Development of post-production process of modern film and television

Development of post-production process of modern film and television

After the film and television industry entered the digital age, the technology developed by leaps and bounds, and post-production has always been an important engine for film and television content production. In the digital age, the visual creation process represented by computer graphics and images has become the most wonderful post-production means, and the modern film and television post-production process has evolved into an industrialized system with detailed division of labor. The following is about the development of modern film and television post-production process, I hope everyone will read it carefully!

Speaking of post-production of film and television programs, what do you think of first? Yes, editing, editing; In non-editing, select the shot material and trim the length of the shot video and audio material, code the timeline, adjust the shooting order, add some transition stunts or 2D and 3D DVE stunts between the materials. The complex timeline has multiple layers of video and audio tracks, and add some key frames and graphic subtitles between the materials of different layers to form a film. This is the most common division of video post-processing, which can be completed without editing at one time. After more than ten years of development, non-editing has generally provided basic functions such as color matching and simple tracking for further video packaging processing, which can produce richer visual effects on the basis of conventional editing. However, the above editing work is basically just a conventional video editing method, which is basically enough for the post-production of TV programs such as news and general feature films. However, in this era of video explosion, it has become increasingly difficult to meet the needs of the development of the film and television industry. Editing is only a part of editing and simply modifying programs in the post-production process. Wonderful works need more or less deep visual creation in post-production. In addition to editing, we also need visual packaging post-production.

With the rapid development of digital image technology and application, visual effect packaging represented by color matching and three-dimensional synthesis has become an indispensable and important technological process in film and television post-production. Film and television is a visual art, an excellent film and television work. In addition to excellent story design, early shooting and exquisite editing, it is also necessary to enhance visual appeal through color, fully show the director's intention through rich CG elements, and even complete artistic visual creation through late three-dimensional synthesis, so as to achieve imaginative and powerful realistic scene effects that are difficult to shoot. The visual enjoyment brought by those special effects shots in Hollywood blockbusters is a good example. Otherwise, no matter how excellent the content creativity is, there is not enough visual packaging, and it is easy to be submerged in a large number of film and television works, and it is difficult to become a masterpiece. To exaggerate, there is no film with color matching and packaging yet. From another point of view, the timeline work method used in editing is better at editing time sequence and structure, and the node (flow chart) work method is more suitable for color matching and artistic creativity in synthetic creation. Therefore, modern film and television post-production technology is not only editing and simple visual effect processing, but also editing programs through non-editing timeline. In the post-production process of modern film and television, color matching and synthesis are no longer just icing on the cake. Visual packaging has become an indispensable means of excellent film and television works, and the creation of deep visual effects has become a more important process link in post-production. In the past, post-toning and composition technology was widely used in the film industry with high investment. With the continuous progress of technology, both high-input large-scale production and low-cost programs have gradually become a necessity in the field of film and television. Editing, color matching and composition together constitute the core of modern film and television post-production process.

Although there are many categories of film and television content, different programs have different requirements for post-production technology. After decades of development and industrial evolution, film and television post-production technology has generally formed a fairly complete and standardized system composed of various technological processes, which is the main framework of modern film and television post-production process. The overall technological process starts from DIT and is closely connected with the previous stage. It consists of material preparation (real shot material arrangement and CG production), editing (divided into direct editing and proxy editing), background color matching, three-dimensional synthesis, visual special effects rendering, finished film arrangement, output film and other major technical links. According to the different equipment used, there are many changes in the combined application of these links, but the overall system framework is shown in the following figure:

From the concept map of process logic of modern film and television post-production technology, we can see that a complete post-production technology basically includes three technical fields, namely, three core technologies: resource preparation, post-editing and post-creation; The first is the field of material management and preparation process, which is mainly composed of DIT process that connects the preparation and management processes of pre-production and post-production resources. DIT is mainly engaged in the preview of filming effect, material labeling, material transcoding, sorting/backup in the early filming process, which originated from film shooting and now gradually occupies an increasingly important position in some demanding later digital film and television projects. The preparation of post-production resources is mainly to manage the material assets after returning to the post-production computer room, design CG elements and scenes according to the program planning, and capture and process some auxiliary data needed for post-production. It seems that the work in this process area is trivial and unnecessary, but in essence it is a very important link to ensure quality, especially to improve the efficiency of the whole post-production process. Editing process domain is a basic process link connecting the preceding with the following. Basic editing, basic visual effect processing, adding basic graphic subtitles, etc. The classified materials are processed. In some film and television programs with low requirements in the later period, there is no need for too much creation. Video and audio editing is basically the main process of post-production, so this editing process field is often considered as the main field of post-production. However, with the development of the film and television content industry, the situation is changing. Editing is still very important, but its ability is often difficult to meet the needs of the program. Post-production process domain is a link of program packaging and visual effect post-production. Different from editing, it focuses on the post-production of visual effects, basically including color matching, the creation of audio-visual effects, the synthesis of three-dimensional environment and the final film finishing. It is a crucial link to improve the film quality (technical and artistic quality). With the continuous development of film and television technology, the creative ability and cost performance of post-production equipment and software are also rapidly improving, and the program packaging and synthesis technology has been widely used in various film and television programs to varying degrees.

