Source code of Windows XP (NT5)
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  1. //------------------------------------------------------------------------------
  2. // File: AMVideo.h
  3. //
  4. // Desc: Video related definitions and interfaces for ActiveMovie.
  5. //
  6. // Copyright (c) 1992 - 2000, Microsoft Corporation. All rights reserved.
  7. //------------------------------------------------------------------------------
  8. #ifndef __AMVIDEO__
  9. #define __AMVIDEO__
  10. #ifdef __cplusplus
  11. extern "C" {
  12. #endif // __cplusplus
  13. #include <ddraw.h>
  14. // This is an interface on the video renderer that provides information about
  15. // DirectDraw with respect to its use by the renderer. For example it allows
  16. // an application to get details of the surface and any hardware capabilities
  17. // that are available. It also allows someone to adjust the surfaces that the
  18. // renderer should use and furthermore even set the DirectDraw instance. We
  19. // allow someone to set the DirectDraw instance because DirectDraw can only
  20. // be opened once per process so it helps resolve conflicts. There is some
  21. // duplication in this interface as the hardware/emulated/FOURCCs available
  22. // can all be found through the IDirectDraw interface, this interface allows
  23. // simple access to that information without calling the DirectDraw provider
  24. // itself. The AMDDS prefix is ActiveMovie DirectDraw Switches abbreviated.
  25. #define AMDDS_NONE 0x00 // No use for DCI/DirectDraw
  26. #define AMDDS_DCIPS 0x01 // Use DCI primary surface
  27. #define AMDDS_PS 0x02 // Use DirectDraw primary
  28. #define AMDDS_RGBOVR 0x04 // RGB overlay surfaces
  29. #define AMDDS_YUVOVR 0x08 // YUV overlay surfaces
  30. #define AMDDS_RGBOFF 0x10 // RGB offscreen surfaces
  31. #define AMDDS_YUVOFF 0x20 // YUV offscreen surfaces
  32. #define AMDDS_RGBFLP 0x40 // RGB flipping surfaces
  33. #define AMDDS_YUVFLP 0x80 // YUV flipping surfaces
  34. #define AMDDS_ALL 0xFF // ALL the previous flags
  35. #define AMDDS_DEFAULT AMDDS_ALL // Use all available surfaces
  36. #define AMDDS_YUV (AMDDS_YUVOFF | AMDDS_YUVOVR | AMDDS_YUVFLP)
  37. #define AMDDS_RGB (AMDDS_RGBOFF | AMDDS_RGBOVR | AMDDS_RGBFLP)
  38. #define AMDDS_PRIMARY (AMDDS_DCIPS | AMDDS_PS)
  39. // be nice to our friends in C
  40. #undef INTERFACE
  41. #define INTERFACE IDirectDrawVideo
  42. DECLARE_INTERFACE_(IDirectDrawVideo, IUnknown)
  43. {
  44. // IUnknown methods
  45. STDMETHOD(QueryInterface)(THIS_ REFIID riid, LPVOID *ppvObj) PURE;
  46. STDMETHOD_(ULONG,AddRef)(THIS) PURE;
  47. STDMETHOD_(ULONG,Release)(THIS) PURE;
  48. // IDirectDrawVideo methods
  49. STDMETHOD(GetSwitches)(THIS_ DWORD *pSwitches) PURE;
  50. STDMETHOD(SetSwitches)(THIS_ DWORD Switches) PURE;
  51. STDMETHOD(GetCaps)(THIS_ DDCAPS *pCaps) PURE;
  52. STDMETHOD(GetEmulatedCaps)(THIS_ DDCAPS *pCaps) PURE;
  53. STDMETHOD(GetSurfaceDesc)(THIS_ DDSURFACEDESC *pSurfaceDesc) PURE;
  54. STDMETHOD(GetFourCCCodes)(THIS_ DWORD *pCount,DWORD *pCodes) PURE;
  55. STDMETHOD(SetDirectDraw)(THIS_ LPDIRECTDRAW pDirectDraw) PURE;
  56. STDMETHOD(GetDirectDraw)(THIS_ LPDIRECTDRAW *ppDirectDraw) PURE;
  57. STDMETHOD(GetSurfaceType)(THIS_ DWORD *pSurfaceType) PURE;
  58. STDMETHOD(SetDefault)(THIS) PURE;
  59. STDMETHOD(UseScanLine)(THIS_ long UseScanLine) PURE;
  60. STDMETHOD(CanUseScanLine)(THIS_ long *UseScanLine) PURE;
  61. STDMETHOD(UseOverlayStretch)(THIS_ long UseOverlayStretch) PURE;
  62. STDMETHOD(CanUseOverlayStretch)(THIS_ long *UseOverlayStretch) PURE;
  63. STDMETHOD(UseWhenFullScreen)(THIS_ long UseWhenFullScreen) PURE;
