在linux下實現用ffmpeg把YUV420幀保存成圖片 2016-09-28 00:00:00 廣州睿豐德信息科技有限公司 閱讀 睿豐德科技 專注RFID識別技術和條碼識別技術與管理軟件的集成項目。質量追溯系統、MES系統、金蝶與條碼系統對接、用友與條碼系統對接 在網上搜了很久相關的問題，但是好像沒有一個在linux下跑得比較完整的例子，不過經過自己一番搜索和總結，終于做出來了，哈哈，看下面的代碼吧。 這個例子可以保存成bmp或者jpeg格式的圖片。 下面的結構是保存bmp圖片是用到的結構： [cpp] view plaincopy //把內存對齊定義為2個字節， //這個可以避免BITMAPFILEHEADER //出現4字節的對齊而使bmp位圖的頭出錯 #pragma pack(2) //下面兩個結構是位圖的結構 typedef struct BITMAPFILEHEADER { u_int16_t bfType; u_int32_t bfSize; u_int16_t bfReserved1; u_int16_t bfReserved2; u_int32_t bfOffBits; }BITMAPFILEHEADER; typedef struct BITMAPINFOHEADER { u_int32_t biSize; u_int32_t biWidth; u_int32_t biHeight; u_int16_t biPlanes; u_int16_t biBitCount; u_int32_t biCompression; u_int32_t biSizeImage; u_int32_t biXPelsPerMeter; u_int32_t biYPelsPerMeter; u_int32_t biClrUsed; u_int32_t biClrImportant; }BITMAPINFODEADER; 下面兩段代碼是把yuv420的數據轉成rgb24的代碼： 下面的是用ffmpeg的庫轉的。 [cpp] view plaincopy //===================把yuv幀數據轉為rgb=========== unsigned char *rgbBuf = new unsigned char[width*height*3]; struct SwsContext* img_convert_ctx = 0; int linesize[4] = {3*width, 0, 0, 0}; img_convert_ctx = sws_getContext(width, height, PIX_FMT_YUV420P, width, height, PIX_FMT_RGB24, SWS_FAST_BILINEAR, 0, 0, 0); if (img_convert_ctx != 0) { sws_scale(img_convert_ctx, pict->data, pict->linesize, 0, height, (uint8_t**)&rgbBuf, linesize); sws_freeContext(img_convert_ctx); saveFrame(rgbBuf, currentFrameNum_/(frameNum_/pictureNum), width, height);//生成圖片 } delete [] rgbBuf; //============================================== 下面給出自己在網上找到的把yuv420轉成rgb24的代碼： [cpp] view plaincopy const int Table_fv1[256]={ -180, -179, -177, -176, -174, -173, -172, -170, -169, -167, -166, -165, -163, -162, -160, -159, -158, -156, -155, -153, -152, -151, -149, -148, -146, -145, -144, -142, -141, -139, -138, -137, -135, -134, -132, -131, -130, -128, -127, -125, -124, -123, -121, -120, -118, -117, -115, -114, -113, -111, -110, -108, -107, -106, -104, -103, -101, -100, -99, -97, -96, -94, -93, -92, -90, -89, -87, -86, -85, -83, -82, -80, -79, -78, -76, -75, -73, -72, -71, -69, -68, -66, -65, -64, -62, -61, -59, -58, -57, -55, -54, -52, -51, -50, -48, -47, -45, -44, -43, -41, -40, -38, -37, -36, -34, -33, -31, -30, -29, -27, -26, -24, -23, -22, -20, -19, -17, -16, -15, -13, -12, -10, -9, -8, -6, -5, -3, -2, 0, 1, 2, 4, 5, 7, 8, 9, 11, 12, 14, 15, 16, 18, 19, 21, 22, 23, 25, 26, 28, 29, 30, 32, 33, 35, 36, 37, 39, 40, 42, 43, 44, 46, 47, 49, 50, 51, 53, 54, 56, 57, 58, 60, 61, 63, 64, 65, 67, 68, 70, 71, 72, 74, 75, 77, 78, 79, 81, 82, 84, 85, 86, 88, 89, 91, 92, 93, 95, 96, 98, 99, 100, 102, 103, 105, 106, 