Innovative research of vertical video creation under the background of mobile communication

The popularity of mobile devices has provided a wider space for the creation of vertical video, reduced the cost of information collection and enhanced the timeliness of production content. Mobile phones have become a necessity for people’s daily travel. Creators can record people or things around them anytime and anywhere, which makes it possible for improvisation. Facing news events that may occur anytime and anywhere, mobile phone users can take multiple roles to complete the shooting, explanation, interview, editing and other work of event, and collect and release information in a timely manner. Lightweight equipment has become an important tool for video creation in the new era, including lightweight pre-shooting equipment and post-video editing apps based on mobile phones.

Firstly, lightweight devices can make content products more time-sensitive. From the perspective of vertical video creation, using mobile phones to shoot and edit vertical video has its unique advantages. The vertical shooting operation of the mobile phone is faster, which is conducive to the first-time recording of on-site emergencies. At the same time, the vertical holding of the mobile phone conforms to the physiological structure, and the shooting can be completed with one hand, and the picture is more stable. These unique advantages of handheld creation encourage users to take vertical screen shooting. The screen does not need to be exported after shooting, and the post-production of the video can be quickly completed by using mobile phone editing software launched by major platforms. The portable and efficient creation mode of lightweight equipment meets the demand of timeliness of content products in the network era.

Secondly, from the perspective of social demand, the low price and convenient operation of mobile devices have promoted the production and consumption demand of vertical video. Mobile devices provide a lower threshold for creation, which is beneficial to the production model of UGC. Users can make videos at a low cost and get started quickly. Mobile phone editing software also provides a large number of templates, such as Tik Tok’s editing software ‘Clipping’, which provides the function of video editing templates for beginners. These templates correspond to the themes photographed by the creators. The rhythm of music and the length of the shots are adjusted in the templates. The creator only needs to select the corresponding shots to generate the corresponding works of sound and picture. This portability makes clips quick to pick up. The popularity of UGC has brought the richness and diversity of content production, attracting more users to participate in it. The huge video production group and receiving group not only bring huge commercial profits but also continuously promote the development of the video creation industry and form a virtuous circle.

Here comes the question. The application of lightweight equipment is becoming more and more popular, so can its shooting quality, shooting effect, clarity, etc. meet the creative requirements of the creator? Can the continued development be comparable to the shooting effect of an SLR camera or a card camera? What is gratifying is that through the unremitting efforts of researchers in recent years, the resolution of mobile phone images is getting clear, more and more easily applied in other functions, and comes with more and more special effects. In some functions, there is a great momentum to replace the card machine. To illustrate this problem, let us first consider the factors that affect the image quality of mobile phones. In short, there are three main factors: the first is the size of the sensor, mainly the complementary metal oxide semiconductor (CMOS) sensor area. As the saying goes, ‘the larger the sensor, the better’. The amount of light captured determines the exposure balance, dynamic range and sharpness of the camera. The size of the sensor determines the amount of light the camera uses to create an image, so a larger sensor captures a large amount of light than a smaller sensor, and more light produces a better image.

However, due to size limitations, the camera sensor of most smartphones is usually only 1/2.55 inch, and some are 1/1.7 inch or even larger, such as Huawei P40 series and Sony IMX700 can reach 1/1.28 inch and Samsung GN2 can reach 1/1.28 inch/1.12 inches, all of which are relatively large sensors available on the market today, while digital SLR cameras can easily reach one inch, so in terms of sensor size, mobile phones do not have an advantage. Figure 1 is a comparison of sensor sizes in smartphones in recent years. It can be seen that the size of the camera sensor used in flagship models has gradually increased in recent years.

Fig. 1

The other two main factors that affect image quality are lens quality and image algorithms. Especially in recent years, with the increasingly powerful computing power of smart phones, many shooting functions can be well realised through image algorithms. For example, in mobile phone shooting, the performance of many scenes such as white balance, HDR, colour matching and night scene all depend on the level of image algorithms.

Take white balance as an example; in photography creation, we know that different light shines on a piece of white paper, giving a different white effect, and there will be a certain colour cast. For example, incandescent lamps, fluorescent lamps and the colour of white paper under natural light. For human eyes, they are all white or close to white because the human brain has some prior information about things and will automatically make some corrections. But the sensor will only faithfully record the real situation, so you will see that the image taken by the camera is more aurantia in orange light and blue in incandescent light. What white balance needs to do is to make white objects photographed under light with different colour temperatures close to white.

So how to make this different white close to real white? When processing images on mobile phones, a computational photography called grey world algorithm was adopted by many manufacturers.

