Screen Recorder C++ FFmpeg 4.2 on Windows
Screen Recorder C++ FFmpeg 4.2 on Windows
螢幕錄影並儲存為 .mp4 檔案 (使用 Visual Studio 2019)
一. 編譯器設定
1.專案屬性 -> C\C++ -> 一般 -> 其他 Include 目錄 : D:\Dev\ffmpeg-4.2.2-win32-dev\include
2.專案屬性 -> 連結器 -> 輸入 -> 其他相依性 :在最前面加入 D:\Dev\ffmpeg-4.2.2-win32-dev\lib\*.lib;Winmm.lib
3. 專案屬性 -> 連結器 -> 進階 -> SAFESEH : NO
二.------------------------------------Source.cpp-------------------------------
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <thread>
#include<time.h>
#include <iostream>
using namespace std;
#define __STDC_CONSTANT_MACROS
extern "C" {
#include <libavutil/avassert.h>
#include <libavutil/channel_layout.h>
#include <libavutil/opt.h>
#include <libavutil/mathematics.h>
#include <libavutil/timestamp.h>
#include <libavformat/avformat.h>
#include "libavutil/imgutils.h"
#include <libswscale/swscale.h>
#include <libswresample/swresample.h>
}
#include <Windows.h>
#define STREAM_DURATION 10.0
#define STREAM_FRAME_RATE 25 /* 25 images/s */
#define STREAM_PIX_FMT AV_PIX_FMT_YUV420P /* default pix_fmt */
#define SCALE_FLAGS SWS_BICUBIC
const int NUMPTS = 44100 * 5;
int sampleRate = 44100;
int channels = 2;
int bitPerSample = 16;
int bytePerSample = 4;//channels * bitPerSample / 8
/* Following fileds are set by the program */
int nb_samples;
//short int* waveIn; // BlockAlign * 441
BYTE* waveIn; // BlockAlign * 441
HWAVEIN hWaveIn;
WAVEHDR WaveInHdr;
MMRESULT result;
HWAVEOUT hWaveOut;
WAVEFORMATEX pFormat;
HANDLE hEvent;//event to notify a video/audio frame is generate
HDC hdc;
HDC hDest;
int height;
int width;
HBITMAP hbDesktop;
int endvideo = 0, endaudio = 0;
int encode_video = 0, encode_audio = 0;
BYTE* BGR_buffer;
AVFormatContext* oc;
/*********************/
// a wrapper around a single output AVStream
typedef struct OutputStream {
AVStream* st;
AVCodecContext* enc;
/* pts of the next frame that will be generated */
int64_t next_pts;
int samples_count;
AVFrame* frame;
AVFrame* tmp_frame;
float t, tincr, tincr2;
struct SwsContext* sws_ctx;
struct SwrContext* swr_ctx;
} OutputStream;
OutputStream video_st = { 0 }, audio_st = { 0 };
static void log_packet(const AVFormatContext* fmt_ctx, const AVPacket* pkt)
{
AVRational* time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;
char buf1[AV_TS_MAX_STRING_SIZE] = { 0 };
av_ts_make_string(buf1, pkt->pts);
char buf2[AV_TS_MAX_STRING_SIZE] = { 0 };
av_ts_make_string(buf1, pkt->dts);
char buf3[AV_TS_MAX_STRING_SIZE] = { 0 };
av_ts_make_string(buf1, pkt->duration);
char buffer1[AV_TS_MAX_STRING_SIZE] = { 0 };
av_ts_make_time_string(buffer1, pkt->pts, time_base);
char buffer2[AV_TS_MAX_STRING_SIZE] = { 0 };
av_ts_make_time_string(buffer2, pkt->dts, time_base);
char buffer3[AV_TS_MAX_STRING_SIZE] = { 0 };
av_ts_make_time_string(buffer3, pkt->duration, time_base);
printf("pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
buf1, buffer1,
buf2, buffer2,
buf3, buffer3,
pkt->stream_index);
