From efc2016a315f450f00bad23e821dcfb394ab86aa Mon Sep 17 00:00:00 2001 From: Urvang Joshi Date: Wed, 21 Mar 2012 06:48:50 +0000 Subject: [PATCH] Make rescaler methods generic to be used in rescaling of lossless bitstreams. (cherry picked from commit 2e12a3045498b6faf13b93bc25391e8226119f0a) --- src/dec/io.c | 20 ++++++++++---------- src/dec/webp.c | 48 ++++++++++++++++++++++++++++-------------------- src/dec/webpi.h | 11 +++++++---- 3 files changed, 45 insertions(+), 34 deletions(-) diff --git a/src/dec/io.c b/src/dec/io.c index 9226760b..0df4d142 100644 --- a/src/dec/io.c +++ b/src/dec/io.c @@ -235,7 +235,7 @@ static int Rescale(const uint8_t* src, int src_stride, int new_lines, WebPRescaler* const wrk) { int num_lines_out = 0; while (new_lines-- > 0) { // import new contribution of one source row. - WebPRescalerImportRow(src, wrk); + WebPRescalerImportRow(src, 0, wrk); src += src_stride; wrk->y_accum -= wrk->y_sub; while (wrk->y_accum <= 0) { // emit output row(s) @@ -291,23 +291,23 @@ static int InitYUVRescaler(const VP8Io* const io, WebPDecParams* const p) { } work = (int32_t*)p->memory; WebPRescalerInit(&p->scaler_y, io->mb_w, io->mb_h, - buf->y, out_width, out_height, buf->y_stride, + buf->y, out_width, out_height, buf->y_stride, 1, io->mb_w, out_width, io->mb_h, out_height, work); WebPRescalerInit(&p->scaler_u, uv_in_width, uv_in_height, - buf->u, uv_out_width, uv_out_height, buf->u_stride, + buf->u, uv_out_width, uv_out_height, buf->u_stride, 1, uv_in_width, uv_out_width, uv_in_height, uv_out_height, work + work_size); WebPRescalerInit(&p->scaler_v, uv_in_width, uv_in_height, - buf->v, uv_out_width, uv_out_height, buf->v_stride, + buf->v, uv_out_width, uv_out_height, buf->v_stride, 1, uv_in_width, uv_out_width, uv_in_height, uv_out_height, work + work_size + uv_work_size); p->emit = EmitRescaledYUV; if (has_alpha) { WebPRescalerInit(&p->scaler_a, io->mb_w, io->mb_h, - buf->a, out_width, out_height, buf->a_stride, + buf->a, out_width, out_height, buf->a_stride, 1, io->mb_w, out_width, io->mb_h, out_height, work + work_size + 2 * uv_work_size); p->emit_alpha = EmitRescaledAlphaYUV; @@ -324,7 +324,7 @@ static int Import(const uint8_t* src, int src_stride, int new_lines, WebPRescaler* const wrk) { int num_lines_in = 0; while (num_lines_in < new_lines && wrk->y_accum > 0) { - WebPRescalerImportRow(src, wrk); + WebPRescalerImportRow(src, 0, wrk); src += src_stride; ++num_lines_in; wrk->y_accum -= wrk->y_sub; @@ -452,22 +452,22 @@ static int InitRGBRescaler(const VP8Io* const io, WebPDecParams* const p) { work = (int32_t*)p->memory; tmp = (uint8_t*)(work + tmp_size1); WebPRescalerInit(&p->scaler_y, io->mb_w, io->mb_h, - tmp + 0 * out_width, out_width, out_height, 0, + tmp + 0 * out_width, out_width, out_height, 0, 1, io->mb_w, out_width, io->mb_h, out_height, work + 0 * work_size); WebPRescalerInit(&p->scaler_u, uv_in_width, uv_in_height, - tmp + 1 * out_width, out_width, out_height, 0, + tmp + 1 * out_width, out_width, out_height, 0, 1, io->mb_w, 2 * out_width, io->mb_h, 2 * out_height, work + 1 * work_size); WebPRescalerInit(&p->scaler_v, uv_in_width, uv_in_height, - tmp + 2 * out_width, out_width, out_height, 