The paper specifies the issues of high-speed video techniques and digital image processing of some fire tests of a modeling solid-fuel gas generator. It becomes possible to use the digital processing of the large video information flow for diagnosing the high-temperature combustion and the course of two-phase flows. The authors introduce a procedure for calibrating the photometric lamp of back-illuminated CCD cameras according to the brightness temperature. They designed software programs for processing, storage, and presentation of the obtained results. Some tests of solid propellant gas generator were conducted, where a high-speed video filming was used to shoot how the combustion products flow from the two-nozzle block. This paper presents some examples of halftone image processing of temperature fields as well as gas-dynamic flow patterns, which illustrate the full-cycle application of the optical non-contact method of diagnosis from experimental tests to receiving quantitative characteristics of the studied temperature fields.