From d0556bc33fba8f8b881f3064db3907c4cd6eccb6 Mon Sep 17 00:00:00 2001
From: Jonathan Thomas <Jonathan.Oomph@gmail.com>
Date: Fri, 25 Jan 2013 02:24:18 -0600
Subject: [PATCH] Fixed a big audio regression, with a buggy isnear() function,
 which did not take into account the amount of frames between the sample
 locations.

---
 include/FFmpegReader.h |  5 +++++
 src/FFmpegReader.cpp   | 39 +++++++++++++++++++++++----------------
 src/Main.cpp           | 10 ++++++++++
 3 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/include/FFmpegReader.h b/include/FFmpegReader.h
index 5e996a6f..5572c30a 100644
--- a/include/FFmpegReader.h
+++ b/include/FFmpegReader.h
@@ -45,6 +45,11 @@ namespace openshot
 
 		int is_near(audio_packet_location location, int samples_per_frame, int amount)
 		{
+			// Is frame even close to this one?
+			if (abs(location.frame - frame) >= 2)
+				// This is too far away to be considered
+				return false;
+
 			int sample_diff = abs(location.sample_start - sample_start);
 			if (location.frame == frame && sample_diff >= 0 && sample_diff <= amount)
 				// close
diff --git a/src/FFmpegReader.cpp b/src/FFmpegReader.cpp
index aeb80631..aa88172c 100644
--- a/src/FFmpegReader.cpp
+++ b/src/FFmpegReader.cpp
@@ -363,14 +363,14 @@ tr1::shared_ptr<Frame> FFmpegReader::ReadStream(int requested_frame)
 	int packet_error = -1;
 
 	// Minimum number of packets to process (for performance reasons)
-	int frames_processed = 0;
-	int minimum_frames = 8;
+	int packets_processed = 0;
+	int minimum_packets = 16;
 
 	//omp_set_num_threads(1);
 	omp_set_nested(true);
 	#pragma omp parallel
 	{
-		#pragma omp single
+		#pragma omp master
 		{
 			// Loop through the stream until the correct frame is found
 			while (true)
@@ -449,11 +449,11 @@ tr1::shared_ptr<Frame> FFmpegReader::ReadStream(int requested_frame)
 					is_cache_found = final_cache.Exists(requested_frame);
 
 					// Increment frames processed
-					frames_processed++;
+					packets_processed++;
 				}
 
 				// Break once the frame is found
-				if (is_cache_found && frames_processed >= minimum_frames)
+				if (is_cache_found && packets_processed >= minimum_packets)
 					break;
 
 			} // end while
@@ -983,15 +983,18 @@ void FFmpegReader::Seek(int requested_frame) throw(TooManySeeks)
 		}
 
 		// Seek audio stream (if not already seeked... and if an audio stream is found)
-		seek_target = ConvertFrameToAudioPTS(requested_frame - buffer_amount);
-		if (!seek_worked && info.has_audio && av_seek_frame(pFormatCtx, info.audio_stream_index, seek_target, AVSEEK_FLAG_BACKWARD) < 0) {
-			seek_worked = false;
-			fprintf(stderr, "%s: error while seeking audio stream\n", pFormatCtx->filename);
-		} else
+		if (!seek_worked)
 		{
-			// AUDIO SEEK
-			seek_worked = true;
-			is_video_seek = false;
+			seek_target = ConvertFrameToAudioPTS(requested_frame - buffer_amount);
+			if (info.has_audio && av_seek_frame(pFormatCtx, info.audio_stream_index, seek_target, AVSEEK_FLAG_BACKWARD) < 0) {
+				seek_worked = false;
+				fprintf(stderr, "%s: error while seeking audio stream\n", pFormatCtx->filename);
+			} else
+			{
+				// AUDIO SEEK
+				seek_worked = true;
+				is_video_seek = false;
+			}
 		}
 
 		// Was the seek successful?
@@ -1005,6 +1008,10 @@ void FFmpegReader::Seek(int requested_frame) throw(TooManySeeks)
 			if (info.has_video)
 				avcodec_flush_buffers(pCodecCtx);
 
+			// Reset previous audio location to zero
+			previous_packet_location.frame = -1;
+			previous_packet_location.sample_start = 0;
+
 			// init seek flags
 			is_seeking = true;
 			seeking_pts = seek_target;
@@ -1129,9 +1136,8 @@ audio_packet_location FFmpegReader::GetAudioPTSLocation(int pts)
 	// Prepare final audio packet location
 	audio_packet_location location = {whole_frame, sample_start};
 
-
 	// Compare to previous audio packet (and fix small gaps due to varying PTS timestamps)
-	if (location.is_near(previous_packet_location, samples_per_frame, samples_per_frame))
+	if (previous_packet_location.frame != -1 && location.is_near(previous_packet_location, samples_per_frame, samples_per_frame))
 	{
 		int orig_frame = location.frame;
 		int orig_start = location.sample_start;
@@ -1149,7 +1155,8 @@ audio_packet_location FFmpegReader::GetAudioPTSLocation(int pts)
 			location.frame++;
 		}
 
-		//cout << "GAP DETECTED!!! Changing frame " << orig_frame << ":" << orig_start << " to frame " << location.frame << ":" << location.sample_start << endl;
+		if (display_debug)
+			cout << "AUDIO GAP DETECTED!!! Changing frame " << orig_frame << ":" << orig_start << " to frame " << location.frame << ":" << location.sample_start << endl;
 	}
 	//else
 	//	cout << "NOT NEAR!!!  frame " << location.frame << ":" << location.sample_start << "  prev frame " << previous_packet_location.frame << ":" << previous_packet_location.sample_start << endl;
diff --git a/src/Main.cpp b/src/Main.cpp
index 56867b99..3686cda0 100644
--- a/src/Main.cpp
+++ b/src/Main.cpp
@@ -18,6 +18,16 @@ void FrameReady(int number)
 int main()
 {
 
+	FFmpegReader r("/home/jonathan/Apps/videcho_site/media/user_files/videos/74c51b3a-66bc-11e2-9c6a-001fd00ee3aa.webm");
+	r.Open();
+	tr1::shared_ptr<Frame> f = r.GetFrame(75);
+	f->Display();
+	r.Close();
+
+	return 0;
+
+
+
 	/* TIMELINE ---------------- */
 	Timeline t(720, 420, Framerate(24,1), 48000, 2);