The grey world algorithm is based on a simple observation: in most of the pictures, we take of the scene, taking the average of all the pixel values, the result should be grey (which was discovered through experiments). Grey is a colour between black and white, which means that the energy of R, G and B channels is roughly equal: R = G = B. Therefore, we can first calculate the mean of each channel in the whole graph according to Formulas (1)–(3): 1 Ravg=1Nr∑Rsensor(r)\begin{align}R_{avg}=\frac{1}{Nr}\sum Rsensor(r)\end{align} r=redpixelsvalues,Nr=#ofredpixels\begin{align*}r = \text{red}\, \text{pixels}\, \text{values,}\qquad Nr = \#\, \text{of}\, \text{red}\, \text{pixels}\end{align*} 2 Gavg=1Ng∑Gsensor(g)\begin{align}G_{avg}=\frac{1}{Ng}\sum Gsensor(g)\end{align} g=greenpixelsvalues,Ng=#ofgreenpixels,\begin{align*}g=\text{green}\, \text{pixels}\, \text{values,}\qquad Ng = \#\, \text{of}\, \text{green}\, \text{pixels,}\end{align*} 3 Bavg=1Nb∑Bsensor(b)\begin{align}B_{avg}=\frac{1}{Nb}\sum Bsensor(b)\end{align} b=bluepixelsvalues,Nb=#ofbluepixels\begin{align*}b = \text{blue}\, \text{pixels}\, \text{values,}\qquad Nb = \#\, \text{of}\, \text{blue}\, \text{pixels}\end{align*}

Then, taking the G channel (human eyes are more sensitive to green) as the benchmark, the scaling coefficients of R and B channels are calculated, and then the scaling coefficients are applied to each pixel:

The final picture is closer to the perception of the naked eye. As a very basic operation, the grey world algorithm is easy to fail in some cases (e.g. the colour mean value of pictures with a pure sky background is not grey). Therefore, more new algorithms with stronger adaptability have emerged in the follow-up [1]. Generally speaking, the closer it is to the perception of the human eye, the better is the white balance algorithm. The algorithm of visible images has a great impact on the shooting quality of image. The shooting performance indicators affected by the image algorithm such as automatic exposure control (AEC), sharpening, gamma correction, denoising and portrait background blur, all of which need the help of algorithm calculation and processing to make the mobile phone take photos to the extreme (not introduced here one by one). Image processing is so complicated, fortunately, after so many years of development of various chips, the technology has been quite mature. Many algorithms are directly solidified (compiled in assembly code) in the chip, so the speed is very fast, ensuring that the moment of mobile phone photographing is almost senseless.

To sum up, the lightweight mobile phone shooting function and image quality can basically meet the hardware requirements of creation. The practice of mobile phone creation has proved that the ingenious use of the shooting function of lightweight mobile phones can create high-level image works. On 23 May 2019, the vertical screen film Wukong created by director Cai Chengjie using Huawei P30 Pro zero external lens was released on Huawei’s official microblog, which was highly praised by netizens, further proving that mobile phones can become a professional image creation tool. The film shows macroshooting effects, stable effects under mobile shooting, excellent image quality in low light and the convenience of wide-angle and telephoto lenses, which further break people’s inherent cognition of mobile phone camera functions and inspire creators to continuously develop shooting modes and creative techniques of mobile phone images.

The main function of the camera equipment is to capture clear and stable images with good image quality to provide material for post-production creation. Equipment can be divided into two categories, one is lightweight equipment for shooting and outputting pictures, and the other is related equipment for assisting picture shooting. In the shooting of traditional movies or TV programs, the equipment for shooting the output picture includes cameras, SLRs, and UAVs, and the auxiliary shooting equipment includes tripods, stabilisers, large rockers, various rails and lighting equipment so as to change scenes or shoot moving lens under the condition of stability. Nowadays, in the shooting of vertical screen works, the trend of daily and life-like expression of images is constantly reflected, and the audience’s pursuit of portability and timeliness of equipment is increasing. Lightweight equipment is widely used on this basis.

Firstly, the most obvious advantage of lightweight equipment is lightness. Mobile phones, action cameras and other devices can replace traditional SLR cameras and bulky cameras to capture images in shooting; secondly, technological advances have made lightweight creative devices with good stability, providing the possibility for direct shooting with handheld devices; for example, Huawei P40 Pro and sports camera DJI Osmo have excellent anti-shake effect for handheld shooting, and the picture has a strong sense of stability, which can be applied to many special scenes, such as lenses in sports scenes, subjective perspective lenses, and follow-up lenses. Thirdly, lightweight equipment is easy to deploy in a small space, such as shooting in a confined space, whereas a handheld camera needs to be equipped with a stabiliser, which is very bulky and difficult to move the mirror. At this time, using a mobile phone or an action camera, instead of a traditional camera, to shoot, panning and panning can be easily used, and the picture clarity and stability are excellent; finally, lightweight devices also have the characteristics of easy to operate, easy to use and low cost, including auxiliary equipment for mobile phones or lightweight action cameras, as well as small tripods, mobile phone stabilisers, simple flashes and simple lenses. These products are relatively cheap, allowing more and more ordinary people to participate in the team of film and television creation, and the content and style of the works are constantly innovating, which also promote the development of vertical video to a certain extent (Tables 1–3, respectively, list the models, functional characteristics and reference prices of some lightweight creation devices).

Mobile video editing app software is a simple video editing software developed for non-professional users or creators who use mobile phones to edit video in mobile scenes with the help of mobile phones. Nowadays, the popularity rate of lightweight editing software is very high. The reason for its popularity is that it can help ordinary users to quickly edit and release video anytime and anywhere so as to meet their psychological demands of using video to record life to express themselves.

