"Brother Pang, Brother Pang, what's wrong with you?"

Seeing Pang Xuelin in deep thought, Liu Fatzi said curiously.

Pang Xuelin shook his head and said with a smile: "It's okay, by the way, Brother Liu, when are we going to Shencheng?" ”

It is now May 20th, and there are still more than three months before Wanyan launches the VCD player in September, and he must get the patent of the VCD player within three months.

In addition, you have to earn enough initial start-up capital to open a factory.

As for how the money will come from, it depends on the next trip to the deep city.

Liu Qi said: "I'll arrange it for you first, I don't have a border certificate, I can only find a smuggler to smuggle through the second-line customs, I have to find a reliable one, it is estimated that it will take at least two or three days." ”

Pang Xuelin smiled: "Brother Liu, then trouble you!" ”

At noon, the nanny made a Cantonese morning tea for everyone, Pang Xuelin had already tasted Cantonese cuisine in later generations, but he didn't think it was so special.

However, Mu Donglai and Mu Qingqing, who have been living in the northwest, are very curious about this pure Cantonese cuisine.

Crystal shrimp dumplings, chicken feet, pork ribs, pork belly, fish fillet porridge, rice noodles, etc., the two people who ate it were full of praise.

After lunch, in the afternoon, everyone watched the LD DVD player in the living room.

All kinds of old versions of Xiangjiang films, "The True Colors of Heroes", "The Story of Ah Lang", etc., can be regarded as allowing Pang Xuelin to experience the feelings of Hong Kong films born in the 80s.

Mu Qingqing, Mu Donglai, and Liu Fatzi were all interested, but Pang Xuelin was not very interested.

After he was a 95th Five-Year Plan, Hong Kong films have declined since he can remember, and in the era of mobile Internet in later generations, the aesthetics have been greatly improved, although these films are classic, they are no longer quite in line with Pang Xuelin's taste.

Early the next morning, Liu Fatzi and Mu Donglai went out.

Liu Fatzi said that he was going to find a friend to arrange for Pang Xuelin to pass the customs.

As for Mu Donglai, he went out to visit a friend from Sun Yat-sen University.

"Brother Pang, we don't have anything to do today, do you want to go out for a walk?"

Mu Qingqing changed into a chiffon short-sleeved dress, stepped on small leather boots, and tied her jet-black hair into two beautiful braids, extending from the forehead on both sides to the back of her head, looking clean, fresh and beautiful.

This girl also belongs to Bai Fumei in this era, born in a Kochi family, has a strict family education since she was a child, has a simple personality, has not experienced any twists and turns, plus she is a scholar, a typical winner in life.

Pang Xuelin actually knew Mu Qingqing's thoughts very well, but he didn't care too much.

He knew very well that he would have to leave the earth sooner or later, so in this world, Pang Xuelin did not have the idea of falling in love and starting a family.

As for Mu Qingqing's feelings, in his opinion, it was more because of the psychological impact of suddenly appearing in front of her at her most desperate moment that night, which caused some attachment to herself.

Anyway, she is going to go to Xiangjiang to study at university next, and as time goes by, such feelings will naturally fade away.

Looking at Mu Qingqing's expectant eyes, Pang Xuelin laughed and said, "Okay, where do you want to go?" ”

Mu Qingqing said with a smile: "Brother Pang, I will go wherever you go." ”

Pang Xuelin thought for a while and said with a smile: "Okay, then let's go to Yangcheng Computer City today." ”

"Yangcheng Computer City?"

Mu Qingqing's eyes lit up.

In this era, digital products have just begun to shine in China, regardless of boys and girls, they are very interested in computers and the like, and naturally there will not be a scene where many girls in later generations are indifferent to digital products.

Not to mention, Mu Qingqing is a science bully herself.

The two went downstairs together, and Huang Mao, who was guarding the store, greeted him, nodded and said, "Brother Lin, Sister Qingqing, where are you going?" I'll send you there. ”

Pang Xuelin said with a smile: "Huang Mao, do you know where Yangcheng Computer City is?" ”

Huang Mao was slightly stunned and said: "I know, Yangcheng Computer City is not far from here, go forward along this road through two intersections, turn right onto Tianhe East Road, and walk for ten minutes." ”

Mu Qingqing said: "Brother Pang, since it's so close, let's walk over, no need to send it." ”

Pang Xuelin said with a smile: "That's okay, Huang Mao, if Professor Mu or Lao Liu come back, you can tell them that Qingqing and I went to the computer city." ”

"Okay! Big brother, then you go slowly! ”

Huang Mao looked at the backs of Pang Xuelin and Mu Qingqing in the distance, and couldn't help but feel a little envious.

