wsippel
L20: Enlightened
- Seit
- 15 Mai 2006
- Beiträge
- 25.225
Weil kürzlich behauptet wurde, ein DSP sein überflüssig weil Audio sowieso kaum Rechenleistung brauche:
bkillian/ Beyond3DOn the XBox 360, audio mixing for a normal game can use as much as two full hardware threads, 1/3 of the CPU dedicated to audio. That's not even considering complex games like car racers, where each vehicle can have dozens of voices and complex filters. That's hugely wasteful in terms of cost. A general purpose CPU is just not optimised for audio processing.
The difference is that a CPU core costs you dollars, and a DSP core costs you pennies. That's why almost all mobile architectures have dedicated audio silicon. By far the most popular request my team gets from game devs is "Make audio cheaper!". Just running a single good reverb will completely blow the L1 and L2 cache, and require ridiculous amounts of memory bandwidth. We support 320 simultaneous voices on the 360 (that's how many the XMA hardware will decode at a time). AAA games use all of them. Even plants vs zombies uses over 100 and most of a core, _just for audio_. If we were to have the choice of adding a full core to the 360 or a DSP that can handle the same load. We'd probably choose the DSP, since it would be vastly cheaper in BOM and essentially give devs an extra 50% CPU for game logic.