Design and implementation of airborne high definition video encoder based on DSP platform

To enhance the capacity of video capturing and ground reconnaissance of an unmanned aerial vehicle (UAV), an efficient MPEG-4 high definition video encoder is designed and implemented on a digital signal processor (DSP) platform, which is characterized by small volume, low power consumption and high reliability. Firstly, the data flow scheme of video encoding is optimized by allocating the on-chip memory of the DSP reasonably, which reduces the impact of data access on encoding speed. Secondly, prediction-based motion estimation is adopted to accelerate the search of matching blocks. Furthermore, optimized variable length coding and predicting all-zero coefficient blocks are proposed to improve coding speed and reduce discrete cosine transformation (DCT) and quantization computation respectively. Experimental results show that, for the video sequence with 720P (1280 pixel×720 pixel resolution) format, the optimized encoder can achieve an encoding speed of over 20 frame/s, and the peak signal to noise ratio (PSNR) is higher than 35 dB, with satisfactory visual quality and relatively low bit rate.