SwsContext Struct Reference

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 ** chrUPixBuf

Ring buffer for scaled horizontal chroma plane lines to be fed to the vertical scaler.

int16_t ** chrVPixBuf

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.

Horizontal and vertical filters.

To better understand the following fields, here is a pseudo-code of their usage in filtering a horizontal line:

 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.
 }

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.

int32_t * hLumFilterPos

Array of horizontal filter starting positions for each dst[i] for luma/alpha planes.

int32_t * hChrFilterPos

Array of horizontal filter starting positions for each dst[i] for chroma planes.

int32_t * vLumFilterPos

Array of vertical filter starting positions for each dst[i] for luma/alpha planes.

int32_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.

void(* readLumPlanar )(uint8_t *dst, const uint8_t *src[4], int width)

Functions to read planar input, such as planar RGB, and convert internally to Y/UV.

void(* readChrPlanar )(uint8_t *dstU, uint8_t *dstV, const uint8_t *src[4], int width)

void(* hyscale_fast )(struct SwsContext *c, int16_t *dst, int dstWidth, const uint8_t *src, int srcW, int xInc)

Scale one horizontal line of input data using a bilinear filter to produce one line of output data.

void(* hcscale_fast )(struct SwsContext *c, int16_t *dst1, int16_t *dst2, int dstWidth, const uint8_t *src1, const uint8_t *src2, int srcW, int xInc)

void(* hyScale )(struct SwsContext *c, int16_t *dst, int dstW, const uint8_t *src, const int16_t *filter, const int32_t *filterPos, int filterSize)

Scale one horizontal line of input data using a filter over the input lines, to produce one (differently sized) line of output data.

void(* hcScale )(struct SwsContext *c, int16_t *dst, int dstW, const uint8_t *src, const int16_t *filter, const int32_t *filterPos, int filterSize)

Detailed Description

Definition at line 225 of file swscale_internal.h.

Field Documentation

int32_t SwsContext::alpMmxFilter[4 *MAX_FILTER_SIZE]

Definition at line 388 of file swscale_internal.h.

Referenced by swScale().

int16_t** SwsContext::alpPixBuf

Ring buffer for scaled horizontal alpha plane lines to be fed to the vertical scaler.

Definition at line 274 of file swscale_internal.h.

Referenced by ff_sws_init_input_funcs(), ff_sws_init_swScale_altivec(), ff_sws_init_swScale_mmx(), sws_freeContext(), sws_init_context(), and swScale().

void(* SwsContext::alpToYV12)(uint8_t *dst, const uint8_t *src, const uint8_t *src2, const uint8_t *src3, int width, uint32_t *pal)

Unscaled conversion of alpha plane to YV12 for horizontal scaler.

Referenced by ff_sws_init_input_funcs(), ff_sws_init_swScale_mmx(), and hyscale().

const AVClass* SwsContext::av_class

info on struct for av_log

Definition at line 229 of file swscale_internal.h.

Referenced by sws_alloc_context().

uint64_t SwsContext::blueDither

Definition at line 370 of file swscale_internal.h.

int SwsContext::brightness

Definition at line 329 of file swscale_internal.h.

Referenced by sws_getColorspaceDetails(), and sws_setColorspaceDetails().

int SwsContext::canMMX2BeUsed

Definition at line 318 of file swscale_internal.h.

Referenced by sws_init_context().

int SwsContext::chrBufIndex

Index in ring buffer of the last scaled horizontal chroma line from source.

Definition at line 280 of file swscale_internal.h.

Referenced by swScale().

void(* SwsContext::chrConvertRange)(int16_t *dst1, int16_t *dst2, int width)

Color range conversion function for chroma planes if needed.

Referenced by hcscale(), and sws_init_swScale_c().

const uint8_t* SwsContext::chrDither8

Definition at line 397 of file swscale_internal.h.

Referenced by swScale(), and yuv2nv12cX_c().

int SwsContext::chrDstH

Height of destination chroma planes.

Definition at line 242 of file swscale_internal.h.

Referenced by sws_init_context().

int SwsContext::chrDstHSubSample

Binary logarithm of horizontal subsampling factor between luma/alpha and chroma planes in destination image.

Definition at line 252 of file swscale_internal.h.

Referenced by ff_get_unscaled_swscale(), planarCopyWrapper(), and sws_init_context().

int SwsContext::chrDstVSubSample

Binary logarithm of vertical subsampling factor between luma/alpha and chroma planes in destination image.

