Who can tell me something about mp4 screen and decoding?

Now MP4 players have entered the RM/RMVB era. In the field of flash memory MP4, the market has basically established the pattern that ADI BF533/BF547 is positioned at the high end, while Ruixinwei RK2706 and Huaxinfei JZ4732 are positioned at the low end. Because the performance difference between the main control schemes of Ruixinwei or Huaxinfei adopted by most MP4s is not obvious, the face competition of MP4s around the screen has become a beautiful landscape in the market.

Next, the author will give you a comprehensive introduction to the technology, size, resolution and hair color number of mainstream MP4 screens, and show you the real charm of MP4 screens.

The first home scan

Screen technology: one strong dominates two strong.

At present, LCD technology has been widely used in various electronic products, including computer monitors, notebook computers, digital televisions, mobile phones and portable players.

In the early era of color screen MP3, CSTN (color super twisted nematic liquid crystal) screen was all the rage. However, with the progress and promotion of liquid crystal display technology in recent years, MP4 has transitioned to the mainstream TFT era. At the same time, LTPS and AMOLED screen technologies with better performance have also been well applied and popularized, among which AMOLED technology has a bright future.

1. Traditional overlord-TFT-LCD technology (thin film transistor/thin film transistor liquid crystal)

I believe everyone is familiar with TFT-LCD screens. It belongs to a branch of AM-LCD (Active Matrix -LCD/ Active Matrix Liquid Crystal Display). By arranging a backlight plate and a color filter on the back of the liquid crystal substrate, each pixel on the screen can be actively controlled.

Compared with the early STN-LCD (super twisted nematic liquid crystal), TFT-LCD technology has the advantages of higher color saturation, stronger color reproduction ability, higher contrast (200: 1) and better response speed (30ms). As a pioneer of liquid crystal display, TFT-LCD technology has defeated the traditional CRT screen technology and become the leading industry.

TFT-LCD, as a mature liquid crystal technology, has been widely used in various fields because of its advantages such as large capacity, low cost and flexible configuration. Most MP4 players in the market use this kind of screen, and the products of local manufacturers such as Meizu, Onda and Blue Devils and most foreign manufacturers basically use TFT-LCD screens. However, with the improvement of hardware technology and the increase of consumer demand, TFT-LCD with increasingly backward display parameters is facing upgrading.

2. Improvement and transcendence-LTPS liquid crystal display technology (low temperature polysilicon/low temperature polysilicon)

LTPS liquid crystal display is a new generation technology based on TFT-LCD. In the process of screen packaging, the traditional amorphous silicon (a-Si) glass panel was transformed into polysilicon structure by excimer laser treatment, which increased the electron flow speed in the transistor by about 65,438+000 times, thus obtaining higher resolution and richer colors.

The characteristic of LTPS-LCD technology is to simplify the structure of the peripheral circuit of the screen. The number of components in LTPS-LCD module can be reduced by 40%, and the connection part can be reduced by 95%, which greatly reduces the failure rate of products. In addition, the energy consumption of LTPS liquid crystal technology is lower. In terms of display parameters, the vertical and horizontal viewing angles of LTPS-LCD screen can reach 170 degrees, the display response time can reach 12ms, the display brightness can reach 500 nits, and the contrast ratio can reach 500: 1, which greatly exceeds the traditional TFT-LCD in all aspects.

At present, the popularization and application process of LTPS- LCD screen is accelerating day by day, and manufacturers such as BOE and Bao Tong Optoelectronics in the upstream field have initially achieved mass production. Although the current cost is slightly higher than that of traditional TFT, MP4 manufacturers who pay more attention to product quality in China, such as Enoch, Patriot, Meg and Haichang, are vigorously promoting products adopting this technology, but the technology is transitional to some extent and the prospect is not clear.

3. Hope Star -AMOLED technology (active matrix organic light emitting diode/active matrix organic light emitting diode panel)

AMOLED technology is called the next generation display technology, which mainly stores signals through the matching of capacitors and thin film transistors, thus controlling the brightness and gray performance of OLED panels. Because the organic light-emitting diode is self-luminous, the screen does not need the backlight and color filter used in TFT and LTPS screens, so the structure of AMOLED screen is lighter and smaller, which meets the development requirements of light and thin consumer electronics products. Moreover, its screen power consumption is only 60% of the same size TFT screen, which can significantly improve the endurance of the product.

The display parameters of AMOLED technology are also excellent, its response time can reach 0.0 1ms, the display color gamut can reach 1 14% NTFS color gamut (traditional TFT is 68% NTFS color gamut), the contrast can reach 10000: 1, and the screen is vertical and horizontal.

It can be said that AMOLED technology represents the first-class level of liquid crystal display technology at present. However, due to the complex process, low yield and high cost at present, the wider application of this technology has been affected. At present, only iriver and Taipower have launched corresponding products in MP4 market. However, upstream manufacturers such as Samsung Electronics, Samsung SDI, LG Philips, AUO Optoelectronics, and TV manufacturers such as Sony, Toshiba, Panasonic, and Sharp are vigorously promoting the research and development and promotion of AMOLED technology, and the prospect of this technology is quite optimistic.

