x264庫的編譯可以見之前部落格：http://blog.csdn.net/li_wen01/article/details/53571929

在PC上編譯X264,可以直接執行下面三條命令：

./configure --enable-shared
make
make install

/*=============================================================================
#     FileName: h264encoder.c
#         Desc: this program aim to get image from USB camera,
#               used the V4L2 interface.
#       Author: licaibiao
#      Version: 
#   LastChange: 2017-02-21 
=============================================================================*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "./include/h264encoder.h"
 
int WIDTH = 640;
int HEIGHT = 480;
 
void compress_begin(Encoder *en, int width, int height) {
	en->param = (x264_param_t *) malloc(sizeof(x264_param_t));
	en->picture = (x264_picture_t *) malloc(sizeof(x264_picture_t));
	x264_param_default(en->param); //set default param
	//en->param->rc.i_rc_method = X264_RC_CQP;
	// en->param->i_log_level = X264_LOG_NONE;
 
	en->param->i_threads  = X264_SYNC_LOOKAHEAD_AUTO;
	en->param->i_width = width; //set frame width
	en->param->i_height = height; //set frame height
	WIDTH = width;
	HEIGHT = height;
 
	//en->param->i_frame_total = 0;
 
	//en->param->i_keyint_max = 10;
	en->param->rc.i_lookahead = 0; 
	//en->param->i_bframe = 5; 
 
	//en->param->b_open_gop = 0;
	//en->param->i_bframe_pyramid = 0;
	//en->param->i_bframe_adaptive = X264_B_ADAPT_TRELLIS;
 
	//en->param->rc.i_bitrate = 1024 * 10;//rate 10 kbps
	en->param->i_fps_num = 30; 
	en->param->i_fps_den = 1;
	en->param->i_csp = X264_CSP_I422;
 
	x264_param_apply_profile(en->param, x264_profile_names[4]); 
 
	if ((en->handle = x264_encoder_open(en->param)) == 0) {
		return;
	}
	/* Create a new pic */
	x264_picture_alloc(en->picture, X264_CSP_I422, en->param->i_width,
			en->param->i_height);
}
 
int compress_frame(Encoder *en, int type, uint8_t *in, uint8_t *out) {
	x264_picture_t pic_out;
	int index_y, index_u, index_v;
	int num;
	int nNal = -1;
	int result = 0;
	int i = 0;
	static long int pts = 0;
	uint8_t *p_out = out;
	char *y = en->picture->img.plane[0];   
	char *u = en->picture->img.plane[1];   
	char *v = en->picture->img.plane[2];   
	char * ptr;
 
	index_y = 0;
        index_u = 0;
        index_v = 0;
 
        num = WIDTH * HEIGHT * 2 - 4  ;
 
        for(i=0; i<num; i=i+4)
        {
                *(y + (index_y++)) = *(in + i);
                *(u + (index_u++)) = *(in + i + 1);
                *(y + (index_y++)) = *(in + i + 2);
                *(v + (index_v++)) = *(in + i + 3);
        }
 
	switch (type) {
	case 0:
		en->picture->i_type = X264_TYPE_P;
		break;
	case 1:
		en->picture->i_type = X264_TYPE_IDR;
		break;
	case 2:
		en->picture->i_type = X264_TYPE_I;
		break;
	default:
		en->picture->i_type = X264_TYPE_AUTO;
		break;
	}
 
	en->picture->i_pts = pts++;
 
	if (x264_encoder_encode(en->handle, &(en->nal), &nNal, en->picture,
			&pic_out) < 0) {
		return -1;
	}
 
	for (i = 0; i < nNal; i++) {
		memcpy(p_out, en->nal[i].p_payload, en->nal[i].i_payload);   
		p_out += en->nal[i].i_payload;								 
		result += en->nal[i].i_payload;
	}
 
	return result;
}
 
void compress_end(Encoder *en) {
	if (en->handle) {
		x264_encoder_close(en->handle);
	}
	if (en->picture) {
		x264_picture_clean(en->picture);
		free(en->picture);
		en->picture = 0;
	}
	if (en->param) {
		free(en->param);
		en->param = 0;
	}
}
 

en->param->i_csp = X264_CSP_I422;

在X264中預設的i_csp值是3，也就是X264_CSP_NV12 的值，如果採用YUYV(422)輸入格式，這個值一定需要重新設定，不然會出現錯誤提示：x264 [error]: Invalid input colorspace 。這是因為在x264核心中他會把輸入格式裝換為下面三種中的一種:X264_CSP_NV12,X264_CSP_NV16,X264_CSP_I444.轉換如下：
 

static int x264_frame_internal_csp( int external_csp )
{
    switch( external_csp & X264_CSP_MASK )
    {
        case X264_CSP_NV12:
        case X264_CSP_NV21:
        case X264_CSP_I420:
        case X264_CSP_YV12:
            return X264_CSP_NV12;
        case X264_CSP_NV16:
        case X264_CSP_I422:
        case X264_CSP_YV16:
        case X264_CSP_V210:
            return X264_CSP_NV16;
        case X264_CSP_I444:
        case X264_CSP_YV24:
        case X264_CSP_BGR:
        case X264_CSP_BGRA:
        case X264_CSP_RGB:
            return X264_CSP_I444;
        default:
            return X264_CSP_NONE;
    }
}
 

（2）profile型別設定
x264_param_apply_profile(en->param, x264_profile_names[4]); 
在YUV422中，它不支援baseline，預設設定會提示：x264 [error]: baseline profile doesn't support 4:2:2 可以設定下面的其他引數：
x264_profile_names[] = { "baseline", "main", "high", "high10", "high422", "high444", 0 };

（3）圖片記憶體分配

x264_picture_alloc(en->picture, X264_CSP_I422, en->param->i_width,
            en->param->i_height);
這裡的第二個引數一定要與你的輸入格式先對應，不然的話會出現記憶體溢位的錯誤。因為預設的分配圖片記憶體大小是YUV420的。以640*480 解析度來舉例，YUV420 分配一幀影象的記憶體是450K,而我們YUV422的資料量是600K。

（4）Y,U,V 資料需要分離
for(i=0; i<num; i=i+4)
        {
                *(y + (index_y++)) = *(in + i);
                *(u + (index_u++)) = *(in + i + 1);
                *(y + (index_y++)) = *(in + i + 2);
                *(v + (index_v++)) = *(in + i + 3);
        }
    YUYV的資料是交錯儲存的，因此需要把他們分離出來單獨儲存，如果這裡不做處理，影象就會出現異常。

（5）i_pts 引數需要遞增

en->picture->i_pts = pts++;
    i_pts = pts的引數是需要遞增的，不讓回出現警告：x264 [warning]: non-strictly-monotonic PTS