From a668653ae1229ff5574fb42b151d6289ddf6bb02 Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Tue, 1 Jul 2014 15:18:36 +0100
Subject: [PATCH] Tidy up a bit.

---
 src/lib/decoder.h         |  9 +++++----
 src/lib/ffmpeg_decoder.cc | 37 +++++++++++++++----------------------
 src/lib/ffmpeg_decoder.h  |  2 --
 3 files changed, 20 insertions(+), 28 deletions(-)

diff --git a/src/lib/decoder.h b/src/lib/decoder.h
index 18f612e53..583a92636 100644
--- a/src/lib/decoder.h
+++ b/src/lib/decoder.h
@@ -43,10 +43,11 @@ public:
 protected:	
 	/** Seek so that the next pass() will yield the next thing
 	 *  (video/sound frame, subtitle etc.) at or after the requested
-	 *  time.  Pass accurate = true to try harder to get close to
-	 *  the request.  Note that seeking to time t may mean that
-	 *  the next pass() yields, for example, audio at time t and then
-	 *  video before it.
+	 *  time.  Pass accurate = true to try harder to ensure that, at worst,
+	 *  the next thing we yield comes before `time'.  This may entail
+	 *  seeking some way before `time' to be on the safe side.
+	 *  Alternatively, if seeking is 100% accurate for this decoder,
+	 *  it may seek to just the right spot.
 	 */
 	virtual void seek (ContentTime time, bool accurate) = 0;
 	virtual bool pass () = 0;
diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index dfd8786b3..ce6fb1984 100644
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -283,9 +283,22 @@ FFmpegDecoder::bytes_per_audio_sample () const
 }
 
 void
-FFmpegDecoder::seek_and_flush (ContentTime t)
+FFmpegDecoder::seek (ContentTime time, bool accurate)
 {
-	ContentTime const u = t - _pts_offset;
+	VideoDecoder::seek (time, accurate);
+	AudioDecoder::seek (time, accurate);
+	
+	/* If we are doing an `accurate' seek, we need to use pre-roll, as
+	   we don't really know what the seek will give us.
+	*/
+
+	ContentTime pre_roll = accurate ? ContentTime::from_seconds (2) : ContentTime (0);
+	time - pre_roll;
+	if (time < ContentTime (0)) {
+		time = ContentTime (0);
+	}
+
+	ContentTime const u = time - _pts_offset;
 	int64_t s = u.seconds() / av_q2d (_format_context->streams[_video_stream]->time_base);
 
 	if (_ffmpeg_content->audio_stream ()) {
@@ -311,26 +324,6 @@ FFmpegDecoder::seek_and_flush (ContentTime t)
 	}
 }
 
-void
-FFmpegDecoder::seek (ContentTime time, bool accurate)
-{
-	VideoDecoder::seek (time, accurate);
-	AudioDecoder::seek (time, accurate);
-	
-	/* If we are doing an accurate seek, our initial shot will be 2s (2 being
-	   a number plucked from the air) earlier than we want to end up.  The loop below
-	   will hopefully then step through to where we want to be.
-	*/
-
-	ContentTime pre_roll = accurate ? ContentTime::from_seconds (2) : ContentTime (0);
-	ContentTime initial_seek = time - pre_roll;
-	if (initial_seek < ContentTime (0)) {
-		initial_seek = ContentTime (0);
-	}
-
-	seek_and_flush (initial_seek);
-}
-
 void
 FFmpegDecoder::decode_audio_packet ()
 {
diff --git a/src/lib/ffmpeg_decoder.h b/src/lib/ffmpeg_decoder.h
index e44ac152f..d6cb8c246 100644
--- a/src/lib/ffmpeg_decoder.h
+++ b/src/lib/ffmpeg_decoder.h
@@ -66,8 +66,6 @@ private:
 	void maybe_add_subtitle ();
 	boost::shared_ptr<AudioBuffers> deinterleave_audio (uint8_t** data, int size);
 
-	void seek_and_flush (ContentTime);
-
 	bool has_subtitle_during (ContentTimePeriod) const;
 	
 	boost::shared_ptr<Log> _log;
-- 
2.30.2