Try to allow users to specify that the film's header should be trusted wrt length when building thumbnails, thus speeding up examine-content by a factor of 2-ish.

8 files changed, 80 insertions, 33 deletions

diff --git a/src/lib/examine_content_job.cc b/src/lib/examine_content_job.cc
index 8db74801f..93333605b 100644
--- a/src/lib/examine_content_job.cc
+++ b/src/lib/examine_content_job.cc
@@ -60,51 +60,78 @@ ExamineContentJob::name () const
 void
 ExamineContentJob::run ()
 {
-	/* Decode the content to get an accurate length */
+	float progress_remaining = 1;
 
-	/* We don't want to use any existing length here, as progress
-	   will be messed up.
+	/* Set the film's length to either
+	   a) a length judged by running through the content or
+	   b) the length from a decoder's header.
 	*/
-	_film->unset_length ();
-	
-	shared_ptr<Options> o (new Options ("", "", ""));
-	o->out_size = Size (512, 512);
-	o->apply_crop = false;
-	o->decode_audio = false;
-
-	descend (0.5);
 
-	pair<shared_ptr<VideoDecoder>, shared_ptr<AudioDecoder> > decoders = decoder_factory (_film, o, this);
+	if (!_film->trust_content_header()) {
+		/* Decode the content to get an accurate length */
+		
+		/* We don't want to use any existing length here, as progress
+		   will be messed up.
+		*/
+		_film->unset_length ();
+		
+		shared_ptr<Options> o (new Options ("", "", ""));
+		o->out_size = Size (512, 512);
+		o->apply_crop = false;
+		o->decode_audio = false;
+		
+		descend (0.5);
+		
+		pair<shared_ptr<VideoDecoder>, shared_ptr<AudioDecoder> > decoders = decoder_factory (_film, o, this);
+		
+		set_progress_unknown ();
+		while (!decoders.first->pass()) {
+			/* keep going */
+		}
+		
+		_film->set_length (decoders.first->video_frame());
+		
+		_film->log()->log (String::compose ("Video length examined as %1 frames", _film->length().get()));
+		
+		ascend ();
+		
+		progress_remaining -= 0.5;
+		
+	} else {
 
-	set_progress_unknown ();
-	while (!decoders.first->pass()) {
-		/* keep going */
+		/* Get a quick decoder to get the content's length from its header.
+		   It would have been nice to just use the thumbnail transcoder's decoder,
+		   but that's a bit fiddly, and this isn't too expensive.
+		*/
+		
+		shared_ptr<Options> o (new Options ("", "", ""));
+		o->out_size = Size (1024, 1024);
+		pair<shared_ptr<VideoDecoder>, shared_ptr<AudioDecoder> > d = decoder_factory (_film, o, 0);
+		_film->set_length (d.first->length());
+	
+		_film->log()->log (String::compose ("Video length obtained from header as %1 frames", _film->length().get()));
 	}
 
-	_film->set_length (decoders.first->video_frame());
-
-	_film->log()->log (String::compose ("Video length is %1 frames", _film->length()));
-
-	ascend ();
-
 	/* Now make thumbnails for it */
 
-	descend (0.5);
+	descend (progress_remaining);
 
 	try {
-		o.reset (new Options (_film->dir ("thumbs"), ".png", ""));
+		shared_ptr<Options> o (new Options (_film->dir ("thumbs"), ".png", ""));
 		o->out_size = _film->size ();
 		o->apply_crop = false;
 		o->decode_audio = false;
-		if (_film->length() > 0) {
-			o->decode_video_skip = _film->length().get() / 128;
-		} else {
-			o->decode_video_skip = 0;
-		}
+		o->decode_video_skip = _film->length().get() / 128;
 		o->decode_subtitles = true;
 		shared_ptr<ImageMagickEncoder> e (new ImageMagickEncoder (_film, o));
 		Transcoder w (_film, o, this, e);
 		w.go ();
+
+		/* Now set the film's length from the transcoder's decoder, since we
+		   went to all the trouble of going through the content.
+		*/
+
+		_film->set_length (w.video_decoder()->video_frame());
 		
 	} catch (std::exception& e) {
 
diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index ef9c05fa6..fd522a5ac 100644
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -629,3 +629,9 @@ FFmpegAudioStream::to_string () const
 	return String::compose ("ffmpeg %1 %2 %3 %4", _id, _sample_rate, _channel_layout, _name);
 }
 