Definition at line 253 of file swscale_internal.h.

Referenced by ff_get_unscaled_swscale(), planarCopyWrapper(), sws_init_context(), sws_scale(), and swScale().

int SwsContext::chrDstW

Width of destination chroma planes.

Definition at line 241 of file swscale_internal.h.

Referenced by sws_init_context(), and swScale().

uint8_t* SwsContext::chrMmx2FilterCode

Runtime-generated MMX2 horizontal fast bilinear scaler code for chroma planes.

Definition at line 316 of file swscale_internal.h.

Referenced by sws_freeContext(), and sws_init_context().

int SwsContext::chrMmx2FilterCodeSize

Runtime-generated MMX2 horizontal fast bilinear scaler code size for chroma planes.

Definition at line 314 of file swscale_internal.h.

Referenced by sws_freeContext(), and sws_init_context().

int32_t SwsContext::chrMmxFilter[4 *MAX_FILTER_SIZE]

Definition at line 381 of file swscale_internal.h.

Referenced by swScale().

int SwsContext::chrSrcH

Height of source chroma planes.

Definition at line 240 of file swscale_internal.h.

Referenced by sws_init_context(), and swScale().

int SwsContext::chrSrcHSubSample

Binary logarithm of horizontal subsampling factor between luma/alpha and chroma planes in source image.

Definition at line 250 of file swscale_internal.h.

Referenced by ff_get_unscaled_swscale(), ff_sws_init_input_funcs(), and sws_init_context().

int SwsContext::chrSrcVSubSample

Binary logarithm of vertical subsampling factor between luma/alpha and chroma planes in source image.

Definition at line 251 of file swscale_internal.h.

Referenced by ff_get_unscaled_swscale(), sws_init_context(), sws_scale(), and swScale().

int SwsContext::chrSrcW

Width of source chroma planes.

Definition at line 239 of file swscale_internal.h.

Referenced by sws_init_context(), swScale(), and yvu9ToYv12Wrapper().

void(* SwsContext::chrToYV12)(uint8_t *dstU, uint8_t *dstV, const uint8_t *src1, const uint8_t *src2, const uint8_t *src3, int width, uint32_t *pal)

Unscaled conversion of chroma planes to YV12 for horizontal scaler.

Referenced by ff_sws_init_input_funcs(), ff_sws_init_swScale_mmx(), and hcscale().

int16_t** SwsContext::chrUPixBuf

Ring buffer for scaled horizontal chroma plane lines to be fed to the vertical scaler.

Definition at line 272 of file swscale_internal.h.

Referenced by sws_freeContext(), sws_init_context(), and swScale().

int16_t** SwsContext::chrVPixBuf

Ring buffer for scaled horizontal chroma plane lines to be fed to the vertical scaler.

Definition at line 273 of file swscale_internal.h.

Referenced by sws_freeContext(), sws_init_context(), and swScale().

int SwsContext::chrXInc

Definition at line 243 of file swscale_internal.h.

Referenced by sws_init_context(), and swScale().

int SwsContext::chrYInc

Definition at line 244 of file swscale_internal.h.

Referenced by sws_init_context().

int SwsContext::contrast

Definition at line 329 of file swscale_internal.h.

Referenced by sws_getColorspaceDetails(), and sws_setColorspaceDetails().

uint16_t SwsContext::dither16[8]

Definition at line 394 of file swscale_internal.h.

uint32_t SwsContext::dither32[8]

Definition at line 395 of file swscale_internal.h.

int SwsContext::dst0Alpha

Definition at line 335 of file swscale_internal.h.

Referenced by sws_getCachedContext(), sws_getContext(), and sws_scale().

int SwsContext::dstBpc

Definition at line 249 of file swscale_internal.h.

Referenced by ff_sws_init_swScale_altivec(), ff_sws_init_swScale_mmx(), sws_init_context(), and sws_init_swScale_c().

int SwsContext::dstColorspaceTable[4]

Definition at line 331 of file swscale_internal.h.

Referenced by sws_getColorspaceDetails(), and sws_setColorspaceDetails().

enum PixelFormat SwsContext::dstFormat

Destination pixel format.

Definition at line 245 of file swscale_internal.h.

