H.264 has made huge advances in video compression and is expected to be the video standard of choice in the coming years.
It offers techniques that allow better compression efficiency due to more accurate prediction capabilities, as well as increased tolerance of errors.
It also yields new possibilities for creating enhanced video encoders that permit higher quality video, more frames per second and better resolutions at higher bit rates or lower bit rates at the same quality video.
H.264 is an open, licensed compression format that supports the most effective video compression techniques available today. It’s the result of a joint venture by the ISO/IEC Moving Picture Experts Group (MPEG) and the ITU-T’s Video Coding Experts Group.
An H.264 encoder can diminish the size of a video file by greater than 80% more than with the Motion JPEG format and up to 50% more than with the MPEG-4 Part 2 standard, without compromising image quality.
This translates to much less storage space and bandwidth being needed for a video file, saving users money while achieving higher video quality.
H.264 will most assuredly find the quickest acceptance in applications where there’s demands for high frame rates and better resolution, such as the video surveillance industry.
This is where the advantages of decreased bandwidth and storage needs will bring the biggest savings.
An assortment of techniques can be used to compress video data, both within an individual video frame and among a progression of frames.
Within an image frame, data can be reduced by removing unnecessary information, which will have negative consequences on the image resolution.
In a series of frames, video data can be reduced by such methods as difference coding, which most video compression standards use, including H.264.
Difference coding means that only the pixels of each frame that have changed with respect to a previous reference frame are coded.
This way the amount of pixel values that are coded and transmitted is condensed.
A progressive intra prediction method for encoding reference frames is introduced with H.264.
This technique can drastically condense the size of a reference frame and retain a higher quality image by allowing the consecutive prediction of smaller blocks of pixels in each macroblock of a frame.
This is accomplished by finding matching pixels in the earlier encoded pixels that are on the fringe of a new 4×4 pixel block to be intra-coded.
By using pixel values that have previously been encoded, the bit size can be significantly compressed.
This improved intraprediction technique is a key part of why H.264 has such improved compression efficiency and quality.
Block-based motion compensation is another area where H.264 has vastly improved over previous video compression technologies.
An H.264 encoder can search for matching blocks in many areas of one or multiple reference frames.
The size and shape of the block can also be adjusted (down to a sub pixel level) to provide better matching capabilities. If no matching blocks can be located in an area of a reference frame, intra-coded macroblocks are used.
The high level of versatility in H.264’s block-based motion compensation is ideal for busy surveillance scenes, video quality can be maintained better in this challenging application.
H.264 is the first time that the ITU, ISO and IEC have collaborated on a universal standard for compressing digital video data. Because of such efficient performance and it’s superior versatility, H.264 has been adopted in a variety of applications such as in digital video broadcasting including high-definition TV, Flash, online video storage, mobile phones, and video game consoles such PlayStation 3.
With so many industries and applications supporting H.264, it’s quickly turning into the standard in compression technology.
So as you can see although H.264 is a great technology for video compression, it can place great demands on your hardware.
Our PC DVRs utilize high end chipsets that compress video right on the card very efficiently allowing for the smoothest playback and highest quality video.
