The Reaserach And Realization Of Video Capture On Smartphone

The video capture application in embedded system has became more and more popular. Video capture and processing have became one of the most important applications of embedded system. Now,most mobile use the hardware to encode the video stream and decode the JPEG file,this makes the price of mobile more high. The PXA270processor which Intel Corporation brings out for mobile phone and handheld PC uses QuickCapture technology,its frequence can be 600M. The technology which gives the interface to video capture device will help to improve the video quality and to reduce the system cost.How to realize the video capture function which includes still-picture snapshot and dynamic-video.On the condition of the ADCM-2650 Sensor with JPEG hardware-encoding, The Reaserach and Realization of Video Capture On Smartphone is realized on the PXA270 hardware and the Linux-2.4 kernel software platform. The main research is described as follow:(1) The basic structure of the embedded image encoding and decoding system is analyzed and one embedded static JPEG image decoding and the video encoding based on the MPEG-4 algorithm is selected.(2) Has studied the embedded Linux essence characteristic as well as the development debugging environment, analyzed the embedded system filing system, made the Linux kernel suitable for us.(3) After has analyzed the Linux driver architecture, then research the framebuffer technology used for LCD in Linux, the programming has realized for the video capture driver as well as the application procedure, has completed the JPEG document decoding and demonstration on Smartphone with emphasis as well as the video frequency gathering data encoding based on the MPEG-4 algorithm.(4) Focused on the display system's optimization in view of the Pxa270 Overlay 2 pairs, and tested to show that the performance of view on LCD after open the Overlay2 has obviously enhanced largely. The difficulty of the task lies on the software design and performance optimization of video capture driver. To make sure the quality of the driver, three rules are given: reliability, practicability and flexibility and the method of state-machine is used. After several tests, the final realization has met the designed requirement: the capability of the captured video preview, the capability of still picture capture and compression, the capability of dynamic video capture.In the article,I use the software to carry on the JPEG decoding and the MPEG video encoding, comparing to the field hardware-encoding and decoding technology realization to say, can reduce the handset effectively the overall cost, has very good practical value.The mobile using this Technology has been made.