/*printf("pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, time_base),
pkt->stream_index);*/
}
static int write_frame(AVFormatContext* fmt_ctx, const AVRational* time_base, AVStream* st, AVPacket* pkt)
{
/* rescale output packet timestamp values from codec to stream timebase */
av_packet_rescale_ts(pkt, *time_base, st->time_base);
pkt->stream_index = st->index;
/* Write the compressed frame to the media file. */
log_packet(fmt_ctx, pkt);
return av_interleaved_write_frame(fmt_ctx, pkt);
}
/* Add an output stream. */
static void add_stream(OutputStream* ost, AVFormatContext* oc,
AVCodec** codec,
enum AVCodecID codec_id)
{
AVCodecContext* c;
int i;
/* find the encoder */
*codec = avcodec_find_encoder(codec_id);
if (!(*codec)) {
fprintf(stderr, "Could not find encoder for '%s'\n",
avcodec_get_name(codec_id));
exit(1);
}
ost->st = avformat_new_stream(oc, NULL);
if (!ost->st) {
fprintf(stderr, "Could not allocate stream\n");
exit(1);
}
ost->st->id = oc->nb_streams - 1;
c = avcodec_alloc_context3(*codec);
if (!c) {
fprintf(stderr, "Could not alloc an encoding context\n");
exit(1);
}
ost->enc = c;
switch ((*codec)->type) {
case AVMEDIA_TYPE_AUDIO:
c->sample_fmt = (*codec)->sample_fmts ?
(*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
c->bit_rate = 64000;
c->sample_rate = 44100;
if ((*codec)->supported_samplerates) {
c->sample_rate = (*codec)->supported_samplerates[0];
for (i = 0; (*codec)->supported_samplerates[i]; i++) {
if ((*codec)->supported_samplerates[i] == 44100)
c->sample_rate = 44100;
}
}
c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
c->channel_layout = AV_CH_LAYOUT_STEREO;
if ((*codec)->channel_layouts) {
c->channel_layout = (*codec)->channel_layouts[0];
for (i = 0; (*codec)->channel_layouts[i]; i++) {
if ((*codec)->channel_layouts[i] == AV_CH_LAYOUT_STEREO)
c->channel_layout = AV_CH_LAYOUT_STEREO;
}
}
c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
//ost->st->time_base = (AVRational){ 1, c->sample_rate };
ost->st->time_base.num = 1;
ost->st->time_base.den = c->sample_rate;
break;
case AVMEDIA_TYPE_VIDEO:
c->codec_id = codec_id;
c->bit_rate = 400000;
/* Resolution must be a multiple of two. */
c->width = width;
c->height = height;
/* timebase: This is the fundamental unit of time (in seconds) in terms
* of which frame timestamps are represented. For fixed-fps content,
* timebase should be 1/framerate and timestamp increments should be
* identical to 1. */
//ost->st->time_base = (AVRational){ 1, STREAM_FRAME_RATE };
ost->st->time_base.num = 1;
ost->st->time_base.den = STREAM_FRAME_RATE;
c->time_base = ost->st->time_base;
c->gop_size = 12; /* emit one intra frame every twelve frames at most */
c->pix_fmt = STREAM_PIX_FMT;
if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
/* just for testing, we also add B-frames */
c->max_b_frames = 2;
}
if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
/* Needed to avoid using macroblocks in which some coeffs overflow.
