畢設系列之Libx264實時視訊流(YUV 420P轉H264視訊編碼篇)
阿新 • • 發佈:2019-02-18
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#PS:這個只是 《 我自己 》理解,如果和你的
#原則相沖突,請諒解,勿噴
1、現在網上關於H264的文章有很多,但是我個人認為最好的就是雷霄驊博士的x264部分的文章最詳細。所以許多的細節部分,我推薦大家去雷博士的blog去看。本文只提及我們使用Libx264時候,我們要注意的問題。
2、 使用Libx264時候,我們需要關注的東西(下面用我的程式碼來說明假如我們要使用Libx264,那麼我們需要注意的幾個事情)。
//encoder
x264_t * pX264Handle;//結構體是一個編碼器例項控制代碼,要使用這個編碼庫,我們必須有一個這種變數,沒有為啥。
//param
x264_param_t * pX264Param;//這個結構體就比較重要了,他是我們設定編碼器引數的載體,我們必須具體的瞭解各種引數的意義。具體引數在下一節進行分析。
//input,output pic
x264_picture_t *pPic_In;//這就是YUV輸入影象和輸出影象的載體,這裡面有一個pts引數需要注意,下面小節進行說明。
x264_picture_t *pPic_Out;
//output h264 stream
x264_nal_t * pNals;//這個也是比較重要的一個東西,他的作用是用來儲存編碼後,網路抽象層所儲存的資料(NAL HEADER,NAL BODY),想具體瞭解,可以去看H264編碼原理。
//user config callback
//UESER_CONF_CALLBACK yX264_UserConfig;
int (*yX264_UserConfig)(struct ymx264 * mvl);//私有,忽略
//pi_nal is the number of NAL units
int pi_nal;//網路抽象單元個數
3、 編碼器引數分析
//* cpuFlags
mvl->pX264Param->i_threads = X264_SYNC_LOOKAHEAD_AUTO;//* 取空緩衝區繼續使用不死鎖的保證.
//* 視訊選項
mvl->pX264Param->i_width = FRAME_WIDTH; //* 要編碼的影象寬度.
mvl->pX264Param->i_height = FRAME_HEIGHT; //* 要編碼的影象高度
mvl->pX264Param->i_frame_total = 0; //* 編碼總幀數.不知道用0.
/* Force an IDR keyframe at this interval */
mvl->pX264Param->i_keyint_max = 10; //這個引數很重要,控制i幀的頻率
mvl->pX264Param->b_repeat_headers = 1; // 重複SPS/PPS 放到關鍵幀前面//做實時流播放,此引數必須ENABLE
//* 流引數
//* how many b-frame between 2 references pictures */
mvl->pX264Param->i_bframe = 5;
//
mvl->pX264Param->b_open_gop = 0;
//* Keep some B-frames as references: 0=off, 1=strict hierarchical, 2=normal */
mvl->pX264Param->i_bframe_pyramid = 0;
//
mvl->pX264Param->i_bframe_adaptive = X264_B_ADAPT_TRELLIS;
//* Log引數,不需要列印編碼資訊時直接註釋掉就行
//mvl->pX264Param->i_log_level = X264_LOG_DEBUG;
//* 速率控制引數
//pX264Param->rc.i_bitrate = 1024 * 10;//* 位元速率(位元率,單位Kbps) ,重要
//* muxing parameters 幀率控制,重要。
mvl->pX264Param->i_fps_den = 1; //* 幀率分母
mvl->pX264Param->i_fps_num = Y_STREAM_FPS;//* 幀率分子
mvl->pX264Param->i_timebase_den = mvl->pX264Param->i_fps_num;
mvl->pX264Param->i_timebase_num = mvl->pX264Param->i_fps_den;
最後,我們需要注意一點:關於我們設定的幀率的問題,不一定是設定多少,播放的時候就是多少,只是一個參考值,編碼器會盡量的把視訊編碼為這個幀率。
4、x264_picture_t * pPic_In->i_pts += 1; 此引數非常重要。如果不進行設定,視訊流將不會正常播放。
/*
PTS:Presentation Time Stamp。PTS主要用於度量解碼後的視訊幀什麼時候被顯示出來
DTS:Decode Time Stamp。DTS主要是標識讀入記憶體中的bit流在什麼時候開始送入解碼器中進行解碼。
*/
5、關於顏色空間的問題,大家可以去百度YUV 420 ,YUV 422,YUV 444等這些原始影象的儲存問題。具體來說,他們分為兩類,一種是分組儲存(例如:YYY*UUU*VVV*),一種是交叉儲存(例如:YUYV)
6、此模組我的原始碼
ym_x264.h
/*
FileName:ym_x264.h
Version:1.0
Description:
Created On: 2017-3-19
Modified date:
