PJMEID学习之视频的捕捉与播放
pjmedia是pjsip的视频部分,官网明确提示,要想使用pjmedia离不开directshow/sdl/ffmpeg这三个库。
软件版本的限制:
ffmpeg不能高于1.25。(建议下载1.01左右的版本)
pjsip下载版本要高于2.0.
directshow/sdl/ffmpeg在pjmedia的作用:
directshow:流媒体开发包,负责音视频的捕捉等。
ffmpeg:主要用于视频的编解码。
SDL:用于视频的播放。
下面贴出一博主建议先熟悉的例子:
pjmedia_test 视频的捕捉和播放
pjmedia 的视频捕捉和传输vid_streamutil.c
simpleua.c 简单的sip 和视频的协作
pjsip_ua.c 完整的sip 和视频的协作
上面的例子源码可以在pjmedia_test工程和sample中找到。
下面简单的实现一下视频的捕捉和播放。
首先简单了解一些函数:
pjmedia_vid_dev_get_info 获取端口信息
pjmedia_vid_dev_default_param 初始化视频设备用特定设备的参数值
enum pjmedia_dir
关于Media direction.
Enumerator | |
---|---|
PJMEDIA_DIR_NONE |
None |
PJMEDIA_DIR_ENCODING |
Encoding (outgoing to network) stream, also known as capture |
PJMEDIA_DIR_CAPTURE |
Same as encoding direction. |
PJMEDIA_DIR_DECODING |
Decoding (incoming from network) stream, also known as playback. |
PJMEDIA_DIR_PLAYBACK |
Same as decoding. |
PJMEDIA_DIR_RENDER |
Same as decoding. |
PJMEDIA_DIR_ENCODING_DECODING |
Incoming and outgoing stream, same as PJMEDIA_DIR_CAPTURE_PLAYBACK |
PJMEDIA_DIR_CAPTURE_PLAYBACK |
Same as ENCODING_DECODING |
PJMEDIA_DIR_CAPTURE_RENDER |
Same as ENCODING_DECODING |
关于pjmedia_vid_dev_info结构体各个成员说明:
pjmedia_vid_dev_index pjmedia_vid_dev_info::id
The device ID
char pjmedia_vid_dev_info::name[64] |
The device name
char pjmedia_vid_dev_info::driver[32] |
The underlying driver name
pjmedia_dir pjmedia_vid_dev_info::dir |
The supported direction of the video device, i.e. whether it supports capture only, render only, or both.
pj_bool_t pjmedia_vid_dev_info::has_callback |
Specify whether the device supports callback. Devices that implement "active interface" will actively call the callbacks to give or ask for video frames. If the device doesn't support callback, application must actively request or give video frames from/to the device by using pjmedia_vid_dev_stream_get_frame()/pjmedia_vid_dev_stream_put_frame().
unsigned pjmedia_vid_dev_info::caps |
Device capabilities, as bitmask combination of pjmedia_vid_dev_cap
unsigned pjmedia_vid_dev_info::fmt_cnt |
Number of video formats supported by this device
pjmedia_format pjmedia_vid_dev_info::fmt[PJMEDIA_VID_DEV_INFO_FMT_CNT] |
Array of supported video formats. Some fields in each supported video format may be set to zero or of "unknown" value, to indicate that the value is unknown or should be ignored. When these value are not set to zero, it indicates that the exact format combination is being used.
