Video compression

Broadcast Engineering by Dr. Chin Koh

Here’s a technical comparison between MPEG-2, H.264 and JPEG 2000.

Broadcasters have a range of choices when it comes to signal compression solutions. For advanced, professional-grade compression, MPEG-2, H.264 and JPEG 2000 are all viable options. Ultimately, network infrastructure, bandwidth requirements and budget all help to define the “right” choice for a broadcaster. MPEG-2 and H.264 are strong options for compression for next-generation multimedia applications.

Increasingly, a strong case can be made for JPEG 2000, whose advanced intra-frame based encoding provides a degree of flexibility and control not found in other compression schemes. Furthermore, the surge in the amount of video transport applications requiring both very low latency and very high visual quality make JPEG 2000 an optimum solution to meet the demands of a video landscape moving toward HD.

For all broadcasters — regardless of network infrastructure, compression solution and application specifics — the goal is to deliver maximum quality given bandwidth and cost limitations with the sole purpose of maximizing revenue. Keeping in mind that video transport is a complete value chain. Anything done along the chain affects overall processing with consequences of a misstep dire and resulting in devaluation downstream. Of course, how the chosen compression solution is engineered and managed is also critical to achieving the best performance, regardless of the compression scheme selected.

MPEG-2: A legacy codec
Video compression algorithms such as MPEG-2 and H.264 are Discrete Cosine Transform (DCT)-based codecs that use inter-frame prediction to reduce video data between a series of frames. This involves techniques such as difference coding, where one frame is compared with a reference frame and only pixels that have changed from the reference frame are coded. In this way, the number of pixel values that are coded and sent is reduced. When such an encoded sequence is displayed, the images appear as in the original video sequence. read more...