[英]Error using FFMPEG to convert each input image into H264 compiling in Visual Studio running in MevisLab
我正在MevisLab Framework中创建ML模块,正在使用FFMPEG将获取的每个图像转换为H264视频,并在获取所有帧后将其保存。 但不幸的是,我在分配输出缓冲区大小时遇到问题。 当我将其包含在代码中时,应用程序崩溃。如果不包含它,则输出文件大小仅为4kb。 没有存储任何内容。
我也不太确定将HBitmap放入编码器的正确方法。 收到您的建议会很棒。
我的代码:
BITMAPINFO bitmapInfo;
HDC hdc;
ZeroMemory(&bitmapInfo, sizeof(bitmapInfo));
BITMAPINFOHEADER &bitmapInfoHeader = bitmapInfo.bmiHeader;
bitmapInfoHeader.biSize = sizeof(bitmapInfoHeader);
bitmapInfoHeader.biWidth = _imgWidth;
bitmapInfoHeader.biHeight = _imgHeight;
bitmapInfoHeader.biPlanes = 1;
bitmapInfoHeader.biBitCount = 24;
bitmapInfoHeader.biCompression = BI_RGB;
bitmapInfoHeader.biSizeImage = ((bitmapInfoHeader.biWidth * bitmapInfoHeader.biBitCount / 8 + 3) & 0xFFFFFFFC) * bitmapInfoHeader.biHeight;
bitmapInfoHeader.biXPelsPerMeter = 10000;
bitmapInfoHeader.biYPelsPerMeter = 10000;
bitmapInfoHeader.biClrUsed = 0;
bitmapInfoHeader.biClrImportant = 0;
//RGBQUAD* Ref = new RGBQUAD[_imgWidth,_imgHeight];
HDC hdcscreen = GetDC(0);
hdc = CreateCompatibleDC(hdcscreen);
ReleaseDC(0, hdcscreen);
_hbitmap = CreateDIBSection(hdc, (BITMAPINFO*) &bitmapInfoHeader, DIB_RGB_COLORS, &_bits, NULL, NULL);
要获取BitMap,请使用上面的代码。 然后我按照以下方式分配编解码器上下文
c->bit_rate = 400000;
// resolution must be a multiple of two
c->width = 1920;
c->height = 1080;
// frames per second
frame_rate = _framesPerSecondFld->getIntValue();
//AVRational rational = {1,10};
//c->time_base = (AVRational){1,25};
//c->time_base = (AVRational){1,25};
c->gop_size = 10; // emit one intra frame every ten frames
c->max_b_frames = 1;
c->keyint_min = 1; //minimum GOP size
c->time_base.num = 1; // framerate numerator
c->time_base.den = _framesPerSecondFld->getIntValue();
c->i_quant_factor = (float)0.71; // qscale factor between P and I frames
c->pix_fmt = AV_PIX_FMT_RGB32;
std::string msg;
msg.append("Context is stored");
_messageFld->setStringValue(msg.c_str());
我从输入中创建位图图像,如下所示
PagedImage *inImg = getUpdatedInputImage(0);
ML_CHECK(inImg);
ImageVector imgExt = inImg->getImageExtent();
if ((imgExt.x = _imgWidth) && (imgExt.y == _imgHeight))
{
if (((imgExt.x % 4)==0) && ((imgExt.y % 4) == 0))
{
// read out input image and write output image into video
// get input image as an array
void* imgData = NULL;
SubImageBox imageBox(imgExt); // get the whole image
getTile(inImg, imageBox, MLuint8Type, &imgData);
iData = (MLuint8*)imgData;
int r = 0; int g = 0;int b = 0;
// since we have only images with
// a z-ext of 1, we can compute the c stride as follows
int cStride = _imgWidth * _imgHeight;
uint8_t offset = 0;
// pointer into the bitmap that is
// used to write images into the avi
UCHAR* dst = (UCHAR*)_bits;
for (int y = _imgHeight-1; y >= 0; y--)
{ // reversely scan the image. if y-rows of DIB are set in normal order, no compression will be available.