Author:Sky
*/
#ifndef _YM_X264_H
#define _YM_X264_H
#ifdef __cplusplus
#if __cplusplus
extern "C"{
#endif
#endif /* __cplusplus */
#include <stdint.h>
#include <stdio.h>
#include <ym_x264_config.h>
#include <x264.h>
#include <stdlib.h>
#define CLEAR_MEM(x) memset(&(x),0,sizeof(x))
enum yX264Cmd{
DO_DEFAULT_PRESET = 0,
DO_DEFAULT_USERCONF = 1,
DO_PARAM_APPLY_PROFILE = 2,
OPEN_ENCODER = 3,
ENCODER_ENCODE = 4,
};
enum yX264ColorSpace{
Y_CSP_I444 = 0,
Y_CSP_I422 = 1,
Y_CSP_I420 = 2,
Y_CSP_YUYV = 3,
};
//typedef struct ymx264 yMX264;
typedef struct ymx264{
//encoder
x264_t * pX264Handle;
//param
x264_param_t * pX264Param;
//input,output pic
x264_picture_t *pPic_In;
x264_picture_t *pPic_Out;
//output h264 stream
x264_nal_t * pNals;
//user config callback
//UESER_CONF_CALLBACK yX264_UserConfig;
int (*yX264_UserConfig)(struct ymx264 * mvl);
//pi_nal is the number of NAL units
int pi_nal;
long cur_pts;
}yMX264;
typedef int (*UESER_CONF_CALLBACK)(yMX264 * mvl);
int yInitMX264(yMX264 * mvl);
int yDestroyMX264(yMX264 * mvl);
int yIoctlX264(enum yX264Cmd cmd,...);
//CSC = ColorSpaceCovert,FIP = Fill In_Pic
int yDoCSC_And_FIP(yMX264 * mvl,enum yX264ColorSpace t_csp, int cache_id);
int yDo_Default_UserConf(yMX264 * mvl);
#ifdef __cplusplus
#if __cplusplus
}
#endif
#endif /* __cplusplus */
#endif
ym_x264.c
/*
FileName:ym_x264.c
Version:1.0
Description:
Created On: 2017-3-19
Modified date:
Author:Sky
*/
/*
x264_param_default():設定引數集結構體x264_param_t的預設值。
x264_picture_alloc():為影象結構體x264_picture_t分配記憶體。
x264_encoder_open():開啟編碼器。
x264_encoder_encode():編碼一幀影象。
x264_encoder_close():關閉編碼器。
x264_picture_clean():釋放x264_picture_alloc()申請的資源。
儲存資料的結構體如下所示。
x264_picture_t:儲存壓縮編碼前的畫素資料。
x264_nal_t:儲存壓縮編碼後的碼流資料。
*/
#include <ym_x264.h>
uint8_t ImgCache[ImageCacheNum][FRAME_SIZE];
int yInitMX264(yMX264 * mvl){
mvl->pX264Param = (x264_param_t *)malloc(sizeof(x264_param_t));
// for (int i = 0; i < ImageCacheNum; i++){
mvl->pPic_In = (x264_picture_t *)malloc(sizeof(x264_picture_t));
mvl->pPic_Out = (x264_picture_t *)malloc(sizeof(x264_picture_t));
mvl->pNals = NULL;
mvl->pi_nal = 0;
x264_picture_init(mvl->pPic_Out);
x264_picture_alloc(mvl->pPic_In, FRAME_COLORSPACE, FRAME_WIDTH, FRAME_HEIGHT);
// PTS FROM 0,AND AUTO INCRESE 1
mvl->pPic_In->i_pts = 0;
// }
mvl->cur_pts = 0;
return 0;
}
int yDestroyMX264(yMX264 * mvl){
// 清除影象區域
//for (int i = 0; i < ImageCacheNum; i++)
x264_picture_clean(mvl->pPic_In);
x264_encoder_close(mvl->pX264Handle);
free(mvl->pX264Param);
//for (int i = 0; i < ImageCacheNum; i++){
free(mvl->pPic_In);
