文章目录
- 1.下载ffmpeg
- 2.交叉编译
- 3.修改cmakelist.txt
- 4.将lib文件复制到install目录下的lib目录
- 5.测试文件
- 6.运行测试样例
- 7.错误
- n.测试文件源码
1.下载ffmpeg
git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg
2.交叉编译
进入下载目录，将ffmpeg编译成arm64平台的版本，编译后的文件存放于./instal_arm64中。
sudo ./configure --prefix=./instal_arm64 --enable-shared --disable-static --enable-cross-compile --arch=arm64 --disable-stripping --target-os=linux --cc=aarch64-linux-gnu-gcc
验证：进入instal_arm64/lib文件夹，使用file命令查看文件格式，若显示为ARM aarch64即成功。
3.修改cmakelist.txt
需要将交叉编译好的lib/include 文件夹导入项目中，修改cmakelist.txt如下图所示。
为方便复制这里将改动内容的文字贴在下面，路径需要改成自己的下载路径。
#ffmpeg
# 设置ffmpeg依赖库及头文件所在目录，并存进指定变量
set(ffmpeg_libs_DIR /home/yi/Downloads/ffmpeg/instal_arm64/lib)
set(ffmpeg_headers_DIR /home/yi/Downloads/ffmpeg/instal_arm64/include)
add_library( avcodec SHARED IMPORTED)
add_library( avfilter SHARED IMPORTED )
add_library( swresample SHARED IMPORTED )
add_library( swscale SHARED IMPORTED )
add_library( avformat SHARED IMPORTED )
add_library( avutil SHARED IMPORTED )
#指定所添加依赖库的导入路径
set_target_properties( avcodec PROPERTIES IMPORTED_LOCATION ${ffmpeg_libs_DIR}/libavcodec.so )
set_target_properties( avfilter PROPERTIES IMPORTED_LOCATION ${ffmpeg_libs_DIR}/libavfilter.so )
set_target_properties( swresample PROPERTIES IMPORTED_LOCATION ${ffmpeg_libs_DIR}/libswresample.so )
set_target_properties( swscale PROPERTIES IMPORTED_LOCATION ${ffmpeg_libs_DIR}/libswscale.so )
set_target_properties( avformat PROPERTIES IMPORTED_LOCATION ${ffmpeg_libs_DIR}/libavformat.so )
set_target_properties( avutil PROPERTIES IMPORTED_LOCATION ${ffmpeg_libs_DIR}/libavutil.so )
# 添加头文件路径到编译器的头文件搜索路径下，多个路径以空格分隔
include_directories(${ffmpeg_headers_DIR})
link_directories(${ffmpeg_libs_DIR})--------省略若干字。。。。。----------------------target_link_libraries(rknn_yolov5_demo${RKNN_RT_LIB}${RGA_LIB}${OpenCV_LIBS}${ffmpeg_libs_DIR}avcodec avformat avutil swresample swscale swscale avfilter
)4.将lib文件复制到install目录下的lib目录
这里也许可以只复制项目中需要的lib文件.