offset = _imgWidth * y;
for (int x = 0; x < _imgWidth; x++)
{
if (_isGreyValueImage)
{
r = iData[offset + x];
*dst++ = (UCHAR)r;
*dst++ = (UCHAR)r;
*dst++ = (UCHAR)r;
}
else
{
b = iData[offset + x]; // windows bitmap need reverse order: bgr instead of rgb
g = iData[offset + x + cStride ];
r = iData[offset + x + cStride + cStride];
*dst++ = (UCHAR)r;
*dst++ = (UCHAR)g;
*dst++ = (UCHAR)b;
}
// alpha channel in input image is ignored
}
}
然后我将其添加到编码器中,然后写为H264
in_width = c->width;
in_height = c->height;
out_width = c->width;
out_height = c->height;
ibytes = avpicture_get_size(PIX_FMT_BGR32, in_width, in_height);
obytes = avpicture_get_size(PIX_FMT_YUV420P, out_width, out_height);
outbuf_size = 100000 + c->width*c->height*(32>>3); // allocate output buffer
outbuf = static_cast<uint8_t *>(malloc(outbuf_size));
if(!obytes)
{
std::string msg;
msg.append("Bytes cannot be allocated");
_messageFld->setStringValue(msg.c_str());
}
else
{
std::string msg;
msg.append("Bytes allocation done");
_messageFld->setStringValue(msg.c_str());
}
//create buffer for the output image
inbuffer = (uint8_t*)av_malloc(ibytes);
outbuffer = (uint8_t*)av_malloc(obytes);
inbuffer = (uint8_t*)dst;
//create ffmpeg frame structures. These do not allocate space for image data,
//just the pointers and other information about the image.
AVFrame* inpic = avcodec_alloc_frame();
AVFrame* outpic = avcodec_alloc_frame();
//this will set the pointers in the frame structures to the right points in
//the input and output buffers.
avpicture_fill((AVPicture*)inpic, inbuffer, PIX_FMT_BGR32, in_width, in_height);
avpicture_fill((AVPicture*)outpic, outbuffer, PIX_FMT_YUV420P, out_width, out_height);
av_image_alloc(outpic->data, outpic->linesize, c->width, c->height, c->pix_fmt, 1);
inpic->data[0] += inpic->linesize[0]*(_imgHeight-1); // flipping frame
inpic->linesize[0] = -inpic->linesize[0];
if(!inpic)
{
std::string msg;
msg.append("Image is empty");
_messageFld->setStringValue(msg.c_str());
}
else
{
std::string msg;
msg.append("Picture has allocations");
_messageFld->setStringValue(msg.c_str());
}
//create the conversion context
fooContext = sws_getContext(in_width, in_height, PIX_FMT_BGR32, out_width, out_height, PIX_FMT_YUV420P, SWS_FAST_BILINEAR, NULL, NULL, NULL);
//perform the conversion
sws_scale(fooContext, inpic->data, inpic->linesize, 0, in_height, outpic->data, outpic->linesize);
//out_size = avcodec_encode_video(c, outbuf,outbuf_size, outpic);
if(!out_size)
{
std::string msg;
msg.append("Outsize is not valid");
_messageFld->setStringValue(msg.c_str());
}
else
{
std::string msg;
msg.append("Outsize is valid");
_messageFld->setStringValue(msg.c_str());
}
fwrite(outbuf, 1, out_size, f);
if(!fwrite)
{
std::string msg;
msg.append("Frames couldnt be written");
_messageFld->setStringValue(msg.c_str());
}
else
{
std::string msg;
msg.append("Frames written to the file");
_messageFld->setStringValue(msg.c_str());
}
// for (;out_size; i++)
// {
out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
std::string msg;
msg.append("Writing Frames");
_messageFld->setStringValue(msg.c_str());// encode the delayed frames
_numFramesFld->setIntValue(_numFramesFld->getIntValue()+1);
fwrite(outbuf, 1, out_size, f);
// }
outbuf[0] = 0x00;
outbuf[1] = 0x00; // add sequence end code to have a real mpeg file
outbuf[2] = 0x01;
outbuf[3] = 0xb7;
fwrite(outbuf, 1, 4, f);
}
然后关闭并清理图像缓冲区和文件
ML_TRACE_IN("MovieCreator::_endRecording()")
if (_numFramesFld->getIntValue() == 0)
{
_messageFld->setStringValue("Empty movie, nothing saved.");
}
else
{
_messageFld->setStringValue("Movie written to disk.");
_numFramesFld->setIntValue(0);
if (_hbitmap)
{
DeleteObject(_hbitmap);
}
if (c != NULL)
{
av_free(outbuffer);
av_free(inpic);
av_free(outpic);
fclose(f);
avcodec_close(c); // freeing memory
free(outbuf);
av_free(c);
}
}
}
我认为主要问题就在这里!
//out_size = avcodec_encode_video(c, outbuf,outbuf_size, outpic);
H264无法读取RGB帧。 更改此行:
c->pix_fmt = AV_PIX_FMT_RGB32
对此:
c->pix_fmt = AV_PIX_FMT_YUV420P
还指定较少的输入到编码器,让FFMPEG决定最佳设置。 删除这些行,然后看是否行得通:
c->i_quant_factor = (float)0.71;
c->max_b_frames = 1;
c->keyint_min = 1;
另外,您也可以尝试从以下工作代码示例开始:
http://www.imc-store.com.au/Articles.asp?ID=276
该示例在VS2010中进行,并使用FFMPEG将帧编码为H264编码的AVI文件。 它有很多评论,我发现它真的很有帮助。
您可以将从位图读取的BGR字符数组传递给FFMPEG类(只需将颜色交换为RGB)。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.