Skipping hacks.

8 files changed, 91 insertions, 48 deletions

diff --git a/src/lib/encoder.cc b/src/lib/encoder.cc
index 17a6726a6..dfb154f72 100644
--- a/src/lib/encoder.cc
+++ b/src/lib/encoder.cc
@@ -107,11 +107,6 @@ Encoder::frame_skipped ()
 void
 Encoder::process_video (shared_ptr<Image> i, boost::shared_ptr<Subtitle> s)
 {
-	if (_opt->decode_video_skip != 0 && (_video_frame % _opt->decode_video_skip) != 0) {
-		++_video_frame;
-		return;
-	}
-
 	if (_opt->video_decode_range) {
 		pair<SourceFrame, SourceFrame> const r = _opt->video_decode_range.get();
 		if (_video_frame < r.first || _video_frame >= r.second) {
diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index acaf149f4..1e473b6a3 100644
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -265,46 +265,10 @@ FFmpegDecoder::pass ()
 				_film->log()->log (String::compose ("Used only %1 bytes of %2 in packet", r, _packet.size));
 			}
 
-			/* Where we are in the output, in seconds */
-			double const out_pts_seconds = video_frame() / frames_per_second();
-
-			/* Where we are in the source, in seconds */
-			double const source_pts_seconds = av_q2d (_format_context->streams[_packet.stream_index]->time_base)
-				* av_frame_get_best_effort_timestamp(_frame);
-
-			_film->log()->log (
-				String::compose ("Source video frame ready; source at %1, output at %2", source_pts_seconds, out_pts_seconds),
-				Log::VERBOSE
-				);
-
-			if (!_first_video) {
-				_first_video = source_pts_seconds;
-			}
-
-			/* Difference between where we are and where we should be */
-			double const delta = source_pts_seconds - _first_video.get() - out_pts_seconds;
-			double const one_frame = 1 / frames_per_second();
-
-			/* Insert frames if required to get out_pts_seconds up to pts_seconds */
-			if (delta > one_frame) {
-				int const extra = rint (delta / one_frame);
-				for (int i = 0; i < extra; ++i) {
-					repeat_last_video ();
-					_film->log()->log (
-						String::compose (
-							"Extra video frame inserted at %1s; source frame %2, source PTS %3 (at %4 fps)",
-							out_pts_seconds, video_frame(), source_pts_seconds, frames_per_second()
-							)
-						);
-				}
-			}
-
-			if (delta > -one_frame) {
-				/* Process this frame */
-				filter_and_emit_video (_frame);
+			if (_opt->rough_decode_video_skip) {
+				rough_video_output ();
 			} else {
-				/* Otherwise we are omitting a frame to keep things right */
-				_film->log()->log (String::compose ("Frame removed at %1s", out_pts_seconds));
+				precise_video_output ();
 			}
 		}
 
@@ -637,3 +601,70 @@ FFmpegDecoder::length () const
 {
 	return (double(_format_context->duration) / AV_TIME_BASE) * frames_per_second();
 }
+
+void
+FFmpegDecoder::precise_video_output ()
+{
+	/* Where we are in the output, in seconds */
+	double const out_pts_seconds = video_frame() / frames_per_second();
+	
+	/* Where we are in the source, in seconds */
+	double const source_pts_seconds = av_q2d (_format_context->streams[_packet.stream_index]->time_base)
+		* av_frame_get_best_effort_timestamp(_frame);
+	
+	_film->log()->log (
+		String::compose ("Source video frame ready; source at %1, output at %2", source_pts_seconds, out_pts_seconds),
+		Log::VERBOSE
+		);
+	
+	if (!_first_video) {
+		_first_video = source_pts_seconds;
+	}
+	
+	/* Difference between where we are and where we should be */
+	double const delta = source_pts_seconds - _first_video.get() - out_pts_seconds;
+	double const one_frame = 1 / frames_per_second();
+	
+	/* Insert frames if required to get out_pts_seconds up to pts_seconds */
+	if (delta > one_frame) {
+		int const extra = rint (delta / one_frame);
+		for (int i = 0; i < extra; ++i) {
+			repeat_last_video ();
+			_film->log()->log (
+				String::compose (
+					"Extra video frame inserted at %1s; source frame %2, source PTS %3 (at %4 fps)",
+					out_pts_seconds, video_frame(), source_pts_seconds, frames_per_second()
+					)
+				);
+		}
+	}
+	
+	if (delta > -one_frame) {
+		/* Process this frame */
+		filter_and_emit_video (_frame);
+	} else {
+		/* Otherwise we are omitting a frame to keep things right */
+		_film->log()->log (String::compose ("Frame removed at %1s", out_pts_seconds));
+	}
+}
+
+void
+FFmpegDecoder::rough_video_output ()
+{
+	/* Where we are in the source, in seconds */
+	double const source_pts_seconds = av_q2d (_format_context->streams[_packet.stream_index]->time_base)
+		* av_frame_get_best_effort_timestamp(_frame);
+
+	if (!_last_rough_output || _last_rough_output.get() != source_pts_seconds) {
+		filter_and_emit_video (_frame);
+		_last_rough_output = source_pts_seconds;
+	}
+	
+	int64_t const t = static_cast<int64_t>(f) / (av_q2d (_format_context->streams[_video_stream]->time_base) * frames_per_second());
+	cout << "seek to " << t << " in stream tb\n";
+	int const r = av_seek_frame (_format_context, _video_stream, t, 0);
+	avcodec_flush_buffers (_video_codec_context);
+	if (r < 0) {
+		cout << "seek to " << t << " failed.\n";
+	}
+}
diff --git a/src/lib/ffmpeg_decoder.h b/src/lib/ffmpeg_decoder.h
index 1771551fc..141b40da0 100644
--- a/src/lib/ffmpeg_decoder.h
+++ b/src/lib/ffmpeg_decoder.h
@@ -105,6 +105,8 @@ private:
 	AVSampleFormat audio_sample_format () const;
 	int bytes_per_audio_sample () const;
 
