I am having issues encoding screen captures, into a h.264 file for viewing. The program below is cobbled together from examples here and here. The first example, uses an older version of the ffmpeg api. So I tried to update that example for use in my program. The file is created and has something written to it, but when I view the file. The encoded images are all distorted. I am able to run the video encoding example from the ffmpeg api successfully. This is my first time posting, so if I missed anything please let me know.
I appreciate any assistance that is given.
My program:
#include <Windows.h>
#include <string>
#include <sstream>
#include <time.h>
#include <iostream>
#include <dwmapi.h>
extern "C"{
#include <stdint.h>
#include <libavcodec/avcodec.h>
#include <libavutil/imgutils.h>
#include <libswscale/swscale.h>
#include <libavutil/opt.h>
}
using namespace std;
void ScreenShot(const char* BmpName, uint8_t *frame)
{
HWND DesktopHwnd = GetDesktopWindow();
RECT DesktopParams;
HDC DevC = GetDC(DesktopHwnd);
GetWindowRect(DesktopHwnd,&DesktopParams);
DWORD Width = DesktopParams.right - DesktopParams.left;
DWORD Height = DesktopParams.bottom - DesktopParams.top;
DWORD FileSize = sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)+(sizeof(RGBTRIPLE)+1*(Width*Height*4));
char *BmpFileData = (char*)GlobalAlloc(0x0040,FileSize);
PBITMAPFILEHEADER BFileHeader = (PBITMAPFILEHEADER)BmpFileData;
PBITMAPINFOHEADER BInfoHeader = (PBITMAPINFOHEADER)&BmpFileData[sizeof(BITMAPFILEHEADER)];
BFileHeader->bfType = 0x4D42; // BM
BFileHeader->bfSize = sizeof(BITMAPFILEHEADER);
BFileHeader->bfOffBits = sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER);
BInfoHeader->biSize = sizeof(BITMAPINFOHEADER);
BInfoHeader->biPlanes = 1;
BInfoHeader->biBitCount = 32;
BInfoHeader->biCompression = BI_RGB;
BInfoHeader->biHeight = Height;
BInfoHeader->biWidth = Width;
RGBTRIPLE *Image = (RGBTRIPLE*)&BmpFileData[sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)];
RGBTRIPLE color;
//pPixels = (RGBQUAD **)new RGBQUAD[sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER)];
int start = clock();
HDC CaptureDC = CreateCompatibleDC(DevC);
HBITMAP CaptureBitmap = CreateCompatibleBitmap(DevC,Width,Height);
SelectObject(CaptureDC,CaptureBitmap);
BitBlt(CaptureDC,0,0,Width,Height,DevC,0,0,SRCCOPY|CAPTUREBLT);
GetDIBits(CaptureDC,CaptureBitmap,0,Height,frame,(LPBITMAPINFO)BInfoHeader, DIB_RGB_COLORS);
int end = clock();
cout << "it took " << end - start << " to capture a frame" << endl;
DWORD Junk;
HANDLE FH = CreateFileA(BmpName,GENERIC_WRITE,FILE_SHARE_WRITE,0,CREATE_ALWAYS,0,0);
WriteFile(FH,BmpFileData,FileSize,&Junk,0);
CloseHandle(FH);
GlobalFree(BmpFileData);
}
void video_encode_example(const char *filename, int codec_id)
{
AVCodec *codec;
AVCodecContext *c= NULL;
int i, ret, x, y, got_output;
FILE *f;
AVFrame *frame;
AVPacket pkt;
uint8_t endcode[] = { 0, 0, 1, 0xb7 };
printf("Encode video file %s\n", filename);
/* find the mpeg1 video encoder */
