V4L2捕捉画面+H264压缩视频+帧缓冲显示视频————帧缓冲显示视频
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帧缓冲显示主要步骤
- 打开设备文件, 比如/dev/fb0
- 获取framebuffer的一些信息, 比如分辨率
- 设置参数
- 映射framebuffer内存到用户空间
- 写入要显示的画面
/* display.c */
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <linux/fb.h>
#include <pthread.h>
#include "config.h"
#include "queue.h"
#include "display.h"
typedef enum {
DISPLAY_STATE_STOP,
DISPLAY_STATE_START
} eDisplayState;
static struct {
int DevFd;
int ScreenSize;
uint8_t* pMmap;
eDisplayState State;
pthread_t DisplayThreadId;
sQueue QueuePrivateData;
uint32_t ScreenWidth;
uint32_t ScreenHeight;
} sDisplayPrivateData;
static const int BufferSize = CONFIG_CAPTURE_WIDTH * CONFIG_CAPTURE_HEIGHT * 4;
extern int Yuyv2Rgb32(uint8_t* pYuv, uint8_t* pRgb, uint32_t Width, uint32_t Height);
int DisplayInit(const char* pDevName)
{
QueueInit(&sDisplayPrivateData.QueuePrivateData);
struct fb_fix_screeninfo FbFix;
struct fb_var_screeninfo FbVar;
if((sDisplayPrivateData.DevFd = open(pDevName, O_RDWR)) < 0){
perror("Open Framebuffer Device");
return -1;
}
printf("Open Framebuffer Device:%s successful!\n", pDevName);
if(ioctl(sDisplayPrivateData.DevFd, FBIOGET_FSCREENINFO, &FbFix)){
perror("Get Fb_fix_info error!");
return -1;
}
printf("Get Fb_fix_info successful!\n");
if(ioctl(sDisplayPrivateData.DevFd, FBIOGET_VSCREENINFO, &FbVar)){
printf("Get Fb_var_info error!\n");
return -1;
}
printf("Get Fb_var_info successful!\n");
printf("Screen origin param: physics resultion %dx%d, line length: %d\n", FbVar.xres, FbVar.yres, FbFix.line_length);
printf("Screen origin param: virtual resultion %dx%d\n", FbVar.xres_virtual, FbVar.yres_virtual);
// FbVar.xres = CONFIG_CAPTURE_WIDTH;
// FbVar.yres = CONFIG_CAPTURE_HEIGHT;
FbVar.xres_virtual = CONFIG_CAPTURE_WIDTH;
FbVar.yres_virtual = CONFIG_CAPTURE_WIDTH;
if(ioctl(sDisplayPrivateData.DevFd, FBIOPUT_VSCREENINFO, &FbVar)) {
printf("Set Fb_var_info error!\n");
// return -1;
}
printf("Set Fb_var_info successful!\n");
if(ioctl(sDisplayPrivateData.DevFd, FBIOGET_VSCREENINFO, &FbVar)) {
printf("Get Fb_var_info error!\n");
return -1;
}
printf("Get Fb_var_info successful!\n");
printf("Screen after param: physics resultion %dx%d, line length: %d\n", FbVar.xres, FbVar.yres, FbFix.line_length);
printf("Screen after param: virtual resultion %dx%d\n", FbVar.xres_virtual, FbVar.yres_virtual);
sDisplayPrivateData.ScreenWidth = FbVar.xres;
sDisplayPrivateData.ScreenHeight = FbVar.yres;
sDisplayPrivateData.ScreenSize = FbVar.xres * FbVar.yres * (FbVar.bits_per_pixel / 8);
printf("Screen size: %d\n", sDisplayPrivateData.ScreenSize);
sDisplayPrivateData.pMmap = mmap(NULL, sDisplayPrivateData.ScreenSize, PROT_READ | PROT_WRITE, MAP_SHARED, sDisplayPrivateData.DevFd, 0);
if(!sDisplayPrivateData.pMmap){
perror("Memory Mmap error");
return -1;
}
printf("Memory Mmap successful!\n");
return 0;
}
static void* DisplayThread(void* pParam)
{
int Ret = -1;
sDisplayPrivateData.State = DISPLAY_STATE_START;
uint8_t* pRgbBuffer = malloc(BufferSize);
if(!pRgbBuffer) {
perror("Malloc failed");
return NULL;
}
while(sDisplayPrivateData.State == DISPLAY_STATE_START) {
sQueueData QueueData;
Ret = QueuePopData(&sDisplayPrivateData.QueuePrivateData, &QueueData);
if(Ret) {
continue;
}
Yuyv2Rgb32(QueueData.pData, pRgbBuffer, CONFIG_CAPTURE_WIDTH, CONFIG_CAPTURE_HEIGHT);
// printf("Copy length: %d\n", BufferSize);
// memcpy(sDisplayPrivateData.pMmap, pRgbBuffer, BufferSize);
uint32_t CopyWidthLength = sDisplayPrivateData.ScreenWidth > CONFIG_CAPTURE_WIDTH ?
CONFIG_CAPTURE_WIDTH : sDisplayPrivateData.ScreenWidth;
for(int i = 0; i < CONFIG_CAPTURE_HEIGHT; i++) {
memcpy(sDisplayPrivateData.pMmap + sDisplayPrivateData.ScreenWidth * 4 * i,
&pRgbBuffer[CONFIG_CAPTURE_WIDTH * 4 * i],
CopyWidthLength * 4);
}
QueueCallback(&QueueData);
}
free(pRgbBuffer);
DisplayStop();
return NULL;
}
int DisplayStart(void)
{
if(sDisplayPrivateData.State == DISPLAY_STATE_START) {
return -1;
}
pthread_create(&sDisplayPrivateData.DisplayThreadId, NULL, DisplayThread, (void *)NULL);
return 0;
}
int DisplayStop(void)
{
if(sDisplayPrivateData.State == DISPLAY_STATE_STOP) {
return 0;
}
sDisplayPrivateData.State = DISPLAY_STATE_STOP;
pthread_join(sDisplayPrivateData.DisplayThreadId, NULL);
munmap(sDisplayPrivateData.pMmap, sDisplayPrivateData.ScreenSize);
close(sDisplayPrivateData.DevFd);
printf("Display thread stop\n");
return 0;
}
/* display.h */
#ifndef DISPLAY_H
#define DISPLAY_H
int DisplayInit(const char* pDevName);
int DisplayStart(void);
int DisplayStop(void);
#endif
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