Analysis of the Recording Types of Excellent Courses under the Semi-automatic Recording and Broadcasting System
The construction of high-quality courses is an important part of teaching quality and teaching reform in colleges and universities. It is a systematic project and the foundation of professional construction and discipline construction. The quality engineering and quality curriculum construction plan initiated by the Ministry of Education has played a role in promoting and improving the teaching work, increasing teaching input, and improving teaching quality of colleges and universities across the country. The video recording of quality courses is the process of promoting and building quality courses The key part is that whether the recording of the excellent course can accurately and completely convey the content of the course taught by the teacher, whether it can capture the students' psychology and make them immersive, and whether it can fully reflect the teacher's classroom charm, etc. The communication effect and demonstration effect of the course.
Looking at the current video recording of high-quality courses in Chinese universities, there are three main modes:
(1) Pure manual video recording system, that is, a camera with multiple cameras installed in the classroom, multiple videographers take the course on site, and then take it to the computer room for post-editing. This mode requires multiple people to participate, the best effect, but it takes time and effort.
(2) Fully automatic recording and broadcasting system, including single-machine automatic recording and broadcasting system and multi-machine automatic recording and broadcasting system. That is, one or more cameras are installed in the classroom, and some displacement sensors are installed to track the movement of teachers, and the hardware and software of recording and broadcasting are installed on the computer of the classroom multimedia system. The instructor initiates the recording button to record the entire course. . This mode saves manpower, but the connection of the lens is easy to cause problems, the picture is not artistic, and the effect is not ideal.
(3) Semi-automatic recording and broadcasting system, that is, hoisting multiple cameras (generally 2 to 3) at different locations in the classroom, aiming at teachers, students and PPT, etc., and at the same time in the recording and broadcasting machine room (a single room is created) Set up a switcher and a mixer, and a staff member can push, pull, shake and switch the video of each station on the switcher, and enlarge or reduce different types of audio. This mode is not expensive in terms of manpower and material resources, and as long as the director who participated in the recording and broadcasting has a strong sense of responsibility and control, it can achieve a more ideal recording effect.
1 All-round transfer type
It is mainly aimed at some courses that are more interactive and use more multimedia methods. Recording such high-quality courses requires timely switching of different camera positions and audio and video signals according to the scene. It is the type that can best mobilize the thinking and reaction ability of the broadcaster. Sometimes it is even used "hands and feet" to describe this process. Ever. Taking the excellent college English courses that the author has recorded as an example, under the current background of the continuous reform of college English teaching and examinations in colleges and universities across the country, college English classrooms have changed a lot in terms of content and form. The teacher's explanation of the students 'listening mode resulted in the students' "dumb English". Now the college English classroom is lively and interesting, with lively forms, the use of various methods such as listening and speaking training, PPT and video, and the active interaction between teachers and students, which greatly enhances the students' autonomy and initiative in learning. However, this also adds a lot of difficulty to the recording of English excellent courses. When recording such courses, the broadcaster needs to fully communicate with the instructor in advance. It is necessary to understand the multimedia methods to be used in each lesson, such as which videos need to be played and when they should be played. It is also necessary to understand what forms of interaction the teacher will take, whether it is "question-collective answer", or individual self-speaking, or group discussion and referral. In addition, we must understand some details such as the distribution of student seats that usually like to actively speak. In this way, when recording and broadcasting, every student who speaks can be captured quickly, so as not to "just hear the sound and not see the person". In this case, we generally set a close-up camera position for a teacher and a panoramic camera position for a student. These two camera positions are the positions that require the broadcaster to continuously zoom and do sports lenses such as push-pull panning. The guide has spent his time to master. In addition, you need to set up a PPT camera (or computer computer connected to the internal line). If conditions permit, you can set up a transitional "universal camera"-a large panoramic camera for the entire classroom. All planes are equally important, and the proportion of each plane in a class is basically the same. The broadcaster must listen carefully to the content of the teacher when recording, with a high sensitivity and quick response ability Respond to the next aircraft change. In addition, in terms of audio, the lecture teacher uses a wireless microphone, and the students who answer questions use the microphone in turn (or use a few area microphones suspended at the top of the classroom), and the video and audio files played by the teacher on the computer are another audio. Therefore, it is necessary to quickly switch several audio signals on the mixer while switching the screen.
