Video encoding
What is video encoding?
Video encoding, also known as video compression, is the process of converting raw video files into a format that is easily transmitted or stored. It involves the use of algorithms to reduce the size of the video file without significantly lowering its quality.
Raw video files aren’t easy to send or store because they’re large and unwieldy. Transmitting these files in their original format would waste bandwidth and storage space, affecting both the device and its network.
How does video encoding work?
Video encoding works by identifying and removing redundant data from the raw video file. This redundancy can be spatial (within a single frame) or temporal (across multiple frames). For instance, in a video of a static landscape, the sky's color may remain the same across multiple frames. An encoder can represent this information more efficiently by stating that the color remains the same, rather than repeating the color value for each pixel in each frame.
Another key aspect of video encoding is the use of lossy and lossless compression techniques. Lossless compression allows for the original data to be perfectly reconstructed from the compressed data. ZIP files are a well-known example of lossless compression.
By contrast, lossy compression removes some data while encoding, but if done correctly, the loss is not noticeable to the human eye. Video encoding usually results in some lossy compression, but a quality codec (coder-decoder) will conceal it well.
Why is video encoding important?
Video encoding is crucial in online environments where video content is ubiquitous. Encoding video files lets streaming services like Netflix and YouTube deliver high-quality video content to millions of users simultaneously.
Moreover, video encoding also plays a vital role in preserving the quality of the video. A well-encoded video maintains its quality even when transmitted over low-bandwidth networks or viewed on different devices with varying screen resolutions.
Video encoding standards (codecs)
Video encoding standards are called codecs, and each has its own set of algorithms and techniques. Some of the most popular codecs include H.264 (also known as AVC), H.265 (HEVC), and VP9. These standards define how the video data should be compressed and decompressed, and they are continually evolving to improve video quality after compression.
Choosing the right codec should factor in the nature of the video content, the available bandwidth, and the device’s storage. For instance, H.265 is more efficient than H.264, but uses more computer resources and bandwidth when compressing video files.
Understanding video encoding parameters
When encoding a video, there are several parameters that you can adjust to control the quality and size of the output video. These parameters include the bitrate, frame rate, resolution, and keyframe interval.
The bitrate determines the amount of data processed per unit of time, and it directly impacts the video quality and file size. A higher bitrate results in better video quality at the cost of a larger file size. The frame rate is the number of frames displayed per second, and it affects the smoothness of the video. The resolution refers to the number of vertical and horizontal pixels that the video displays, affecting sharpness and clarity.
If video quality is your top priority, you might opt for a high bitrate, high resolution, and high frame rate while encoding. However, keep in mind that the video file will be larger and take longer to upload.
On the other hand, if you need to minimize the file size or the bandwidth usage, you might need to compromise on the video quality. Reducing the bitrate, lowering the resolution, or decreasing the frame rate will make for a smaller file size. These adjustments should be made carefully to avoid significantly degrading the video quality.