codec = avcodec_find_encoder(AV_CODEC_ID_H264);
if (!codec) {
fprintf(stderr, "Codec not found\n");
cin.get();
exit(1);
}
c = avcodec_alloc_context3(codec);
if (!c) {
fprintf(stderr, "Could not allocate video codec context\n");
cin.get();
exit(1);
}
/* put sample parameters */
c->bit_rate = 400000;
/* resolution must be a multiple of two */
c->width = 352;
c->height = 288;
/* frames per second */
c->time_base.num=1;
c->time_base.den = 25;
c->gop_size = 10; /* emit one intra frame every ten frames */
c->max_b_frames=1;
c->pix_fmt = AV_PIX_FMT_YUV420P;
if(codec_id == AV_CODEC_ID_H264)
av_opt_set(c->priv_data, "preset", "slow", 0);
/* open it */
if (avcodec_open2(c, codec, NULL) < 0) {
fprintf(stderr, "Could not open codec\n");
exit(1);
}
f = fopen(filename, "wb");
if (!f) {
fprintf(stderr, "Could not open %s\n", filename);
exit(1);
}
frame = av_frame_alloc();
if (!frame) {
fprintf(stderr, "Could not allocate video frame\n");
exit(1);
}
frame->format = c->pix_fmt;
frame->width = c->width;
frame->height = c->height;
/* the image can be allocated by any means and av_image_alloc() is
just the most convenient way if av_malloc() is to be used */
ret = av_image_alloc(frame->data, frame->linesize, c->width, c->height, c->pix_fmt, 32);
if (ret < 0) {
fprintf(stderr, "Could not allocate raw picture buffer\n");
exit(1);
}
/* encode 1 second of video */
for(i=0;i<250;i++) {
av_init_packet(&pkt);
pkt.data = NULL; // packet data will be allocated by the encoder
pkt.size = 0;
fflush(stdout);
/* prepare a dummy image */
/* Y */
for(y=0;y<c->height;y++) {
for(x=0;x<c->width;x++) {
frame->data[0][y * frame->linesize[0] + x] = x + y + i * 3;
}
}
/* Cb and Cr */
for(y=0;y<c->height/2;y++) {
for(x=0;x<c->width/2;x++) {
frame->data[1][y * frame->linesize[1] + x] = 128 + y + i * 2;
frame->data[2][y * frame->linesize[2] + x] = 64 + x + i * 5;
}
}
frame->pts = i;
/* encode the image */
ret = avcodec_encode_video2(c, &pkt, frame, &got_output);
if (ret < 0) {
fprintf(stderr, "Error encoding frame\n");
exit(1);
}
if (got_output) {
printf("Write frame %3d (size=%5d)\n", i, pkt.size);
fwrite(pkt.data, 1, pkt.size, f);
av_free_packet(&pkt);
}
}
/* get the delayed frames */
for (got_output = 1; got_output; i++) {
fflush(stdout);
ret = avcodec_encode_video2(c, &pkt, NULL, &got_output);
if (ret < 0) {
fprintf(stderr, "Error encoding frame\n");
exit(1);
}
if (got_output) {
printf("Write frame %3d (size=%5d)\n", i, pkt.size);
fwrite(pkt.data, 1, pkt.size, f);
av_free_packet(&pkt);
}
}
/* add sequence end code to have a real mpeg file */
fwrite(endcode, 1, sizeof(endcode), f);
fclose(f);
avcodec_close(c);
av_free(c);
av_freep(&frame->data[0]);
av_frame_free(&frame);
printf("\n");
}
void write_video_frame()
{
}
int lineSizeOfFrame(int width)
{
return (width*24 + 31)/32 * 4;//((width*24 / 8) + 3) & ~3;//(width*24 + 31)/32 * 4;
}
int getScreenshotWithCursor(uint8_t* frame)
{
int successful = 0;
HDC screen, bitmapDC;
HBITMAP screen_bitmap;