sudo cp ~/Downloads/ffmpeg/instal_arm64/lib/* install/rknn_yolov5_demo_Linux/lib/
5.测试文件
这里用一个ffpeg解析rtsp流的案例来测试是否成功。因为源码篇幅过长，放到本文最后。程序大意是：读取rtsp流，将rtsp流解析成帧，并且输入到输出文件，同时统计帧数。
6.运行测试样例
sudo ./build-rk3588…
adb push …
这里省略
最终可得到如图所示的结果，表示编译运行成功。
7.错误
运行时出现了Failed to resolve hostname …无法解析域名的错误。
解决方案：
有两种可能的原因，1.没有配置域名服务器114.114.114.114 。2.开发板没有网络。
- 配置域名服务器
- 连接网络
可以尝试ping www.baidu.com，若没有问题的话，则不是网络问题。
1、安装nmcli
sudo apt-get install nmcli
2、查看网络设备
sudo nmcli dev
3、开启wifi
sudo nmcli r wifi on
4、扫描wifi
sudo nmcli dev wifi
5、连接wifi
sudo nmcli dev wifi connect “wifi名” password “密码”
n.测试文件源码
案例源码：
#ifndef INT64_C
#define INT64_C(c) (c ## LL)
#define UINT64_C(c) (c ## ULL)
#endif extern "C" {/*Include ffmpeg header file*/
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libswscale/swscale.h> #include <libavutil/imgutils.h>
#include <libavutil/opt.h>
#include <libavutil/mathematics.h>
#include <libavutil/samplefmt.h>
}#include <iostream>
using namespace std;int main(void)
{AVFormatContext* ifmt_ctx = NULL, * ofmt_ctx = NULL;const char* in_filename, * out_filename;//in_filename = "rtsp://admin:WY@123456@192.168.0.64/h264/ch1/main/av_stream";in_filename="rtsp://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mp4";out_filename = "output.flv";avformat_network_init();AVDictionary* avdic = NULL;char option_key[] = "rtsp_transport";char option_value[] = "tcp";av_dict_set(&avdic, option_key, option_value, 0);char option_key2[] = "max_delay";char option_value2[] = "5000000";av_dict_set(&avdic, option_key2, option_value2, 0);AVPacket pkt;AVOutputFormat* ofmt = NULL;int video_index = -1;int frame_index = 0;int i;//打开输入流int ret;if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, &avdic)) < 0){cout<<"Could not open input file."<<endl;goto end;}if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0){cout<<"Failed to retrieve input stream information"<<endl;goto end;}//nb_streams代表有几路流for (i = 0; i < ifmt_ctx->nb_streams; i++) {if (ifmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO){//视频流video_index = i;cout << "get videostream." << endl;break;}}av_dump_format(ifmt_ctx, 0, in_filename, 0);//打开输出流avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename);if (!ofmt_ctx){printf("Could not create output context\n");ret = AVERROR_UNKNOWN;goto end;}ofmt = ofmt_ctx->oformat;for (i = 0; i < ifmt_ctx->nb_streams; i++){AVStream* in_stream = ifmt_ctx->streams[i];AVStream* out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);if (!out_stream){printf("Failed allocating output stream.\n");ret = AVERROR_UNKNOWN;goto end;}//将输出流的编码信息复制到输入流ret = avcodec_copy_context(out_stream->codec, in_stream->codec);if (ret < 0){printf("Failed to copy context from input to output stream codec context\n");goto end;}out_stream->codec->codec_tag = 0;if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)out_stream->codec->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;}av_dump_format(ofmt_ctx, 0, out_filename, 1);if (!(ofmt->flags & AVFMT_NOFILE)){ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);if (ret < 0){printf("Could not open output URL '%s'", out_filename);goto end;}}//写文件头到输出文件ret = avformat_write_header(ofmt_ctx, NULL);if (ret < 0){printf("Error occured when opening output URL\n");goto end;}//while循环中持续获取数据包，不管音频视频都存入文件while (1){AVStream* in_stream, * out_stream;//从输入流获取一个数据包ret = av_read_frame(ifmt_ctx, &pkt);if (ret < 0)break;in_stream = ifmt_ctx->streams[pkt.stream_index];out_stream = ofmt_ctx->streams[pkt.stream_index];//copy packet//转换 PTS/DTS 时序pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, (enum AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, (enum AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));//printf("pts %d dts %d base %d\n",pkt.pts,pkt.dts, in_stream->time_base);pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);pkt.pos = -1;//此while循环中并非所有packet都是视频帧，当收到视频帧时记录一下if (pkt.stream_index == video_index){printf("Receive %8d video frames from input URL\n", frame_index);frame_index++;}//将包数据写入到文件。ret = av_interleaved_write_frame(ofmt_ctx, &pkt);if (ret < 0){if (ret == -22) {continue;}else {printf("Error muxing packet.error code %d\n", ret);break;}}//av_free_packet(&pkt); //此句在新版本中已deprecated 由av_packet_unref代替av_packet_unref(&pkt);}//写文件尾av_write_trailer(ofmt_ctx);end:av_dict_free(&avdic);avformat_close_input(&ifmt_ctx);//Close inputif (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))avio_close(ofmt_ctx->pb);avformat_free_context(ofmt_ctx);if (ret < 0 && ret != AVERROR_EOF){cout<<"Error occured."<<endl;return -1;}return 0;
}