+	void rough_video_output ();
+	void precise_video_output ();
 	void filter_and_emit_video (AVFrame *);
 
 	void setup_general ();
@@ -133,6 +135,7 @@ private:
 
 	boost::optional<double> _first_video;
 	boost::optional<double> _first_audio;
+	boost::optional<double> _last_rough_output;
 
 	std::list<boost::shared_ptr<FilterGraph> > _filter_graphs;
 };
diff --git a/src/lib/film.cc b/src/lib/film.cc
index e2a4cbeda..ecf37f033 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) && !content().empty()) {
+	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_encoder.cc b/src/lib/imagemagick_encoder.cc
index 480dec8bc..4fa702369 100644
--- a/src/lib/imagemagick_encoder.cc
+++ b/src/lib/imagemagick_encoder.cc
@@ -38,6 +38,7 @@
 
 using std::string;
 using std::ofstream;
+using std::cout;
 using boost::shared_ptr;
 
 /** @param f Film that we are encoding.
@@ -55,6 +56,8 @@ ImageMagickEncoder::do_process_video (shared_ptr<Image> image, shared_ptr<Subtit
 	shared_ptr<Image> scaled = image->scale_and_convert_to_rgb (_opt->out_size, _opt->padding, _film->scaler());
 	shared_ptr<Image> compact (new CompactImage (scaled));
 
+	cout << "IME writes frame " << _video_frame << "\n";
+
 	string tmp_file = _opt->frame_out_path (_video_frame, true);
 	Magick::Image thumb (compact->size().width, compact->size().height, "RGB", MagickCore::CharPixel, compact->data()[0]);
 	thumb.magick ("PNG");
diff --git a/src/lib/options.h b/src/lib/options.h
index 29b3b71cd..2fc3e5599 100644
--- a/src/lib/options.h
+++ b/src/lib/options.h
@@ -104,9 +104,14 @@ public:
 	boost::optional<std::pair<int64_t, int64_t> > audio_decode_range;
 	
 	/** Skip frames such that we don't decode any frame where (index % decode_video_skip) != 0; e.g.
-	 *  1 for every frame, 2 for every other frame, etc.
+	 *  1 for every frame, 2 for every other frame, etc.  With the `precise' skip, we do it
+	 *  by running the decoder without seeking and throwing away frames that we don't want.
 	 */
-	SourceFrame decode_video_skip; 
+	boost::optional<SourceFrame> precise_decode_video_skip;
+	/** As for precise_decode_video_skip, except that it is achieved by skipping the decoder, so
+	 *  things are made less precise by the presence of keyframes and other complications.
+	 */
+	boost::optional<SourceFrame> rough_decode_video_skip;
 	bool decode_audio;          ///< true to decode audio, otherwise false
 	bool decode_subtitles;
 
diff --git a/src/lib/transcoder.cc b/src/lib/transcoder.cc
index a7e79b05f..f764c65fb 100644
--- a/src/lib/transcoder.cc
+++ b/src/lib/transcoder.cc
@@ -49,7 +49,9 @@ using boost::dynamic_pointer_cast;
  *  @param e Encoder to use.
  */
 Transcoder::Transcoder (shared_ptr<Film> f, shared_ptr<const Options> o, Job* j, shared_ptr<Encoder> e)
-	: _job (j)
+	: _film (f)
+	, _opt (o)
+	, _job (j)
 	, _encoder (e)
 	, _decoders (decoder_factory (f, o, j))
 {
@@ -90,6 +92,8 @@ void
 Transcoder::go ()
 {
 	_encoder->process_begin ();
+	SourceFrame s = 0;
+	
 	try {
 		bool done[2] = { false, false };
 		
diff --git a/src/lib/transcoder.h b/src/lib/transcoder.h
index 4a9667b3c..43c70df00 100644
--- a/src/lib/transcoder.h
+++ b/src/lib/transcoder.h
@@ -54,6 +54,8 @@ public:
 	}
 
 protected:
+	boost::shared_ptr<Film> _film;
+	boost::shared_ptr<const Options> _opt;
 	/** A Job that is running this Transcoder, or 0 */
 	Job* _job;
 	/** The encoder that we will use */