Disable use of stream IDs if there are duplicates, rather than rewriting.

It turns out that FFmpeg decoders (e.g. flv, see FFmpeg
25faaa311a74efdfdc4fed56996d7338ed807488) check stream IDs and sometimes
create new streams if they see one that they didn't see before.  If we
change stream IDs we break this.

Here we try to use stream indices in cases where the IDs are duplicated.
We also account for the case where a new stream appears during
examination. This wasn't covered by tests until the FFmpeg commit
mentioned above, were the flv decoder creates a new stream during
examination of boon_telly.mkv.

1 files changed, 10 insertions, 4 deletions

diff --git a/src/lib/ffmpeg_stream.h b/src/lib/ffmpeg_stream.h
index 0ed0b3be2..1583e5221 100644
--- a/src/lib/ffmpeg_stream.h
+++ b/src/lib/ffmpeg_stream.h
@@ -30,9 +30,10 @@ struct AVStream;
 class FFmpegStream
 {
 public:
-	FFmpegStream(std::string n, int i)
+	FFmpegStream(std::string n, int id, int index)
 		: name(n)
-		, _id(i)
+		, _id(id)
+		, _index(index)
 	{}
 
 	explicit FFmpegStream(cxml::ConstNodePtr);
@@ -49,10 +50,14 @@ public:
 	std::string technical_summary() const;
 	std::string identifier() const;
 
-	int id() const {
+	boost::optional<int> id() const {
 		return _id;
 	}
 
+	void unset_id() {
+		_id = boost::none;
+	}
+
 	int index(AVFormatContext const * c) const;
 
 	std::string name;
@@ -61,7 +66,8 @@ public:
 	friend bool operator!=(FFmpegStream const & a, FFmpegStream const & b);
 
 private:
-	int _id;
+	boost::optional<int> _id;
+	boost::optional<int> _index;
 };
 
 #endif