應上次有留言朋友的要求，我把部分代碼帖出來：
頭文件：
#include <gst/gst.h>
#include <gst/app/gstappsrc.h>
#include <gst/app/gstappsink.h>
#include <glib-2.0/glib.h>
#include "gdk-pixbuf-2.0/gdk-pixbuf/gdk-pixbuf.h"
#include "../defines.h"
#ifndef GSTCODE_H
#define GSTCODE_H
#ifdef __JETSON_TX2__
#define VIDEOSRC "nvarguscamerasrc"
#define VIDEOTYPE "NV12"
#define VIDEOCONVERT "nvvidconv"
#define VIDEOSINK "nvoverlaysink"
#define VIDEOSRCCAPS "video/x-raw(memory:NVMM)"
#define VIDEOENCODER "nvv4l2h264enc"
#else
#define VIDEOSRC "rkisp"
#define VIDEOTYPE "NV12"
#define VIDEOCONVERT "videoconvert"
#define VIDEOSINK "rkximagesink"
#define VIDEOSRCCAPS "video/x-raw"
#define VIDEOENCODER "nvv4l2h264enc"
#endif
#define FILESINK "filesink"
typedef struct {
GstPipeline *pipeline;
GstElement *src;
GstElement *srcconvert;
GstCaps *caps;
GstElement *tee;
//
GstElement *queue;
GstElement *convert;
GstElement *videosink;
//
GstElement *appqueue;
GstElement *appconvert;
GstCaps *appcaps;
GstElement *appsink;
//
GMainLoop *loop;
guint sourceid;
}gst_app_t;
extern gst_app_t gst_app;
extern gst_app_t *app;
void init_gst_elements(int argc, char *argv[]);
void terminal_gst_element();
class gstcode
{
public:
gstcode();
};
#endif // GSTCODE_H
程序源文件：
#include "gstcode.h"
#define CVWIN "cvwindows"
gst_app_t gst_app;
gst_app_t *app = &gst_app;
gstcode::gstcode()
{
}
static int idx = 0;
static gboolean bus_callback(GstBus *bus, GstMessage *message, gpointer *ptr)
{
gst_app_t *app = (gst_app_t*)ptr;
switch(GST_MESSAGE_TYPE(message)){
case GST_MESSAGE_ERROR:{
gchar *debug;
GError *err;
gst_message_parse_error(message, &err, &debug);
g_print("Error %s\n", err->message);
g_error_free(err);
g_free(debug);
g_main_loop_quit(app->loop);
}
break;
case GST_MESSAGE_WARNING:{
gchar *debug;
GError *err;
gchar *name;
gst_message_parse_warning(message, &err, &debug);
g_print("Warning %s\nDebug %s\n", err->message, debug);
name = GST_MESSAGE_SRC_NAME(message);
g_print("Name of src %s\n", name ? name : "nil");
g_error_free(err);
g_free(debug);
}
break;
case GST_MESSAGE_EOS:
g_print("End of stream\n");
g_main_loop_quit(app->loop);
break;
case GST_MESSAGE_STATE_CHANGED:
break;
default:
g_print("got message %s\n", \
gst_message_type_get_name (GST_MESSAGE_TYPE (message)));
break;
}
return TRUE;
}
static char filename[256] = {0};
static int exitticks = 0;
static int deel_appsink_buffer(GstAppSink * sink){
GstSample *sample;
GstBuffer *buffer;
GstCaps *caps;
GstStructure *s;
gint width, height;
bool res;
// g_print("new sample %d\n", idx);
sample = gst_app_sink_pull_sample(sink); //blocks
// sample = gst_base_sink_get_last_sample(GST_BASE_SINK_CAST(self));
if(sample){
/* get the snapshot buffer format now. We set the caps on the appsink so
* that it can only be an rgb buffer. The only thing we have not specified
* on the caps is the height, which is dependant on the pixel-aspect-ratio
* of the source material */
caps = gst_sample_get_caps (sample);
if (!caps) {
g_print ("could not get snapshot format\n");
exit (-1);
}
s = gst_caps_get_structure (caps, 0);