  64. STDMETHOD(WillUseFullScreen)(THIS_ long *UseWhenFullScreen) PURE;
  65. };
  66. // be nice to our friends in C
  67. #undef INTERFACE
  68. #define INTERFACE IQualProp
  69. DECLARE_INTERFACE_(IQualProp, IUnknown)
  70. {
  71. // IUnknown methods
  72. STDMETHOD(QueryInterface)(THIS_ REFIID riid, LPVOID *ppvObj) PURE;
  73. STDMETHOD_(ULONG,AddRef)(THIS) PURE;
  74. STDMETHOD_(ULONG,Release)(THIS) PURE;
  75. // Compare these with the functions in class CGargle in gargle.h
  76. STDMETHOD(get_FramesDroppedInRenderer)(THIS_ int *pcFrames) PURE; // Out
  77. STDMETHOD(get_FramesDrawn)(THIS_ int *pcFramesDrawn) PURE; // Out
  78. STDMETHOD(get_AvgFrameRate)(THIS_ int *piAvgFrameRate) PURE; // Out
  79. STDMETHOD(get_Jitter)(THIS_ int *iJitter) PURE; // Out
  80. STDMETHOD(get_AvgSyncOffset)(THIS_ int *piAvg) PURE; // Out
  81. STDMETHOD(get_DevSyncOffset)(THIS_ int *piDev) PURE; // Out
  82. };
  83. // This interface allows an application or plug in distributor to control a
  84. // full screen renderer. The Modex renderer supports this interface. When
  85. // connected a renderer should load the display modes it has available
  86. // The number of modes available can be obtained through CountModes. Then
  87. // information on each individual mode is available by calling GetModeInfo
  88. // and IsModeAvailable. An application may enable and disable any modes
  89. // by calling the SetEnabled flag with OATRUE or OAFALSE (not C/C++ TRUE
  90. // and FALSE values) - the current value may be queried by IsModeEnabled
  91. // A more generic way of setting the modes enabled that is easier to use
  92. // when writing applications is the clip loss factor. This defines the
  93. // amount of video that can be lost when deciding which display mode to
  94. // use. Assuming the decoder cannot compress the video then playing an
  95. // MPEG file (say 352x288) into a 320x200 display will lose about 25% of
  96. // the image. The clip loss factor specifies the upper range permissible.
  97. // To allow typical MPEG video to be played in 320x200 it defaults to 25%
  98. // be nice to our friends in C
  99. #undef INTERFACE
  100. #define INTERFACE IFullScreenVideo
  101. DECLARE_INTERFACE_(IFullScreenVideo, IUnknown)
  102. {
  103. // IUnknown methods
  104. STDMETHOD(QueryInterface)(THIS_ REFIID riid, LPVOID *ppvObj) PURE;
  105. STDMETHOD_(ULONG,AddRef)(THIS) PURE;
  106. STDMETHOD_(ULONG,Release)(THIS) PURE;
  107. // IFullScreenVideo methods
  108. STDMETHOD(CountModes)(THIS_ long *pModes) PURE;
  109. STDMETHOD(GetModeInfo)(THIS_ long Mode,long *pWidth,long *pHeight,long *pDepth) PURE;
  110. STDMETHOD(GetCurrentMode)(THIS_ long *pMode) PURE;
  111. STDMETHOD(IsModeAvailable)(THIS_ long Mode) PURE;
  112. STDMETHOD(IsModeEnabled)(THIS_ long Mode) PURE;
  113. STDMETHOD(SetEnabled)(THIS_ long Mode,long bEnabled) PURE;
  114. STDMETHOD(GetClipFactor)(THIS_ long *pClipFactor) PURE;
  115. STDMETHOD(SetClipFactor)(THIS_ long ClipFactor) PURE;
  116. STDMETHOD(SetMessageDrain)(THIS_ HWND hwnd) PURE;
  117. STDMETHOD(GetMessageDrain)(THIS_ HWND *hwnd) PURE;
  118. STDMETHOD(SetMonitor)(THIS_ long Monitor) PURE;
  119. STDMETHOD(GetMonitor)(THIS_ long *Monitor) PURE;
  120. STDMETHOD(HideOnDeactivate)(THIS_ long Hide) PURE;
  121. STDMETHOD(IsHideOnDeactivate)(THIS) PURE;
  122. STDMETHOD(SetCaption)(THIS_ BSTR strCaption) PURE;
  123. STDMETHOD(GetCaption)(THIS_ BSTR *pstrCaption) PURE;
  124. STDMETHOD(SetDefault)(THIS) PURE;
  125. };
  126. // This adds the accelerator table capabilities in fullscreen. This is being