* This does not happen with normal video, it just happens here as
* the motion of the chroma plane does not match the luma plane. */
c->mb_decision = 2;
}
break;
default:
break;
}
/* Some formats want stream headers to be separate. */
if (oc->oformat->flags & AVFMT_GLOBALHEADER)
c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
}
/**************************************************************/
/* audio output */
static AVFrame* alloc_audio_frame(enum AVSampleFormat sample_fmt,
uint64_t channel_layout,
int sample_rate, int nb_samples)
{
AVFrame* frame = av_frame_alloc();
int ret;
if (!frame) {
fprintf(stderr, "Error allocating an audio frame\n");
exit(1);
}
frame->format = sample_fmt;
frame->channel_layout = channel_layout;
frame->sample_rate = sample_rate;
frame->nb_samples = nb_samples;
if (nb_samples) {
ret = av_frame_get_buffer(frame, 0);
if (ret < 0) {
fprintf(stderr, "Error allocating an audio buffer\n");
exit(1);
}
}
return frame;
}
static void open_audio(AVFormatContext* oc, AVCodec* codec, OutputStream* ost, AVDictionary* opt_arg)
{
AVCodecContext* c;
//int nb_samples;
int ret;
AVDictionary* opt = NULL;
c = ost->enc;
/* open it */
av_dict_copy(&opt, opt_arg, 0);
ret = avcodec_open2(c, codec, &opt);
av_dict_free(&opt);
if (ret < 0) {
//fprintf(stderr, "Could not open audio codec: %s\n", av_err2str(ret));
fprintf(stderr, "Could not open audio codec: \n");
exit(1);
}
/* init signal generator */
ost->t = 0;
ost->tincr = 2 * M_PI * 110.0 / c->sample_rate;
/* increment frequency by 110 Hz per second */
ost->tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
if (c->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE)
nb_samples = 4410;
else
nb_samples = c->frame_size;
ost->frame = alloc_audio_frame(c->sample_fmt, c->channel_layout,
c->sample_rate, nb_samples);
ost->tmp_frame = alloc_audio_frame(AV_SAMPLE_FMT_S16, c->channel_layout,
c->sample_rate, nb_samples);
/* copy the stream parameters to the muxer */
ret = avcodec_parameters_from_context(ost->st->codecpar, c);
if (ret < 0) {
fprintf(stderr, "Could not copy the stream parameters\n");
exit(1);
}
/* create resampler context */
ost->swr_ctx = swr_alloc();
if (!ost->swr_ctx) {
fprintf(stderr, "Could not allocate resampler context\n");
exit(1);
}
/* set options */
av_opt_set_int(ost->swr_ctx, "in_channel_count", c->channels, 0);
av_opt_set_int(ost->swr_ctx, "in_sample_rate", c->sample_rate, 0);
av_opt_set_sample_fmt(ost->swr_ctx, "in_sample_fmt", AV_SAMPLE_FMT_S16, 0);
av_opt_set_int(ost->swr_ctx, "out_channel_count", c->channels, 0);
av_opt_set_int(ost->swr_ctx, "out_sample_rate", c->sample_rate, 0);
av_opt_set_sample_fmt(ost->swr_ctx, "out_sample_fmt", c->sample_fmt, 0);
/* initialize the resampling context */
if ((ret = swr_init(ost->swr_ctx)) < 0) {
fprintf(stderr, "Failed to initialize the resampling context\n");
exit(1);
}
}
/* Prepare a 16 bit dummy audio frame of 'frame_size' samples and
* 'nb_channels' channels. */
static AVFrame* get_audio_frame(OutputStream* ost, DWORD dwBytesRecorded)
{
AVCodecContext* c = ost->enc;
AVFrame* frame = ost->tmp_frame;
AVRational temp;
temp.num = 1;
temp.den = 1;
/* check if we want to generate more frames */
/*if (av_compare_ts(ost->next_pts, ost->enc->time_base,
STREAM_DURATION, temp) >= 0)
return NULL;*/
/*if (c->frame_size * c->channels != nb_samples * bytePerSample)
cout << "c->frame_size " << c->frame_size << " * c->channels " << c->channels << "= (" << c->frame_size * c->channels << ") != nb_samples * bytePerSample (" << nb_samples * bytePerSample << ")" << endl;*/
//for (int i = 0; i < nb_samples * bytePerSample; i++)
for (int i = 0; i < dwBytesRecorded; i++)
frame->data[0][i] = waveIn[i];
frame->pts = ost->next_pts;
ost->next_pts += frame->nb_samples;
return frame;
}
/*
* encode one audio frame and send it to the muxer
* return 1 when encoding is finished, 0 otherwise
*/
static int write_audio_frame(AVFormatContext* oc, OutputStream* ost, bool isLast, DWORD dwBytesRecorded)
{
AVCodecContext* c;
AVPacket pkt = { 0 }; // data and size must be 0;
AVFrame* frame;
int ret;
int got_packet;
int dst_nb_samples;
