What's video encoding and how does it work? Technique for compressing videos

IES Italia has designed and developed Tangram, a video encoding platform, that works through Blockchain technology. But what do we mean when we talk about video encoding?

In simple words, video encoding is the process of compressing and converting video content. The ultimate goal is to take up less space, consume less bandwidth and make the experience more fluid for users. It’s normal that the compression process causes a substantial loss of informations, so that the higher the applied one, the more data will be eliminated in the video. The result will be a different version of the original due to the lack of data.

Why is video encoding so important?

Video encoding is essential for streaming, as it simplifies the transmission of video over internet, through a compression process. Compression reduces the required bandwidth and, at the same time, offers a quality experience. Without this operation, in fact, raw video content would not allow many users to be able to see content on internet due to inadequate connection speeds. Protagonist of this process is bitrate or the transmission rate of digital data that can be transferred to a communication channel in a time interval. In streaming, the bitrate will determine if users can easily see the content or if they will be at the mercy of video buffering.

Another key aspect of video encoding is compatibility. In fact, sometimes the content is already compressed to an adequate size, but it still needs to be encoded to be compatible with different devices and applications, although this is often described as transcoding.

The video encoding process is dictated by video codecs that are compression standards performed by software or hardware applications. Each codec consists of an encoder to compress the video and a decoder to recreate an approximation of the video for playback.

The codec name derives, in fact, from the merger of the words "encoder" and "decoder".

But what is the best codec?

It depends on the type of video. On this occasion we will describe the most used.

For high quality video streaming over internet, H.264 is definitely the most used codec for most multimedia traffic. This codec is considered to be of excellent quality, coding speed and compression efficiency, although not as efficient as the next HEVC compression standard (High Efficiency Video Coding, also known as H.265). H.264 can also support 4K video streaming, a real achievement for a codec created in 2003.

Now that we have an overview on codecs, let's look at some compression techniques.

Compression techniques

The most used one for compression is the resizing of the resolution. In fact, the higher the resolution of a video, the more information is included in each frame.

One way to decrease the amount of data is to reduce the size of the image and then resample it. This will create less pixels, reducing the level of image detail, all to the advantage of reducing the amount of information needed. This process allows you to have multiple levels of quality for a video, which correspond to different resolutions created. A practical example is when watching a film in streaming, before playing it, you can choose which resolution to watch it, as long as your device supports it.

A video compression technique that may not be widely implemented is the interframe. This process reduces "redundant" information from one frame to another. Another technique is the P-frame, short for a predictive frame, that is, it has the ability to look back towards an i-frame or another p-frame and to understand if there are equal images. If so, that part will be excluded to save space.

B-frame, on the other hand, is the bidirectional predictive frame, which offers good compression without detracting from the visual experience. This technique, however, requires a higher coding profile.

Another method, called chroma subsampling, allows to intervene on color and tries to preserve the brightness of the image by sacrificing the quality of the color. Finally, last technique of compressing video is to reduce the amount of frames per second. This can be a bit more invasive than other compression systems, because lowering the frame rate too much causes a less fluid use of the content.

Tangram

IES Italia has designed Tangram for video encoding and transmission, a digital platform that uses Blockchain technology, a real innovation in this kind of service. The peer-to-peer network that processes tasks can work on an extensive number of nodes without the need for new manual configurations. Thanks to the Blockchain, the traceability of all video encoding service is guaranteed, as is quality control and protection of the customer's copyright. The distribution of work on public nodes allows infrastructure costs reduction, lower costs for using the service and a consistent improvement in terms of speed.

Tangram was possible thanks to Blockchain, a secure technology, which isn’t a trend, it’s the future. This sophisticated technology has already proved to be very versatile and has the potential to generate deep and positive change in different areas of the digital market. IES team is only at the beginning of the fascinating journey of exploration of its infinite fields of application. Stay tuned!