screen = GetDC(NULL);
RECT DesktopParams;
HWND desktop = GetDesktopWindow();
GetWindowRect(desktop, &DesktopParams);
int width = DesktopParams.right;
int height = DesktopParams.bottom;
bitmapDC = CreateCompatibleDC(screen);
screen_bitmap = CreateCompatibleBitmap(screen, width, height);
SelectObject(bitmapDC, screen_bitmap);
if (BitBlt(bitmapDC, 0, 0, width, height, screen, 0, 0, SRCCOPY))
{
int pos_x, pos_y;
HICON hcur;
ICONINFO icon_info;
CURSORINFO cursor_info;
cursor_info.cbSize = sizeof(CURSORINFO);
if (GetCursorInfo(&cursor_info))
{
if (cursor_info.flags == CURSOR_SHOWING)
{
hcur = CopyIcon(cursor_info.hCursor);
if (GetIconInfo(hcur, &icon_info))
{
pos_x = cursor_info.ptScreenPos.x - icon_info.xHotspot;
pos_y = cursor_info.ptScreenPos.y - icon_info.yHotspot;
DrawIcon(bitmapDC, pos_x, pos_y, hcur);
if (icon_info.hbmColor) DeleteObject(icon_info.hbmColor);
if (icon_info.hbmMask) DeleteObject(icon_info.hbmMask);
}
}
}
int header_size = sizeof(BITMAPINFOHEADER) + 256*sizeof(RGBQUAD);
size_t line_size = lineSizeOfFrame(width);
PBITMAPINFO lpbi = (PBITMAPINFO) malloc(header_size);
lpbi->bmiHeader.biSize = header_size;
lpbi->bmiHeader.biWidth = width;
lpbi->bmiHeader.biHeight = height;
lpbi->bmiHeader.biPlanes = 1;
lpbi->bmiHeader.biBitCount = 24;
lpbi->bmiHeader.biCompression = BI_RGB;
lpbi->bmiHeader.biSizeImage = height*line_size;
lpbi->bmiHeader.biXPelsPerMeter = 0;
lpbi->bmiHeader.biYPelsPerMeter = 0;
lpbi->bmiHeader.biClrUsed = 0;
lpbi->bmiHeader.biClrImportant = 0;
if (GetDIBits(bitmapDC, screen_bitmap, 0, height, (LPVOID)frame, lpbi, DIB_RGB_COLORS))
{
int i;
uint8_t *buf_begin = frame;
uint8_t *buf_end = frame + line_size*(lpbi->bmiHeader.biHeight - 1);
void *temp = malloc(line_size);
for (i = 0; i < lpbi->bmiHeader.biHeight / 2; ++i)
{
memcpy(temp, buf_begin, line_size);
memcpy(buf_begin, buf_end, line_size);
memcpy(buf_end, temp, line_size);
buf_begin += line_size;
buf_end -= line_size;
}
cout << *buf_begin << endl;
free(temp);
successful = 1;
}
free(lpbi);
}
DeleteObject(screen_bitmap);
DeleteDC(bitmapDC);
ReleaseDC(NULL, screen);
return successful;
}
int main()
{
RECT DesktopParams;
HWND desktop = GetDesktopWindow();
GetWindowRect(desktop, &DesktopParams);
int width = DesktopParams.right;
int height = DesktopParams.bottom;
uint8_t *frame = (uint8_t *)malloc(width * height);
AVCodec *codec;
AVCodecContext *codecContext = NULL;
AVPacket packet;
FILE *f;
AVFrame *pictureYUV = NULL;
AVFrame *pictureRGB;
avcodec_register_all();
codec = avcodec_find_encoder(AV_CODEC_ID_H264);
if(!codec)
{
cout << "codec not found!" << endl;
cin.get();
return 1;
}
else
{
cout << "codec h265 found!" << endl;
}
codecContext = avcodec_alloc_context3(codec);
codecContext->bit_rate = width * height * 4;
codecContext->width = width;
codecContext->height = height;
codecContext->time_base.num = 1;
codecContext->time_base.den = 250;
codecContext->gop_size = 10;
codecContext->max_b_frames = 1;
codecContext->keyint_min = 1;