av_init_packet(&pkt);
c = ost->enc;
if (isLast)
frame = NULL;
else
frame = get_audio_frame(ost, dwBytesRecorded);
if (frame) {
/* convert samples from native format to destination codec format, using the resampler */
/* compute destination number of samples */
dst_nb_samples = av_rescale_rnd(swr_get_delay(ost->swr_ctx, c->sample_rate) + frame->nb_samples,
c->sample_rate, c->sample_rate, AV_ROUND_UP);
av_assert0(dst_nb_samples == frame->nb_samples);
/* when we pass a frame to the encoder, it may keep a reference to it
* internally;
* make sure we do not overwrite it here
*/
ret = av_frame_make_writable(ost->frame);
if (ret < 0)
exit(1);
/* convert to destination format */
ret = swr_convert(ost->swr_ctx,
ost->frame->data, dst_nb_samples,
(const uint8_t**)frame->data, frame->nb_samples);
if (ret < 0) {
fprintf(stderr, "Error while converting\n");
exit(1);
}
frame = ost->frame;
AVRational temp;
temp.num = 1;
temp.den = c->sample_rate;
//frame->pts = av_rescale_q(ost->samples_count, (AVRational) { 1, c->sample_rate }, c->time_base);
frame->pts = av_rescale_q(ost->samples_count, temp, c->time_base);
ost->samples_count += dst_nb_samples;
}
//ret = avcodec_encode_audio2(c, &pkt, frame, &got_packet);
ret = avcodec_send_frame(c, frame);
if (ret < 0) {
//fprintf(stderr, "Error encoding audio frame: %s\n", av_err2str(ret));
fprintf(stderr, "Error encoding audio frame: \n");
if (ret == AVERROR_EOF)
return 1;
exit(1);
}
got_packet = 1;
while (ret >= 0) {
ret = avcodec_receive_packet(c, &pkt);
if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
got_packet = 0;
return 0;
}
if (write_frame(oc, &c->time_base, ost->st, &pkt) < 0) {
fprintf(stderr, "Error while writing audio frame: \n");
exit(1);
}
}
return (frame || got_packet) ? 0 : 1;
}
/**************************************************************/
/* video output */
static AVFrame* alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
{
AVFrame* picture;
int ret;
picture = av_frame_alloc();
if (!picture)
return NULL;
picture->format = pix_fmt;
picture->width = width;
picture->height = height;
/* allocate the buffers for the frame data */
ret = av_frame_get_buffer(picture, 32);
if (ret < 0) {
fprintf(stderr, "Could not allocate frame data.\n");
exit(1);
}
return picture;
}
static void open_video(AVFormatContext* oc, AVCodec* codec, OutputStream* ost, AVDictionary* opt_arg)
{
int ret;
AVCodecContext* c = ost->enc;
AVDictionary* opt = NULL;
av_dict_copy(&opt, opt_arg, 0);
/* open the codec */
ret = avcodec_open2(c, codec, &opt);
av_dict_free(&opt);
if (ret < 0) {
//fprintf(stderr, "Could not open video codec: %s\n", av_err2str(ret));
fprintf(stderr, "Could not open video codec: \n");
exit(1);
}
/* allocate and init a re-usable frame */
ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
if (!ost->frame) {
fprintf(stderr, "Could not allocate video frame\n");
exit(1);
}
/* If the output format is not YUV420P, then a temporary YUV420P
* picture is needed too. It is then converted to the required
* output format. */
ost->tmp_frame = NULL;
if (c->pix_fmt != AV_PIX_FMT_BGR24) {
ost->tmp_frame = alloc_picture(AV_PIX_FMT_BGR24, c->width, c->height);
if (!ost->tmp_frame) {
fprintf(stderr, "Could not allocate temporary picture\n");
exit(1);
}
}
/* copy the stream parameters to the muxer */
ret = avcodec_parameters_from_context(ost->st->codecpar, c);
if (ret < 0) {
fprintf(stderr, "Could not copy the stream parameters\n");
exit(1);
}
}
HBITMAP GetScreenBmp(HDC hdc) {
BitBlt(hDest, 0, 0, width, height, hdc, 0, 0, SRCCOPY);
return hbDesktop;
}
/*return [BGRA] [BGRA] ... image*/
BYTE* get_screen_image(HBITMAP hBitmap) {//(HDC hdc,HBITMAP hBitmap)
BITMAPINFO MyBMInfo = { 0 };
MyBMInfo.bmiHeader.biSize = sizeof(MyBMInfo.bmiHeader);
// Get the BITMAPINFO structure from the bitmap
if (0 == GetDIBits(hdc, hBitmap, 0, 0, NULL, &MyBMInfo, DIB_RGB_COLORS)) {
return NULL;
}
// create the bitmap buffer
BYTE* lpPixels = new BYTE[MyBMInfo.bmiHeader.biSizeImage];
// Better do this here - the original bitmap might have BI_BITFILEDS, which makes it
// necessary to read the color table - you might not want this.