  127. // added between the original runtime release and the full SDK release. We
  128. // cannot just add the method to IFullScreenVideo as we don't want to force
  129. // applications to have to ship the ActiveMovie support DLLs - this is very
  130. // important to applications that plan on being downloaded over the Internet
  131. // be nice to our friends in C
  132. #undef INTERFACE
  133. #define INTERFACE IFullScreenVideoEx
  134. DECLARE_INTERFACE_(IFullScreenVideoEx, IFullScreenVideo)
  135. {
  136. // IUnknown methods
  137. STDMETHOD(QueryInterface)(THIS_ REFIID riid, LPVOID *ppvObj) PURE;
  138. STDMETHOD_(ULONG,AddRef)(THIS) PURE;
  139. STDMETHOD_(ULONG,Release)(THIS) PURE;
  140. // IFullScreenVideo methods
  141. STDMETHOD(CountModes)(THIS_ long *pModes) PURE;
  142. STDMETHOD(GetModeInfo)(THIS_ long Mode,long *pWidth,long *pHeight,long *pDepth) PURE;
  143. STDMETHOD(GetCurrentMode)(THIS_ long *pMode) PURE;
  144. STDMETHOD(IsModeAvailable)(THIS_ long Mode) PURE;
  145. STDMETHOD(IsModeEnabled)(THIS_ long Mode) PURE;
  146. STDMETHOD(SetEnabled)(THIS_ long Mode,long bEnabled) PURE;
  147. STDMETHOD(GetClipFactor)(THIS_ long *pClipFactor) PURE;
  148. STDMETHOD(SetClipFactor)(THIS_ long ClipFactor) PURE;
  149. STDMETHOD(SetMessageDrain)(THIS_ HWND hwnd) PURE;
  150. STDMETHOD(GetMessageDrain)(THIS_ HWND *hwnd) PURE;
  151. STDMETHOD(SetMonitor)(THIS_ long Monitor) PURE;
  152. STDMETHOD(GetMonitor)(THIS_ long *Monitor) PURE;
  153. STDMETHOD(HideOnDeactivate)(THIS_ long Hide) PURE;
  154. STDMETHOD(IsHideOnDeactivate)(THIS) PURE;
  155. STDMETHOD(SetCaption)(THIS_ BSTR strCaption) PURE;
  156. STDMETHOD(GetCaption)(THIS_ BSTR *pstrCaption) PURE;
  157. STDMETHOD(SetDefault)(THIS) PURE;
  158. // IFullScreenVideoEx
  159. STDMETHOD(SetAcceleratorTable)(THIS_ HWND hwnd,HACCEL hAccel) PURE;
  160. STDMETHOD(GetAcceleratorTable)(THIS_ HWND *phwnd,HACCEL *phAccel) PURE;
  161. STDMETHOD(KeepPixelAspectRatio)(THIS_ long KeepAspect) PURE;
  162. STDMETHOD(IsKeepPixelAspectRatio)(THIS_ long *pKeepAspect) PURE;
  163. };
  164. // The SDK base classes contain a base video mixer class. Video mixing in a
  165. // software environment is tricky because we typically have multiple streams
  166. // each sending data at unpredictable times. To work with this we defined a
  167. // pin that is the lead pin, when data arrives on this pin we do a mix. As
  168. // an alternative we may not want to have a lead pin but output samples at
  169. // predefined spaces, like one every 1/15 of a second, this interfaces also
  170. // supports that mode of operations (there is a working video mixer sample)
  171. // be nice to our friends in C
  172. #undef INTERFACE
  173. #define INTERFACE IBaseVideoMixer
  174. DECLARE_INTERFACE_(IBaseVideoMixer, IUnknown)
  175. {
  176. STDMETHOD(SetLeadPin)(THIS_ int iPin) PURE;
  177. STDMETHOD(GetLeadPin)(THIS_ int *piPin) PURE;
  178. STDMETHOD(GetInputPinCount)(THIS_ int *piPinCount) PURE;
  179. STDMETHOD(IsUsingClock)(THIS_ int *pbValue) PURE;
  180. STDMETHOD(SetUsingClock)(THIS_ int bValue) PURE;
  181. STDMETHOD(GetClockPeriod)(THIS_ int *pbValue) PURE;
  182. STDMETHOD(SetClockPeriod)(THIS_ int bValue) PURE;
  183. };
  184. #define iPALETTE_COLORS 256 // Maximum colours in palette
  185. #define iEGA_COLORS 16 // Number colours in EGA palette
  186. #define iMASK_COLORS 3 // Maximum three components
  187. #define iTRUECOLOR 16 // Minimum true colour device
  188. #define iRED 0 // Index position for RED mask
  189. #define iGREEN 1 // Index position for GREEN mask
  190. #define iBLUE 2 // Index position for BLUE mask
  191. #define iPALETTE 8 // Maximum colour depth using a palette
