Demystifying Video Codecs

Demystifying Video Codecs

Video and image compression has become a very important part in communication, broadcasting, and storage. In transferring video from source to destination many processes are involved out of which, compression (coding) and decompression (decoding) are the two important processes.

In an attempt to improve video conferencing immersive experience, various technology vendors are trying hard to create the so-called “best video codec” for business. The current collection of codecs supported across most of the video endpoints and MCU’s are H.264 AVC, H.264 SVC, H.265 (HEVC), Real-Time Video, VP9 & VP8, just to name few.

Before going into the specific Codec details, let’s talks about- What is a Codec and why it is important for choosing the right video conferencing solution for your organization?

Video Compression algorithms are applied to the source video to create a compressed file so that it can be transmitted and then produce same content as of original source video at the receiving side with the reverse algorithms.  The pair of such algorithms together is called video codecs.

codec

In traditional video systems, it was always assumed that the bandwidth required by a video client will be guaranteed. A software/hardware called encoder used to compress the input video signal at a bit rate that is less than and close to the predefined bit rate, and the on the receiver side decoder reconstructs the video using all the bits received from the channel.

However, in modern video transmission, it is almost impossible for the encoder to know the available bandwidth in advance. The video should be encoded over a bit rate range instead of a given bit rate to make sure best possible video quality is available to the participants. Therefore out of various video codec choices available today, each one of them is attempting to solve some kind of technical/business challenge. It becomes important to choose the video solution with the right codec for your own enterprise network by looking at different benefits of these various codecs.

The codec choices are further categorized into 2 categories as standards are important in ensuring compatibility and interoperability.

  1. Standard based Codecs
  2. Proprietary or modified Codecs

codec 2

The H.264 Codec H.264 defines the syntax of an encoded bitstream and also the method of decoding it. Video compression or video coding is the process of reducing the amount of data to represent a digital video signal before transmission or storage. H.264 has different profiles as the baseline, main and extended profiles. Levels define the performance limits such as sample processing rate, picture size, coded bitrate and memory size.

H.264 HP (High Profile) High Profile, an extension of H.264 advanced compression and efficient video coding capabilities. With its ability to preserve high video quality at lower bandwidth requirements, it certainly helps in reducing the total cost of ownership and improves the rate of return. High Profile reduces the required network bandwidth for video by up to 50%

H.264 SVC (Scalable Video Codec) In July 2007, a scalable extension of H.264 AVC (Advanced Video Coding) was jointly published by MPEG and ITU-T, which makes the scalable extension to be the state-of-the-art scalable video codec. scalable video coding involves generating a bit-stream that allows decoding of appropriate subsets to reconstruct complete pictures of resolution/quality proportionate with the proportion of the bitstream decoded. 

With fast changing customer applications, varied industry specific solutions and non-guaranteed/reserve or lossy networks bandwidth deployments, there can be scenarios, where the traditional type of video encoding fails or does not perform as per the requirement. This fundamental problem gave rise to the need for such video codec technologies to overcome lossy environments.