//video captrue and show
#include<pjmedia.h>
#include<pjmedia_audiodev.h>
#include<pjmedia_videodev.h>
#include<pjmedia-codec.h>
#include<pjlib.h>
pj_pool_factory *mem;
static find_device(pjmedia_dir dir,pj_bool_t has_callback)
{
unsigned i,count=pjmedia_vid_dev_count();
// printf("count=%d\n",count);
for(i=;i<count;i++)
{
pjmedia_vid_dev_info cdi;
if(pjmedia_vid_dev_get_info(i,&cdi)!=PJ_SUCCESS)
continue;
if((cdi.dir & dir)!=&& cdi.has_callback==has_callback)
return i;
}
return -;
}
static int capture_render_lookback(pj_bool_t active,int cap_dev_id,int rend_dev_id,const pjmedia_format *fmt)
{
pj_pool_t *pool;
pjmedia_vid_port *capture=NULL,*renderer=NULL;
pjmedia_vid_dev_info cdi,rdi;
pjmedia_vid_port_param param;
pjmedia_video_format_detail *vfd;
pj_status_t status;
int rc=,i; pool=pj_pool_create(mem,"vidportloop",,,NULL);
/*
status=pjmedia_vid_dev_get_info(rend_dev_id,&cdi);
if(status!=PJ_SUCCESS)
{
printf("cdi failed\n");
}
status=pjmedia_vid_dev_get_info(rend_dev_id,&rdi);
if(status!=PJ_SUCCESS)
{
printf("rend failed\n");
}
*/
pjmedia_vid_port_param_default(¶m);
//create capture
status=pjmedia_vid_dev_default_param(pool,cap_dev_id,¶m.vidparam);
if(status!=PJ_SUCCESS)
{
printf("param failed\n");
}
param.vidparam.dir=PJMEDIA_DIR_CAPTURE;
param.vidparam.fmt=*fmt;
param.active=PJ_TRUE; vfd=pjmedia_format_get_video_format_detail(¶m.vidparam.fmt,PJ_TRUE);
if(vfd==PJ_SUCCESS)
{
printf("get vfd failed\n");
} status=pjmedia_vid_port_create(pool,¶m,&capture);
if(status!=PJ_SUCCESS)
{
printf("vid create failed\n");
}
//create render
status=pjmedia_vid_dev_default_param(pool,rend_dev_id,¶m.vidparam);
if(status!=PJ_SUCCESS)
{
printf("render param failed\n");
}
param.active=PJ_FALSE;
param.vidparam.dir=PJMEDIA_DIR_RENDER;
param.vidparam.rend_id=rend_dev_id;
param.vidparam.fmt=*fmt;
param.vidparam.disp_size=vfd->size; status=pjmedia_vid_port_create(pool,¶m,&renderer);
if(status!=PJ_SUCCESS)
{
printf("render vid port create failed\n");
} // set event handler //connect capture to renderer
status=pjmedia_vid_port_connect(capture,pjmedia_vid_port_get_passive_port(renderer),PJ_FALSE);
if(status!=PJ_SUCCESS)
{
printf("connect failed\n");
} status=pjmedia_vid_port_start(renderer);
if(status!=PJ_SUCCESS)
{
printf("renderer start failed\n");
} status=pjmedia_vid_port_start(capture);
if(status!=PJ_SUCCESS)
{
printf("capture start failed\n");
} return rc;
}
int main()
{
int i,j,k,l;
int count;
int cap_id,rend_id;
pj_status_t status;
pj_caching_pool caching_pool;
pj_pool_t *pool; pjmedia_format fmt;
pjmedia_format_id test_fmts[]={
PJMEDIA_FORMAT_RGBA,
PJMEDIA_FORMAT_I420,
// PJMEDIA_FORMAT_H261
}; pj_init();//pjlib init
pj_caching_pool_init(&caching_pool,&pj_pool_factory_default_policy,);//init
pool=pj_pool_create(&caching_pool.factory,"test",,,NULL);
mem=&caching_pool.factory; pjmedia_video_format_mgr_create(pool, , , NULL);
pjmedia_converter_mgr_create(pool, NULL);
pjmedia_event_mgr_create(pool, , NULL);
pjmedia_vid_codec_mgr_create(pool, NULL); status=pjmedia_vid_dev_subsys_init(mem); //get the video device's id
cap_id=find_device(PJMEDIA_DIR_CAPTURE,);
rend_id=find_device(PJMEDIA_DIR_RENDER,); //printf("c=%d,r=%d\n"); pjmedia_format_init_video(&fmt,test_fmts[],,,,);
capture_render_lookback(,cap_id,rend_id,&fmt); getchar(); }
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