基于FPGA的H.264码流实时传输系统设计

Design of H.264 Real-time Transmission System Based on FPGA

摘要:

在研究华为海思Hi3516A进行视频编码压缩的过程中，针对其压缩码流仅支持本地保存和网络流媒体应用的局限性，提出了一种基于FPGA和以太网接口的H.264码流实时传输方案。Hi3516A视频编码端采用RAW_SOCKET原始套接字协议构建UDP帧,通过网口传输H.264压缩码流到FPGA平台；FPGA使用一片2Gbit的DDR3作为数据缓存介质，保证网口速率的匹配和一次传输的H.264 Nalu包的完整性；利用USB2.0接口回传码流到PC进行功能测试。从模拟传输本地文件和实际传输视频两方面对系统功能进行测试。模拟传输本地文件测试中，PC端网口发送55,844,864字节本地文件到本系统，USB上位机接收的系统返回数据大小与发送数据大小相同，证明数据传输完整；实际传输视频测试中，MilkPlayer软件播放USB上位机保存的码流文件，画面流畅，无卡顿及明显丢帧，使用FFmpeg软件解码码流文件，测试表明，数据压缩比均值达143:1，与系统设定值相比，存在4%左右的误差，USB上位机12h和24h保存接收码流测试中，数据量分别达到22.3GB和43.5GB，码流文件播放效果良好。因此，此系统能实现H.264码流的实时传输，满足设计要求，具有很好的实用价值。

Abstract:

In the process of studying the video encoding and compression of Huawei HiSilicon Hi3516A, in view of the limitation of its compressed code stream that only supports local storage and network streaming media applications, a real-time transmission of H.264 code stream based on FPGA and Ethernet interface is proposed. Hi3516A uses RAW_SOCKET original socket protocol to construct UDP frame, and transmits H.264 compressed code stream to FPGA platform through network port; FPGA uses a piece of 2Gbit DDR3 as data buffer medium to ensure the matching of network port rate and the integrity of the H.264 Nalu package during one-time transmission; use the USB2.0 interface to return the code stream to the PC for functional testing. The system function is tested from two aspects of simulated transmission of local files and actual transmission of video. In the test of simulated transmission of local files, the PC-side network port sends 55,844,864 bytes of local files to the system, and the size of the returned data received by the USB host computer is the same as that of the sent data, which proves that the data transmission is complete; in the actual video transmission test, the MilkPlayer software plays the stream file saved by the USB host computer has a smooth picture, no freezes and obvious frame loss. The FFmpeg software is used to decode the stream file. The test shows that the average data compression ratio is 143:1. Compared with the system setting value, there is an error of about 4%, the USB host computer save and receive the stream test during 12h and 24h, the data volume reached 22.3GB and 43.5GB respectively, the streaming files play well. Therefore, this system can realize the real-time transmission of H.264 code stream, meet the design requirements, and has very good practical value.