  192. #define iMAXBITS 8 // Maximum bits per colour component
  193. // Used for true colour images that also have a palette
  194. typedef struct tag_TRUECOLORINFO {
  195. DWORD dwBitMasks[iMASK_COLORS];
  196. RGBQUAD bmiColors[iPALETTE_COLORS];
  197. } TRUECOLORINFO;
  198. // The BITMAPINFOHEADER contains all the details about the video stream such
  199. // as the actual image dimensions and their pixel depth. A source filter may
  200. // also request that the sink take only a section of the video by providing a
  201. // clipping rectangle in rcSource. In the worst case where the sink filter
  202. // forgets to check this on connection it will simply render the whole thing
  203. // which isn't a disaster. Ideally a sink filter will check the rcSource and
  204. // if it doesn't support image extraction and the rectangle is not empty then
  205. // it will reject the connection. A filter should use SetRectEmpty to reset a
  206. // rectangle to all zeroes (and IsRectEmpty to later check the rectangle).
  207. // The rcTarget specifies the destination rectangle for the video, for most
  208. // source filters they will set this to all zeroes, a downstream filter may
  209. // request that the video be placed in a particular area of the buffers it
  210. // supplies in which case it will call QueryAccept with a non empty target
  211. typedef struct tagVIDEOINFOHEADER {
  212. RECT rcSource; // The bit we really want to use
  213. RECT rcTarget; // Where the video should go
  214. DWORD dwBitRate; // Approximate bit data rate
  215. DWORD dwBitErrorRate; // Bit error rate for this stream
  216. REFERENCE_TIME AvgTimePerFrame; // Average time per frame (100ns units)
  217. BITMAPINFOHEADER bmiHeader;
  218. } VIDEOINFOHEADER;
  219. // make sure the pbmi is initialized before using these macros
  220. #define TRUECOLOR(pbmi) ((TRUECOLORINFO *)(((LPBYTE)&((pbmi)->bmiHeader)) \
  221. + (pbmi)->bmiHeader.biSize))
  222. #define COLORS(pbmi) ((RGBQUAD *)(((LPBYTE)&((pbmi)->bmiHeader)) \
  223. + (pbmi)->bmiHeader.biSize))
  224. #define BITMASKS(pbmi) ((DWORD *)(((LPBYTE)&((pbmi)->bmiHeader)) \
  225. + (pbmi)->bmiHeader.biSize))
  226. // All the image based filters use this to communicate their media types. It's
  227. // centred principally around the BITMAPINFO. This structure always contains a
  228. // BITMAPINFOHEADER followed by a number of other fields depending on what the
  229. // BITMAPINFOHEADER contains. If it contains details of a palettised format it
  230. // will be followed by one or more RGBQUADs defining the palette. If it holds
  231. // details of a true colour format then it may be followed by a set of three
  232. // DWORD bit masks that specify where the RGB data can be found in the image
  233. // (For more information regarding BITMAPINFOs see the Win32 documentation)
  234. // The rcSource and rcTarget fields are not for use by filters supplying the
  235. // data. The destination (target) rectangle should be set to all zeroes. The
  236. // source may also be zero filled or set with the dimensions of the video. So
  237. // if the video is 352x288 pixels then set it to (0,0,352,288). These fields
  238. // are mainly used by downstream filters that want to ask the source filter
  239. // to place the image in a different position in an output buffer. So when
  240. // using for example the primary surface the video renderer may ask a filter
  241. // to place the video images in a destination position of (100,100,452,388)
  242. // on the display since that's where the window is positioned on the display
  243. // !!! WARNING !!!
