What is mjpeg compressor

Video compression technologies are commonly known as codecs. They use an algorithm called an encoder that compresses data at the source i. At the destination, they use another algorithm called a decoder to decode and decompress the data.

Codecs are used in pairs and are not cross compatible. There are three standard compression technologies used in digital video recorders and IP cameras:. It forms a video sequence and gives the impression of motion by combining several still JPEG images.

MJPEG is a robust video compression format. One should as why the movie is needed for: I was looking for a car DVR camera, and was considering the different compresseion formats. Well, you should think what is the most important function needed? Then, beside this, you may enjoy casual recording of the trips. But, if I'm using it for surveillance, then I may tolerate dropping a whole frame or two, and favor disk space saving to quality.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Asked 9 years, 9 months ago. Active 8 years ago. Viewed 16k times. Talk with an Expert. Follow us on social media. What is Video Compression?

How Video Compression Works To compress your files, the codec looks for unnecessary files or frames it can reduce or eliminate without impacting the final version of the video. This process is done automatically by your surveillance camera, but you can often choose which style of video compression to use and the compression level within the video: H.

Planet Fitness A national fitness franchise has security cameras installed to monitor the 21, sq. Read Now. The more complex or the more seemingly random a pattern is, the less likely it is for a pattern to be compressed or the harder it is to accomplish this. Stream Analyzer : In this test, we used a free stream analyzer from Avinaptic to examine the H.

Download the Avinaptic software. In our screencast case study, we examine a test video clip showing variations in complexity and quality download the stream analyzer test sample [link no longer available].

However, it is even more important to understand this when using H. This is because variation in bit rates for H. By scene complexity, we mean how much activity is occurring in the scene of video that you are capturing.

For instance, a person talking in front of a white wall is far less 'complex' than a crowded stadium. In general, the more color, shapes, sizes, objects and movements in a scene, the more complex that scene will be.

The more complex a scene is the more bandwidth will be needed to maintain the same quality level. Equally important, the complexity of a scene can change depending on the time or day or the time of year. For instance, a group of people meeting in a lunch room is a far more complex scene than that same lunchroom on Saturday when the office is closed. To maintain the same quality, all CODECs will require more bandwidth for the period when a group of people meet than when the lunch room is unoccupied.

More complex scenes are often the most important scenes within video surveillance as they reflect activity and potentially problems or at least activities of interest. In the video below we show you bandwidth consumption differs for a variety of common scenes:The impact of complexity on bandwidth differs significantly between MJPEG and H.

In our tests, with MJPEG, the difference in bandwidth needed for the least to most complex scenes only differed by a factor of 3. However, in our tests with H. The H. It is a fallacy that MJPEG's bandwidth demands are constant or that the stream size does not vary with complexity. They can safely do this because the variance in bandwidth size due to complexity is relatively limited for MJPEG.

However, this does expose some modest level of quality loss or bandwidth inefficiency. Even though H. While our tests show that fixed image size can be used fairly safely for MJPEG without thought or planning, such an approach is risky and problematic for H.

With Constant Bit Rate, the IP camera will maintain the same bandwidth level regardless of the scene's complexity. If bandwidth is insufficient to match the complexity, quality will be sacrificed.

With Variable Bit Rate, the IP camera will keep adjusting the bandwidth level to hold the quality steady with the scene's complexity. In the video below, we show how VBR bit rate changes rapidly when the scene changes but with CBR it always stay the same:.

Resolution does not ensure quality.