MyBMInfo.bmiHeader.biCompression = BI_RGB;
// get the actual bitmap buffer
if (0 == GetDIBits(hdc, hBitmap, 0, MyBMInfo.bmiHeader.biHeight, (LPVOID)lpPixels, &MyBMInfo, DIB_RGB_COLORS)) {
return NULL;
}
return lpPixels;
}
BYTE* BGRA2BGR(BYTE* arr) {
//BYTE* buffer = new BYTE[width * height * 3];
for (int y = 0; y < height; y++) {
//if (y == height - 1) cout << "copy data from lpPixels to BGR_buffer[height-1]" << endl;
for (int x = 0; x < width; x++) {
BGR_buffer[y * width * 3 + x * 3] = *arr;
BGR_buffer[y * width * 3 + x * 3 + 1] = *(arr + 1);
BGR_buffer[y * width * 3 + x * 3 + 2] = *(arr + 2);
arr += 4;
}
}
return BGR_buffer;
}
// fill data of pFrame
void get_BGR_screen_image(AVFrame* pFrame, int width, int height) {
//HDC hdc = GetDC(0);
HBITMAP hBitmap = GetScreenBmp(hdc);
BYTE* lpPixels = get_screen_image(hBitmap);
BGR_buffer = BGRA2BGR(lpPixels);
delete[] lpPixels;
av_image_fill_arrays(pFrame->data, pFrame->linesize, (uint8_t*)BGR_buffer, AV_PIX_FMT_BGR24, width, height, 1);//!
}
static AVFrame* get_video_frame(OutputStream* ost)
{
AVCodecContext* c = ost->enc;
AVRational temp;
temp.num = 1;
temp.den = 1;
/* check if we want to generate more frames */
//if (av_compare_ts(ost->next_pts, c->time_base, STREAM_DURATION, (AVRational) { 1, 1 }) >= 0)
if (av_compare_ts(ost->next_pts, c->time_base, STREAM_DURATION, temp) >= 0) {
ost->frame = NULL;
return NULL;
}
/* when we pass a frame to the encoder, it may keep a reference to it
* internally; make sure we do not overwrite it here */
if (av_frame_make_writable(ost->frame) < 0)
exit(1);
if (c->pix_fmt != AV_PIX_FMT_BGR24) {
/* as we only generate a YUV420P picture, we must convert it
* to the codec pixel format if needed */
if (!ost->sws_ctx) {
ost->sws_ctx = sws_getContext(c->width, c->height,
AV_PIX_FMT_BGR24,
c->width, c->height,
c->pix_fmt,
SCALE_FLAGS, NULL, NULL, NULL);
if (!ost->sws_ctx) {
fprintf(stderr,
"Could not initialize the conversion context\n");
exit(1);
}
}
get_BGR_screen_image(ost->tmp_frame, c->width, c->height);
sws_scale(ost->sws_ctx, (const uint8_t* const*)ost->tmp_frame->data,
ost->tmp_frame->linesize, 0, c->height, ost->frame->data,
ost->frame->linesize);
}
else {
get_BGR_screen_image(ost->frame, c->width, c->height);
}
ost->frame->data[0] += ost->frame->linesize[0] * (height - 1);
ost->frame->linesize[0] *= -1;
ost->frame->data[1] += ost->frame->linesize[1] * (height / 2 - 1);
ost->frame->linesize[1] *= -1;
ost->frame->data[2] += ost->frame->linesize[2] * (height / 2 - 1);
ost->frame->linesize[2] *= -1;
ost->frame->pts = ost->next_pts++;
return ost->frame;
}
//!