  244. // DO NOT use this structure unless you are sure that the BITMAPINFOHEADER
  245. // has a normal biSize == sizeof(BITMAPINFOHEADER) !
  246. // !!! WARNING !!!
  247. typedef struct tagVIDEOINFO {
  248. RECT rcSource; // The bit we really want to use
  249. RECT rcTarget; // Where the video should go
  250. DWORD dwBitRate; // Approximate bit data rate
  251. DWORD dwBitErrorRate; // Bit error rate for this stream
  252. REFERENCE_TIME AvgTimePerFrame; // Average time per frame (100ns units)
  253. BITMAPINFOHEADER bmiHeader;
  254. union {
  255. RGBQUAD bmiColors[iPALETTE_COLORS]; // Colour palette
  256. DWORD dwBitMasks[iMASK_COLORS]; // True colour masks
  257. TRUECOLORINFO TrueColorInfo; // Both of the above
  258. };
  259. } VIDEOINFO;
  260. // These macros define some standard bitmap format sizes
  261. #define SIZE_EGA_PALETTE (iEGA_COLORS * sizeof(RGBQUAD))
  262. #define SIZE_PALETTE (iPALETTE_COLORS * sizeof(RGBQUAD))
  263. #define SIZE_MASKS (iMASK_COLORS * sizeof(DWORD))
  264. #define SIZE_PREHEADER (FIELD_OFFSET(VIDEOINFOHEADER,bmiHeader))
  265. #define SIZE_VIDEOHEADER (sizeof(BITMAPINFOHEADER) + SIZE_PREHEADER)
  266. // !!! for abnormal biSizes
  267. // #define SIZE_VIDEOHEADER(pbmi) ((pbmi)->bmiHeader.biSize + SIZE_PREHEADER)
  268. // DIBSIZE calculates the number of bytes required by an image
  269. #define WIDTHBYTES(bits) ((DWORD)(((bits)+31) & (~31)) / 8)
  270. #define DIBWIDTHBYTES(bi) (DWORD)WIDTHBYTES((DWORD)(bi).biWidth * (DWORD)(bi).biBitCount)
  271. #define _DIBSIZE(bi) (DIBWIDTHBYTES(bi) * (DWORD)(bi).biHeight)
  272. #define DIBSIZE(bi) ((bi).biHeight < 0 ? (-1)*(_DIBSIZE(bi)) : _DIBSIZE(bi))
  273. // This compares the bit masks between two VIDEOINFOHEADERs
  274. #define BIT_MASKS_MATCH(pbmi1,pbmi2) \
  275. (((pbmi1)->dwBitMasks[iRED] == (pbmi2)->dwBitMasks[iRED]) && \
  276. ((pbmi1)->dwBitMasks[iGREEN] == (pbmi2)->dwBitMasks[iGREEN]) && \
  277. ((pbmi1)->dwBitMasks[iBLUE] == (pbmi2)->dwBitMasks[iBLUE]))
  278. // These zero fill different parts of the VIDEOINFOHEADER structure
  279. // Only use these macros for pbmi's with a normal BITMAPINFOHEADER biSize
  280. #define RESET_MASKS(pbmi) (ZeroMemory((PVOID)(pbmi)->dwBitFields,SIZE_MASKS))
  281. #define RESET_HEADER(pbmi) (ZeroMemory((PVOID)(pbmi),SIZE_VIDEOHEADER))
  282. #define RESET_PALETTE(pbmi) (ZeroMemory((PVOID)(pbmi)->bmiColors,SIZE_PALETTE));
  283. #if 0
  284. // !!! This is the right way to do it, but may break existing code
  285. #define RESET_MASKS(pbmi) (ZeroMemory((PVOID)(((LPBYTE)(pbmi)->bmiHeader) + \
  286. (pbmi)->bmiHeader.biSize,SIZE_MASKS)))
  287. #define RESET_HEADER(pbmi) (ZeroMemory((PVOID)(pbmi), SIZE_PREHEADER + \
  288. sizeof(BITMAPINFOHEADER)))
  289. #define RESET_PALETTE(pbmi) (ZeroMemory((PVOID)(((LPBYTE)(pbmi)->bmiHeader) + \
  290. (pbmi)->bmiHeader.biSize,SIZE_PALETTE))
  291. #endif
  292. // Other (hopefully) useful bits and bobs
  293. #define PALETTISED(pbmi) ((pbmi)->bmiHeader.biBitCount <= iPALETTE)
  294. #define PALETTE_ENTRIES(pbmi) ((DWORD) 1 << (pbmi)->bmiHeader.biBitCount)
  295. // Returns the address of the BITMAPINFOHEADER from the VIDEOINFOHEADER
  296. #define HEADER(pVideoInfo) (&(((VIDEOINFOHEADER *) (pVideoInfo))->bmiHeader))
  297. // MPEG variant - includes a DWORD length followed by the
  298. // video sequence header after the video header.