107, 109, 110, 112, 113, 114, 116, 117, 119, 120, 122, 123, 124, 126, 127, 129, 130, 131, 133, 134, 136, 137, 138, 140, 141, 143, 144, 145, 147, 148, 150, 151, 152, 154, 155, 157, 158, 159, 161, 162, 164, 165, 166, 168, 169, 171, 172, 173, 175, 176, 178 }; const int Table_fv2[256]={ -92, -91, -91, -90, -89, -88, -88, -87, -86, -86, -85, -84, -83, -83, -82, -81, -81, -80, -79, -78, -78, -77, -76, -76, -75, -74, -73, -73, -72, -71, -71, -70, -69, -68, -68, -67, -66, -66, -65, -64, -63, -63, -62, -61, -61, -60, -59, -58, -58, -57, -56, -56, -55, -54, -53, -53, -52, -51, -51, -50, -49, -48, -48, -47, -46, -46, -45, -44, -43, -43, -42, -41, -41, -40, -39, -38, -38, -37, -36, -36, -35, -34, -33, -33, -32, -31, -31, -30, -29, -28, -28, -27, -26, -26, -25, -24, -23, -23, -22, -21, -21, -20, -19, -18, -18, -17, -16, -16, -15, -14, -13, -13, -12, -11, -11, -10, -9, -8, -8, -7, -6, -6, -5, -4, -3, -3, -2, -1, 0, 0, 1, 2, 2, 3, 4, 5, 5, 6, 7, 7, 8, 9, 10, 10, 11, 12, 12, 13, 14, 15, 15, 16, 17, 17, 18, 19, 20, 20, 21, 22, 22, 23, 24, 25, 25, 26, 27, 27, 28, 29, 30, 30, 31, 32, 32, 33, 34, 35, 35, 36, 37, 37, 38, 39, 40, 40, 41, 42, 42, 43, 44, 45, 45, 46, 47, 47, 48, 49, 50, 50, 51, 52, 52, 53, 54, 55, 55, 56, 57, 57, 58, 59, 60, 60, 61, 62, 62, 63, 64, 65, 65, 66, 67, 67, 68, 69, 70, 70, 71, 72, 72, 73, 74, 75, 75, 76, 77, 77, 78, 79, 80, 80, 81, 82, 82, 83, 84, 85, 85, 86, 87, 87, 88, 89, 90, 90 }; const int Table_fu1[256]={ -44, -44, -44, -43, -43, -43, -42, -42, -42, -41, -41, -41, -40, -40, -40, -39, -39, -39, -38, -38, -38, -37, -37, -37, -36, -36, -36, -35, -35, -35, -34, -34, -33, -33, -33, -32, -32, -32, -31, -31, -31, -30, -30, -30, -29, -29, -29, -28, -28, -28, -27, -27, -27, -26, -26, -26, -25, -25, -25, -24, -24, -24, -23, -23, -22, -22, -22, -21, -21, -21, -20, -20, -20, -19, -19, -19, -18, -18, -18, -17, -17, -17, -16, -16, -16, -15, -15, -15, -14, -14, -14, -13, -13, -13, -12, -12, -11, -11, -11, -10, -10, -10, -9, -9, -9, -8, -8, -8, -7, -7, -7, -6, -6, -6, -5, -5, -5, -4, -4, -4, -3, -3, -3, -2, -2, -2, -1, -1, 0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 14, 14, 14, 15, 15, 15, 16, 16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 19, 20, 20, 20, 21, 21, 22, 22, 22, 23, 23, 23, 24, 24, 24, 25, 25, 25, 26, 26, 26, 27, 27, 27, 28, 28, 28, 29, 29, 29, 30, 30, 30, 31, 31, 31, 32, 32, 33, 33, 33, 34, 34, 34, 35, 35, 35, 36, 36, 36, 37, 37, 37, 38, 38, 38, 39, 39, 39, 40, 40, 40, 41, 41, 41, 42, 42, 42, 43, 43 }; const int Table_fu2[256]={ -227, -226, -224, -222, -220, -219, -217, -215, -213, -212, -210, -208, -206, -204, -203, -201, -199, -197, -196, -194, -192, -190, -188, -187, -185, -183, -181, -180, -178, -176, -174, -173, -171, -169, -167, -165, -164, -162, -160, -158, -157, -155, -153, -151, -149, -148, -146, -144, -142, -141, -139, -137, -135, -134, -132, -130, -128, -126, -125, -123, -121, -119, -118, -116, -114, -112, -110, -109, -107, -105, -103, -102, -100, -98, -96, -94, -93, -91, -89, -87, -86, -84, -82, -80, -79, -77, -75, -73, -71, -70, -68, -66, -64, -63, -61, -59, -57, -55, -54, -52, -50, -48, -47, -45, -43, -41, -40, -38, -36, -34, -32, -31, -29, -27, -25, -24, -22, -20, -18, -16, -15, -13, -11, -9, -8, -6, -4, -2, 0, 1, 3, 5, 7, 8, 10, 12, 14, 15, 17, 19, 21, 23, 24, 26, 28, 30, 31, 33, 35, 37, 39, 40, 42, 44, 46, 47, 49, 51, 53, 54, 56, 58, 60, 62, 63, 65, 67, 69, 70, 72, 74, 76, 78, 79, 81, 83, 85, 86, 88, 90, 92, 93, 95, 97, 99, 101, 102, 104, 106, 108, 109, 111, 113, 115, 117, 118, 120, 122, 124, 125, 127, 129, 131, 133, 134, 136, 138, 140, 141, 143, 145, 147, 148, 150, 152, 154, 156, 157, 159, 161, 163, 164, 166, 168, 170, 172, 173, 175, 177, 179, 180, 182, 184, 186, 187, 189, 191, 193, 195, 196, 198, 200, 202, 203, 205, 207, 209, 211, 212, 214, 216, 218, 219, 221, 223, 225 }; bool YV12_To_RGB24(const unsigned char* pYV12, unsigned char* &pRGB24, const int& width, const int& height) { if(NULL == pYV12) return false; long buffsize = width * 24 * height; pRGB24 = new unsigned char[buffsize]; if(!pYV12 || !pRGB24) return false; const long nYLen = long(width*height); const int nHfWidth = (width>>1); if(nYLen<1 || nHfWidth<1) return false; // Y data const unsigned char* yData = pYV12; // v data const unsigned char* vData = &yData[nYLen]; // u data const unsigned char* uData = &vData[nYLen>>2]; if(!uData || !vData) return false; int rgb[3]; int i, j, m, n, x, y, py, rdif, invgdif, bdif; m = -width; n = -nHfWidth; bool addhalf = true; for(y=0; y<height;y++) { m += width; if( addhalf ){ n+=nHfWidth; addhalf = false; } else { addhalf = true; } for(x=0; x<width;x++) { i = m + x; j = n + (x>>1); py = yData[i]; // search tables to get rdif invgdif and bidif rdif = Table_fv1[vData[j]]; // fv1 invgdif = Table_fu1[uData[j]] + Table_fv2[vData[j]]; // fu1+fv2 bdif = Table_fu2[uData[j]]; // fu2 rgb[2] = py+rdif; // R rgb[1] = py-invgdif; // G rgb[0] = py+bdif; // B //j = nYLen - width - m + x;//Õâ?ö»áÍŒÏñµßµ¹ j = m + x; i = (j<<1) + j; // copy this pixel to rgb data for(j=0; j<3; j++){ if(rgb[j]>=0 && rgb[j]<=255){ pRGB24[i + j] = rgb[j]; }else{ pRGB24[i + j] = (rgb[j] < 0)? 0 : 255; } } } } return true; } 下面是實際執行生成圖片的代碼，輸入rgb24的數據。