/*
* encode one video frame and send it to the muxer
* return 1 when encoding is finished, 0 otherwise
*/
static int write_video_frame(AVFormatContext* oc, OutputStream* ost)
{
int ret;
AVCodecContext* c;
AVFrame* frame;
int got_packet = 0;
//AVPacket pkt = { 0 };
AVPacket* pkt;
c = ost->enc;
//av_init_packet(&pkt);
pkt = av_packet_alloc();
/* encode the image */
//ret = avcodec_encode_video2(c, &pkt, frame, &got_packet);
ret = avcodec_send_frame(c, ost->frame);
if (ret < 0) {
char buf[AV_ERROR_MAX_STRING_SIZE] = { 0 };
av_make_error_string(buf, AV_ERROR_MAX_STRING_SIZE, ret);
fprintf(stderr, "Error encoding video frame: %s\n", buf);
if (ret == AVERROR_EOF)
return 1;
//fprintf(stderr, "Error encoding video frame: \n");
exit(1);
}
got_packet = 1;
while (ret >= 0) {
ret = avcodec_receive_packet(c, pkt);
if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
got_packet = 0;
return 0;
}
if (write_frame(oc, &(c->time_base), ost->st, pkt) < 0) {
//fprintf(stderr, "Error while writing video frame: %s\n", av_err2str(ret));
fprintf(stderr, "Error while writing video frame: \n");
exit(1);
}
av_packet_unref(pkt);
}
//return (frame || got_packet) ? 0 : 1;
return 0;
}
static void close_stream(AVFormatContext* oc, OutputStream* ost)
{
avcodec_free_context(&ost->enc);
av_frame_free(&ost->frame);
av_frame_free(&ost->tmp_frame);
sws_freeContext(ost->sws_ctx);
swr_free(&ost->swr_ctx);
}
/* save video frame to the data of OutputStream every 40ms */
unsigned __stdcall RecordVideo(void* arg) {
DWORD duration = 1000 / STREAM_FRAME_RATE;
long END, START;
while (true) {
/*AVRational temp;
temp.num = 1;
temp.den = 1;
if (av_compare_ts(video_st.next_pts, video_st.enc->time_base, STREAM_DURATION, temp) <= 0) {
get_video_frame(&video_st);
}
else
{
endvideo = 1;
SetEvent(hEvent);
break;
}*/
START = clock();
if (!get_video_frame(&video_st)) {
endvideo = 1;
encode_video = 1;
SetEvent(hEvent);
break;
}
END = clock();
encode_video = 1;
SetEvent(hEvent);
if (END - START < duration)
Sleep(duration - END + START);
}
_endthreadex(0);
return 0;
}
void CALLBACK waveInProc(HWAVEIN hwi, UINT uMsg, DWORD dwInstance, DWORD dwParam1, DWORD dwParam2)
{
//printf("(waveInProc) hWaveIn 0x%p, nMessage 0x%04X, nInstance %d, nParameter1 %d, nParameter2 %d\n", hwi, uMsg, dwInstance, dwParam1, dwParam2);
//cout << "waveInProc()..." << endl;
WAVEHDR* pHdr = NULL;
WAVEHDR pHdr2;
switch (uMsg)
{
case WIM_CLOSE:
cout << "waveInProc()... WIM_CLOSE" << endl;
break;
case WIM_DATA:
{
pHdr = (WAVEHDR*)dwParam1;
pHdr2.lpData = (LPSTR)pHdr->lpData;
pHdr2.dwBufferLength = pHdr->dwBufferLength;
pHdr2.dwBytesRecorded = pHdr->dwBytesRecorded;
pHdr2.dwUser = 0;
pHdr2.dwFlags = 0;
pHdr2.dwLoops = 0;
//cout << "waveInProc()... WIM_DATA : " << "pHdr->dwBufferLength:" << pHdr->dwBufferLength << " pHdr->dwBytesRecorded:" << pHdr->dwBytesRecorded << endl;//
//waveOutPrepareHeader(hWaveOut, &pHdr2, sizeof(WAVEHDR));//!
//waveOutWrite(hWaveOut, &pHdr2, sizeof(WAVEHDR));//!
