A study on the application of digital cameras to derive audio information from the TVs on trains

Digital camera can help people take videos anytime with ease. For this reason, application of digital video camera\´s technology is the hottest topic right now. Due to the fact that the TV on the train is in a public place it can\´t give audio information. We were trying to find a way to get the audio information by second time (ST) detection video only. "Second time" (ST) means the user uses their digital camera to take video from the original video. We propose a new way to use digital watermarking by embedding some pointer symbols into the source video, so passengers can use this kind of video to detect high quality audio in ST situations. In order to show other possible application for this process in the future, in this study we also use VB programming to design simulation software "DDAS" (directly detection audio system). The software was designed to handle uncompressed AVl files. We tested this software using ST video. In the Experiments of this software successfully detected audio information and audio file types covering AVI, MPEG, MIDI and WAV file type. According to the questionnaires from the users, DDAS system\´s output audio file was given a 3.8 MOS level which shows the system has enough audio embedded ability. From the questionnaires, we also found ST video\´s screen size affects the detected audio\´s MOS quality. We found the best MOS quality was located in 1:1∼1:4/3 screen size. We also use this kind of technology for study and we found that using multimedia improves the student\´s grades and the grades about 6 average grades.