0, + tmp + 2 * out_width, out_width, out_height, 0, 1, io->mb_w, 2 * out_width, io->mb_h, 2 * out_height, work + 2 * work_size); p->emit = EmitRescaledRGB; if (has_alpha) { WebPRescalerInit(&p->scaler_a, io->mb_w, io->mb_h, - tmp + 3 * out_width, out_width, out_height, 0, + tmp + 3 * out_width, out_width, out_height, 0, 1, io->mb_w, out_width, io->mb_h, out_height, work + 3 * work_size); p->emit_alpha = EmitRescaledAlphaRGB; diff --git a/src/dec/webp.c b/src/dec/webp.c index 9faf6e0a..ffb0555b 100644 --- a/src/dec/webp.c +++ b/src/dec/webp.c @@ -610,7 +610,7 @@ VP8StatusCode WebPDecode(const uint8_t* data, uint32_t data_size, } //------------------------------------------------------------------------------ -// Simple picture rescaler +// Cropping & rescaling. int WebPIoInitFromOptions(const WebPDecoderOptions* const options, VP8Io* const io) { @@ -665,12 +665,12 @@ int WebPIoInitFromOptions(const WebPDecoderOptions* const options, } #define RFIX 30 -#define MULT(x,y) (((int64_t)(x) * (y) + (1 << (RFIX - 1))) >> RFIX) +#define MULT_FIX(x,y) (((int64_t)(x) * (y) + (1 << (RFIX - 1))) >> RFIX) void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height, - uint8_t* dst, int dst_width, int dst_height, - int dst_stride, int x_add, int x_sub, int y_add, - int y_sub, int32_t* work) { + uint8_t* const dst, int dst_width, int dst_height, + int dst_stride, int num_channels, int x_add, int x_sub, + int y_add, int y_sub, int32_t* const work) { wrk->x_expand = (src_width < dst_width); wrk->src_width = src_width; wrk->src_height = src_height; @@ -678,6 +678,7 @@ void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height, wrk->dst_height = dst_height; wrk->dst = dst; wrk->dst_stride = dst_stride; + wrk->num_channels = num_channels; // for 'x_expand', we use bilinear interpolation wrk->x_add = wrk->x_expand ? (x_sub - 1) : x_add - x_sub; wrk->x_sub = wrk->x_expand ? (x_add - 1) : x_sub; @@ -690,34 +691,40 @@ void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height, ((int64_t)dst_height << RFIX) / (x_sub * src_height) : ((int64_t)dst_height << RFIX) / (x_add * src_height); wrk->irow = work; - wrk->frow = work + dst_width; + wrk->frow = work + num_channels * dst_width; } -void WebPRescalerImportRow(const uint8_t* const src, WebPRescaler* const wrk) { - int x_in = 0; +void WebPRescalerImportRow(const uint8_t* const src, int channel, + WebPRescaler* const wrk) { + const int x_stride = wrk->num_channels; + const int x_out_max = wrk->dst_width * wrk->num_channels; + int x_in = channel; int x_out; int accum = 0; if (!wrk->x_expand) { int sum = 0; - for (x_out = 0; x_out < wrk->dst_width; ++x_out) { + for (x_out = channel; x_out < x_out_max; x_out += x_stride) { accum += wrk->x_add; for (; accum > 0; accum -= wrk->x_sub) { - sum += src[x_in++]; + sum += src[x_in]; + x_in += x_stride; } { // Emit next horizontal pixel. - const int32_t base = src[x_in++]; + const int32_t base = src[x_in]; const int32_t frac = base * (-accum); + x_in += x_stride; wrk->frow[x_out] = (sum + base) * wrk->x_sub - frac; // fresh fractional start for next pixel - sum = (int)MULT(frac, wrk->fx_scale); + sum = (int)MULT_FIX(frac, wrk->fx_scale); } } } else { // simple bilinear interpolation - int left = src[0], right = src[0]; - for (x_out = 0; x_out < wrk->dst_width; ++x_out) { + int left = src[channel], right = src[channel]; + for (x_out = channel; x_out < x_out_max; x_out += x_stride) { if (accum < 0) { left = right; - right = src[++x_in]; + x_in += x_stride; + right = src[x_in]; accum += wrk->x_add; } wrk->frow[x_out] = right * wrk->x_add + (left - right) * accum; @@ -725,7 +732,7 @@ void WebPRescalerImportRow(const uint8_t* const src, WebPRescaler* const wrk) { } } // Accumulate the new row's contribution - for (x_out = 0; x_out < wrk->dst_width; ++x_out) { + for (x_out = channel; x_out < x_out_max; x_out += x_stride) { wrk->irow[x_out] += wrk->frow[x_out]; } } @@ -733,10 +740,11 @@ void WebPRescalerImportRow(const uint8_t* const src, WebPRescaler* const wrk) { void WebPRescalerExportRow(WebPRescaler* const wrk) { int x_out; const int yscale = wrk->fy_scale * (-wrk->y_accum); + const int x_out_max = wrk->dst_width * wrk->num_channels; assert(wrk->y_accum <= 0); - for (x_out = 0; x_out < wrk->dst_width; ++x_out) { - const int frac = (int)MULT(wrk->frow[x_out], yscale); - const int v = (int)MULT(wrk->irow[x_out] - frac, wrk->fxy_scale); + for (x_out = 0; x_out < x_out_max; ++x_out) { + const int frac = (int)MULT_FIX(wrk->frow[x_out], yscale); + const int v = (int)MULT_FIX(wrk->irow[x_out] - frac, wrk->fxy_scale); wrk->dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255; wrk->irow[x_out] = frac; // new fractional start } @@ -744,7 +752,7 @@ void WebPRescalerExportRow(WebPRescaler* const wrk) { wrk->dst += wrk->dst_stride; } -#undef MULT +#undef MULT_FIX #undef RFIX //------------------------------------------------------------------------------ diff --git a/src/dec/webpi.h b/src/dec/webpi.h index d78a1b5e..c22ee0df 100644 --- a/src/dec/webpi.h +++ b/src/dec/webpi.h @@ -27,6 +27,7 @@ typedef int (*OutputFunc)(const VP8Io* const io, WebPDecParams* const p); // Structure use for on-the-fly rescaling typedef struct { int x_expand; // true if we're expanding in the x direction + int num_channels; // bytes to jump between pixels int fy_scale, fx_scale; // fixed-point scaling factor int64_t fxy_scale; // '' // we need hpel-precise add/sub increments, for the downsampled U/V planes. @@ -168,12 +169,14 @@ int WebPIoInitFromOptions(const WebPDecoderOptions* const options, // Initialize a rescaler given scratch area 'work' and dimensions of src & dst. void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height, - uint8_t* dst, int dst_width, int dst_height, - int dst_stride, int x_add, int x_sub, int y_add, - int y_sub, int32_t* work); + uint8_t* const dst, int dst_width, int dst_height, + int dst_stride, int num_channels, int x_add, int x_sub, + int y_add, int y_sub, int32_t* const work); // Import a row of data and save its contribution in the rescaler. -void WebPRescalerImportRow(const uint8_t* const src, WebPRescaler* const wrk); +// 'channel' denotes the channel number to be imported. +void WebPRescalerImportRow(const uint8_t* const src, int channel, + WebPRescaler* const wrk); // Export a row from rescaler. void WebPRescalerExportRow(WebPRescaler* const wrk);