//cout << "buffer : " << pHdr->lpData[0] << pHdr->lpData[1] << endl;
write_audio_frame(oc, &audio_st, false, pHdr->dwBytesRecorded);
waveInPrepareHeader(hwi, pHdr, sizeof(WAVEHDR));
waveInAddBuffer(hwi, pHdr, sizeof(WAVEHDR));
}
break;
case WIM_OPEN:
cout << "waveInProc()... WIM_OPEN" << endl;
break;
default:
break;
}
}
/**************************************************************/
/* media file output */
int main(int argc, char** argv)
{
const char* filename;
AVOutputFormat* fmt;
//AVFormatContext* oc;
AVCodec* audio_codec = NULL, * video_codec = NULL;
int ret;
int have_video = 0, have_audio = 0;
//int encode_video = 0, encode_audio = 0;
AVDictionary* opt = NULL;
int i;
hdc = GetDC(NULL); // get the desktop device context
hDest = CreateCompatibleDC(hdc); // create a device context to use yourself
height = GetSystemMetrics(SM_CYVIRTUALSCREEN);
width = GetSystemMetrics(SM_CXVIRTUALSCREEN);
hbDesktop = CreateCompatibleBitmap(hdc, width, height);
SelectObject(hDest, hbDesktop);
BGR_buffer = new BYTE[width * height * 3];
//-----------------------------------------
pFormat.wFormatTag = WAVE_FORMAT_PCM;
pFormat.nChannels = channels;
pFormat.nSamplesPerSec = sampleRate;
pFormat.wBitsPerSample = bitPerSample;
//pFormat.nAvgBytesPerSec = 2 * sampleRate;
pFormat.nAvgBytesPerSec = pFormat.nSamplesPerSec * pFormat.nChannels * pFormat.wBitsPerSample / 8;
//pFormat.nBlockAlign = 2;
pFormat.nBlockAlign = pFormat.nChannels * pFormat.wBitsPerSample / 8;
pFormat.cbSize = 0;
result = waveInOpen(&hWaveIn, WAVE_MAPPER, &pFormat, (DWORD_PTR)waveInProc, NULL, CALLBACK_FUNCTION);
if (result)
{
char fault[256];
waveInGetErrorTextA(result, fault, 256);
MessageBoxA(NULL, fault, "Failed to open waveform input device.", MB_OK | MB_ICONEXCLAMATION);
return 1;
}
//-----------------------------------------
if (argc < 2) {
printf("usage: %s output_file\n"
"API example program to output a media file with libavformat.\n"
"This program generates a synthetic audio and video stream, encodes and\n"
"muxes them into a file named output_file.\n"
"The output format is automatically guessed according to the file extension.\n"
"Raw images can also be output by using '%%d' in the filename.\n"
"\n", argv[0]);
return 1;
}
filename = argv[1];
for (i = 2; i + 1 < argc; i += 2) {
if (!strcmp(argv[i], "-flags") || !strcmp(argv[i], "-fflags"))
av_dict_set(&opt, argv[i] + 1, argv[i + 1], 0);
}
/* allocate the output media context */
avformat_alloc_output_context2(&oc, NULL, NULL, filename);
if (!oc) {
printf("Could not deduce output format from file extension: using MPEG.\n");
avformat_alloc_output_context2(&oc, NULL, "mpeg", filename);
}
if (!oc)
return 1;
fmt = oc->oformat;
/* Add the audio and video streams using the default format codecs
* and initialize the codecs. */
if (fmt->video_codec != AV_CODEC_ID_NONE) {
add_stream(&video_st, oc, &video_codec, fmt->video_codec);
have_video = 1;
encode_video = 1;
}
if (fmt->audio_codec != AV_CODEC_ID_NONE) {
add_stream(&audio_st, oc, &audio_codec, fmt->audio_codec);
have_audio = 1;
encode_audio = 1;
}
/* Now that all the parameters are set, we can open the audio and
* video codecs and allocate the necessary encode buffers. */
if (have_video)
open_video(oc, video_codec, &video_st, opt);
if (have_audio)
open_audio(oc, audio_codec, &audio_st, opt);
av_dump_format(oc, 0, filename, 1);
