Fix subtitle colouring (#152).

diff --git a/ChangeLog b/ChangeLog
index 1e5c1a6ef4e63ff0fb27cef24cedade52b1010fc..4836b5dff73d285a4eba0c6dfcec33414848a8fd 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2014-01-06  Carl Hetherington  <cth@carlh.net>
 
+       * Fix subtitle colouring (#152).
+
        * Fix mis-timed subtitles when there is a non-zero video PTS offset.
 
        * Remove seemingly unnecessary checks on image directories.

diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index 1546031b880b56ffb2af25adcff9258f40b13f09..d9b7796599b8c7cdf7687454fd6dc668db5195ef 100644 (file)
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -570,21 +570,27 @@ FFmpegDecoder::decode_subtitle_packet ()
        if (rect->type != SUBTITLE_BITMAP) {
                throw DecodeError (_("non-bitmap subtitles not yet supported"));
        }
-       
+
+       /* Note RGBA is expressed little-endian, so the first byte in the word is R, second
+          G, third B, fourth A.
+       */
        shared_ptr<Image> image (new Image (PIX_FMT_RGBA, libdcp::Size (rect->w, rect->h), true));
 
        /* Start of the first line in the subtitle */
        uint8_t* sub_p = rect->pict.data[0];
-       /* sub_p looks up into a RGB palette which is here */
+       /* sub_p looks up into a BGRA palette which is here
+          (i.e. first byte B, second G, third R, fourth A)
+       */
        uint32_t const * palette = (uint32_t *) rect->pict.data[1];
        /* Start of the output data */
        uint32_t* out_p = (uint32_t *) image->data()[0];
-       
+
        for (int y = 0; y < rect->h; ++y) {
                uint8_t* sub_line_p = sub_p;
                uint32_t* out_line_p = out_p;
                for (int x = 0; x < rect->w; ++x) {
-                       *out_line_p++ = palette[*sub_line_p++];
+                       uint32_t const p = palette[*sub_line_p++];
+                       *out_line_p++ = ((p & 0xff) << 16) | (p & 0xff00) | ((p & 0xff0000) >> 16) | (p & 0xff000000);
                }
                sub_p += rect->pict.linesize[0];
                out_p += image->stride()[0] / sizeof (uint32_t);