Add FFmpegExaminer::has_alpha().

2 files changed, 15 insertions, 0 deletions

diff --git a/src/lib/ffmpeg_examiner.cc b/src/lib/ffmpeg_examiner.cc
index 46f4f236e..ed6f21094 100644
--- a/src/lib/ffmpeg_examiner.cc
+++ b/src/lib/ffmpeg_examiner.cc
@@ -384,6 +384,19 @@ FFmpegExaminer::bits_per_pixel () const
 
 
 bool
+FFmpegExaminer::has_alpha() const
+{
+	if (video_codec_context()->pix_fmt == -1) {
+		return false;
+	}
+
+	auto const d = av_pix_fmt_desc_get(video_codec_context()->pix_fmt);
+	DCPOMATIC_ASSERT(d);
+	return d->flags & AV_PIX_FMT_FLAG_ALPHA;
+}
+
+
+bool
 FFmpegExaminer::yuv () const
 {
 	switch (video_codec_context()->pix_fmt) {
diff --git a/src/lib/ffmpeg_examiner.h b/src/lib/ffmpeg_examiner.h
index 10d060707..4747929b5 100644
--- a/src/lib/ffmpeg_examiner.h
+++ b/src/lib/ffmpeg_examiner.h
@@ -77,6 +77,8 @@ public:
 
 	boost::optional<int> bits_per_pixel () const;
 
+	bool has_alpha() const;
+
 	boost::optional<double> rotation () const {
 		return _rotation;
 	}