Referenced by ff_bfin_get_unscaled_swscale(), ff_get_unscaled_swscale(), ff_sws_init_swScale_altivec(), ff_sws_init_swScale_mmx(), ff_swscale_get_unscaled_altivec(), ff_yuv2packedX_altivec(), ff_yuv2rgb_c_init_tables(), ff_yuv2rgb_get_func_ptr_bfin(), ff_yuv2rgb_init_altivec(), ff_yuv2rgb_init_mmx(), ff_yuv2rgb_init_vis(), findRgbConvFn(), palToRgbWrapper(), planarCopyWrapper(), planarRgbToRgbWrapper(), planarToNv12Wrapper(), rgbToRgbWrapper(), selfTest(), sws_getCachedContext(), sws_getColorspaceDetails(), sws_getContext(), sws_init_context(), sws_init_swScale_c(), sws_scale(), sws_setColorspaceDetails(), swScale(), and yuv2nv12cX_c().

int SwsContext::dstFormatBpp

Number of bits per pixel of the destination pixel format.

Definition at line 247 of file swscale_internal.h.

Referenced by ff_get_unscaled_swscale(), ff_yuv2rgb_c_init_tables(), findRgbConvFn(), rgbToRgbWrapper(), sws_init_context(), and sws_setColorspaceDetails().

int SwsContext::dstH

Height of destination luma/alpha planes.

Definition at line 238 of file swscale_internal.h.

Referenced by ff_get_unscaled_swscale(), selfTest(), sws_getCachedContext(), sws_getContext(), sws_init_context(), sws_scale(), and swScale().

int SwsContext::dstRange

0 = MPG YUV range, 1 = JPG YUV range (destination image).

Definition at line 333 of file swscale_internal.h.

Referenced by sws_getCachedContext(), sws_getColorspaceDetails(), sws_getContext(), sws_init_context(), sws_init_swScale_c(), and sws_setColorspaceDetails().

int SwsContext::dstW

Width of destination luma/alpha planes.

Definition at line 382 of file swscale_internal.h.

Referenced by ff_yuv2rgb_init_vis(), selfTest(), sws_getCachedContext(), sws_getContext(), sws_init_context(), swScale(), vis_420P_ARGB32(), vis_422P_ARGB32(), yuv2bgr24_X_ar_TMPL(), yuv2bgr24_X_TMPL(), yuv2rgb32_X_ar_TMPL(), yuv2rgb32_X_TMPL(), yuv2rgb555_X_ar_TMPL(), yuv2rgb555_X_TMPL(), yuv2rgb565_X_ar_TMPL(), yuv2rgb565_X_TMPL(), yuv2yuvX_TMPL(), yuv2yuyv422_X_ar_TMPL(), and yuv2yuyv422_X_TMPL().

int SwsContext::dstY

Last destination vertical line output from last slice.

Definition at line 320 of file swscale_internal.h.

Referenced by swScale().

uint64_t SwsContext::esp

Definition at line 383 of file swscale_internal.h.

int SwsContext::flags

Flags passed by the user to select scaler algorithm, optimizations, subsampling, etc...

Definition at line 321 of file swscale_internal.h.

Referenced by ff_get_unscaled_swscale(), ff_sws_init_swScale_altivec(), ff_sws_init_swScale_mmx(), ff_swscale_get_unscaled_altivec(), sws_getCachedContext(), sws_getContext(), sws_init_context(), sws_init_swScale_c(), and swScale().

uint8_t* SwsContext::formatConvBuffer

Definition at line 283 of file swscale_internal.h.

Referenced by rgbToRgbWrapper(), sws_freeContext(), sws_init_context(), and swScale().

uint64_t SwsContext::greenDither

Definition at line 369 of file swscale_internal.h.

int16_t* SwsContext::hChrFilter

Array of horizontal filter coefficients for chroma planes.

Definition at line 300 of file swscale_internal.h.

Referenced by sws_freeContext(), sws_init_context(), and swScale().

int32_t* SwsContext::hChrFilterPos

Array of horizontal filter starting positions for each dst[i] for chroma planes.

Definition at line 304 of file swscale_internal.h.

Referenced by sws_freeContext(), sws_init_context(), and swScale().

int SwsContext::hChrFilterSize

Horizontal filter size for chroma pixels.

Definition at line 308 of file swscale_internal.h.