As the most important performance of the screen, the screen size and resolution of MP4 determine consumers' external impression and perceptual evaluation of an MP4. These two indicators are closely combined, and it is really difficult to explain them separately, so we discuss them together here.

Screen size refers to the linear distance between diagonal lines of the screen. At present, the MP4 screen size in the mainstream market ranges from 2.4 inches, 2.6 inches and 2.8 inches, to 3 inches and 3.5 inches, and then to 4.0 inches and 4.3 inches, which basically covers the needs of general use.

Easy to wear and comfortable to watch are the overall requirements of consumers for MP4, but for manufacturers, it is like two poles of contradictory unity. When it is more portable, it is necessary to keep the product small, so it is difficult to use a large screen, which will affect the viewing comfort. However, if you need to use a larger screen to watch, it is difficult to keep the volume of the product and limit the portability of the product. But specific to each consumer, different tastes and different needs, manufacturers can still find a suitable balance point.

Screen resolution refers to the resolution of the picture, which is expressed by multiplying the number of pixels in the horizontal direction and the number of pixels in the vertical direction of the screen. For example, the common resolution of 320×240 means that the screen has 320 pixels in the horizontal direction and 240 pixels in the vertical direction. The larger the number, the clearer the displayed image.

Of course, the clarity of the display screen is also related to the pitch and size of the screen. Point spacing refers to the distance between two adjacent fluorescent points on the screen. Divide the width and height of the display area (in millimeters) by the pixels of the screen in the horizontal and vertical directions (that is, the screen resolution) to get the point distance of the screen. The smaller the point distance, the clearer the screen display.

The resolution of 320×240 mentioned above is the most common QVGA (Quarter VGA) resolution, and the number of pixels in both horizontal and vertical directions is equal to 1/2 of the standard VGA resolution (640×480 resolution), so the total number of pixels is 1/4 of the VGA resolution. Recently, with the promotion of wide-screen MP4 products by local manufacturers, a new resolution of 400×240 (wide QVGA) is gradually known to everyone. In fact, careful friends can find that the resolution of 400×240 only increases the horizontal pixels on the basis of QVGA resolution, and the vertical pixels have not changed, but simply lengthen the screen, and its screen ratio is 15. The international standard WQVGA resolution should be 480×272 resolution (16: 9 screen ratio), which is achieved by adding horizontal and vertical pixels on the basis of QVGA resolution. However, due to the vigorous promotion of manufacturers, it seems that the market has recognized 400×240 pixels as the resolution of WQVGA, so we will not reject this title too much.

This is where the screen size affects the clarity. Under the condition of the same resolution, the larger the screen size and the greater the dot distance, the clarity of the display will of course become worse (that is, the graininess is obvious). Below, the author will combine the relationship between screen size and resolution to briefly talk about the collocation positioning and product characteristics of mainstream MP4 screen size and resolution:

In order to show the characteristics of various screen designs intuitively and clearly, the author makes a simple comparison of the characteristics of various screen sizes/resolutions. You can refer to the following comparisons and results, and choose the screen design that best suits your needs according to your own preferences. (Comparison is for reference only)

Comparison of mainstream MP4 screens under 3 inches (including): (The single score is from low to high 1-6, and the two are equal, so take the average score and rank the comprehensive evaluation according to the total score).

Portability:

2.4 inch screen (6 points) > 2.6 inch widescreen (5 points) > 2.8 inch widescreen (4 points) > 3.0 inch widescreen (3 points) > 2.8 inch widescreen (2 points) > 3.0 inch widescreen (1 minute)

4.3 Program playback screen area:

3.0 inch screen (6 points) > 2.8 inch screen (5 points) > 3.0 inch screen = 2.4 inch screen (3.5 points) > 2.8 inch screen (2 points) > 2.6 inch screen (1 minute)

16: 9 Program playback screen area:

3.0 inch widescreen (6 points) > 2.8 inch widescreen (5 points) > 3.0 inch widescreen (4 points) > 2.6 inch widescreen (3 points) > 2.8 inch widescreen (2 points) > 2.4 inch widescreen (1 minute)

Comprehensive evaluation:

3.0 inch widescreen (12.5 min) > 2.8 inch widescreen (1 1 min) = 3.0 inch widescreen (1 1 min) > 2.4 inch widescreen (10.5

2. Reserve group: size s-3.5 inches &; 4.3 inches

By appropriately relaxing the restrictions on portability, manufacturers can exert their efforts on a larger screen size. At present, Apple's iPod Touch is the first to adopt a 3.5-inch screen design (480×320 resolution, 3: 2 ratio). Because of its smaller screen spacing and better display clarity than the mainstream MP4, its high price also widens the distance from the mainstream MP4.