int ff_sws_alphablendaway(SwsContext *c, const uint8_t *src[], int srcStride[], int srcSliceY, int srcSliceH, uint8_t *dst[], int dstStride[]) { const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->srcFormat); int nb_components = desc->nb_components; int plane, x, y; int plane_count = isGray(c->srcFormat) ? 1 : 3; int sixteen_bits = desc->comp[0].depth_minus1 >= 8; unsigned off = 1<<desc->comp[0].depth_minus1; unsigned shift = desc->comp[0].depth_minus1 + 1; unsigned max = (1<<shift) - 1; av_assert0(plane_count == nb_components - 1); if (desc->flags & AV_PIX_FMT_FLAG_PLANAR) { for (plane = 0; plane < plane_count; plane++) { int w = plane ? c->chrSrcW : c->srcW; int y_subsample = plane ? desc->log2_chroma_h: 0; for (y = srcSliceY >> y_subsample; y < FF_CEIL_RSHIFT(srcSliceH, y_subsample); y++) { if (sixteen_bits) { const uint16_t *s = src[plane ] + srcStride[plane] * y; const uint16_t *a = src[plane_count] + srcStride[plane_count] * y; uint16_t *d = dst[plane ] + dstStride[plane] * y; unsigned target = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 1<<desc->comp[0].depth_minus1 : 0; if ((!isBE(c->srcFormat)) == !HAVE_BIGENDIAN) { for (x = 0; x < w; x++) { unsigned u = s[x]*a[x] + target*(max-a[x]) + off; d[x] = av_clip((u + (u >> shift)) >> shift, 0, max); } } else { for (x = 0; x < w; x++) { unsigned aswap =av_bswap16(a[x]); unsigned u = av_bswap16(s[x])*aswap + target*(max-aswap) + off; d[x] = av_clip((u + (u >> shift)) >> shift, 0, max); } } } else { const uint8_t *s = src[plane ] + srcStride[plane] * y; const uint8_t *a = src[plane_count] + srcStride[plane_count] * y; uint8_t *d = dst[plane ] + dstStride[plane] * y; unsigned target = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 128 : 0; for (x = 0; x < w; x++) { unsigned u = s[x]*a[x] + target*(255-a[x]) + 128; d[x] = (257*u) >> 16; } } } } } else { int alpha_pos = desc->comp[plane_count].offset_plus1 - 1; int w = c->srcW; for (y = srcSliceY; y < srcSliceH; y++) { if (sixteen_bits) { const uint16_t *s = src[0] + srcStride[0] * y + 2*!alpha_pos; const uint16_t *a = src[0] + srcStride[0] * y + alpha_pos; uint16_t *d = dst[0] + dstStride[0] * y; if ((!isBE(c->srcFormat)) == !HAVE_BIGENDIAN) { for (x = 0; x < w; x++) { for (plane = 0; plane < plane_count; plane++) { unsigned target = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 1<<desc->comp[0].depth_minus1 : 0; int x_index = (plane_count + 1) * x; unsigned u = s[x_index + plane]*a[x_index] + target*(max-a[x_index]) + off; d[plane_count*x + plane] = av_clip((u + (u >> shift)) >> shift, 0, max); } } } else { for (x = 0; x < w; x++) { for (plane = 0; plane < plane_count; plane++) { unsigned target = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 1<<desc->comp[0].depth_minus1 : 0; int x_index = (plane_count + 1) * x; unsigned aswap =av_bswap16(a[x_index]); unsigned u = av_bswap16(s[x_index + plane])*aswap + target*(max-aswap) + off; d[plane_count*x + plane] = av_clip((u + (u >> shift)) >> shift, 0, max); } } } } else { const uint8_t *s = src[0] + srcStride[0] * y + !alpha_pos; const uint8_t *a = src[0] + srcStride[0] * y + alpha_pos; uint8_t *d = dst[0] + dstStride[0] * y; for (x = 0; x < w; x++) { for (plane = 0; plane < plane_count; plane++) { unsigned target = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 128 : 0; int x_index = (plane_count + 1) * x; unsigned u = s[x_index + plane]*a[x_index] + target*(255-a[x_index]) + 128; d[plane_count*x + plane] = (257*u) >> 16; } } } } } return 0; }