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Fix: Bug fix in determination of scanline direction

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YUV and other compressed frame formats are always TopToBottom. Only for uncompressed RGB formats the sign of their height is used to indicate the scanline direction.

Change-Id: I6474783583672861eeeb538b79d14ee3d6995f59
Reviewed-by: Dmytro Poplavskiy <dmytro.poplavskiy@gmail.com>
This commit is contained in:
Wouter Huysentruit
2013-01-11 11:21:35 +01:00
committed by The Qt Project
parent 9a9293df5a
commit da55ada028
2 changed files with 33 additions and 6 deletions
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36
src/plugins/directshow/player/directshowmediatype.cpp
View File

@@ -127,9 +127,7 @@ QVideoSurfaceFormat DirectShowMediaType::formatFromType(const AM_MEDIA_TYPE &typ
if (header->AvgTimePerFrame > 0)
format.setFrameRate(10000 /header->AvgTimePerFrame);
format.setScanLineDirection(header->bmiHeader.biHeight < 0
? QVideoSurfaceFormat::TopToBottom
: QVideoSurfaceFormat::BottomToTop);
format.setScanLineDirection(scanLineDirection(format.pixelFormat(), header->bmiHeader));
return format;
} else if (IsEqualGUID(type.formattype, FORMAT_VideoInfo2)) {
@@ -142,9 +140,7 @@ QVideoSurfaceFormat DirectShowMediaType::formatFromType(const AM_MEDIA_TYPE &typ
if (header->AvgTimePerFrame > 0)
format.setFrameRate(10000 / header->AvgTimePerFrame);
format.setScanLineDirection(header->bmiHeader.biHeight < 0
? QVideoSurfaceFormat::TopToBottom
: QVideoSurfaceFormat::BottomToTop);
format.setScanLineDirection(scanLineDirection(format.pixelFormat(), header->bmiHeader));
return format;
}
@@ -183,3 +179,31 @@ int DirectShowMediaType::bytesPerLine(const QVideoSurfaceFormat &format)
return 0;
}
}
QVideoSurfaceFormat::Direction DirectShowMediaType::scanLineDirection(QVideoFrame::PixelFormat pixelFormat, const BITMAPINFOHEADER &bmiHeader)
{
/* MSDN http://msdn.microsoft.com/en-us/library/windows/desktop/dd318229(v=vs.85).aspx */
/* For uncompressed RGB bitmaps:
* if biHeight is positive, the bitmap is a bottom-up DIB with the origin at the lower left corner.
* If biHeight is negative, the bitmap is a top-down DIB with the origin at the upper left corner.
*
* For YUV bitmaps:
* the bitmap is always top-down, regardless of the sign of biHeight.
* Decoders should offer YUV formats with postive biHeight, but for backward compatibility they should accept YUV formats with either positive or negative biHeight.
*
* For compressed formats:
* biHeight must be positive, regardless of image orientation.
*/
switch (pixelFormat)
{
case QVideoFrame::Format_RGB32:
case QVideoFrame::Format_BGR24:
case QVideoFrame::Format_RGB565:
case QVideoFrame::Format_RGB555:
return bmiHeader.biHeight < 0
? QVideoSurfaceFormat::TopToBottom
: QVideoSurfaceFormat::BottomToTop;
default:
return QVideoSurfaceFormat::TopToBottom;
}
}

3
src/plugins/directshow/player/directshowmediatype.h
View File

@@ -69,6 +69,9 @@ public:
static QVideoSurfaceFormat formatFromType(const AM_MEDIA_TYPE &type);
static int bytesPerLine(const QVideoSurfaceFormat &format);
private:
static QVideoSurfaceFormat::Direction scanLineDirection(QVideoFrame::PixelFormat pixelFormat, const BITMAPINFOHEADER &bmiHeader);
};
#endif