The difference between MJPEG and H.264
Introduction MJPEG and H.264 are the compression format of the network camera. It is also the mainstream compression format. Almost all video surveillance equipment manufacturers are dominated by these two products. Want to make the image pixels, the picture quality is clearer, and it must be optimized by compression techniques. The use of the two is consistent, but there is a significant difference. In 2013, the arrival of the 4G network era has made MJPEG and H.264's distinction concept again.
Directory Index Nounted Mist MJPEG VS H.264
Name Release: MJPEG MJPEG is 24-bit "True-Color" image standard, MJPEG's work is to convert the image of the RGB format into YCRCB format, with the purpose of reducing file size, generally reduced by 1/3 ~ 1/2 about. MJPEG is developed on JPEG. JPEG compression technology is to process the entire screen, etc. The compressed file is transferred until the decompression is started. MJPEG compresses each frame (one separate JPG data), and then stores each frame. Just like JPEG is a few document packaging compressed mail, and MJPEG can be sent directly from QQ online. MJPEG This compression technology avoids the delay of JPEG transmission. Moreover, since each frame is independent, it can be edited arbitrarily, and the image sharpness is also higher than JPEG. MJPEG has always been the backbone of civilian monitoring, which can be said to be the overall hometown of the monitoring industry. Its appearance is a historic milestone H.264 H.264, which is also the MPEG-4 section (VCEG) and ISO / IEC Dynamic Image Expert Group (MPEG) by ITU-T video coding expert group (VCEG) and ISO / IEC The height compressed digital video codec standard proposed by JVT, JOINT VIDEO TEAM. H.264 is one of the standards named after the ITU-T of the H.26X series, and the AVC is the name of the ISO / IEC MPEG. With the development of the network, video compression technology proposes new technologies to adapt to different network environments, with higher compression ratio, more real pictures, less cost, faster transmission speed to pass video, allowing webcams to be more Close to the people's lives. So H.264 was born
MJPEG VS H.264:
Code stream: The code stream is equivalent to the water flow speed of the video file in the broadband, which affects the transmission speed and picture quality and the memory. First introduce the formula: Video file size = code stream × 3600S ÷ 8 ÷ 1024 =? M / hour first use different code streams to see screen effects and video file size, for example: MJPEG with 2048kb / s speed upload file video file size = 2048kb / s × 3600S ÷ 8 ÷ 1024 = 900Mbps / hour! 32G memory card Storage 1.5 days
MJPEG code stream 2048kb / s surveillance screen
H.264 Upload file video file size with 512 kb / s = 512 kb / s × 3600s ÷ 8 ÷ 1024 = 225m / h 32g of memory card can be stored for 5-6 days;
The H.264 code stream 512kb / s monitor screen Even if MJPEG uses a 512 kb / s stream with a 512 kb / s code stream with 2048kb / s, because the compression ratio of H.264 is larger, the calculation method is more advanced, which can make the screen quality Due to the same effect. H.264 saves more than 80% of the code rate than MJPEG, saving 4 times storage space than MJPEG. H.264 can also complete 720P, 1080i / P broadcast video resolution under lower broadband. Now the arrival of 4G networks makes the broadband speed of the home network very wide, and the MJPEG network transmission reaches 2048kb / s, the code stream is also theoretically. Furthermore, the network camera video transmission is the upload speed of use instead of the download speed. Regardless of the download speed, 90% of the network operator's upload speed is 512kb / s. We use the same code stream 512 kb / s to see the effects of the screen and the video file size.
Code stream MJPEG picture quality
Code stream H.264 picture quality
Obviously, the code quality is very different. In order to achieve high compression ratio, MJPEG reduces video quality, there is a mosaic, and the picture is serious. However, MJPEG is more suitable for video editing, and there is an advantage when the number of frames is not very strict. H.26 Because there is a more advanced compression algorithm, the compression ratio is high, it can quickly compress and transfer to the shooting video, so the picture is very clear and smooth. Compression ratio: 1, MJPEG compression ratio is 20: 1 2, H.264 compression ratio is 200: 1 network compatibility: 1, MJPEG improves the inter prediction mechanism, improves error correction and network compatibility, and has network transmission Better support function. But each manufacturer's network camera applies to a network of all networks. 2, network compatibility, whether your network is CDMA, GPRS, WCDMA or CDMA2000 can be used. Network applicability: 1. MJPEG network transmission network is greatly used, suitable for short-range wireless monitoring, long-distance mobile phones, iPad wireless monitoring networks fail to transfer requirements, poor picture effect. An error occurred in an unstable network environment, and the video file is easily lost. 2, H.264 Not only provides better image quality in the same broadband, even if mobile phones, PAD wireless networks are transmitted, remote monitoring is still well adapted. MJPEG Mobile Monitoring Screen H.264 Mobile Monitoring Screen Standard: 1, MJPEG is developed by JPEG expert group, is not a standard compression method, each manufacturer has its own MJPEG version, and both parties cannot identify and transmit. 2, H.264 is the first video coding technical standards jointly developed by ITU-T (ITU) and ISO (International Standardization), which is conceivable to know its authority and scientific. 2
ITU-T (ITU) and ISO (International Standardization Organization) cost: 1, MJPEG has the lowest cost, advanced technology and mature technology in the market. MJPEG gets better single image quality, accurate to the frame editing, which is conducive to editing, which has little affected by network packet loss problems, so there is still a wide range of medium and low products. But under low cost temptations, many manufacturers still use MJPEG products as the main product.
2, the H.264 decoding algorithm is complicated, the code requirements are demanding, and the demand for chip is also an important factor in restricting its development. Products: In 2013, for two compressed formats, many manufacturers have conducted price war. Based on the same hardware (robotic shell, wireless WiFi, P2P technology, 300,000 pixels, two-way voice function), MJPEG or H.264 compression formats are used, respectively, there are different price and after-sales service. Although network cameras have remote and wireless access functions, MJGEG and H.264 determine the fluency of network cameras remote and wireless access. This also brings different visual effects to users. Regularly, the compression technology of H.264 is highly required to high product prices relative to MJPEG. However, some products have mastered skilled network camera technology to save costs. In the biasing technique, the use of infrared filtering techniques instead of IR-CUT technology can also reduce costs accordingly.
Therefore, H.264 has gradually decreased with the development of technology. Now the high cost of H, 264 is no longer hindering the low price of the product. Instead, MJPEG has poor movement, high broadband occupation, and high storage space occupies large defects exposed. Moreover, MJPEG encoding efficiency restricts its extensive application of its application to a certain extent. H.264 can adapt to the complete solution of most network cameras at the front end, transmission, management center, and rear end links provided by the actual application.
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