  299. //
  300. // The sequence header includes the sequence header start code and the
  301. // quantization matrices associated with the first sequence header in the
  302. // stream so is a maximum of 140 bytes long.
  303. typedef struct tagMPEG1VIDEOINFO {
  304. VIDEOINFOHEADER hdr; // Compatible with VIDEOINFO
  305. DWORD dwStartTimeCode; // 25-bit Group of pictures time code
  306. // at start of data
  307. DWORD cbSequenceHeader; // Length in bytes of bSequenceHeader
  308. BYTE bSequenceHeader[1]; // Sequence header including
  309. // quantization matrices if any
  310. } MPEG1VIDEOINFO;
  311. #define MAX_SIZE_MPEG1_SEQUENCE_INFO 140
  312. #define SIZE_MPEG1VIDEOINFO(pv) (FIELD_OFFSET(MPEG1VIDEOINFO, bSequenceHeader[0]) + (pv)->cbSequenceHeader)
  313. #define MPEG1_SEQUENCE_INFO(pv) ((const BYTE *)(pv)->bSequenceHeader)
  314. // Analog video variant - Use this when the format is FORMAT_AnalogVideo
  315. //
  316. // rcSource defines the portion of the active video signal to use
  317. // rcTarget defines the destination rectangle
  318. // both of the above are relative to the dwActiveWidth and dwActiveHeight fields
  319. // dwActiveWidth is currently set to 720 for all formats (but could change for HDTV)
  320. // dwActiveHeight is 483 for NTSC and 575 for PAL/SECAM (but could change for HDTV)
  321. typedef struct tagAnalogVideoInfo {
  322. RECT rcSource; // Width max is 720, height varies w/ TransmissionStd
  323. RECT rcTarget; // Where the video should go
  324. DWORD dwActiveWidth; // Always 720 (CCIR-601 active samples per line)
  325. DWORD dwActiveHeight; // 483 for NTSC, 575 for PAL/SECAM
  326. REFERENCE_TIME AvgTimePerFrame; // Normal ActiveMovie units (100 nS)
  327. } ANALOGVIDEOINFO;
  328. //
  329. // AM_KSPROPSETID_FrameStep property set definitions
  330. //
  331. typedef enum {
  332. // Step
  333. AM_PROPERTY_FRAMESTEP_STEP = 0x01,
  334. AM_PROPERTY_FRAMESTEP_CANCEL = 0x02,
  335. // S_OK for these 2 means we can - S_FALSE if we can't
  336. AM_PROPERTY_FRAMESTEP_CANSTEP = 0x03,
  337. AM_PROPERTY_FRAMESTEP_CANSTEPMULTIPLE = 0x04
  338. } AM_PROPERTY_FRAMESTEP;
  339. typedef struct _AM_FRAMESTEP_STEP
  340. {
  341. // 1 means step 1 frame forward
  342. // 0 is invalid
  343. // n (n > 1) means skip n - 1 frames and show the nth
  344. DWORD dwFramesToStep;
  345. } AM_FRAMESTEP_STEP;
  346. #ifdef __cplusplus
  347. }
  348. #endif // __cplusplus
  349. #endif // __AMVIDEO__