free(mvl->pPic_Out);
//}
return 0;
}
int yIoctlX264(enum yX264Cmd cmd,...){
va_list arg;
va_start(arg,cmd);
yMX264 *mx264;
mx264 = va_arg(arg,yMX264 *);
va_end(arg);
switch(cmd){
case DO_DEFAULT_PRESET:
{
/* Get default params for preset/tuning */
//x264_param_default(pParam); //this do default set for x264,but can not config some info
if( x264_param_default_preset( mx264->pX264Param, "veryfast", "zerolatency" ) < 0 ){
printf("x264_param_default_preset failed!\n");
return -1;
}
break;
}
case DO_DEFAULT_USERCONF:
{
//va_list arg;
//va_start(arg,cmd);
//mx264->yX264_UserConfig = va_arg(arg,UESER_CONF_CALLBACK);
//mx264->yX264_UserConfig = NULL;
//va_end(arg);
if ( (*mx264->yX264_UserConfig)(mx264) < 0){
printf("Do user conf callback failed.\n");
return -1;
}
break;
}
case DO_PARAM_APPLY_PROFILE:
{
//x264_profile_names[0] = baseline , to set stream-quality
if (x264_param_apply_profile(mx264->pX264Param, x264_profile_names[0]) < 0 ){
printf("x264_param_apply_profile failed.\n");
return -1;
}
break;
}
case OPEN_ENCODER:
{
//open encoder
if( (mx264->pX264Handle = x264_encoder_open(mx264->pX264Param)) == NULL){
printf("x264_encoder_open failed.\n");
return -1;
}
break;
}
case ENCODER_ENCODE:
{
/*
x264_encoder_encode:
* encode one picture.
* *pi_nal is the number of NAL units outputted in pp_nal.
* returns the number of bytes in the returned NALs.
* returns negative on error and zero if no NAL units returned.
* the payloads of all output NALs are guaranteed to be sequential in memory.
int x264_encoder_encode( x264_t *, x264_nal_t **pp_nal, int *pi_nal, x264_picture_t *pic_in, x264_picture_t *pic_out );
*/
if ( x264_encoder_encode(mx264->pX264Handle, &mx264->pNals, &mx264->pi_nal, mx264->pPic_In, mx264->pPic_Out) < 0){
printf("x264_encoder_encode failed.\n");
return -1;
}
/*
PTS:Presentation Time Stamp。PTS主要用於度量解碼後的視訊幀什麼時候被顯示出來
DTS:Decode Time Stamp。DTS主要是標識讀入記憶體中的bit流在什麼時候開始送入解碼器中進行解碼。
*/
//Presentation Time Stamp。PTS主要用於度量解碼後的視訊幀什麼時候被顯示出來
//MUST DO THIS ,IT DECIDE ,主要用於度量解碼後的視訊幀什麼時候被顯示出來
//mx264->pPic_In->i_pts += 1;
mx264->pPic_In->i_pts += 1;
printf("pts = %d\n",mx264->pPic_In->i_pts);
break;
}
default :
{
printf("No this cmd to analyse\n");
return -1;
break;
}
}
return 0;
}
int yDoCSC_And_FIP(yMX264 * mvl,enum yX264ColorSpace t_csp, int cache_id){
switch(t_csp){
case Y_CSP_I444:
{
/*
read(fd_in,pPic_In->img.plane[0],FRAME_SIZE); //Y
read(fd_in,pPic_In->img.plane[1],FRAME_SIZE); //U
read(fd_in,pPic_In->img.plane[2],FRAME_SIZE); //V
*/
break;
}
case Y_CSP_I420:
{
/*
#ifndef ENABLE_YUYVTOI420
