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102 lines
3.5 KiB
102 lines
3.5 KiB
CHANGES TO MCIAVI FOR 1.X:
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"other" streams are handled correctly, rectangle's will be
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mapped correctly and draw handlers will be called.
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draw handlers:
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DIB draw handler, there can now be a draw device for uncomressed
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frames, for example hardware can stretch frames, but does not
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need to decomptress.
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the full screen draw handler (DIB draw handler...) can be replaced.
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custom draw handlers can be installed per stream. (a app can
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override the default). This is done with a new MCI command
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to set the draw procedure.
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formats:
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32 bit DIBs are supported, a decompressor can decompress to
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a 32 bit DIB if wants to.
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decompression to special DIB formats:
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upside down DIB
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MCIAVI will ask the decompressor in decompress to a "upside down"
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DIB. a "upside down" is a DIB with the scans stored in memory
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top scan to bottom scan, (normal DIBs are stored bottom to top)
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a "upside down" DIB will have a negative biHeight, the height
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of the DIB is abs(biHeight). the bits pointer passed points
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to the top scan, ie the first one.
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special DIB formats:
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to handle decompression to internal bitmaps in memory, a "new"
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DIB format is used, when biCompression == 'BITM' the DIB memory
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is in HUGE BITMAP format:
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biCompression 'BITM'
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biHeight will be <0 for a top to bottom bitmap.
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biXPelsPerMeter will be the width bytes of the bitmap.
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biYPelsPerMeter will be the fill bytes of the bitmap.
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key frame info:
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a new structure is passed to ICM_DECOMPRESS:
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struct {
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DWORD dwFlags; // flags (from AVI index...)
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LPBITMAPINFOHEADER lpbiInput; // BITMAPINFO of compressed data
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LPVOID lpInput; // compressed data
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LPBITMAPINFOHEADER lpbiOutput; // DIB to decompress to
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LPVOID lpOutput;
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DWORD ckid; // ckid from AVI file
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int iFrame; // frame info.
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int iNextKey;
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int iPrevKey;
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} ICDECOMPRESSX;
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NOTE before using any of the extra info in this structure the
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deompressor should check the size field.
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example:
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case ICM_DECOMPRESS:
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//
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// make sure we have a ICDECOMPRESSX structure
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//
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if ((DWORD)lParam2 >= sizeof(ICDEOMPRESSX))
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return DecompressX(pi,
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(ICDECOMPRESSX FAR *)lParam1, (DWORD)lParam2);
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else
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return Decompress(pi,
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(ICDECOMPRESS FAR *)lParam1, (DWORD)lParam2);
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NEW MESSAGE ICM_SET
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#define ICM_SET (ICM_RESERVED+40)
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#define ICM_FRAMERATE mmioFOURCC('F','r','m','R')
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#define ICM_KEYFRAMERATE mmioFOURCC('K','e','y','R')
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before playing starts two params get sent down to the decompressor:
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ICM_SET
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lParam1 = 'FrmR' (set the frame rate)
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lParam2 = microseconds per frame
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ICM_SET
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lParam1 = 'KeyR' (set the key frame "rate")
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lParam2 = average key frame rate (ie key frame every 15)
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NOTE the key frame rate is a average.
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TO DO:
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named streams.
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multiple video streams.
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linked streams (data in another file...)
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