Historically, optimization solutions started with text, image and then moved to video. The younger players jumped directly on the most lucrative media - Video, but it seems that they still need to go the basics, and provide the full solution.
Skyfire (see "Optimization Market: Verizon Invests in Skyfire" - here) announced that it added "image and audio optimization to its carrier-grade product line.. Skyfire’s [existing] video optimization solution increases effective network capacity by 25-30 percent across RAN and network core. With the addition of image and audio support, Skyfire can increase network capacity by an additional 10 percent for a total of up to 40 percent capacity increase".
See "Loud and Clear: Skyfire Rocket 2.0 Platform Gets Enhanced With Image and Audio Optimization" - here.