Merge tag 'v0.21.6'

release v0.21.6

src/lib/xiph/OggVisitor.cxx

@@ -20,6 +20,7 @@
 #include "OggVisitor.hxx"
 
 #include <stdexcept>
+#include <utility>
 
 void
 OggVisitor::EndStream()
@@ -51,7 +52,13 @@ OggVisitor::ReadNextPage()
 inline void
 OggVisitor::HandlePacket(const ogg_packet &packet)
 {
+	const bool _post_seek = std::exchange(post_seek, false);
+
 	if (packet.b_o_s) {
+		if (_post_seek)
+			/* ignore the BOS packet after seeking */
+			return;
+
 		EndStream();
 		has_stream = true;
 		OnOggBeginning(packet);
@@ -97,4 +104,6 @@ OggVisitor::PostSeek()
 
 	/* find the next Ogg page and feed it into the stream */
 	sync.ExpectPageSeekIn(stream);
+
+	post_seek = true;
 }

src/lib/xiph/OggVisitor.hxx

@@ -39,6 +39,14 @@ class OggVisitor {
 
 	bool has_stream = false;
 
+	/**
+	 * This is true after seeking; its one-time effect is to
+	 * ignore the BOS packet, just in case we have been seeking to
+	 * the beginning of the file, because that would disrupt
+	 * playback.
+	 */
+	bool post_seek = false;
+
 public:
 	explicit OggVisitor(Reader &reader)
 		:sync(reader), stream(0) {}

src/lib/xiph/meson.build

@@ -1,7 +1,20 @@
 libflac_dep = dependency('flac', version: '>= 1.2', required: get_option('flac'))
 libopus_dep = dependency('opus', required: get_option('opus'))
-libvorbis_dep = dependency('vorbis', required: get_option('vorbis'))
-libvorbisidec_dep = dependency('vorbisidec', required: get_option('tremor'))
+
+if get_option('tremor').enabled()
+  # no libvorbis if Tremor was explicitly enabled
+  libvorbis_dep = dependency('', required: false)
+else
+  libvorbis_dep = dependency('vorbis', required: get_option('vorbis'))
+endif
+
+if libvorbis_dep.found()
+  # no Tremor if libvorbis is used
+  libvorbisidec_dep = dependency('', required: false)
+else
+  # attempt to auto-detect Tremor only if libvorbis was disabled or not found
+  libvorbisidec_dep = dependency('vorbisidec', required: get_option('tremor'))
+endif
 
 if get_option('vorbis').enabled() and get_option('tremor').enabled()
 	error('Cannot build both, the Vorbis decoder AND the Tremor (Vorbis fixed-point) decoder')