/* we need to get the final caps on the buffer to get the size */
res = gst_structure_get_int (s, "width", &width);
res |= gst_structure_get_int (s, "height", &height);
if (!res) {
g_print ("could not get snapshot dimension\n");
exit (-1);
}
/* create pixmap from buffer and save, gstreamer video buffers have a stride
* that is rounded up to the nearest multiple of 4 */
buffer = gst_sample_get_buffer (sample);
// GstMemory * mem = gst_buffer_get_all_memory(buffer);
GstMapInfo map;
/* Mapping a buffer can fail (non-readable) */
if (gst_buffer_map (buffer, &map, GST_MAP_READ)) {
// g_print("buffer size:%lu\n", map.size);
// g_print("img width:%d, height:%d\n", width, height);
if(map.data != NULL){
// cv::Mat mat = cv::Mat(cv::Size(width, height), CV_8U, (char*)map.data);
// cv::imshow(CVWIN, mat); //測試顯示OPENCV的窗體
gst_buffer_unmap (buffer, &map);
}else{
g_print("data is null!\n");
if(gst_app_sink_is_eos(GST_APP_SINK_CAST(gst_app.appsink))){
g_warning("gst_app_sink_is_eos !\n");
}
}
// g_print("deel frame: %d !\n", idx);
}else{
g_warning("buffer cant map, buffer size:%lu !\n", gst_buffer_get_size(buffer));
if(exitticks > 1){
g_main_loop_quit(gst_app.loop);
}else{
exitticks ++;
}
}
gst_buffer_unref(buffer);
idx++;
}else{
g_warning("cant get sample from appsink !\n");
}
// g_print("\n\n\n##################################################################################################\n\n\n");
return 1;
}
static GstFlowReturn Freturn;
static GstFlowReturn * new_sample_callback(GstAppSink * self, gst_app_t * app){
deel_appsink_buffer(self);
Freturn = GST_FLOW_OK;
return &Freturn;
}
int frame_deel_thread(void *){
deel_appsink_buffer(GST_APP_SINK_CAST(gst_app.appsink));
}
GstStateChangeReturn state_ret;
void init_gst_elements(int argc, char *argv[]){
GstBus *bus;
GstSample *sample;
GSourceFunc func = frame_deel_thread;
gst_init(&argc, &argv);
app->pipeline = (GstPipeline*)gst_pipeline_new("mypipeline");
/*bus = gst_pipeline_get_bus(app->pipeline);
gst_bus_add_watch(bus, (GstBusFunc)bus_callback, app);
gst_object_unref(bus);*/
app->src = gst_element_factory_make(VIDEOSRC, "mysrc");
#ifdef JETSON_TX2
g_object_set(app->src, "sensor-id", 1, NULL);
#else
g_object_set(app->src, "io-mode", 4, "device", "/dev/video0", NULL);
#endif
app->srcconvert = gst_element_factory_make(VIDEOCONVERT, "mysrcconvert");
#ifdef JETSON_TX2
g_object_set(app->srcconvert, "flip-method", 6, NULL);
app->caps = gst_caps_new_simple("video/x-raw(memory:NVMM)",//
"width", G_TYPE_INT, VIDEO_WIDTH,
"height", G_TYPE_INT, VIDEO_HEIGHT,
"framerate", GST_TYPE_FRACTION, 30, 1,
"format", G_TYPE_STRING, "NV12",
NULL);
#else
app->caps = gst_caps_new_simple("video/x-raw",//
"width", G_TYPE_INT, VIDEO_WIDTH,
"height", G_TYPE_INT, VIDEO_HEIGHT,
"framerate", GST_TYPE_FRACTION, 30, 1,
"format", G_TYPE_STRING, "NV12",
NULL);
#endif
app->tee = gst_element_factory_make("tee", "mytee");
app->convert = gst_element_factory_make("videoconvert", "myconvert");
app->queue = gst_element_factory_make("queue2", "myqueue");
app->videosink = gst_element_factory_make(VIDEOSINK, "myvsink");
