Commit 5d4d503f authored by Ramiro Polla's avatar Ramiro Polla
Browse files

Document some more of SwsContext.

Originally committed as revision 30380 to svn://svn.mplayerhq.hu/mplayer/trunk/libswscale
parent 97775235
......@@ -86,35 +86,67 @@ typedef struct SwsContext {
int lumYInc, chrYInc;
enum PixelFormat dstFormat; ///< Destination pixel format.
enum PixelFormat srcFormat; ///< Source pixel format.
int chrSrcHSubSample, chrSrcVSubSample;
int chrDstHSubSample, chrDstVSubSample;
int vChrDrop;
int sliceDir;
int chrSrcHSubSample; ///< Binary logarithm of horizontal subsampling factor between luma/alpha and chroma planes in source image.
int chrSrcVSubSample; ///< Binary logarithm of vertical subsampling factor between luma/alpha and chroma planes in source image.
int chrDstHSubSample; ///< Binary logarithm of horizontal subsampling factor between luma/alpha and chroma planes in destination image.
int chrDstVSubSample; ///< Binary logarithm of vertical subsampling factor between luma/alpha and chroma planes in destination image.
int vChrDrop; ///< Binary logarithm of extra vertical subsampling factor in source image chroma planes specified by user.
int sliceDir; ///< Direction that slices are fed to the scaler (1 = top-to-bottom, -1 = bottom-to-top).
double param[2]; ///< Input parameters for scaling algorithms that need them.
uint32_t pal_yuv[256];
uint32_t pal_rgb[256];
int16_t **lumPixBuf;
int16_t **chrPixBuf;
int16_t **alpPixBuf;
int16_t *hLumFilter;
int16_t *hLumFilterPos;
int16_t *hChrFilter;
int16_t *hChrFilterPos;
int16_t *vLumFilter;
int16_t *vLumFilterPos;
int16_t *vChrFilter;
int16_t *vChrFilterPos;
/**
* @name Scaled horizontal lines ring buffer.
* The horizontal scaler keeps just enough scaled lines in a ring buffer
* so they may be passed to the vertical scaler. The pointers to the
* allocated buffers for each line are duplicated in sequence in the ring
* buffer to simplify indexing and avoid wrapping around between lines
* inside the vertical scaler code. The wrapping is done before the
* vertical scaler is called.
*/
//@{
int16_t **lumPixBuf; ///< Ring buffer for scaled horizontal luma plane lines to be fed to the vertical scaler.
int16_t **chrPixBuf; ///< Ring buffer for scaled horizontal chroma plane lines to be fed to the vertical scaler.
int16_t **alpPixBuf; ///< Ring buffer for scaled horizontal alpha plane lines to be fed to the vertical scaler.
int vLumBufSize; ///< Number of vertical luma/alpha lines allocated in the ring buffer.
int vChrBufSize; ///< Number of vertical chroma lines allocated in the ring buffer.
int lastInLumBuf; ///< Last scaled horizontal luma/alpha line from source in the ring buffer.
int lastInChrBuf; ///< Last scaled horizontal chroma line from source in the ring buffer.
int lumBufIndex; ///< Index in ring buffer of the last scaled horizontal luma/alpha line from source.
int chrBufIndex; ///< Index in ring buffer of the last scaled horizontal chroma line from source.
//@}
uint8_t formatConvBuffer[VOF]; //FIXME dynamic allocation, but we have to change a lot of code for this to be useful
int hLumFilterSize;
int hChrFilterSize;
int vLumFilterSize;
int vChrFilterSize;
int vLumBufSize;
int vChrBufSize;
/**
* @name Horizontal and vertical filters.
* To better understand the following fields, here is a pseudo-code of
* their usage in filtering a horizontal line:
* @code
* for (i = 0; i < width; i++) {
* dst[i] = 0;
* for (j = 0; j < filterSize; j++)
* dst[i] += src[ filterPos[i] + j ] * filter[ filterSize * i + j ];
* dst[i] >>= FRAC_BITS; // The actual implementation is fixed-point.
* }
* @endcode
*/
//@{
int16_t *hLumFilter; ///< Array of horizontal filter coefficients for luma/alpha planes.
int16_t *hChrFilter; ///< Array of horizontal filter coefficients for chroma planes.
int16_t *vLumFilter; ///< Array of vertical filter coefficients for luma/alpha planes.
int16_t *vChrFilter; ///< Array of vertical filter coefficients for chroma planes.
int16_t *hLumFilterPos; ///< Array of horizontal filter starting positions for each dst[i] for luma/alpha planes.
int16_t *hChrFilterPos; ///< Array of horizontal filter starting positions for each dst[i] for chroma planes.
int16_t *vLumFilterPos; ///< Array of vertical filter starting positions for each dst[i] for luma/alpha planes.
int16_t *vChrFilterPos; ///< Array of vertical filter starting positions for each dst[i] for chroma planes.
int hLumFilterSize; ///< Horizontal filter size for luma/alpha pixels.
int hChrFilterSize; ///< Horizontal filter size for chroma pixels.
int vLumFilterSize; ///< Vertical filter size for luma/alpha pixels.
int vChrFilterSize; ///< Vertical filter size for chroma pixels.
//@}
int lumMmx2FilterCodeSize; ///< Runtime-generated MMX2 horizontal fast bilinear scaler code size for luma/alpha planes.
int chrMmx2FilterCodeSize; ///< Runtime-generated MMX2 horizontal fast bilinear scaler code size for chroma planes.
......@@ -123,10 +155,6 @@ typedef struct SwsContext {
int canMMX2BeUsed;
int lastInLumBuf;
int lastInChrBuf;
int lumBufIndex;
int chrBufIndex;
int dstY; ///< Last destination vertical line output from last slice.
int flags; ///< Flags passed by the user to select scaler algorithm, optimizations, subsampling, etc...
void * yuvTable; // pointer to the yuv->rgb table start so it can be freed()
......@@ -183,7 +211,7 @@ typedef struct SwsContext {
DECLARE_ALIGNED(8, uint64_t, vOffset);
int32_t lumMmxFilter[4*MAX_FILTER_SIZE];
int32_t chrMmxFilter[4*MAX_FILTER_SIZE];
int dstW;
int dstW; ///< Width of destination luma/alpha planes.
DECLARE_ALIGNED(8, uint64_t, esp);
DECLARE_ALIGNED(8, uint64_t, vRounder);
DECLARE_ALIGNED(8, uint64_t, u_temp);
......
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