使用live555 直播来自v4l2的摄像头数据，在我的这个工程中，基本思路是：使用V4L2采集摄像头数据，然后使用x264库对摄像头数据进行编码，编成H264数据格式，然后把数据写入到命名管道中。最后使用live555 从管道中读出数据发送出去,实现视频的直播。
在我的工程调试过程中，使用的是罗技C270摄像头，出来的是YUYV数据格式。x264和live555 使用最新的库。工程目录如下：
├── H264FramedLiveSource.cpp ├── H264VideoStreamer.cpp ├── include │ ├── encoder │ │ ├── encoder_define.hh │ │ ├── H264FramedLiveSource.hh │ │ └── stdint.h │ ├── live555 │ │ ├── basicUsageEnvironment │ │ ├── groupsock │ │ ├── liveMedia │ │ └── usageEnvironment │ └── x264 │ ├── x264_config.h │ └── x264.h ├── lib │ ├── livelib │ │ ├── libBasicUsageEnvironment.a │ │ ├── libgroupsock.a │ │ ├── libliveMedia.a │ │ └── libUsageEnvironment.a │ └── x264lib │ ├── libx264.a │ └── libx264.so.148 └── MakefileH264FramedLiveSource.cpp 中新建了一个Device 类，用来实现v4l2数据的采集和x264编码的实现。其函数定义如下：
/*=============================================================================
* # FileName: H264FramedLiveSource.hh
* # Desc:
* #
* # Author: licaibiao
* # Version:
* # LastChange: 2017-02-24
* =============================================================================*/
#ifndef _H264FRAMEDLIVESOURCE_HH
#define _H264FRAMEDLIVESOURCE_HH
#include <FramedSource.hh>
#include <UsageEnvironment.hh>
#include "encoder_define.hh"
class Device
{
public:
void init_mmap(void);
void init_camera(void);
void init_encoder(void);
void open_camera(void);
void close_camera(void);
void read_one_frame(void);
void getnextframe(void);
void start_capture(void);
void stop_capture(void);
void close_encoder();
int camera_able_read(void);
void compress_begin(Encoder *en, int width, int height);
int compress_frame(Encoder *en, int type, char *in, int len, char *out);
void compress_end(Encoder *en);
void Init();
void intoloop();;
void Destory();
public:
int fd;
FILE *save_fd;
int n_nal;
int frame_len;
char *h264_buf;
unsigned int n_buffer;
Encoder en;
FILE *h264_fp;
BUFTYPE *usr_buf;
FILE *pipe_fd;
};
#endif H264VideoStreamer.cpp 实现RTSP的创建。其代码实现如下：
/**********
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
This library is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
more details.
You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
**********/
// Copyright (c) 1996-2017, Live Networks, Inc. All rights reserved
// A test program that reads a H.264 Elementary Stream video file
// and streams it using RTP
// main program
//
// NOTE: For this application to work, the H.264 Elementary Stream video file *must* contain SPS and PPS NAL units,
// ideally at or near the start of the file. These SPS and PPS NAL units are used to specify 'configuration' information
// that is set in the output stream's SDP description (by the RTSP server that is built in to this application).
// Note also that - unlike some other "*Streamer" demo applications - the resulting stream can be received only using a
// RTSP client (such as "openRTSP")
#include <liveMedia.hh>
#include <BasicUsageEnvironment.hh>
#include <GroupsockHelper.hh>
#include <H264FramedLiveSource.hh>
#include <sys/types.h>
#include <sys/stat.h>
UsageEnvironment* env;
char const* inputFileName = "/tmp/fifo";
char *ptr;
H264VideoStreamFramer* videoSource;
RTPSink* videoSink;
class Device Camera;
void play(); // forward
EventTriggerId DeviceSource::eventTriggerId = 0;
int main(int argc, char** argv) {
// Begin by setting up our usage environment:
TaskScheduler* scheduler = BasicTaskScheduler::createNew();
env = BasicUsageEnvironment::createNew(*scheduler);
// Create 'groupsocks' for RTP and RTCP:
struct in_addr destinationAddress;
destinationAddress.s_addr = chooseRandomIPv4SSMAddress(*env);
// Note: This is a multicast address. If you wish instead to stream
// using unicast, then you should use the "testOnDemandRTSPServer"
// test program - not this test program - as a model.