At this time, behind him, another employee of Liu Qi's store stepped forward and said, "Brother Huangmao, is that Sister Qingqing you said?" It's really beautiful, that pretty boy is really blessed......"

Huang Mao patted his head and said, "Stinky boy, don't think about it, do you know who that pretty boy is?" ”

"Who is it?"

Huang Mao said: "Have you read the news from Shonan two days ago?" It is said that the police smashed a gang of railroad bandits and seized a lot of gunpowder guns and axes. ”

The young man was curious: "Brother Huangmao, what's wrong?" Does it have anything to do with that pretty boy? ”

"Don't scream in a pretty boy, when I see it in the future, I want to call Brother Lin, that gang of robbers, and the eldest brother cleaned it up alone. I heard that when they got on the train to rob, there were more than a dozen people, not only guns, but also explosives, and they were killed by Brother Lin alone. ”

"Really?"

"Then there can be fake, it's all seen by the boss's green eyes, otherwise why would the boss stammer."

"Hey, you're right!"

……

Pang Xuelin naturally didn't know that he had become the target of yellow-haired gossip.

He and Mu Qingqing walked through the streets of Yangcheng, Mu Qingqing jumped up and down, happily like a lark.

Many people passing by have set their eyes on this young man and girl.

Mu Qingqing is certainly the focus of people's attention, and Pang Xuelin, who is dressed in a simple T-shirt and jeans, is not much inferior.

Pang Xuelin is not bad-looking, and he has experienced the tempering of many worlds, and the whole person has a faint scholarly temperament at the same time, but also has a wild charm.

Otherwise, Mu Qingqing would not have fallen in love with him at first sight.

After all, any form of love at first sight is nothing more than a sight to behold.

If Pang Xuelin grows into Liu Fatzi, Mu Qingqing will be grateful to him at most, and he will not have a tendency to fall into it as he does now.

Before arriving at the computer city, Pang Xuelin did not see the busy and crowded scene of the digital city before the rise of e-commerce, but it seemed a little deserted.

Yangcheng Computer City was established not long ago, is a pioneer in the digital professional market in South China, which has the maintenance department of various digital product brands and a variety of compatible machines, electronic parts, genuine software, consumables and so on.

After the two entered, Pang Xuelin did not go straight to the brand stores set up by those computer brand manufacturers, but first walked around inside, and then stopped in front of a relatively small electronic product consumables store.

"Brother Pang, are you going to buy a computer?"

Mu Qingqing said with some curiosity.

Pang Xuelin shook his head with a smile and said, "I'll just buy some parts." ”

As he spoke, he stepped forward and said to the owner of the consumables store who was sitting at the counter doing nothing, "Boss, do you have a CD-ROM drive here?" ”

The boss was slightly stunned, and said with some doubts: "Young man, what do you want that thing for?" ”

Pang Xuelin said with a smile: "The CD-ROM drive of my computer is broken, and I am going to replace it myself." ”

The boss pondered for a moment and said: "Yes, yes, but the price is not cheap, it costs more than five hundred, if you change it yourself, if it is not successful, I will not return it." ”

Pang Xuelin said with a smile: "Don't worry, I will install it myself." In addition, you have a pen and paper, I still have a list of parts that need to be listed, including DSP chips, diodes, transistors, resistors, capacitors, power transformers, and some small servo mechanisms......"

The boss was stunned, found a pen and paper and handed it to Pang Xuelin, and said curiously: "Young man, what do you want these things for?" ”

Pang Xuelin said with a smile: "Do a little experiment." ”

Next, Pang Xuelin didn't say much, wrote a series of dense lists on the paper, and handed it to the owner of the consumables store.

The owner of the consumables store was a little surprised, there are many things on it, only more professional electronic engineers understand, some things are not very familiar to him, who is this high school student in front of him?

As if seeing the curiosity of the owner of the consumables store, Pang Xuelin said with a smile: "I am a graduate student majoring in electronic information engineering at Sun Yat-sen University, and I will help my tutor buy something by the way." ”

"It turned out to be a top student at CUHK."

The owner of the consumables store was immediately relieved, and said with a smile: "Liangzai, the parts you listed here are about 1,200 yuan in total, and some parts may not be available on my side, so let's do it, you pay a deposit of 500 yuan first, and come to pick it up tomorrow, I'll help you get it all together today, okay?" ”

"No problem!"

