标签：des class blog http tar ext
这里实现一个简单的多媒体数据流的处理库，它是以Filter的思想来实现的，通过Filter可以实现多路数据采集，处理和输出;
一. 如何实现一个filter
1.定义一个Filter descripter 结构，它包含了Filter的主要属性和行为；
typedef struct McFilterDesc{
McFilterId id;
const char* name;
const char* text;
McFilterCategory category;
const char* encFormat;
int ninputs;
int noutputs;
McFilterFunc init;
McFilterFunc preprocess;
McFilterFunc process;
McFilterFunc postProcess;
McFilterFunc uninit;
McFilterMethod* methods;
}UC_McFilterDesc;
2. 定义Filter结构体
struct McFilter{
UC_McFilterDesc* desc;
pthread_mutex_t lock;
struct McQueue **inputs;
struct McQueue **outputs;
McFilterNotifyFunc notify;
void* notifyUd;
void* data;
struct McTicker* ticker;
uint32_t lastTick;
bool seen;
};
3. 根据Filter descripter 创建Filter 实例
UC_McFilter* mc_filter_new_from_desc(UC_McFilterDesc* desc){
UC_McFilter* filter;
filter = (UC_McFilter*)malloc(sizeof(UC_McFilter));
pthread_mutex_init(&filter->lock, NULL);
filter->desc = desc;
if(desc->ninputs > 0) filter->inputs = (UC_McQueue**)malloc(sizeof(UC_McQueue*) * desc->ninputs);
if(desc->noutputs > 0) filter->outputs = (UC_McQueue**)malloc(sizeof(UC_McQueue*) * desc->noutputs);
if(desc->init != NULL)
desc->init(filter);
return filter;
}
二. 将创建的Filter 链接起来
UC_McQueue* mc_queue_new(UC_McFilter* filter1, int pin1, UC_McFilter* filter2, int pin2){
UC_McQueue* queue = (UC_McQueue*)malloc(sizeof(UC_McQueue));
uc_queue_init(&queue->q);
queue->prev.filter = filter1;
queue->prev.pin = pin1;
queue->next.filter = filter2;
queue->next.pin = pin2;
return queue;
}
int mc_filter_link(UC_McFilter* filter1, int pin1, UC_McFilter* filter2, int pin2){
UC_McQueue* queue;
queue = mc_queue_new(filter1, pin1, filter2, pin2);
filter1->outputs[pin1] = queue;
filter2->inputs[pin2] = queue;
return 0;
}
三. 将Filter链表加入运行表中
1. 创建Ticker结构，并启动运行线程
struct McTicker{
pthread_mutex_t lock;
pthread_cond_t cond;
pthread_t thread;
UC_McList* execList;
int interval;
int execId;
uint32_t ticks;
uint64_t time;
bool run;
};
typedef struct McTicker UC_McTicker;
static void ticker_start(UC_McTicker* ticker){
ticker->run = TRUE;
pthread_create(&ticker->thread, NULL, ticker_run, ticker);
}
static void ticker_init(UC_McTicker* ticker){
pthread_mutex_init(&ticker->lock, NULL);
pthread_cond_init(&ticker->cond, NULL);
ticker->execList = NULL;
ticker->ticks = 1;
ticker->time = 0;
ticker->interval = 10;
ticker->run = FALSE;
ticker->execId = 0;
ticker_start(ticker);
}
2. 将source filter 加入到Ticker的execList中
int mc_ticker_attach(UC_McTicker* ticker, UC_McFilter* filter){
UC_McList* sources = NULL;
UC_McList* filters = NULL;
UC_McList* iter;
if(filter->ticker != NULL){
printf("Filter %s had beeb scheded\n", filter->desc->name);
return 0;
}
printf("%s is invoked\n", __FUNCTION__);
ticker_find_filters(&filters, filter);
sources = ticker_get_sources(filters);
//printf("%s is invoked 2\n", __FUNCTION__);
if(sources == NULL){
mc_list_free(filters);
return -1;
}
//printf("%s is invoked 3\n", __FUNCTION__);
for(iter = filters; iter != NULL; iter = iter->next){
mc_filter_preprocess((UC_McFilter*)iter->data, ticker);
}
//printf("%s is invoked 4\n", __FUNCTION__);
pthread_mutex_lock(&ticker->lock);
ticker->execList = mc_list_concat(ticker->execList, sources);
pthread_mutex_unlock(&ticker->lock);
mc_list_free(filters);
printf("%s is invoked exit\n", __FUNCTION__);
return 0;
}
3. 运行流程图
标签：des class blog http tar ext
原文地址：http://www.cnblogs.com/xw022/p/3791063.html
