8bps: decode 24bit files correctly as rgb32 on bigendian

libavcodec/8bps.c

@@ -168,17 +168,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
     case 32:
         avctx->pix_fmt = AV_PIX_FMT_RGB32;
         c->planes      = 4;
-#if HAVE_BIGENDIAN
-        c->planemap[0] = 1; // 1st plane is red
-        c->planemap[1] = 2; // 2nd plane is green
-        c->planemap[2] = 3; // 3rd plane is blue
-        c->planemap[3] = 0; // 4th plane is alpha???
-#else
-        c->planemap[0] = 2; // 1st plane is red
-        c->planemap[1] = 1; // 2nd plane is green
-        c->planemap[2] = 0; // 3rd plane is blue
-        c->planemap[3] = 3; // 4th plane is alpha???
-#endif
+        /* handle planemap setup later for decoding rgb24 data as rbg32 */
         break;
     default:
         av_log(avctx, AV_LOG_ERROR, "Error: Unsupported color depth: %u.\n",
@@ -186,6 +176,12 @@ static av_cold int decode_init(AVCodecContext *avctx)
         return AVERROR_INVALIDDATA;
     }
 
+    if (avctx->pix_fmt == AV_PIX_FMT_RGB32) {
+        c->planemap[0] = HAVE_BIGENDIAN ? 1 : 2; // 1st plane is red
+        c->planemap[1] = HAVE_BIGENDIAN ? 2 : 1; // 2nd plane is green
+        c->planemap[2] = HAVE_BIGENDIAN ? 3 : 0; // 3rd plane is blue
+        c->planemap[3] = HAVE_BIGENDIAN ? 0 : 3; // 4th plane is alpha???
+    }
     return 0;
 }