Modern post-production process is an industrial integrated production system integrating editing, creation and management, which has many technical links, more or less related to the process. The core equipment and resources used are also flexible as shown on the right side of the above figure, and the requirements for the producers are also diverse. On the management level, according to the final program form, artistic effect and the proportion of production cost, different types, different timeliness and different planning of film and television programs will flexibly organize and configure the applicable process links and management processes. The attention and value tendency of these programs in different links in the shooting process may be as shown in the following figure, so as to effectively control the input-output ratio and achieve a balance between artistic value and commercial value.

In the post-production process of modern industrialized film and television, how to ensure program quality, improve production efficiency and reduce management complexity is fundamentally the core driving force for the development of modern film and television post-production technology.

There is no doubt that the quality of a film and television work is a very important part, if not the most important part. With the development of digital film and television technology, the resolution of film and television works is constantly improving, the color gamut is constantly expanding, the dynamic range is gradually improving, and high frame rate is gradually being used more and more. The development of these film and television shooting techniques is to make the final film and television works more real, more on-the-spot and more shocking to the audience. In the post-production process of modern film and television, the pursuit and control of image quality is a very important aspect.

In order to achieve the best possible picture quality, in the process of film and television works creation, we should first use the best possible digital photography/camera and lens in the early stage of shooting, and at the same time record as much as possible in RAW format or new high-quality and high-bit-rate video compressed format or even uncompressed video format to ensure the highest possible picture quality at the source entrance of post-production. Secondly, in every link of film and television post-production, even if only simple editing is done, most substantial video processing is carried out on the so-called baseband data level, that is, uncompressed RGB or YUV image data, that is to say, no matter which link in the process of editing, color matching and composition (except audio-related), if the compressed image format is adopted when the intermediate results of programs are exchanged in different process links, in fact, Each link can only be processed by decoding the compressed image data from the previous link into uncompressed baseband image data, so there will be repeated encoding and decoding processes between compressed image data and baseband data, which will undoubtedly cause irreversible damage to the final image quality; Therefore, in the whole post-production process, it is best to use high-quality lossless and low-loss video compression format or even uncompressed video format for processing, so as to minimize the loss of image quality caused by repeated encoding and decoding in the multi-channel production process.

RAW format is a material format different from video pixel format, which records the original photoelectric conversion data obtained by photosensitive devices during shooting. Under the current technical conditions, it has the largest photosensitive dynamic range, the highest resolution and the highest quantization level. Based on these original photosensitive data, the color, exposure, dynamic range and output resolution can be controlled as needed in the post-production process to form video pixel materials with different visual effects with as high quality as possible, which can be maximized compared with the standard video image format with limited adjustable range. However, the RAW format itself is a kind of binary data that can't be directly seen, and it has a large amount of data, so it needs to be parsed into visible video pixel image copies such as RGB or YUV in the post-production process for further post-editing or creation. The typical basic solution framework of RAW is as follows:

This calculation process usually takes a lot of time, which will affect the efficiency of the whole post-production and bring great pressure to the storage system. Not only that, because the RAW format itself is very flexible, it can flexibly create copies of video pixel materials with different visual effects, but also because photographic equipment manufacturers have their own incomplete standardized RAW format specifications and calculation algorithms. In the whole post-production process, strict process management is needed, and the intermediate results and film quality are controlled according to the calculated color gamut, color tone and resolution of the copy material.

If high-quality uncompressed or low-loss video compression format is used as the initial source entry material in post-production, although RAW solution is not needed and process management is relatively simple, the data volume of the material is also very large because of the low video compression rate. For example, the bit rate of uncompressed 4:2:2 YUV 10bit 50P 4K video is close to 8Gbps. Using prores 422HQ compression, the bit rate is also around1.4 Gbps. If the higher quality 4: 4 RGB12 bit specification is adopted, 15Gbps can be achieved without compression, and the bit rate using prores 444 compression is also around 2.2Gbps In recent years, some post-production fields such as XAVC and AVC- have appeared.

Although the pursuit of image quality is one of the core demands, we should not pay too much attention to cost and efficiency. There are many technical links in the post-production process of modern film and television. If these links are processed in RAW or original high-quality uncompressed or low-loss compressed format, there are high requirements for the performance of editing and authoring equipment, the capacity and speed of storage system, which will obviously increase the production cost and have a more obvious impact on production efficiency. Therefore, in order to balance the picture quality, cost and efficiency, and to facilitate one-time production and multi-channel distribution, the post-production process of modern film and television often adopts the processing flow of agent editing and high-quality digital intermediate film, and its technical framework is shown in the following figure.

