Application of FH8735 in Multi-channel H.264 High Definition Video Coding System

Abstract: High-definition video applications have become a hot topic in the market. In order to meet the actual needs of more and more high-definition video acquisition and encoding, Fullan Microelectronics has released FH8735 and FH8736 high-performance video encoding chips and a series of the most competitive high-definition video encoding solutions. These solutions support real-time encoding of 1-channel 1080p30 format or 2-channel 720p60 format high-definition video, and support video input from multiple high-definition video receivers such as HDMI, DVI, YPbPr, VGA, SDI, etc. At present, this solution has been widely used in video security monitoring, video conferencing, high-definition video games, remote computer room control, distance education and telemedicine.

1 Introduction

After the development of the analog era, digital era, and network era, video surveillance products have gradually entered the high-definition era. Compared with traditional standard-definition video, high-definition video has made a qualitative leap in video quality. In the past, due to the limitations of many factors such as chip encoding capabilities, network bandwidth, and storage technology, high-definition video has not been widely used. However, with the rapid development of technologies such as video encoding, IC design, broadband networks, and large-capacity storage, the main obstacles to the application of high-definition video have been cleared. The H.264/AVC video encoding standard has excellent encoding efficiency and can greatly reduce the network bandwidth and storage capacity requirements for high-definition video transmission. It has been widely used and has become the inevitable choice for high-definition video encoding.

At present, high-definition video surveillance has been paid attention to and applied by more and more industries. The common characteristics of users in these industries are that they need higher-definition video images. In September 2008, Shanghai Fu Han Microelectronics Co., Ltd. launched the FH8735 H.264 encoding ASIC and corresponding solutions. It has the ability to encode high-definition videos in real time with a single chip of 1080p@30fps or 2 channels of 720p@30fps . It is the most competitive high-performance video encoding chip on the market and can greatly meet the development needs of high-definition video.

Fudan Microelectronics has launched a series of high-definition video product solutions based on the FH8735 chip, such as high-definition network camera solutions, high-definition network video server solutions and PCI high-definition video compression cards.

After more than a year of market testing, FH8735 has been widely used in various fields such as video security monitoring, video conferencing, distance education, telemedicine, high-definition screen recording and personal consumer electronics.

2 Introduction to FH8735 HD Encoding Chip

FH8735 is a high-performance audio and video encoding chip that supports H.264 Main profile and Baseline profile video encoding standards. It can encode and control one 1080i and two 720p high-definition signals in real time. While encoding video data, it also encodes related multi-channel audio data, completes audio and video synchronization, and outputs compressed code streams in ES/PES/PS/TS formats. The internal functional modules of FH8735 are shown in Figure 1.

The main technical features of FH8735 are as follows:

1) Super strong encoding performance

The H.264 encoding of FH8735 is completed by pure hardware, with the characteristics of high encoding capability, high encoding quality and low power consumption. FH8735 supports video input with a maximum resolution of 2048x1024, and supports real-time encoding of 1 channel 1920x1080@30fps or 2 channels 1280x720 ( 1280x720@60fps ). The comparison results of typical video encoding show that at the same bit rate, the video encoding quality of FH8735 is close to that of JM12.0.

2) Rich peripheral interfaces

FH8735 supports multiple HD video input modes. The data format and synchronization mode of HD video can be configured. It can receive digital video output from CMOS/CCD modules, video decoders, etc.:

Support ITU-R BT.709/SMPTE 274M (24Bit 4:4:4 YCbCr, 16Bit 4:2:2 YCbCr, RGB 24 (8:8:8));

Support SMPTE296M-2001 (24Bit 4:4:4 YCbCr, 16Bit 4:2:2 YCbCr, RGB 24 (8:8:8))

Support 8bit 4:2:2 YCbCr;

Support internal synchronization and external synchronization;

In addition, FH8735 also has multiple peripheral interfaces such as SPI/PCI/SD/UART/I2S/GPIO/I2C/MAC, etc.

3) Patented rate control technology

FH8735 provides four bit rate control strategies: fixed quantization coefficient (QP: quantisation parameter), constant bit rate (CBR: Constant Bit Rate), variable bit rate (VBR: Variable Bit Rate) and average bit rate (ABR: Average Bit Rate). Each algorithm has been carefully optimized and can adaptively pre-detect and judge the video scene, so as to ensure the subjective quality of the video while making the encoder output bit rate smooth and stable, ensuring the efficiency and stability of network transmission.

4) Flexible function settings

In addition to high-performance video encoding capabilities, FH8735 provides a wealth of video preprocessing functions and flexible video encoding options. The encoder's search range, Intra prediction type, GOP length, number of reference frames, encoding bit rate and bit rate control method, encoding Profile and Level, etc. can be flexibly set according to needs, so as to ensure seamless connection with decoders with different decoding capabilities. In addition, FH8735 supports multiple image processing functions such as de-interlacing, de-noising, multiple text and graphic OSD overlay, image reduction, motion detection, etc. for input video, and also supports capturing lossless original video signals for the host side to perform some intelligent analysis and processing such as license plate recognition, face recognition, etc.

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FH8735 has two independent DDR controllers inside, which can connect to two external DDR SDRAMs. Configure one or two external DDR SDRAMs according to the actual system's requirements for encoder performance. For example, when encoding a 720p video, only one DDR is needed, thus reducing the system BOM cost.

5) Optimized ultra-low latency real-time encoding technology

In high-definition video systems, system latency is also an important consideration. FH8735 reduces the internal latency of the entire video encoding by supporting flexible image segmentation encoding. For example, when encoding 720P high-definition video, the time for each frame of data to enter the system buffer is about 16.7ms. The time from the start of the input of the first valid line of image data into the system buffer to the output of the encoder for the entire frame of compressed code stream can be controlled within 20ms. This ultra-low latency real-time encoding technology can greatly reduce the end-to-end latency of the entire system, thereby improving and enhancing the user's subjective experience.

2 Multi-channel HD video encoding board based on FH8735

In order to meet the needs of early evaluation and development of FH8735 in HD encoding applications, Fu Han provides a reference design of a multi-channel HD video encoding card based on FH8735. This HD encoding card supports HD video input and PCI host interface of DVI/HDMI and YPbPr interfaces, and can complete the acquisition and encoding of HD video, and send it to the host through the PCI interface. This reference design supports Windows XP and Linux. Fu Han provides the corresponding driver and evaluation software, and can modify the firmware to meet the customized functions according to the user's specific application.

The system diagram of the multi-channel high-definition video encoding card is as follows:

3. Conclusion

FH8735 has the capability of real-time encoding of high-definition video at 1920x1080@30fps on a single chip , and is the most competitive new generation high-performance video encoding chip on the market.

The high performance and ease of use of FH8735 provide new options and space for high-definition or multi-channel video compression applications, which can significantly improve customer product performance and reduce development time.