276 lines
9.4 KiB
C++
276 lines
9.4 KiB
C++
//------------------------------------------------------------------------------
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// File: AMVideo.cpp
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//
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// Desc: DirectShow base classes - implements helper functions for
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// bitmap formats.
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//
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// Copyright (c) 1992-2001 Microsoft Corporation. All rights reserved.
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//------------------------------------------------------------------------------
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#include <streams.h>
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#include <limits.h>
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// These are bit field masks for true colour devices
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const DWORD bits555[] = {0x007C00,0x0003E0,0x00001F};
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const DWORD bits565[] = {0x00F800,0x0007E0,0x00001F};
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const DWORD bits888[] = {0xFF0000,0x00FF00,0x0000FF};
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// This maps bitmap subtypes into a bits per pixel value and also a
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// name. unicode and ansi versions are stored because we have to
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// return a pointer to a static string.
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const struct {
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const GUID *pSubtype;
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WORD BitCount;
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const CHAR *pName;
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const WCHAR *wszName;
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} BitCountMap[] = { &MEDIASUBTYPE_RGB1, 1, "RGB Monochrome", L"RGB Monochrome",
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&MEDIASUBTYPE_RGB4, 4, "RGB VGA", L"RGB VGA",
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&MEDIASUBTYPE_RGB8, 8, "RGB 8", L"RGB 8",
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&MEDIASUBTYPE_RGB565, 16, "RGB 565 (16 bit)", L"RGB 565 (16 bit)",
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&MEDIASUBTYPE_RGB555, 16, "RGB 555 (16 bit)", L"RGB 555 (16 bit)",
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&MEDIASUBTYPE_RGB24, 24, "RGB 24", L"RGB 24",
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&MEDIASUBTYPE_RGB32, 32, "RGB 32", L"RGB 32",
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&MEDIASUBTYPE_ARGB32, 32, "ARGB 32", L"ARGB 32",
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&MEDIASUBTYPE_Overlay, 0, "Overlay", L"Overlay",
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&GUID_NULL, 0, "UNKNOWN", L"UNKNOWN"
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};
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// Return the size of the bitmap as defined by this header
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STDAPI_(DWORD) GetBitmapSize(const BITMAPINFOHEADER *pHeader)
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{
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return DIBSIZE(*pHeader);
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}
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// This is called if the header has a 16 bit colour depth and needs to work
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// out the detailed type from the bit fields (either RGB 565 or RGB 555)
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STDAPI_(const GUID) GetTrueColorType(const BITMAPINFOHEADER *pbmiHeader)
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{
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BITMAPINFO *pbmInfo = (BITMAPINFO *) pbmiHeader;
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ASSERT(pbmiHeader->biBitCount == 16);
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// If its BI_RGB then it's RGB 555 by default
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if (pbmiHeader->biCompression == BI_RGB) {
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return MEDIASUBTYPE_RGB555;
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}
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// Compare the bit fields with RGB 555
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DWORD *pMask = (DWORD *) pbmInfo->bmiColors;
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if (pMask[0] == bits555[0]) {
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if (pMask[1] == bits555[1]) {
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if (pMask[2] == bits555[2]) {
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return MEDIASUBTYPE_RGB555;
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}
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}
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}
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// Compare the bit fields with RGB 565
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pMask = (DWORD *) pbmInfo->bmiColors;
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if (pMask[0] == bits565[0]) {
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if (pMask[1] == bits565[1]) {
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if (pMask[2] == bits565[2]) {
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return MEDIASUBTYPE_RGB565;
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}
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}
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}
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return GUID_NULL;
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}
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// Given a BITMAPINFOHEADER structure this returns the GUID sub type that is
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// used to describe it in format negotiations. For example a video codec fills
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// in the format block with a VIDEOINFO structure, it also fills in the major
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// type with MEDIATYPE_VIDEO and the subtype with a GUID that matches the bit
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// count, for example if it is an eight bit image then MEDIASUBTYPE_RGB8
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STDAPI_(const GUID) GetBitmapSubtype(const BITMAPINFOHEADER *pbmiHeader)
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{
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ASSERT(pbmiHeader);
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// If it's not RGB then create a GUID from the compression type
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if (pbmiHeader->biCompression != BI_RGB) {
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if (pbmiHeader->biCompression != BI_BITFIELDS) {
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FOURCCMap FourCCMap(pbmiHeader->biCompression);
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return (const GUID) FourCCMap;
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}
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}
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// Map the RGB DIB bit depth to a image GUID
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switch(pbmiHeader->biBitCount) {
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case 1 : return MEDIASUBTYPE_RGB1;
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case 4 : return MEDIASUBTYPE_RGB4;
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case 8 : return MEDIASUBTYPE_RGB8;
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case 16 : return GetTrueColorType(pbmiHeader);
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case 24 : return MEDIASUBTYPE_RGB24;
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case 32 : return MEDIASUBTYPE_RGB32;
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}
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return GUID_NULL;
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}
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// Given a video bitmap subtype we return the number of bits per pixel it uses
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// We return a WORD bit count as thats what the BITMAPINFOHEADER uses. If the
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// GUID subtype is not found in the table we return an invalid USHRT_MAX
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STDAPI_(WORD) GetBitCount(const GUID *pSubtype)
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{
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ASSERT(pSubtype);
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const GUID *pMediaSubtype;
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INT iPosition = 0;
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// Scan the mapping list seeing if the source GUID matches any known
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// bitmap subtypes, the list is terminated by a GUID_NULL entry
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while (TRUE) {
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pMediaSubtype = BitCountMap[iPosition].pSubtype;
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if (IsEqualGUID(*pMediaSubtype,GUID_NULL)) {
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return USHRT_MAX;
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}