codecContext->i_quant_factor = (float)0.71; // qscale factor between P and I frames
codecContext->b_frame_strategy = 20; ///// find out exactly what this does
codecContext->qcompress = (float)0.6; ///// find out exactly what this does
codecContext->qmin = 20; // minimum quantizer
codecContext->qmax = 51; // maximum quantizer
codecContext->max_qdiff = 4; // maximum quantizer difference between frames
codecContext->refs = 4; // number of reference frames
codecContext->trellis = 1;
codecContext->pix_fmt = AV_PIX_FMT_YUV420P;
codecContext->codec_id = AV_CODEC_ID_H264;
codecContext->codec_type = AVMEDIA_TYPE_VIDEO;
if(avcodec_open2(codecContext, codec, NULL) < 0)
{
cout << "couldn't open codec" << endl;
cout << stderr << endl;
cin.get();
return 1;
}
else
{
cout << "opened h265 codec!" << endl;
cin.get();
}
f = fopen("test.h264", "wb");
if(!f)
{
cout << "Unable to open file" << endl;
return 1;
}
struct SwsContext *img_convert_ctx = sws_getContext(codecContext->width, codecContext->height, PIX_FMT_RGB32, codecContext->width,
codecContext->height, codecContext->pix_fmt, SWS_BILINEAR, NULL, NULL, NULL);
int got_output = 0, i = 0;
uint8_t encode[] = { 0, 0, 1, 0xb7 };
try
{
for(i = 0; i < codecContext->time_base.den; i++)
{
av_init_packet(&packet);
packet.data = NULL;
packet.size = 0;
pictureRGB = av_frame_alloc();
pictureYUV = av_frame_alloc();
getScreenshotWithCursor(frame);
//ScreenShot("example.bmp", frame);
int nbytes = avpicture_get_size(AV_PIX_FMT_YUV420P, codecContext->width, codecContext->height); // allocating outbuffer
uint8_t* outbuffer = (uint8_t*)av_malloc(nbytes*sizeof(uint8_t));
pictureRGB = av_frame_alloc();
pictureYUV = av_frame_alloc();
avpicture_fill((AVPicture*)pictureRGB, frame, PIX_FMT_RGB32, codecContext->width, codecContext->height); // fill image with input screenshot
avpicture_fill((AVPicture*)pictureYUV, outbuffer, PIX_FMT_YUV420P, codecContext->width, codecContext->height);
av_image_alloc(pictureYUV->data, pictureYUV->linesize, codecContext->width, codecContext->height, codecContext->pix_fmt, 32);
sws_scale(img_convert_ctx, pictureRGB->data, pictureRGB->linesize, 0, codecContext->height, pictureYUV->data, pictureYUV->linesize);
pictureYUV->pts = i;
avcodec_encode_video2(codecContext, &packet, pictureYUV, &got_output);
if(got_output)
{
printf("Write frame %3d (size=%5d)\n", i, packet.size);
fwrite(packet.data, 1, packet.size, f);
av_free_packet(&packet);
}
//av_frame_free(&pictureRGB);
//av_frame_free(&pictureYUV);
}
for(got_output = 1; got_output; i++)
{
fflush(stdout);
avcodec_encode_video2(codecContext, &packet, NULL, &got_output);
if (got_output) {
printf("Write frame %3d (size=%5d)\n", i, packet.size);
fwrite(packet.data, 1, packet.size, f);
av_free_packet(&packet);
}
}
}
catch(std::exception ex)
{
cout << ex.what() << endl;
}
avcodec_close(codecContext);
av_free(codecContext);
av_freep(&pictureYUV->data[0]);
//av_frame_free(&picture);
fwrite(encode, 1, sizeof(encode), f);
fclose(f);
cin.get();
return 0;
}
