1 files changed, 104 insertions, 61 deletions

diff --git a/src/lib/decoder.cc b/src/lib/decoder.cc
index 110d2aa88..1f93c6c60 100644
--- a/src/lib/decoder.cc
+++ b/src/lib/decoder.cc
@@ -40,6 +40,7 @@
 using std::string;
 using std::stringstream;
 using std::min;
+using std::pair;
 using std::list;
 using boost::shared_ptr;
 
@@ -48,18 +49,18 @@ using boost::shared_ptr;
  *  @param j Job that we are running within, or 0
  *  @param minimal true to do the bare minimum of work; just run through the content.  Useful for acquiring
  *  accurate frame counts as quickly as possible.  This generates no video or audio output.
- *  @param ignore_length Ignore the content's claimed length when computing progress.
  */
-Decoder::Decoder (boost::shared_ptr<Film> f, boost::shared_ptr<const Options> o, Job* j, bool minimal, bool ignore_length)
+Decoder::Decoder (boost::shared_ptr<Film> f, boost::shared_ptr<const Options> o, Job* j, bool minimal)
 	: _film (f)
 	, _opt (o)
 	, _job (j)
 	, _minimal (minimal)
-	, _ignore_length (ignore_length)
-	, _video_frame_index (0)
+	, _video_frames_in (0)
+	, _video_frames_out (0)
+	, _audio_frames_in (0)
+	, _audio_frames_out (0)
 	, _delay_line (0)
 	, _delay_in_frames (0)
-	, _audio_frames_processed (0)
 {
 	
 }
@@ -69,15 +70,14 @@ Decoder::~Decoder ()
 	delete _delay_line;
 }
 
-/** Start off a decode processing run */
+/** Start off a decode processing run.  This should only be called once on
+ *  a given Decoder object.
+ */
 void
 Decoder::process_begin ()
 {
 	_delay_in_frames = _film->audio_delay() * audio_sample_rate() / 1000;
-	delete _delay_line;
 	_delay_line = new DelayLine (audio_channels(), _delay_in_frames);
-
-	_audio_frames_processed = 0;
 }
 
 /** Finish off a decode processing run */
@@ -90,28 +90,44 @@ Decoder::process_end ()
 		emit_audio (b);
 	}
 
-	/* If we cut the decode off, the audio may be short; push some silence
-	   in to get it to the right length.
-	*/
+	if (_opt->decode_audio && audio_channels()) {
 
-	int64_t const video_length_in_audio_frames = ((int64_t) video_frame_index() * audio_sample_rate() / frames_per_second());
-	int64_t const audio_short_by_frames = video_length_in_audio_frames - _audio_frames_processed;
+		/* Ensure that our video and audio emissions are the same length */
 
-	_film->log()->log (
-		String::compose ("Source length is %1 (%2 audio frames); %3 frames of audio processed.",
-				 video_frame_index(),
-				 video_length_in_audio_frames,
-				 _audio_frames_processed)
-		);
-	
-	if (audio_short_by_frames > 0 && _opt->decode_audio && audio_channels()) {
+		int64_t audio_short_by_frames = video_frames_to_audio_frames (_video_frames_out) - _audio_frames_out;
 
-		_film->log()->log (String::compose ("Source length is %1; %2 frames of audio processed.", video_frame_index(), _audio_frames_processed));
-		_film->log()->log (String::compose ("Adding %1 frames of silence to the end.", audio_short_by_frames));
+		_film->log()->log (
+			String::compose ("Decoder has emitted %1 video frames (which equals %2 audio frames) and %3 audio frames",
+					 _video_frames_out,
+					 video_frames_to_audio_frames (_video_frames_out),
+					 _audio_frames_out)
+			);
 
-		shared_ptr<AudioBuffers> b (new AudioBuffers (audio_channels(), audio_short_by_frames));
-		b->make_silent ();
-		emit_audio (b);
+		if (audio_short_by_frames < 0) {
+
+			_film->log()->log (String::compose ("Emitted %1 too many audio frames", -audio_short_by_frames));
+			
+			/* We have emitted more audio than video.  Emit enough black video frames so that we reverse this */
+			int const black_video_frames = ceil (-audio_short_by_frames * frames_per_second() / audio_sample_rate());
+
+			_film->log()->log (String::compose ("Emitting %1 frames of black video", black_video_frames));
+
+			shared_ptr<Image> black (new CompactImage (pixel_format(), native_size()));
+			black->make_black ();
+			for (int i = 0; i < black_video_frames; ++i) {
+				emit_video (black, shared_ptr<Subtitle> ());
+			}
+
+			/* Now recompute our check value */
+			audio_short_by_frames = video_frames_to_audio_frames (_video_frames_out) - _audio_frames_out;
+		}
+	
+		if (audio_short_by_frames > 0) {
+			_film->log()->log (String::compose ("Emitted %1 too few audio frames", audio_short_by_frames));
+			shared_ptr<AudioBuffers> b (new AudioBuffers (audio_channels(), audio_short_by_frames));
+			b->make_silent ();
+			emit_audio (b);
+		}
 	}
 }
 