Nowadays, the competition of the video platform is increasingly fierce, and editing software provided is also very rich, which is not only convenient for users to create but also a means to improve users’ stickiness. For example, the ‘cut image’ developed by the Tik Tok platform and the ‘quick image’ developed by the Kwai platform have simple video creation steps, which can be quickly shared on the corresponding platform after creation, increasing the user’s dependence on the platform and utilisation rate.

After the rise of smartphones, the frequency of people using them to record their lives has increased greatly. Mobile phones are not only a communication tool but also a carrier for people to express themselves and record beautiful moments. Today, when vertical videos are prosperous, it does not necessarily require proficient editing skills to impress the audience. Simple editing software can meet the needs of users. As a result, various companies have launched their video editing apps. Even Adobe, the world’s leading digital media provider, launched its own mobile video editing software Clips in April 2017. As a mobile app, the biggest advantage is convenience. In the era of mobile Internet, people have become accustomed to taking photos and videos with smartphones. The emergence of video editing apps enables users to edit their shooting content anytime and anywhere, instead of transferring the material to the PC for secondary editing. Easy sharing is also an advantage of video editing apps. Almost all current video editing apps have the function of one-click sharing to social platforms. People can watch their edited videos anytime and anywhere and share their video achievements with friends. Compared with the video editing software on the PC, the output time of the finished video product is greatly shortened in the video editing app, and there are fixed templates and styles for replacement [2]. Introduction to some app editing software and functions shown in Table 4.

In the vertical screen program with a mobile phone as the communication carrier, the host changes the traditional style of previous TV programs and strengthens the interaction of communication with innovative tone, language and paraphrase, and the program is more in line with the Internet. The characteristics of the communication are conducive to the improvement of the communication effect. For example, the words ‘meeting emphasis’, ‘meeting pointed out’, ‘high importance’ and ‘implementation’ in the traditional ‘news broadcast’ appear frequently, which can easily create the illusion of abstraction, macroscopic, formalisation, etc. to the audience, and even the psychology of exclusion; thus, the important ideas transmitted cannot be accepted by the audience, especially the young people. Taking the mobile Internet as the communication carrier, the vertical screen news information program The anchor said the broadcat, which is broadcast by mobile phone users, has made transformative adjustments, which can be used for reference.

Firstly, the text style of the past News broadcast has been changed in The anchor said the broadcast. When creating commentaries, the style is much sharp and the words are bolder. Haixia used ‘Japan and South Korea delete each other’s friends and blackmail each other’. Describe the relationship between Japan and South Korea; Kanghui reminded Cathay Pacific ‘no Zuo no die’ [3]. This breaks the stereotype of the serious and unsmiling host in traditional hard news. It effectively shortens the distance between the audience and the communicator and completes the task of publicising and educating the audience in a relaxed and harmonious atmosphere.

The second is the use of paralanguage in the process of communication. In order to enhance interactivity, the use of paralanguage is a very effective means. The so-called paralanguage refers to the modal sounds with changing laws that naturally emerge in the process of communication, including tone, intonation, exclamation words, gestures and actions, including mood and intonation, exclamations and gesture movements. This kind of paralanguage can not only strengthen the appeal of communication but sometimes the emotions transmitted from it can also replace the voice language expression. For example, the host’s tone of voice is more vivid in The anchor said the broadcast, and gestures are added to strengthen emotional expression so that the audience has a stronger sense of communication when watching, so as to increase the interactivity of communication.

HTML5 (H5) refers to the fifth-generation version of the hypertext markup language HTML. Different from H1 to H4 versions, the format specification of graphics and text and the support for audio and video are implemented by plug-ins. The H5 version of the web page has a better structure and meaning and provides an unprecedented data open interface. H5 perfectly supports the new features of mobile media, integrating text, pictures, audio and video, panorama, live broadcast and many other media forms. At the same time, H5 also supports mobile interaction algorithms such as touch screen, gyroscope, positioning and recording. It provides a broader innovation space for the change of the interactive mode of digital publishing content [4]. Vertical video is a mainstream direction of H5 in the near future, especially in the hot moment of short video, shooting and live broadcasting on the mobile terminal, which is in line with the habit of vertical holding by users on the mobile terminal.

In this process, H5 technology breaks the traditional way of content product dissemination. On the one hand, H5 breaks the traditional media concomitant communication mode and enhances the autonomy of information reception. Through modes such as sliding screen and clicking options, users’ passive reception is transformed into active reception, which enhances the interactivity and immersion of communication. On the other hand, H5 is a way to detect and strengthen the communication effect in the era of convergent media. For example, in the vertical screen Youth League class ‘Youth Learning’ shot by the ‘Central Committee of the Communist Youth League’, through the communication mode of ‘video explanation + H5’ answer test, the audience can take the corresponding answering test after watching the course and mark the right and wrong to explanation, which strengthen the viewer’s understanding and memory of the viewer and the learning effect.