[FFmpeg-devel] [PATCH]Support cmyk in tiff

[Carl Eugen Hoyos]

Hi!

Attached patch fixes ticket #3459 for me, based on a05635ee.

Please comment, Carl Eugen
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diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
index 1caad84..5371c9a 100644
--- a/libavcodec/tiff.c
+++ b/libavcodec/tiff.c
@@ -830,11 +830,11 @@ static int tiff_decode_tag(TiffContext *s, AVFrame *frame)
         case TIFF_PHOTOMETRIC_BLACK_IS_ZERO:
         case TIFF_PHOTOMETRIC_RGB:
         case TIFF_PHOTOMETRIC_PALETTE:
+        case TIFF_PHOTOMETRIC_SEPARATED:
         case TIFF_PHOTOMETRIC_YCBCR:
             s->photometric = value;
             break;
         case TIFF_PHOTOMETRIC_ALPHA_MASK:
-        case TIFF_PHOTOMETRIC_SEPARATED:
         case TIFF_PHOTOMETRIC_CIE_LAB:
         case TIFF_PHOTOMETRIC_ICC_LAB:
         case TIFF_PHOTOMETRIC_ITU_LAB:
@@ -1209,6 +1209,23 @@ static int decode_frame(AVCodecContext *avctx,
             dst += stride;
         }
     }
+    if (s->photometric == TIFF_PHOTOMETRIC_SEPARATED &&
+        s->avctx->pix_fmt == AV_PIX_FMT_RGBA) {
+        dst = p->data[plane];
+        for (i = 0; i < s->height; i++) {
+            for (j = 0; j < s->width; j++) {
+                int k =  255 - dst[4 * j + 3];
+                int r = (255 - dst[4 * j    ]) * k;
+                int g = (255 - dst[4 * j + 1]) * k;
+                int b = (255 - dst[4 * j + 2]) * k;
+                dst[4 * j    ] = r * 257 >> 16;
+                dst[4 * j + 1] = g * 257 >> 16;
+                dst[4 * j + 2] = b * 257 >> 16;
+                dst[4 * j + 3] = 255;
+            }
+            dst += p->linesize[plane];
+        }
+    }
     }
 
     if (s->planar && s->bppcount > 2) {