@@ -127,27 +143,13 @@ Decoder::go ()
 
 	while (pass () == false) {
 		if (_job && _film->dcp_length()) {
-			_job->set_progress (float (_video_frame_index) / _film->dcp_length().get());
+			_job->set_progress (float (_video_frames_out) / _film->dcp_length().get());
 		}
 	}
 
 	process_end ();
 }
 
-/** Run one pass.  This may or may not generate any actual video / audio data;
- *  some decoders may require several passes to generate a single frame.
- *  @return true if we have finished processing all data; otherwise false.
- */
-bool
-Decoder::pass ()
-{
-	if (!_ignore_length && _video_frame_index >= _film->dcp_length()) {
-		return true;
-	}
-
-	return do_pass ();
-}
-
 /** Called by subclasses to tell the world that some audio data is ready
  *  @param data Audio data, in Film::audio_sample_format.
  *  @param size Number of bytes of data.
@@ -229,14 +231,41 @@ Decoder::process_audio (uint8_t* data, int size)
 	}
 
 	_delay_line->feed (audio);
-	emit_audio (audio);
+
+	/* Decode range in audio frames */
+	pair<int64_t, int64_t> required_range (
+		video_frames_to_audio_frames (_film->dcp_trim_start()),
+		video_frames_to_audio_frames (_film->dcp_trim_start() + _film->dcp_length().get())
+		);
+
+	/* Range of this block of data */
+	pair<int64_t, int64_t> this_range (
+		_audio_frames_in,
+		_audio_frames_in + audio->frames()
+		);
+
+	/* Trim start */
+	if (required_range.first >= this_range.first && required_range.first < this_range.second) {
+		int64_t const shift = this_range.first - required_range.first;
+		audio->move (shift, 0, audio->frames() - shift);
+		audio->set_frames (audio->frames() - shift);
+	}
+
+	/* Trim end */
+	if (required_range.second >= this_range.first && required_range.second < this_range.second) {
+		audio->set_frames (this_range.first - required_range.second);
+	}
+
+	if (audio->frames()) {
+		emit_audio (audio);
+	}
 }
 
 void
 Decoder::emit_audio (shared_ptr<AudioBuffers> audio)
 {
 	Audio (audio);
-	_audio_frames_processed += audio->frames ();
+	_audio_frames_out += audio->frames ();
 }
 
 /** Called by subclasses to tell the world that some video data is ready.
@@ -246,15 +275,22 @@ Decoder::emit_audio (shared_ptr<AudioBuffers> audio)
 void
 Decoder::process_video (AVFrame* frame)
 {
+	assert (_film->length());
+
 	if (_minimal) {
-		++_video_frame_index;
+		++_video_frames_in;
 		return;
 	}
 
 	/* Use Film::length here as our one may be wrong */
 
-	if (_opt->decode_video_skip != 0 && (_video_frame_index % _opt->decode_video_skip) != 0) {
-		++_video_frame_index;
+	if (_opt->decode_video_skip != 0 && (_video_frames_in % _opt->decode_video_skip) != 0) {
+		++_video_frames_in;
+		return;
+	}
+
+	if (_video_frames_in < _film->dcp_trim_start() || _video_frames_in > (_film->dcp_trim_start() + _film->length().get())) {
+		++_video_frames_in;
 		return;
 	}
 
@@ -276,20 +312,12 @@ Decoder::process_video (AVFrame* frame)
 	list<shared_ptr<Image> > images = graph->process (frame);
 
 	for (list<shared_ptr<Image> >::iterator i = images.begin(); i != images.end(); ++i) {
-		if (_opt->black_after > 0 && _video_frame_index > _opt->black_after) {
-			(*i)->make_black ();
-		}
-		
 		shared_ptr<Subtitle> sub;
-		if (_timed_subtitle && _timed_subtitle->displayed_at (double (video_frame_index()) / _film->frames_per_second())) {
+		if (_timed_subtitle && _timed_subtitle->displayed_at (double (video_frames_in()) / _film->frames_per_second())) {
 			sub = _timed_subtitle->subtitle ();
 		}
-		
-		TIMING ("Decoder emits %1", _video_frame_index);
-		Video (*i, _video_frame_index, sub);
-		++_video_frame_index;
-		_last_image = *i;
-		_last_subtitle = sub;
+
+		emit_video (*i, sub);
 	}
 }
 
@@ -300,9 +328,18 @@ Decoder::repeat_last_video ()
 		_last_image.reset (new CompactImage (pixel_format(), native_size()));
 		_last_image->make_black ();
 	}
-	
-	Video (_last_image, _video_frame_index, _last_subtitle);
-	++_video_frame_index;
+
+	emit_video (_last_image, _last_subtitle);
+}
+
+void
+Decoder::emit_video (shared_ptr<Image> image, shared_ptr<Subtitle> sub)
+{
+	TIMING ("Decoder emits %1", _video_frames_out);
+	Video (image, _video_frames_out, sub);
+	++_video_frames_out;
+	_last_image = image;
+	_last_subtitle = sub;
 }
 
 void
@@ -322,3 +359,9 @@ Decoder::bytes_per_audio_sample () const
 {
 	return av_get_bytes_per_sample (audio_sample_format ());
 }
+
+int64_t
+Decoder::video_frames_to_audio_frames (SourceFrame v) const
+{
+	return ((int64_t) v * audio_sample_rate() / frames_per_second());
+}