2 Teacher-oriented
It is mainly aimed at some excellent courses with less interaction and mainly teacher explanations. In such courses, the role of PPT is usually relatively weak. It only lists an outline of the lead frame or the title of the textbook content, prompts the teacher's explanation, and does not have video or picture presentations. Multimedia means are used less. On the one hand, this may be because the teachers who teach these courses are mostly experienced and experienced teachers. Years of lecture experience make them familiar with the content they speak, without having to refer to too many tips; on the other hand Due to the limitations of the course content, there are not too many pictures or materials to demonstrate (such as some basic principles and knowledge, etc.). For such courses, the focus should be on tracking the teacher ’s movements and aiming the camera at the teacher. Normally, we take a close-up teacher's camera position as the host position. During the recording process, we always use this camera position to zoom and push and pull the teacher's movement to achieve the purpose of reproducing the teacher's lecture scene. It should be noted that some teachers have little or no fixed movement range, and some teachers are used to moving back and forth. Therefore, when recording such excellent courses, it is necessary to adjust the lens and camera position according to the movement range and frequency of different teachers. If the movement amplitude is large or the frequency is high, it is necessary to switch to another panoramic camera or student camera appropriately. However, since this type of course recording basically does not require frequent switching between cameras, it is relatively easy to control, and there is generally no phenomenon of "missing people" or empty mirrors.
3 PPT-based
It is mainly aimed at two situations: (1) The production of PPT is detailed and complete. Teachers have a high degree of dependence on PPT, and basically explain according to the content of PPT. (2) The content of the course itself is esoteric and requires students to continue to watch to understand. For example, science and engineering courses that contain a large number of charts and calculation formulas. When recording such courses, you can use a panoramic camera that includes the teacher (the teacher is in the lower left or lower right corner of the screen) and the PPT (excluding students and others), and a computer PPT connected through the line as the auxiliary camera. . The previous camera position, that is, the PPT picture taken by the camera is not perfect in terms of light perception and clarity, but because teachers may often use electronic pens to read and explain part of the content on the PPT in a targeted manner, it is the primary machine Bit. The latter camera is used as a supplement to make the content of the PPT more clearly displayed, because its clarity is exactly the same as that displayed by the computer. In addition, a large panorama of the classroom can be set as a transition plane, and a close-up plane to track teachers can be set up to deal with teachers who walk back and forth during the explanation. The recording of this type of course is mainly to switch between the first two stations, and occasionally to track the teacher.
4 Student-oriented
It is mainly aimed at those excellent courses that take the form of student discussions, debates, speeches on stage, etc. as the main subject of the course, and the role of teachers as organizers or moderators. It can also be divided into two situations: (1) A single student takes turns to speak or lecture on the podium, then a close-range camera with the podium as the background is required as the main station, and the reaction lens of the students under the stage is used as the secondary station. Switch the teacher's tandem and evaluation lens at the appropriate time between the students' speeches. (2) Students are divided into two or more groups for debate or discussion under the stage. The speeches and activities of the students are under the stage. The main body of the speech is not single but multiple, and the position distribution of the main body of the speech is also flexible. In this case, we need to first use the panoramic camera of the students as the host computer, and the tracking camera of the speaking student as the auxiliary camera. At the same time, we must also take into account the teachers' interleaving and tandem cameras, and then set up the entire classroom The big panorama serves as a guarantee seat. Among them, the most important thing for the broadcaster to concentrate on coping is still the tracking machine. When tracking student speeches, you should pay attention to the length and style of student speeches, that is, whether these speeches are fragmentary or whole paragraphs, whether they are well-prepared or improvised, if the latter, do not simply Follow the close-up shots and push and pull quickly, because it is likely that the subject of the speech has changed when your lens has not stabilized.
5 Conclusion
Based on some experience of recording quality courses in recent years, starting from the different styles of teachers' teaching and the teaching methods and characteristics restricted by different professional content, a recording type is divided and analyzed simply. In fact, in the actual recording process, the above types cannot be absolutely independent or in parallel, and it is very likely that two or even several of these types will be used cross-recording when recording the same lesson, so according to the actual teaching The situation is modified.
references
[1] Chen Yongyi. Choice of recording and broadcasting system based on teaching style [J]. Laboratory Research and Exploration, 2009, 6.
[2] Li Xianwu. Comparison of two methods of producing teaching videos for excellent courses [J]. Modern Education Technology, 2009, 4.
[3] Li Zhi, Tang Yimin. Research on Intelligent Recording and Broadcasting System Based on Normalized Teaching [J]. China Modern Education Equipment, 2010, 24: 23-26.
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