4K video processing
4K video processing manipulates 4K UHD footage so it can be displayed on different screens, or social media, and altering the relative signals.[1] It is used in devices such as 4K streaming services, video players, UHD BD and video codecs.
The common process in 4K video processing includes decoding, video editing, resizing and scaling, converting formats, storage, transmission and controlling other parameters for smooth playback.[2]
Video processing
In general, there are several processes required before turning the raw 4K footage into the final video. In order to extract the particular video bitstream,[3] the video initially has to be demultiplexed, which refers to extraction of the original data into several corresponding receivers. The following processes include decompression in video decoders, post-processing and video editing. In the final stage, the video would be encoded before it could be stored in media, played on screens, or transmitted into communication channels.[2]
Decoding
Both soft and hard decoders can be used in a video decoding process. An example of a soft decoder includes a video decoder program in a computer, which decodes the audio video data with a software program and is commonly used in video capture devices and frame grabbers.
A video decoder is available in many forms, for example, AC3/AAC/HE-AAC Audio, H.264/ MPEG-2 Video, MOV QuickTime Video and HEVC/H.265 Video.[2] Meanwhile, it is also widely used in areas including automotive, professional and consumer video applications, as well as HDTV, PDAs, PCs, handheld games, monitors, video players or recorders, GPS and others.
In contrast, a DVD or VCD player is the hard decoder that decodes audio video data before playback for saving the audio video data with high quality and low capacity.
Video post-processing
4K video post-processing refers to processes of adjustment and operation on the information of 4k video, which is achieved through video editing, transcoding, compressing and scaling. This helps reduce or hide image artefacts and flaws in the original film material.
4k video editing
An essential part of 4K videos post-processing is 4K video editing. It’s the process of splitting, digitising, integrating recorded footage and rearranging the shots and scenes into a clear order.[4] Typical functions of 4K video editing programs include segment cutting, reordering clips, noise reduction, stabilising shaky footage, adding titles and transitions, adding special effects and color correction.[2]
compression
4K video compression is used to reduce file size and maximise visual effects when the the natural 4K video footage takes too large a space. It is achieved through removing redundant data. For example, by removing temporal redundancy between keyframes and pixel-based spatial redundancy. A video compression ratio is used to describe the ratio of the compressed data volume in comparison to the original data volume. The usual compression ratio for standard digital cameras is 5:1, some other video formats allow a video compression rate at 100:1.[5]
Lossy and lossless compression are used to describe whether or not the whole original data can still be recovered after the video is uncompressed. Lossless Compression describes zero loss of information when a file is decoded back into the original data, whereas lossy compression indicates inconsistency of the data. Lossless compression is required if there will be new analysis on the data; lossy compression is usually applied by high compression algorithms to achieve a lower rate of data.[5]
4K Video Scaling
4K video processing also includes scaling, bit rate modulation, image-quality enhancement, frame rate conversion and audio sample rate adjustment.[6] Scaling is referred to as the process of changing the resolution in a video from one frame size to another. These adjustments on 4K video parameters help reduce file size, enhance image quality, to adapt to screens with different resolutions and reduce the bandwidth consumption.
Backend Processing
4K backend video processing is an essential part of the video processing performed between the video decoder and video monitor.[7] It is related to 4K signal processing, which is used to change the video signal characteristics, transform the signal of a 4k video to a signal that can be received by storage devices and communication channels, and to enhance or degrade the video quality. The workflow of back end processing is: decoding, reducing noise in the video, deinterlacing, video quality enhancement, frame rate and colour space conversion, brightness/contrast/gamma adjustment.[7] Finally, the display of 4k video on a monitor is likely.
Workstation
Generally, 4K video processing has high requirements on hardware components of the computer. Due to the large frame size, long file render time and high CPU usage of video processing, a single CPU decoding is inadequate for processing 4K videos.[2] Therefore a hardware acceleration technology could be utilised in 4K video processing for faster and smoother processes.
Hardware Acceleration
Hardware acceleration is a term describing functions of the device being performed more efficiently, by offloading tasks to specialised hardware.[8] Typical components of hardware accelerators include CPU, GPU, sound cards and graphics cards.The central processing unit, or CPU, is important in hardware acceleration. It is needed for initial processing before the tasks are being offloaded.[9]
As an alternative to CPU, GPU hardware components can also be utilized in 4K video processing. A GPU holds more cores comparing to a CPU and are more specialised in its functions.[10] The key application of a GPU in hardware acceleration includes accelerating graphics, image processing acceleration and rendering 3D operations.[9]
See also
- Video manipulation
- Video processing
- Post-production
- Pre-production
- Linear video editing
- Non-linear editing system
- Intra-frame coding
- Inter frame
- Special effect
References
- ↑ "Video Processing Architecture". vocal.com. Retrieved 2015-03-26.
- ↑ 2.0 2.1 2.2 2.3 2.4 "What is 4K Video Processing | Minimum System Requirements - VideoProc". www.videoproc.com. Retrieved 2019-06-08.
- ↑ "Video Processing Architecture". Retrieved 2019-06-08.
- ↑ "Everything You Need to Know About Professional Video Editing" (PDF).
- ↑ 5.0 5.1 "Video Compression Concepts" (PDF).
- ↑ "Key Concepts / Video Parameters" (PDF).
- ↑ 7.0 7.1 "Backend Video Processing". Retrieved 2019-06-08.
- ↑ Harper, Christopher (2017-01-11). "What Is Hardware Acceleration and Why Does It Matter". Make Tech Easier. Retrieved 2019-06-08.
- ↑ 9.0 9.1 Gulati, K., & Khatri, S. (2010). Hardware Acceleration of EDA Algorithms : Custom ICs, FPGAs, and GPUs. Boston, MA: Springer US.p.3-8
- ↑ Rosenthal, M. (2017). Buyer’s guide for 4K video editing. (Desktop Workstation)(Product/service evaluation). Videomaker, 31(10).
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