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if (IsEqualGUID(*pMediaSubtype,*pSubtype)) {
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return BitCountMap[iPosition].BitCount;
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}
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iPosition++;
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}
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}
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// Given a bitmap subtype we return a description name that can be used for
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// debug purposes. In a retail build this function still returns the names
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// If the subtype isn't found in the lookup table we return string UNKNOWN
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int LocateSubtype(const GUID *pSubtype)
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{
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ASSERT(pSubtype);
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const GUID *pMediaSubtype;
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INT iPosition = 0;
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// Scan the mapping list seeing if the source GUID matches any known
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// bitmap subtypes, the list is terminated by a GUID_NULL entry
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while (TRUE) {
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pMediaSubtype = BitCountMap[iPosition].pSubtype;
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if (IsEqualGUID(*pMediaSubtype,*pSubtype) ||
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IsEqualGUID(*pMediaSubtype,GUID_NULL)
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)
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{
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break;
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}
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iPosition++;
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}
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return iPosition;
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}
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STDAPI_(const WCHAR *) GetSubtypeNameW(const GUID *pSubtype)
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{
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return BitCountMap[LocateSubtype(pSubtype)].wszName;
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}
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STDAPI_(const CHAR *) GetSubtypeNameA(const GUID *pSubtype)
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{
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return BitCountMap[LocateSubtype(pSubtype)].pName;
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}
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#ifndef GetSubtypeName
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#error wxutil.h should have defined GetSubtypeName
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#endif
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#undef GetSubtypeName
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// this is here for people that linked to it directly; most people
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// would use the header file that picks the A or W version.
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STDAPI_(const CHAR *) GetSubtypeName(const GUID *pSubtype)
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{
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return GetSubtypeNameA(pSubtype);
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}
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// The mechanism for describing a bitmap format is with the BITMAPINFOHEADER
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// This is really messy to deal with because it invariably has fields that
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// follow it holding bit fields, palettes and the rest. This function gives
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// the number of bytes required to hold a VIDEOINFO that represents it. This
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// count includes the prefix information (like the rcSource rectangle) the
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// BITMAPINFOHEADER field, and any other colour information on the end.
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//
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// WARNING If you want to copy a BITMAPINFOHEADER into a VIDEOINFO always make
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// sure that you use the HEADER macro because the BITMAPINFOHEADER field isn't
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// right at the start of the VIDEOINFO (there are a number of other fields),
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//
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// CopyMemory(HEADER(pVideoInfo),pbmi,sizeof(BITMAPINFOHEADER));
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//
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STDAPI_(LONG) GetBitmapFormatSize(const BITMAPINFOHEADER *pHeader)
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{
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// Everyone has this to start with this
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LONG Size = SIZE_PREHEADER + pHeader->biSize;
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ASSERT(pHeader->biSize >= sizeof(BITMAPINFOHEADER));
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// Does this format use a palette, if the number of colours actually used
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// is zero then it is set to the maximum that are allowed for that colour
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// depth (an example is 256 for eight bits). Truecolour formats may also
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// pass a palette with them in which case the used count is non zero
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// This would scare me.
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ASSERT(pHeader->biBitCount <= iPALETTE || pHeader->biClrUsed == 0);
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if (pHeader->biBitCount <= iPALETTE || pHeader->biClrUsed) {
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LONG Entries = (DWORD) 1 << pHeader->biBitCount;
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if (pHeader->biClrUsed) {
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Entries = pHeader->biClrUsed;
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}
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Size += Entries * sizeof(RGBQUAD);
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}
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// Truecolour formats may have a BI_BITFIELDS specifier for compression
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// type which means that room for three DWORDs should be allocated that
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// specify where in each pixel the RGB colour components may be found
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if (pHeader->biCompression == BI_BITFIELDS) {
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Size += SIZE_MASKS;
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}
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// A BITMAPINFO for a palettised image may also contain a palette map that
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// provides the information to map from a source palette to a destination
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// palette during a BitBlt for example, because this information is only
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// ever processed during drawing you don't normally store the palette map
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// nor have any way of knowing if it is present in the data structure
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return Size;
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}
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// Returns TRUE if the VIDEOINFO contains a palette
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STDAPI_(BOOL) ContainsPalette(const VIDEOINFOHEADER *pVideoInfo)
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{
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if (PALETTISED(pVideoInfo) == FALSE) {
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if (pVideoInfo->bmiHeader.biClrUsed == 0) {
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return FALSE;
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}
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}
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return TRUE;
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}
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// Return a pointer to the first entry in a palette
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STDAPI_(const RGBQUAD *) GetBitmapPalette(const VIDEOINFOHEADER *pVideoInfo)
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{
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if (pVideoInfo->bmiHeader.biCompression == BI_BITFIELDS) {
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return TRUECOLOR(pVideoInfo)->bmiColors;
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}
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return COLORS(pVideoInfo);
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}
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