Pang Xuelin laughed, and happily took out 500 yuan and handed it to the boss, and the boss wrote a receipt and a pick-up list and returned it to Pang Xuelin.

Twenty minutes later, Pang Xuelin and Mu Qingqing came out of the computer city, and Mu Qingqing was still a little dizzy.

"Brother Pang, what are you buying these things for?"

Like that boss, Mu Qingqing couldn't understand Pang Xuelin's purpose.

Pang Xuelin laughed and said, "Make a small toy, I can't tell you clearly for a while, anyway, you'll know in two days." ”

"Oh!"

Mu Qingqing nodded as if she didn't understand.

Pang Xuelin gave her a mysterious feeling.

Born in an orphan, he has super combat effectiveness, he is handsome, his bearing is extraordinary, and his various insights are even more frighteningly extensive, and even his father, who is a university professor, is amazed at him.

Therefore, although Mu Qingqing didn't understand Pang Xuelin's knowledge of so much electronics, he was quickly relieved.

Anyway, Pang Xuelin is an omnipotent existence in her heart, isn't it strange to have some new skills?

Pang Xuelin naturally didn't know what Mu Qingqing was thinking, and he was going to make a VCD prototype.

In fact, after the advent of MPEG technology, VCD technology has been fully mature.

The so-called MPEG refers to image compression technology.

Before the advent of MPEG technology, the amount of digitized video image data was staggering, and without compressing the original video image data, only 20 seconds of medium-resolution color digital video images could be stored on a 650 megabyte 12 cm disc.

MPEG technology can compress and encode the moving video image of 30 frames per second or 25 frames per second and its stereo sound signal and write it into the CD disk, so that a VCD disk of the same size as the ordinary CD disk can continuously play 74 minutes of video programs, and its image quality is much better than the quality of VHS recorder, and the sound quality reaches the effect of CD laser sound.

The fundamental reason why MPEG image compression can be achieved is that there is a large degree of information redundancy in the original image, such as a TV image, which has a large spatial correlation between adjacent pixels, and a large temporal correlation between the front and back frames.

The MPEG compression algorithm first preprocesses the video image with a specified resolution of 704×408 or 704×576 recommended in the CCIR601 standard, and the compression is to reduce the number of pixels horizontally and vertically by half to a SIM image format of 352×240 or 352×288.

Subsequently, further compression is carried out by two main techniques: discrete cosine transform and motion compensation.

The discrete cosine transform technique based on 8×8 sub-blocks can reduce the spatial redundancy, and the 16×16 fast motion compensation technique can reduce the time redundancy.

For the inter-frame prediction error, the discrete cosine transformation can be used to further compress the data.

At the same time, the MPEG compression standard also takes advantage of the physiological characteristics of the human eye that it is sensitive to image luminance information but not to color information, and adopts a double luminance sampling scheme, that is, for every four bits of luminance value generated, only two bits of chromaticity value are generated.

In the end, this algorithm can obtain a data compression ratio of 1/50 to 1/200%.

In addition, this algorithm also makes use of the basic principle of sound psychology, which is that audio at certain frequencies cannot be heard when audio at other frequencies is present, which is the shielding and filtering function of the human ear.

In this way, the MPEG audio compression system can remove the excess audio signal that is completely or almost inaudible to those people.

It can achieve a compression ratio of 1/8 of the audio signal with a sampling frequency of 44.1k Hz, and the sound quality is not significantly distorted, making it difficult for ordinary users to distinguish the difference between the sound quality of an MPEG system and a standard CD.

At present, the international MPEG compression technology has been fully mature, and the rest is how to write the video information into the CD disk, and re-decode it into a video signal for broadcast on TV.

The two core technologies required for this are the laser reading probe technology commonly used on CDs, and the other is the video decoding chip technology.

At present, the laser reading probe technology is mainly in the hands of the two giants, Philips and Sony, which is why Pang Xuelin bought a CD-ROM optical drive, because it comes with a laser reading probe.

In later generations, there are many DIY enthusiasts on the Internet who have converted CD-ROM drives into VCD players.

Its principle is to take the signal picked up by the laser head assembly on the optical drive from the VCD disc, and after being processed by the digital signal processing chip DSP, the RF signal is output from its RF RF pin, and the RF signal is sent to the installed VCD decompression chip for processing, and the video and audio signals are output.

The only trouble is that there is no dedicated video decoding chip for VCD yet.

Pang Xuelin can only use various small integrated circuits to temporarily design a video decoding chip to output video signals.

That's why he buys so many small electronic components.