page 252 to see how you find out whether you already have these drivers installed), Microsoft have since released the spec for the DirectSound3D component, and the actual release of this (as part of DirectX version 5.0) is scheduled for June '97. Again, the benefits of an open standard are that soundcard manufacturers no longer have to re‑invent the wheel. Three‑dimensional sound positioning is much more likely to appear in mainstream products if software writers know that they don't have to write different drivers to suit each proprietary 3D system. Every soundcard manufacturer is likely to provide DirectSound and DirectSound3D drivers.
Just when people were finally getting their heads around all these new terms, Microsoft got up to their old name‑changing tricks. A new Sound Forge upgrade to version 4.0b has just been released (see Figure 2 for more details), and this new version incorporates Microsoft's DirectX Media Streaming Services (DMSS), which, Sonic Foundry say, was formerly known as ActiveMovie! Although the further change of name is confusing, it does make sense to move DMSS (the technology formerly known as ActiveMovie) across to become a part of DirectX 5.0, since ActiveX is now primarily associated with the Internet, as opposed to DirectX, which deals with sound and vision for Windows. The crossover seems to be ASF (Active Streaming Format), which is now supported by DirectX, as well as being part of ActiveX. Got that?
Tiny Tips
If you don't use a Joystick, Network, Password or other item that appears in Control Panel, you can stop the unwanted icons appearing by using Find, and looking for *.CPL files. Rename the extension of any unwanted item as CP$ (don't delete them unless you're absolutely sure you won't ever need them again). The next time you open Control Panel these superfluous options will have disappeared, making it easier to find the ones you really want.
From using word processors, many people are familiar with the use of Ctrl‑X, ‑C and ‑V to cut, copy and paste selected chunks of text. However, in Windows 95 this has been extended to files. In Explorer, this makes it easier to move files around when you can't easily get both source and destination folders on screen simultaneously. If you want to move a selection of files, here's what to do. First select the files by clicking on them (if you hold down the Ctrl key you can keep clicking on individual additional files without deselecting the first). Then press Ctrl‑X, and the icons of the selected files will be greyed out. Next, open the destination folder. Press Ctrl‑V, and all of your files will be pasted into the folder. If instead you want to make additional copies of files to another folder, leaving the originals where they were, use Ctrl‑C and then Ctrl‑V.
In the continuing quest to streamline your Start menu, here are a few more ways to reduce the quagmire of unused entries. I recently received an upgrade to Cubase Score (now standing at version 3.05). After using Cleansweep to completely remove the previous version (after first saving my customised INI files in a Temp folder for safe keeping), I installed the new version, only to find that there were 16 new entries on my Start menu inside the Cubase folder. Many of these just point to text files, and, once you have read them, their shortcuts can be deleted (of course, the files themselves should remain, in case you need them in future). Shortcuts to the help file are redundant if you always use Help from within the application. Removing any entries surplus to requirements will shrink your Start menu significantly, making it easier to find the application that you really want.
On The Cards
As I mentioned in May's PC Notes, the AC97 audio hardware specification should result in a much wider variety of PCI audio solutions, because it provides a standard that all manufacturers can use, rather than each of them having to re‑invent the PCI wheel. Creative Labs played a significant role in helping to thrash out this spec, and they have now announced an advanced new PCI audio chip intended for OEM motherboard applications. The EMU8008 is an AC97 digital controller chip, providing 100 percent SoundBlaster 16 compatibility and advanced wavetable synthesis with 64‑voice polyphony. Hardware acceleration for DirectSound and DirectSound 3D is built in, and once again (as on the AWE64 soundcard) a full S/PDIF digital output is provided, which will allow direct connection to an external DAT machine or D/A converter. The new chip will be available in production quantities in the third quarter of '97, so expect to see the first motherboards including it starting to appear by Christmas.
I suspect that Creative will be releasing a high‑spec soundcard to take advantage of this chip as well — it has significant performance advantages over the EMU8000, which is currently used by both the AWE32 and AWE64 cards. It will be interesting to see what happens to current high‑end soundcards, as audio quality soars while prices plummet. However, as always, theoretical specs tend to be compromised by the unreal world inside PCs — we'll have to wait and see what 'typical' performance figures are.
On the subject of the AWE cards, yet another has just joined the range — the AWE64 Value. The main differences between this and the AWE64 are that it comes with only 512K of RAM, and has a smaller software bundle, without Cubasis Audio. It is already shipping, and with a retail price of £79 including VAT, it should do extremely well. This new card effectively replaces the AWE32, and so this disappears from the range, leaving the SB16 at the bottom. At the same time, the AWE64 has a new lower retail price of £99, with the AWE64 Gold at £179.99.