Referenced by ff_sws_init_swScale_mmx(), sws_init_context(), and swScale().

void(* SwsContext::hcScale)(struct SwsContext *c, int16_t *dst, int dstW, const uint8_t *src, const int16_t *filter, const int32_t *filterPos, int filterSize)

Referenced by ff_sws_init_swScale_altivec(), ff_sws_init_swScale_mmx(), hcscale(), and sws_init_swScale_c().

void(* SwsContext::hcscale_fast)(struct SwsContext *c, int16_t *dst1, int16_t *dst2, int dstWidth, const uint8_t *src1, const uint8_t *src2, int srcW, int xInc)

Referenced by hcscale(), and sws_init_swScale_c().

int16_t* SwsContext::hLumFilter

Array of horizontal filter coefficients for luma/alpha planes.

Definition at line 299 of file swscale_internal.h.

Referenced by sws_freeContext(), sws_init_context(), and swScale().

int32_t* SwsContext::hLumFilterPos

Array of horizontal filter starting positions for each dst[i] for luma/alpha planes.

Definition at line 303 of file swscale_internal.h.

Referenced by sws_freeContext(), sws_init_context(), and swScale().

int SwsContext::hLumFilterSize

Horizontal filter size for luma/alpha pixels.

Definition at line 307 of file swscale_internal.h.

Referenced by ff_sws_init_swScale_mmx(), sws_init_context(), and swScale().

void(* SwsContext::hyScale)(struct SwsContext *c, int16_t *dst, int dstW, const uint8_t *src, const int16_t *filter, const int32_t *filterPos, int filterSize)

Scale one horizontal line of input data using a filter over the input lines, to produce one (differently sized) line of output data.

Parameters:: dst pointer to destination buffer for horizontally scaled data. If the number of bits per component of one destination pixel (SwsContext->dstBpc) is <= 10, data will be 15bpc in 16bits (int16_t) width. Else (i.e. SwsContext->dstBpc == 16), data will be 19bpc in 32bits (int32_t) width.

dstW width of destination image

src pointer to source data to be scaled. If the number of bits per component of a source pixel (SwsContext->srcBpc) is 8, this is 8bpc in 8bits (uint8_t) width. Else (i.e. SwsContext->dstBpc > 8), this is native depth in 16bits (uint16_t) width. In other words, for 9-bit YUV input, this is 9bpc, for 10-bit YUV input, this is 10bpc, and for 16-bit RGB or YUV, this is 16bpc.

filter filter coefficients to be used per output pixel for scaling. This contains 14bpp filtering coefficients. Guaranteed to contain dstW * filterSize entries.

filterPos position of the first input pixel to be used for each output pixel during scaling. Guaranteed to contain dstW entries.

filterSize the number of input coefficients to be used (and thus the number of input pixels to be used) for creating a single output pixel. Is aligned to 4 (and input coefficients thus padded with zeroes) to simplify creating SIMD code.

Referenced by ff_sws_init_swScale_altivec(), ff_sws_init_swScale_mmx(), hyscale(), and sws_init_swScale_c().

void(* SwsContext::hyscale_fast)(struct SwsContext *c, int16_t *dst, int dstWidth, const uint8_t *src, int srcW, int xInc)

Scale one horizontal line of input data using a bilinear filter to produce one line of output data.

Compared to SwsContext->hScale(), please take note of the following caveats when using these:

Scaling is done using only 7bit instead of 14bit coefficients.
You can use no more than 5 input pixels to produce 4 output pixels. Therefore, this filter should not be used for downscaling by more than ~20% in width (because that equals more than 5/4th downscaling and thus more than 5 pixels input per 4 pixels output).
In general, bilinear filters create artifacts during downscaling (even when <20%), because one output pixel will span more than one input pixel, and thus some pixels will need edges of both neighbor pixels to interpolate the output pixel. Since you can use at most two input pixels per output pixel in bilinear scaling, this is impossible and thus downscaling by any size will create artifacts. To enable this type of scaling, set SWS_FLAG_FAST_BILINEAR in SwsContext->flags.

Referenced by hyscale(), and sws_init_swScale_c().

int SwsContext::lastInChrBuf

Last scaled horizontal chroma line from source in the ring buffer.

Definition at line 278 of file swscale_internal.h.

Referenced by swScale().

int SwsContext::lastInLumBuf

Last scaled horizontal luma/alpha line from source in the ring buffer.

Definition at line 277 of file swscale_internal.h.

Referenced by swScale().

int SwsContext::lumBufIndex

Index in ring buffer of the last scaled horizontal luma/alpha line from source.

Definition at line 279 of file swscale_internal.h.