+/** @return Length (in video frames) according to our content's header */
+SourceFrame
+FFmpegDecoder::length () const
+{
+	return (double(_format_context->duration) / AV_TIME_BASE) * frames_per_second();
+}
diff --git a/src/lib/ffmpeg_decoder.h b/src/lib/ffmpeg_decoder.h
index 87eebe1ec..1771551fc 100644
--- a/src/lib/ffmpeg_decoder.h
+++ b/src/lib/ffmpeg_decoder.h
@@ -56,7 +56,7 @@ public:
 		, _name (n)
 		, _id (i)
 	{}
-		  
+
 	std::string to_string () const;
 
 	std::string name () const {
@@ -89,6 +89,7 @@ public:
 
 	float frames_per_second () const;
 	Size native_size () const;
+	SourceFrame length () const;
 	int time_base_numerator () const;
 	int time_base_denominator () const;
 	int sample_aspect_ratio_numerator () const;
diff --git a/src/lib/film.cc b/src/lib/film.cc
index 563147f68..e2a4cbeda 100644
--- a/src/lib/film.cc
+++ b/src/lib/film.cc
@@ -1003,7 +1003,7 @@ Film::set_trust_content_header (bool t)
 	
 	signal_changed (TRUST_CONTENT_HEADER);
 
-	if (!_trust_content_header) {
+	if (!_trust_content_header) && !content().empty()) {
 		/* We just said that we don't trust the content's header */
 		examine_content ();
 	}
diff --git a/src/lib/imagemagick_decoder.h b/src/lib/imagemagick_decoder.h
index f636191f2..de49c1b56 100644
--- a/src/lib/imagemagick_decoder.h
+++ b/src/lib/imagemagick_decoder.h
@@ -35,6 +35,11 @@ public:
 
 	Size native_size () const;
 
+	SourceFrame length () const {
+		/* We don't know */
+		return 0;
+	}
+
 	int audio_channels () const {
 		return 0;
 	}
diff --git a/src/lib/transcoder.cc b/src/lib/transcoder.cc
index 537b9b664..a7e79b05f 100644
--- a/src/lib/transcoder.cc
+++ b/src/lib/transcoder.cc
@@ -64,7 +64,9 @@ Transcoder::Transcoder (shared_ptr<Film> f, shared_ptr<const Options> o, Job* j,
 
 	/* Set up the decoder to use the film's set streams */
 	_decoders.first->set_subtitle_stream (f->subtitle_stream ());
-	_decoders.second->set_audio_stream (f->audio_stream ());
+	if (_decoders.second) {
+		_decoders.second->set_audio_stream (f->audio_stream ());
+	}
 
 	if (_matcher) {
 		_decoders.first->connect_video (_matcher);
@@ -73,7 +75,7 @@ Transcoder::Transcoder (shared_ptr<Film> f, shared_ptr<const Options> o, Job* j,
 		_decoders.first->connect_video (_encoder);
 	}
 	
-	if (_matcher && _delay_line) {
+	if (_matcher && _delay_line && _decoders.second) {
 		_decoders.second->connect_audio (_delay_line);
 		_delay_line->connect_audio (_matcher);
 		_matcher->connect_audio (_gain);
@@ -97,7 +99,7 @@ Transcoder::go ()
 				_decoders.first->set_progress ();
 			}
 
-			if (!done[1] && dynamic_pointer_cast<Decoder> (_decoders.second) != dynamic_pointer_cast<Decoder> (_decoders.first)) {
+			if (!done[1] && _decoders.second && dynamic_pointer_cast<Decoder> (_decoders.second) != dynamic_pointer_cast<Decoder> (_decoders.first)) {
 				done[1] = _decoders.second->pass ();
 			} else {
 				done[1] = true;
diff --git a/src/lib/transcoder.h b/src/lib/transcoder.h
index e3ca2bb32..4a9667b3c 100644
--- a/src/lib/transcoder.h
+++ b/src/lib/transcoder.h
@@ -49,6 +49,10 @@ public:
 
 	void go ();
 
+	boost::shared_ptr<VideoDecoder> video_decoder () const {
+		return _decoders.first;
+	}
+
 protected:
 	/** A Job that is running this Transcoder, or 0 */
 	Job* _job;
diff --git a/src/lib/video_decoder.h b/src/lib/video_decoder.h
index ea1899840..685138a58 100644
--- a/src/lib/video_decoder.h
+++ b/src/lib/video_decoder.h
@@ -33,6 +33,8 @@ public:
 	virtual float frames_per_second () const = 0;
 	/** @return native size in pixels */
 	virtual Size native_size () const = 0;
+	/** @return length (in source video frames), according to our content's header */
+	virtual SourceFrame length () const = 0;
 
 	virtual int time_base_numerator () const = 0;
 	virtual int time_base_denominator () const = 0;