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Diffstat (limited to 'AVStream/avscamera/sys/NV12Synthesizer.cpp')
| -rw-r--r-- | AVStream/avscamera/sys/NV12Synthesizer.cpp | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/AVStream/avscamera/sys/NV12Synthesizer.cpp b/AVStream/avscamera/sys/NV12Synthesizer.cpp new file mode 100644 index 00000000..2cdbf71b --- /dev/null +++ b/AVStream/avscamera/sys/NV12Synthesizer.cpp @@ -0,0 +1,183 @@ +/************************************************************************** + + A/V Stream Camera Sample + + Copyright (c) 2001, Microsoft Corporation. + + File: + + CNV12Synthesizer.h + + Abstract: + + This file contains the implementation of CNV12Synthesizer. + + CNV12Synthesizer is derived from CYUVSynthesizer. It uses the YUV color + space and defines a Commit() function that reformats pixels into the + NV12 format. From MSDN: + + A format in which all Y samples are found first in memory as an + array of unsigned char with an even number of lines (possibly with + a larger stride for memory alignment). This is followed immediately + by an array of unsigned char containing interleaved Cb and Cr + samples. If these samples are addressed as a little-endian WORD + type, Cb would be in the least significant bits and Cr would be in + the most significant bits with the same total stride as the Y + samples. NV12 is the preferred 4:2:0 pixel format. + + A visual representation of the layout: + YYYY + YYYY + UVUV + + + History: + created 4/14/2013 + +**************************************************************************/ + +#include "Common.h" + +/************************************************************************** + + LOCKED CODE + +**************************************************************************/ + +#ifdef ALLOC_PRAGMA +#pragma code_seg() +#endif // ALLOC_PRAGMA + + +// suppressed due to Esp:773 +#pragma warning (push) +#pragma warning( disable:26015 ) // Suppress OACR error. Seems nonsensical. TODO: Must revisit. +#pragma warning( disable:26019 ) +_Success_(return > 0) +ULONG +CNV12Synthesizer:: +Commit( + _Out_writes_bytes_(Size) + PUCHAR Buffer, + _In_ ULONG Size, + _In_ ULONG Stride +) +/*++ + +Routine Description: + + Copy (and reformat, if necessary) pixels from the internal scratch + buffer. If the output format decimates chrominance, do it here. + +Arguments: + + Buffer - + The output buffer to fill. + + Size - + The size of the output buffer in bytes. + + Stride - + The length of a row in bytes. + +Return Value: + + Number of bytes copied into Buffer. + +--*/ +{ + // We assume the output stride is the same as the original width here. + UNREFERENCED_PARAMETER(Stride); + + // The code actually handles this gracefully. It rounds down. + NT_ASSERT( (m_Width&1) == 0 ); + NT_ASSERT( (m_Height&1) == 0 ); + + // These are impossible conditions. + if( !( Buffer && + m_Buffer && + (Size%6)==0 && // Should be evenly divisible by 1 macropixel + Size>=6 // At least 1 macropixel + ) ) + { + NT_ASSERT(FALSE); + return 0; + } + + ULONG MacroPixelsWide = m_Width/2; + + // Impossible. + if( MacroPixelsWide==0 ) + { + NT_ASSERT(FALSE); + return 0; + } + + // At most, 2/3rds of the available space is used by the Y plane. + // Notice that we limit the number of macro pixel rows to what will + // fit in the space available, no matter what is in the original. + ULONG Y_limit = (Size /3) * 2; + ULONG MacroPixelsHigh = min( m_Height, Y_limit/m_Width)/2; + + // Impossible. + if( MacroPixelsHigh==0 ) + { + NT_ASSERT(FALSE); + return 0; + } + + // Now we work back to arrive at the Y & UV plane sizes. + ULONG UV_size = MacroPixelsWide * MacroPixelsHigh *2; + ULONG Y_size = MacroPixelsWide * MacroPixelsHigh *4; + ULONG YUV_size = Y_size + UV_size; + + // Impossible. + if( Size < YUV_size ) + { + NT_ASSERT(FALSE); + return 0; + } + + PWORD pY = (PWORD) Buffer; + PWORD pUV = (PWORD) (Buffer + Y_size); + + for(ULONG row = 0; row < MacroPixelsHigh; row++) + { + PKS_RGBQUAD pSrc = (PKS_RGBQUAD) GetImageLocation(0, row*2); + for(ULONG col = 0; col < MacroPixelsWide; col++) + { + KS_RGBQUAD TL = pSrc[0]; + KS_RGBQUAD TR = pSrc[1]; + KS_RGBQUAD BL = pSrc[m_Width+0]; + KS_RGBQUAD BR = pSrc[m_Width+1]; + pSrc += 2; + + // Copy luma first + pY[0] = MAKEWORD(TL.rgbGreen, TR.rgbGreen); + pY[MacroPixelsWide] = MAKEWORD(BL.rgbGreen, BR.rgbGreen); + pY++; + + LONG + tU = TL.rgbBlue; //top left + tU += BL.rgbBlue; //bottom left + tU += TR.rgbBlue; //top right + tU += BR.rgbBlue; //bottom right + + LONG + tV = TL.rgbRed; //top left + tV += BL.rgbRed; //bottom left + tV += TR.rgbRed; //top right + tV += BR.rgbRed; //bottom right + + // Copy decimated chroma + *pUV++ = MAKEWORD(((tU+2)>>2), ((tV+2)>>2)); + } + // Skip a scan line, since we've already copied it. + pY += MacroPixelsWide; + } + + return (ULONG) (((PUCHAR) pUV) - Buffer); +} +// suppressed due to Esp:773 +#pragma warning (pop) + |