注釋了的是生成bmp的代碼，沒注釋的是生成jpeg圖片的代碼。 [cpp] view plaincopy void ipcToFile::saveFrame(uint8_t *pRGBBuffer, int iFrame, int width, int height) { /*BITMAPFILEHEADER bmpheader; BITMAPINFOHEADER bmpinfo; FILE *fp; unsigned int uiTmp, uiTmp2; unsigned char *ucTmp = NULL; unsigned char ucRGB; int i; uiTmp = (width*3+3)/4*4*height; uiTmp2 = width*height*3; char szFilename[1024]; sprintf(szFilename, "test%d.bmp", iFrame);//圖片名字為視頻名+號碼 fp=fopen(szFilename, "wb"); if(fp==NULL) return; //文件標識"BM"（即0x4D42）表示位圖 bmpheader.bfType = 0x4D42; //保留。設置為0 bmpheader.bfReserved1 = 0; //保留。設置為0 bmpheader.bfReserved2 = 0; //從文件開始到位圖數據的偏移量（單位：字節） bmpheader.bfOffBits = sizeof(bmpheader) + sizeof(bmpinfo); //整個文件的大小（單位：字節） bmpheader.bfSize = bmpheader.bfOffBits + uiTmp; //信息頭長度（單位：字節）。典型值為28 bmpinfo.biSize = 0x28; //位圖寬度（單位：像素） bmpinfo.biWidth = width; //位圖高度（單位：像素）。若其為正，表示倒向的位圖。若為負，表示正向的位圖 bmpinfo.biHeight = height; //位圖的面數（為1） bmpinfo.biPlanes = 1; //每個像素的位數 bmpinfo.biBitCount = 24; //壓縮說明。0(BI_RGB)表示不壓縮 bmpinfo.biCompression = 0; //用字節數表示的位圖數據的大小（為4的位數） bmpinfo.biSizeImage = uiTmp; //水平分辨率（單位：像素/米） bmpinfo.biXPelsPerMeter = 0; //垂直分辨率（單位：像素/米） bmpinfo.biYPelsPerMeter = 0; //位圖使用的顏色數 bmpinfo.biClrUsed = 0; //重要的顏色數 bmpinfo.biClrImportant = 0; fwrite(&bmpheader,sizeof(bmpheader),1,fp); fwrite(&bmpinfo,sizeof(bmpinfo),1,fp); //把圖像數據倒置 uint8_t tmp[width*3];//臨時數據 for(int i = 0; i < height/2; i++) { memcpy(tmp, &(pRGBBuffer[width*i*3]), width*3); memcpy(&(pRGBBuffer[width*i*3]), &(pRGBBuffer[width*(height-1-i)*3]), width*3); memcpy(&(pRGBBuffer[width*(height-1-i)*3]), tmp, width*3); } fwrite(pRGBBuffer,width*height*3,1,fp); fclose(fp);*/ struct jpeg_compress_struct jcs; // 聲明錯誤處理器，并賦值給jcs.err域 struct jpeg_error_mgr jem; jcs.err = jpeg_std_error(&jem); jpeg_create_compress(&jcs); char szFilename[1024]; sprintf(szFilename, "test%d.jpg", iFrame);//圖片名字為視頻名+號碼 FILE *fp = fopen(szFilename, "wb"); if(fp == NULL) return; jpeg_stdio_dest(&jcs, fp); jcs.image_width = width; // 為圖的寬和高，單位為像素 jcs.image_height = height; jcs.input_components = 3; // 在此為1,表示灰度圖， 如果是彩色位圖，則為3 jcs.in_color_space = JCS_RGB; //JCS_GRAYSCALE表示灰度圖，JCS_RGB表示彩色圖像 jpeg_set_defaults(&jcs); jpeg_set_quality (&jcs, 80, true); jpeg_start_compress(&jcs, TRUE); JSAMPROW row_pointer[1]; // 一行位圖 int row_stride = jcs.image_width * 3;//每一行的字節數,如果不是索引圖,此處需要乘以3 // 對每一行進行壓縮 while (jcs.next_scanline < jcs.image_height) { row_pointer[0] = &(pRGBBuffer[jcs.next_scanline * row_stride]); jpeg_write_scanlines(&jcs, row_pointer, 1); } jpeg_finish_compress(&jcs); jpeg_destroy_compress(&jcs); fclose(fp); } RFID管理系統集成商 RFID中間件 條碼系統中間層 物聯網軟件集成