const unsigned short rtpPortNum = 18888;
const unsigned short rtcpPortNum = rtpPortNum+1;
const unsigned char ttl = 255;
const Port rtpPort(rtpPortNum);
const Port rtcpPort(rtcpPortNum);
Camera.Init();
mkfifo(inputFileName, 0777);
if(0 == fork())
{
Camera.pipe_fd = fopen(inputFileName, "w");
if(NULL == Camera.pipe_fd)
{
printf("===============child process open pipe err =======\n ");
}
while(1)
{
usleep(15000);
Camera.getnextframe();
}
}
Groupsock rtpGroupsock(*env, destinationAddress, rtpPort, ttl);
rtpGroupsock.multicastSendOnly(); // we're a SSM source
Groupsock rtcpGroupsock(*env, destinationAddress, rtcpPort, ttl);
rtcpGroupsock.multicastSendOnly(); // we're a SSM source
// Create a 'H264 Video RTP' sink from the RTP 'groupsock':
OutPacketBuffer::maxSize = 600000;
videoSink = H264VideoRTPSink::createNew(*env, &rtpGroupsock, 96);
// Create (and start) a 'RTCP instance' for this RTP sink:
const unsigned estimatedSessionBandwidth = 10000; // in kbps; for RTCP b/w share
const unsigned maxCNAMElen = 100;
unsigned char CNAME[maxCNAMElen+1];
gethostname((char*)CNAME, maxCNAMElen);
CNAME[maxCNAMElen] = '\0'; // just in case
RTCPInstance* rtcp
= RTCPInstance::createNew(*env, &rtcpGroupsock,
estimatedSessionBandwidth, CNAME,
videoSink, NULL /* we're a server */,
True /* we're a SSM source */);
// Note: This starts RTCP running automatically
RTSPServer* rtspServer = RTSPServer::createNew(*env, 8554);
if (rtspServer == NULL) {
*env << "Failed to create RTSP server: " << env->getResultMsg() << "\n";
exit(1);
}
ServerMediaSession* sms
= ServerMediaSession::createNew(*env, "testStream", inputFileName,
"Session streamed by \"testH264VideoStreamer\"",
True /*SSM*/);
sms->addSubsession(PassiveServerMediaSubsession::createNew(*videoSink, rtcp));
rtspServer->addServerMediaSession(sms);
char* url = rtspServer->rtspURL(sms);
*env << "Play this stream using the URL \"" << url << "\"\n";
delete[] url;
// Start the streaming:
*env << "Beginning streaming...\n";
play();
env->taskScheduler().doEventLoop(); // does not return
return 0; // only to prevent compiler warning
}
void afterPlaying(void* /*clientData*/) {
*env << "...done reading from file\n";
videoSink->stopPlaying();
Medium::close(videoSource);
Camera.Destory();
// Note that this also closes the input file that this source read from.
// Start playing once again:
play();
}
void play() {
// Open the input file as a 'byte-stream file source':
ByteStreamFileSource* fileSource
= ByteStreamFileSource::createNew(*env, inputFileName);
if (fileSource == NULL) {
*env << "Unable to open file \"" << inputFileName
<< "\" as a byte-stream file source\n";
exit(1);
}
FramedSource* videoES = fileSource;
// Create a framer for the Video Elementary Stream:
videoSource = H264VideoStreamFramer::createNew(*env, videoES);
// Finally, start playing:
*env << "Beginning to read from file...\n";
videoSink->startPlaying(*videoSource, afterPlaying, videoSink);
}
x264 和live555库的下载编译安装，在前面的博客中已经讲过，这里不再重复。编译运行整个工程如下：
[root@redhat pipelive]# ls H264FramedLiveSource.cpp H264FramedLiveSource.o H264VideoStreamer H264VideoStreamer.cpp H264VideoStreamer.o include lib Makefile [root@redhat pipelive]# ./H264VideoStreamer camera driver name is : uvcvideo camera device name is : UVC Camera (046d:0825) camera bus information: usb-0000:00:1a.0-1.1 n_buffer = 4 x264 [warning]: lookaheadless mb-tree requires intra refresh or infinite keyint x264 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX x264 [info]: profile High 4:2:2, level 3.0, 4:2:2 8-bit Play this stream using the URL "rtsp://192.168.0.127:8554/testStream" Beginning streaming... Beginning to read from file...在VLC 播放器中打开网络流rtsp://192.168.0.127:8554/testStream 可以看到摄像头中的数据：
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实际测试，使用管道来传输摄像头数据会出现一些延时，如果图片尺寸设置在320*240 延时会很小，但是图片尺寸设置在640*480，延时现象就会非常明显。这与我使用的摄像头也有关系，UVC摄像头读取数据相对会比较慢。
完整的工程可以从这里下载：live555直播来自v4l2 的摄像头数据
================2018-03-16 更新==================
因为工程中包含x264动态库文件，某个网友下载工程文件后杀毒软件报病毒...... 被举报之后下载链接失效了.......
如果有需要工程代码做参考的可以在评论区留个邮箱，看到后会邮件发送给有需要者。