app->appqueue = gst_element_factory_make("queue2", "myappqueue");
app->appconvert = gst_element_factory_make("videoconvert", "myappvconvert");
app->appcaps = gst_caps_new_simple("video/x-raw",
"width", G_TYPE_INT, VIDEO_WIDTH,
"height", G_TYPE_INT, VIDEO_HEIGHT,
"framerate", GST_TYPE_FRACTION, 30, 1,
"format", G_TYPE_STRING, "RGB",
NULL);
app->appsink = gst_element_factory_make("appsink", "myappsink");
g_assert(app->src);
g_assert(app->tee);
g_assert(app->srcconvert);
g_assert(app->queue);
g_assert(app->convert);
g_assert(app->videosink);
g_assert(app->appqueue);
g_assert(app->appconvert);
g_assert(app->appsink);
g_object_set(app->appsink, "emit-signals", false, "drop", true, "max-buffers", 1, "buffer-list", false, NULL);
g_object_set(app->appqueue, "max-size-time", 500, NULL);
gst_app_sink_set_emit_signals(GST_APP_SINK_CAST(app->appsink), true);
gst_bin_add_many(GST_BIN(app->pipeline), (GstElement*)app->src,
app->srcconvert, app->tee, app->queue, app->convert, app->videosink, app->appqueue, app->appconvert, app->appsink, NULL);
if(!gst_element_link_filtered((GstElement*)app->src, app->srcconvert, app->caps)){
g_warning("failed to link src and convert");
}
/*if(!gst_element_link((GstElement*)app->src, app->srcconvert)){
g_warning("failed to link src and convert");
}*/
if(!gst_element_link(app->srcconvert, app->tee)){
g_warning("failed to link convert and tee");
}
if(!gst_element_link(app->tee, app->queue)){
g_warning("failed to link tee and queue");
}
if(!gst_element_link(app->queue, app->convert)){
g_warning("failed to link queue and convert");
}
if(!gst_element_link(app->convert, app->videosink)){
g_warning("failed to link convert and videosink");
}
if(!gst_element_link(app->tee, app->appqueue)){
g_warning("failed to link tee and appqueue");
}
if(!gst_element_link(app->appqueue, app->appsink)){
g_warning("failed to link appconvert and appsink");
}
state_ret = gst_element_set_state((GstElement*)app->pipeline, GST_STATE_PLAYING);
g_warning("set state returned %d\n", state_ret);
app->loop = g_main_loop_new(NULL, FALSE);
if(gst_app_sink_pull_sample(GST_APP_SINK_CAST(app->appsink)) == NULL){
g_warning("app sink sample is null");
}
if(gst_app_sink_get_emit_signals(GST_APP_SINK_CAST(app->appsink))){
g_warning("app sink signal true");
}
if(!gst_app_sink_get_drop(GST_APP_SINK_CAST(app->appsink))){
g_warning("app sink drop is false");
}
g_idle_add(func, app);
}
void terminal_gst_element(){
state_ret = gst_element_set_state((GstElement*)app->pipeline, GST_STATE_NULL);
g_warning("set state null returned %d\n", state_ret);
}
主程序：
/*
I don't know if it is syntax highlighter or blogger, but I can't seem to
put angle brackets around header file names properly.
*/
#include <stdio.h>
#include <stdint.h>
#include <fstream>
#include <X11/Xlib.h>
#include "defines.h"
#include "src/gstcode.h"
#define BUFF_SIZE (1024)
#ifndef VIDEO_WIDTH
#define VIDEO_WIDTH 640
#define VIDEO_HEIGHT 480
#endif
int main(int argc, char *argv[])
{
XInitThreads();
init_gst_elements(argc, argv);
g_main_loop_run(app->loop);
terminal_gst_element();
return 0;
}