read(fd_in,pPic_In->img.plane[0],FRAME_SIZE); //Y
read(fd_in,pPic_In->img.plane[1],FRAME_SIZE/4); //U
read(fd_in,pPic_In->img.plane[2],FRAME_SIZE/4); //V
#else
//YUYV to I420
read(fd_in,Cache,FRAME_SIZE*2); //read one frame to cache
//must set to 0
int id_u = 0, id_v = 0 , id_y = 0;
for (int i = 0; i < FRAME_SIZE*2 ;i+=4){
pPic_In->img.plane[0][id_y] = Cache[i];//get Y
id_y++;
pPic_In->img.plane[0][id_y] = Cache[i+2];//get Y
id_y++;
if ( ((int)((i)/1280)%2) == 0 ){
pPic_In->img.plane[1][id_u] = Cache[i+1];//get U
pPic_In->img.plane[2][id_v] = Cache[i+3];//get V
id_u++;
id_v++;
}
}
#endif
*/
break;
}
case Y_CSP_YUYV:{
// firstly,Do YUYV to I420 ,then, Fill in_pic
int id_u = 0, id_v = 0 , id_y = 0;
for (int i = 0; i < FRAME_SIZE ;i+=4){
mvl->pPic_In->img.plane[0][id_y] = ImgCache[cache_id][i];//get Y
id_y++;
mvl->pPic_In->img.plane[0][id_y] = ImgCache[cache_id][i+2];//get Y
id_y++;
if ( ((int)((i)/1280)%2) == 0 ){
mvl->pPic_In->img.plane[1][id_u] = ImgCache[cache_id][i+1];//get U
mvl->pPic_In->img.plane[2][id_v] = ImgCache[cache_id][i+3];//get V
id_u++;
id_v++;
}
}
break;
}
case Y_CSP_I422:
{
/*
read(fd_in,pPic_In->img.plane[0],FRAME_SIZE); //Y
read(fd_in,pPic_In->img.plane[1],FRAME_SIZE/2); //U
read(fd_in,pPic_In->img.plane[2],FRAME_SIZE/2); //V
*/
break;
}
default:
{
printf("Colorspace Not Support.\n");
return -1;
}
}
}
int yDo_Default_UserConf(yMX264 * mvl){
//* cpuFlags
mvl->pX264Param->i_threads = X264_SYNC_LOOKAHEAD_AUTO;//* 取空緩衝區繼續使用不死鎖的保證.
//* 視訊選項
mvl->pX264Param->i_width = FRAME_WIDTH; //* 要編碼的影象寬度.
mvl->pX264Param->i_height = FRAME_HEIGHT; //* 要編碼的影象高度
mvl->pX264Param->i_frame_total = 0; //* 編碼總幀數.不知道用0.
/* Force an IDR keyframe at this interval */
mvl->pX264Param->i_keyint_max = 10;
mvl->pX264Param->b_repeat_headers = 1; // 重複SPS/PPS 放到關鍵幀前面
//* 流引數
//* how many b-frame between 2 references pictures */
mvl->pX264Param->i_bframe = 5;
//
mvl->pX264Param->b_open_gop = 0;
//* Keep some B-frames as references: 0=off, 1=strict hierarchical, 2=normal */
mvl->pX264Param->i_bframe_pyramid = 0;
//
mvl->pX264Param->i_bframe_adaptive = X264_B_ADAPT_TRELLIS;
//* Log引數,不需要列印編碼資訊時直接註釋掉就行
//mvl->pX264Param->i_log_level = X264_LOG_DEBUG;
//* 速率控制引數
//pX264Param->rc.i_bitrate = 1024 * 10;//* 位元速率(位元率,單位Kbps)
//* muxing parameters
mvl->pX264Param->i_fps_den = 1; //* 幀率分母
mvl->pX264Param->i_fps_num = Y_STREAM_FPS;//* 幀率分子
mvl->pX264Param->i_timebase_den = mvl->pX264Param->i_fps_num;
mvl->pX264Param->i_timebase_num = mvl->pX264Param->i_fps_den;
return 0;
}
#PS:請尊重原創,不喜勿噴
#PS:要轉載請註明出處,本人版權所有.
有問題請留言,看到後我會第一時間回覆