From: Carl Hetherington <cth@carlh.net>
Date: Thu, 11 Jan 2018 00:58:33 +0000 (+0000)
Subject: Fix crash due to alpha_blend requiring BGRA (#1165).
X-Git-Tag: v2.11.41~20
X-Git-Url: https://git.carlh.net/gitweb/?p=dcpomatic.git;a=commitdiff_plain;h=a990b287abee2fcfb7fc12d813265afa9d945646

Fix crash due to alpha_blend requiring BGRA (#1165).
---

diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index 26b1d4bf8..2f46f17c6 100644
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -595,10 +595,10 @@ FFmpegDecoder::decode_subtitle_packet ()
 void
 FFmpegDecoder::decode_bitmap_subtitle (AVSubtitleRect const * rect, ContentTime from)
 {
-	/* Note RGBA is expressed little-endian, so the first byte in the word is R, second
-	   G, third B, fourth A.
+	/* Note BGRA is expressed little-endian, so the first byte in the word is B, second
+	   G, third R, fourth A.
 	*/
-	shared_ptr<Image> image (new Image (AV_PIX_FMT_RGBA, dcp::Size (rect->w, rect->h), true));
+	shared_ptr<Image> image (new Image (AV_PIX_FMT_BGRA, dcp::Size (rect->w, rect->h), true));
 
 #ifdef DCPOMATIC_HAVE_AVSUBTITLERECT_PICT
 	/* Start of the first line in the subtitle */
@@ -642,8 +642,8 @@ FFmpegDecoder::decode_bitmap_subtitle (AVSubtitleRect const * rect, ContentTime
 		uint32_t* out_line_p = out_p;
 		for (int x = 0; x < rect->w; ++x) {
 			RGBA const p = mapped_palette[*sub_line_p++];
-			/* XXX: this seems to be wrong to me (isn't the output image RGBA?) but it looks right on screen */
-			*out_line_p++ = (p.a << 24) | (p.r << 16) | (p.g << 8) | p.b;
+			/* XXX: this seems to be wrong to me (isn't the output image BGRA?) but it looks right on screen */
+			*out_line_p++ = (p.a << 24) | (p.b << 16) | (p.g << 8) | p.r;
 		}
 #ifdef DCPOMATIC_HAVE_AVSUBTITLERECT_PICT
 		sub_p += rect->pict.linesize[0];