[FFmpeg-devel] [PATCH] swscale/unscaled: add pal8 -> gbr(a)p special converter

[Niklas Haas]

From: Niklas Haas <git at haasn.dev>

Fixes: ticket #9520
Signed-off-by: Niklas Haas <git at haasn.dev>
Sponsored-by: Sovereign Tech Fund
---
 libswscale/swscale.c          |  2 +
 libswscale/swscale_unscaled.c | 81 ++++++++++++++++++++++++++++++++++-
 2 files changed, 81 insertions(+), 2 deletions(-)

diff --git a/libswscale/swscale.c b/libswscale/swscale.c
index 96634acfd6..bd5b6370db 100644
--- a/libswscale/swscale.c
+++ b/libswscale/swscale.c
@@ -910,6 +910,8 @@ void ff_update_palette(SwsInternal *c, const uint32_t *pal)
         case AV_PIX_FMT_BGR32_1:
 #if HAVE_BIGENDIAN
         case AV_PIX_FMT_BGR24:
+        case AV_PIX_FMT_BGRP:
+        case AV_PIX_FMT_BGRAP:
 #endif
             c->pal_rgb[i]= a + (r<<8) + (g<<16) + ((unsigned)b<<24);
             break;
diff --git a/libswscale/swscale_unscaled.c b/libswscale/swscale_unscaled.c
index c7ad6b014a..973ffe0299 100644
--- a/libswscale/swscale_unscaled.c
+++ b/libswscale/swscale_unscaled.c
@@ -509,6 +509,34 @@ static void gray8aToPacked24(const uint8_t *src, uint8_t *dst, int num_pixels,
     }
 }
 
+static void gray8aToPlanar8(const uint8_t *src, uint8_t *dstG, uint8_t *dstB,
+                            uint8_t *dstR, uint8_t *dstA, int num_pixels,
+                            const uint8_t *palette)
+{
+    for (int i = 0; i < num_pixels; i++) {
+        const uint8_t *rgb = &palette[src[i << 1] * 4];
+        dstB[i] = rgb[0];
+        dstG[i] = rgb[1];
+        dstR[i] = rgb[2];
+        if (dstA)
+            dstA[i] = src[(i << 1) + 1];
+    }
+}
+
+static void pal8ToPlanar8(const uint8_t *src, uint8_t *dstG, uint8_t *dstB,
+                          uint8_t *dstR, uint8_t *dstA, int num_pixels,
+                          const uint8_t *palette)
+{
+    for (int i = 0; i < num_pixels; i++) {
+        const uint8_t *rgba = &palette[src[i] * 4];
+        dstB[i] = rgba[0];
+        dstG[i] = rgba[1];
+        dstR[i] = rgba[2];
+        if (dstA)
+            dstA[i] = rgba[3];
+    }
+}
+
 static int bswap_16bpc(SwsInternal *c, const uint8_t *const src[],
                               const int srcStride[], int srcSliceY, int srcSliceH,
                               uint8_t *const dst[], const int dstStride[])
@@ -610,6 +638,45 @@ static int palToRgbWrapper(SwsInternal *c, const uint8_t *const src[], const int
     return srcSliceH;
 }
 
+static int palToGbrpWrapper(SwsInternal *c, const uint8_t *const src[],
+                            const int srcStride[], int srcSliceY, int srcSliceH,
+                            uint8_t *const dst[], const int dstStride[])
+{
+    const enum AVPixelFormat srcFormat = c->opts.src_format;
+    const enum AVPixelFormat dstFormat = c->opts.dst_format;
+    void (*conv)(const uint8_t *src, uint8_t *dstG, uint8_t *dstB, uint8_t *dstR,
+                 uint8_t *dstA, int num_pixels, const uint8_t *palette) = NULL;
+
+    const int num_planes = isALPHA(dstFormat) ? 4 : 3;
+    const uint8_t *srcPtr = src[0];
+    uint8_t *dstPtr[4] = {0};
+    for (int i = 0; i < num_planes; i++)
+        dstPtr[i] = dst[i] + dstStride[i] * srcSliceY;
+
+    if (srcFormat == AV_PIX_FMT_YA8) {
+        switch (dstFormat) {
+        case AV_PIX_FMT_GBRP:  conv = gray8aToPlanar8; break;
+        case AV_PIX_FMT_GBRAP: conv = gray8aToPlanar8; break;
+        }
+    } else if (usePal(srcFormat)) {
+        switch (dstFormat) {
+        case AV_PIX_FMT_GBRP:  conv = pal8ToPlanar8; break;
+        case AV_PIX_FMT_GBRAP: conv = pal8ToPlanar8; break;
+        }
+    }
+
+    av_assert1(conv);
+    for (int y = 0; y < srcSliceH; y++) {
+        conv(srcPtr, dstPtr[0], dstPtr[1], dstPtr[2], dstPtr[3], c->opts.src_w,
+            (uint8_t *) c->pal_rgb);
+        srcPtr += srcStride[0];
+        for (int i = 0; i < num_planes; i++)
+            dstPtr[i] += dstStride[i];
+    }
+
+    return srcSliceH;
+}
+
 static void packed16togbra16(const uint8_t *src, int srcStride,
                              uint16_t *dst[], const int dstStride[], int srcSliceH,
                              int src_alpha, int swap, int shift, int width)
@@ -2529,8 +2596,18 @@ void ff_get_unscaled_swscale(SwsInternal *c)
         IS_DIFFERENT_ENDIANESS(srcFormat, dstFormat, AV_PIX_FMT_GBRAPF32))
         c->convert_unscaled = bswap_32bpc;
 
-    if (usePal(srcFormat) && isByteRGB(dstFormat))
-        c->convert_unscaled = palToRgbWrapper;
+    if (usePal(srcFormat)) {
+        switch (dstFormat) {
+        case AV_PIX_FMT_GBRP:
+        case AV_PIX_FMT_GBRAP:
+            c->convert_unscaled = palToGbrpWrapper;
+            break;
+        default:
+            if (isByteRGB(dstFormat))
+                c->convert_unscaled = palToRgbWrapper;
+            break;
+        }
+    }
 
     if (srcFormat == AV_PIX_FMT_YUV422P) {
         if (dstFormat == AV_PIX_FMT_YUYV422)
-- 
2.47.0