This process of proxy editing and digital intermediate film was first widely used in the film industry. With the gradual rise of high-quality TV programs and 4K ultra-clear image services, it is also widely used in the later fields of high-quality TV programs. Its core logic is basically two: one is to highly compress the proxy material through a small format (such as 1/4 resolution or 1/2 resolution). In the process of basic rough editing such as shot selection, time sequence and story structure editing with heavy workload, the requirements for equipment performance are reduced, the occupation of storage space is reduced, the difficulty of visual processing effect is reduced, the time consumption of these tasks is greatly reduced, and the efficiency is improved. In the subsequent steps of color matching, synthesis and film formation, only a small amount of high-quality effective materials that have been roughly cut and screened are used for high-quality editing and synthesis, so that on the premise of maintaining high image quality, secondly, by selecting digital intermediate film (such as DPX/tiff) with wider color gamut, greater resolution and higher latitude as the only high-quality material, the time and cost required for solving the RAW format can be reduced. Moreover, it can reduce the risk of quality control such as color management, resolution management and image quality management brought by using high-quality materials of different formats in the whole production process, and reduce the time-consuming of data conversion when delivering intermediate results in different process links while ensuring 65438.

Modern post-production technology is an industrialized system with multi-job and multi-link cooperation. How to manage the process correctly and quickly? How to improve the production efficiency as much as possible and provide as many artistic ideas as possible is also the core requirement of image post-production system development.

From the perspective of methodology, in the multi-task collaborative process, effective management and control of resources from the beginning of the process is the only way to improve the efficiency of the process; In the whole process of modern film and television industry production, DIT runs through the whole pre-production process, which provides great convenience for the material preparation in the post-production process and is a very effective means to improve the post-production efficiency of complex programs. Simply put, DIT is a pre-technical support and on-site media asset management work. First of all, in the pre-shooting, we provide the on-site director with the guarantee of equipment and shooting technology, provide a preview of the on-site visual effect, and reduce technical mistakes in shooting. At the same time, it is more important to form and manage a series of media asset data, such as the detailed classification and labeling of the original lens material, the resolution of RAW format into digital intermediate film, the transcoding of proxy material, unified storage and safe backup, etc., which have not been processed by DIT department, and the material is only the material. It is a variety of "chaos", and DIT is to organize these "chaos" into orderly, manageable, safe and reliable original production materials, truly form media assets, and output all kinds of sorted source materials and corresponding management data to the post-production process, which can effectively reduce the time-consuming and mistakes in material preparation in the post-production process, thus greatly improving the work efficiency of the whole post-production process. DIT has become a very important process in the film industry and is widely used. In the field of television, high-quality programs are gradually being widely used.

Another key point to improve the efficiency of the whole process is to simplify and integrate the process links as much as possible. Even after the formation and management of DIT's media assets and the effective preparation of materials, there are still many links in the whole post-production process, such as editing, color matching and synthesis, and interactive audio and video data may still need to be converted. Therefore, with the continuous progress of technology, integrated post-production software integrating multi-link functions is gradually becoming the mainstream. For example, the famous color matching software DaVinci Resolve has developed from a simple color matching software to an integrated color matching editing system. When configuring a powerful computing platform, RAW format can be used for direct processing in the whole process. At the same time, the results of editing and color matching can be seamlessly transmitted to Fusion for node synthesis creation through Fusion Connect, and the results of fusion synthesis rendering can be returned to the editing timeline of DaVinci Resolve. This series of integrated collaborative capabilities can greatly reduce the interaction among editing, color matching, composition and data format conversion, and even completely eliminate the working mode of agent editing/nesting/approval, greatly improving work efficiency; The same thing happened to Nuke, the mainstream composition software in the industry. The latest Nuke Studio is no longer just a node-type pure composition tool, which increases the editing ability of the timeline and becomes a complete post-integration tool of editing+composition+color matching; On the one hand, these integrated post-production tools can make post-production artists pay more attention to their own creation without switching and interacting among various softwares, and at the same time make the post-production process more convenient and efficient and the technical quality more controllable, which has become a very important trend in the development of post-production tools.

In addition to merging and streamlining the process links as much as possible, another important means to improve the efficiency of the whole post-production process is network-based collaborative work. The amount of audio and video data is huge, and the exchange of audio and video data in each process is very time-consuming. If it is collaborative production in different places, it will be more time-consuming and laborious. Realizing data sharing and remote collaboration through network and increasingly mature cloud services is the only way to improve the efficiency of the whole process.

Whether it is the global collaboration of the whole network or the business island collaboration based on discrete interconnection and on-demand sharing of working groups, audio-visual media asset data, various standardized metadata and engineering file data can be shared and exchanged in each later stage of the process through the network and cloud services, which can greatly reduce the time-consuming of audio-visual data replication and transmission, improve equipment utilization, and greatly facilitate the computerized realization of process and technical quality control. At the same time, it is also a necessary condition to realize cluster rendering and the development direction of modern film and television post-production system. The continuous progress of network and cloud service technology is also making profound changes in the post-production process of film and television. ;