Voice-Over-IP Software for Games Tested by Blake Wilfong and Bryan Shelton Article by Blake Wilfong May 1, 2000 Introduction Voice-Over-IP software enables you to speak to faraway people via TCP/IP networks such as the Internet. The idea is that you talk into a microphone, your computer compresses your voice into digital data and transmits it over the Internet using the TCP/IP network protocol, and someone else's computer receives the data and decompresses it back into audio speech for them to hear--all in real time. (Well, almost real time; to prevent the sound from being broken up by random delays while traversing the Internet, the data has to be buffered. Thus there's a second or two of delay between the time you say something and your friend hears it--kind of like the delay in conversation experienced between NASA and astronauts on the Moon back during the Apollo missions.) Internet Phone was an early application that popularized voice-over-IP; others soon followed. They demonstrated that voice data could be compressed sufficiently in real time to transmit over a 28.8kbps connection with reasonable sound quality--an impressive feat. But the latest generation of voice-over-IP software is absolutely astounding: these programs consume so little CPU time and bandwidth that it is possible to run them and simultaneously play action games on the same computers and 28.8kbps Internet connections. With these programs, you can talk to your buddies in the games you play online. Everyone wears a headset (headset = headphones + microphone) so their voices come in loud and clear, and they hear other people's voices mixed with the game sounds. If you haven't tried it, you can't imagine what you're missing--especially in cooperative First Person Shooters (FPSs). You can tell your friends where you've found critical items, warn them of dangers you've encountered (perhaps fatally), coordinate attacks on fiendish monsters, and, best of all, joke about the game just like the guys in Mystery Science Theater 3000 joked about movies. All this in real time without stopping to type messages on the keyboard! If a cooperative game of Quake II is fun, a cooperative game of Quake II with voice-over-IP is twice the fun. Bryan and I have been using voice-over-IP to talk while playing cooperative FPS games for about 8 months. (Earlier, we used SVD modems to accomplish the same thing, but that's another story.) The program we chose was Roger Wilco, because to the best of our knowledge it was then the only free gaming-oriented voice-over-IP software. Roger Wilco is an excellent program overall, but its occasionally erratic behavior on our computers made us wonder if there might be something better. The Web pages you're reading now describe our testing of other voice-over-IP software. To be honest, posting the results of these tests online is an afterthought; we were simply looking for software for our own use. We tested only on our own computers and we didn't bother trying features that weren't of interest to us, so you should consider this a report of our particular results, not an all-inclusive review. Here is our test platform: Computers: generic clones Chipset: SIS 5577 Processor: Intel Pentium MMX Clock Speed: Bryan: 225MHz (75x3) Blake: 262MHz (75x3.5) RAM: 64MB Operating System: Windows 95 OSR2 Modem: 56k Lucent Win Modem Sound Card: Bryan: generic Aureal Vortex 1 Blake: Creative Sound Blaster Live! w/SPDIF card Both of us have DirectX 7, with sound drivers that are fairly recent, maybe a few months old. Since we live within local calling distance, we don't use the Internet to connect. We instead set up our own direct modem-to-modem TCP/IP network using Microsoft's DialUp Networking 1.3 upgrade. In our experience, these direct connections are more reliable and less laggy than going through an Internet Service Provider. Plus, our IP addresses are always the same. Sound Samples Here are sound samples of all four programs we tested, along with uncompressed speech for comparison. The procedure for producing all samples was identical: each program features a "test" function that allows the user to hear what his own compressed voice will sound like to others; I recorded this "test" output through the Sound Blaster Live!'s SPDIF interface onto a DAT tape at 48KHz. I then recorded this sample back from the DAT into Sound Recorder using the Sound Blaster Live!'s SPDIF input at 44.1 kHz, 16 bits. (For fairness, even the uncompressed speech went to DAT and back the same way.) I normalized and assembled the samples using Sound Forge XP 4.0, then compressed everything to MP3 format at 56kbps. Where the programs allowed us to select different compression levels, we chose the same compression as in our other testing. This is the same as the default compression except in BattleCom's case, where we used Charlie compression to reduce CPU and bandwidth requirements. To achieve heavy voice compression, each program makes different tradeoffs and thus has its own distinctive sound. To our ears, Roger Wilco sounds the most natural, squeezing the best sound through minimal bandwidth. But we found all four programs to be thoroughly intelligible, so factors other than sound quality are probably more important in choosing voice-over-IP software for gaming. Click here for sound samples.