/* open the output file, if needed */
if (!(fmt->flags & AVFMT_NOFILE)) {
ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE);
if (ret < 0) {
//fprintf(stderr, "Could not open '%s': %s\n", filename, av_err2str(ret));
fprintf(stderr, "Could not open '%s': \n", filename);
return 1;
}
}
/* Write the stream header, if any. */
ret = avformat_write_header(oc, &opt);
if (ret < 0) {
//fprintf(stderr, "Error occurred when opening output file: %s\n", av_err2str(ret));
fprintf(stderr, "Error occurred when opening output file: \n");
return 1;
}
//----------------------------------------------
waveIn = new BYTE[nb_samples * bytePerSample];
WaveInHdr.lpData = (LPSTR)waveIn;
WaveInHdr.dwBufferLength = nb_samples * bytePerSample;
WaveInHdr.dwBytesRecorded = 0;
WaveInHdr.dwUser = 0;
WaveInHdr.dwFlags = 0;
WaveInHdr.dwLoops = 0;
waveInPrepareHeader(hWaveIn, &WaveInHdr, sizeof(WAVEHDR));
cout << "WaveInHdr.dwBufferLength : " << WaveInHdr.dwBufferLength << endl;
result = waveInAddBuffer(hWaveIn, &WaveInHdr, sizeof(WAVEHDR));
if (result)
{
MessageBoxA(NULL, "Failed to read block from device", NULL, MB_OK | MB_ICONEXCLAMATION);
return 1;
}
result = waveInStart(hWaveIn);//
if (result)
{
MessageBoxA(NULL, "Failed to start recording", NULL, MB_OK | MB_ICONEXCLAMATION);
return 1;
}
//--------------------------------------------------
hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
unsigned threadID;
HANDLE hThread = (HANDLE)_beginthreadex(NULL, 0, &RecordVideo, NULL, 0, &threadID);
while (true) {
WaitForSingleObject(hEvent, INFINITE);
/* select the stream to encode */
//if (encode_video && (!encode_audio || av_compare_ts(video_st.next_pts, video_st.enc->time_base, audio_st.next_pts, audio_st.enc->time_base) <= 0)) {
//if (encode_video && av_compare_ts(video_st.next_pts-1, video_st.enc->time_base, audio_st.next_pts, audio_st.enc->time_base) <= 0) {
if (encode_video) {
//encode_video = !write_video_frame(oc, &video_st);
write_video_frame(oc, &video_st);
encode_video = 0;
}
/*while (av_compare_ts(video_st.next_pts, video_st.enc->time_base, audio_st.next_pts, audio_st.enc->time_base) >= 0){
write_audio_frame(oc, &audio_st);
}*/
if (endvideo) endaudio = 1;
/*if (encode_audio) {
write_audio_frame(oc, &audio_st);
}*/
if (endvideo && endaudio) break;
}
waveInUnprepareHeader(hWaveIn, &WaveInHdr, sizeof(WAVEHDR));
waveInStop(hWaveIn);
waveInClose(hWaveIn);
write_audio_frame(oc, &audio_st, true, 0);
/* Write the trailer, if any. The trailer must be written before you
* close the CodecContexts open when you wrote the header; otherwise
* av_write_trailer() may try to use memory that was freed on
* av_codec_close(). */
av_write_trailer(oc);
;
delete[] BGR_buffer;
CloseHandle(hThread);
ReleaseDC(NULL, hdc);
DeleteObject(hbDesktop);
DeleteDC(hDest);
/* Close each codec. */
if (have_video)
close_stream(oc, &video_st);
if (have_audio)
close_stream(oc, &audio_st);
if (!(fmt->flags & AVFMT_NOFILE))
/* Close the output file. */
avio_closep(&oc->pb);
/* free the stream */
avformat_free_context(oc);
return 0;
}
---------------------------------------------------------------------------------------------------
三. 用法 : 會記錄開始執行程式後10秒間的螢幕錄影 並輸出成 .mp4 檔案
1. 打開 CMD
2.
>ScreenRecorder.exe output.mp4
四. 後記
目前問題: 聲音會播得過快 然後大約後面20%的時間 (2秒) 沒聲音
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