X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Fplayer.cc;h=8532b5417b588bfbe9c26f0b4d630570607b880f;hb=57f229171a08567efeaed678381808173e4ef7a5;hp=60917ba0949a6bc272fa20d7e321db7d866e1355;hpb=1bff0990433ab0ce588acaef7c589fa623bd998b;p=dcpomatic.git

diff --git a/src/lib/player.cc b/src/lib/player.cc
index 60917ba09..8532b5417 100644
--- a/src/lib/player.cc
+++ b/src/lib/player.cc
@@ -17,31 +17,89 @@
 
 */
 
+#include <stdint.h>
 #include "player.h"
 #include "film.h"
 #include "ffmpeg_decoder.h"
+#include "ffmpeg_content.h"
 #include "imagemagick_decoder.h"
+#include "imagemagick_content.h"
 #include "sndfile_decoder.h"
+#include "sndfile_content.h"
+#include "subtitle_content.h"
 #include "playlist.h"
 #include "job.h"
+#include "image.h"
+#include "ratio.h"
+#include "resampler.h"
+#include "scaler.h"
 
 using std::list;
+using std::cout;
+using std::min;
+using std::max;
+using std::vector;
+using std::pair;
+using std::map;
 using boost::shared_ptr;
 using boost::weak_ptr;
 using boost::dynamic_pointer_cast;
 
+//#define DEBUG_PLAYER 1
+
+class Piece
+{
+public:
+	Piece (shared_ptr<Content> c)
+		: content (c)
+		, video_position (c->start ())
+		, audio_position (c->start ())
+	{}
+	
+	Piece (shared_ptr<Content> c, shared_ptr<Decoder> d)
+		: content (c)
+		, decoder (d)
+		, video_position (c->start ())
+		, audio_position (c->start ())
+	{}
+	
+	shared_ptr<Content> content;
+	shared_ptr<Decoder> decoder;
+	Time video_position;
+	Time audio_position;
+};
+
+#ifdef DEBUG_PLAYER
+std::ostream& operator<<(std::ostream& s, Piece const & p)
+{
+	if (dynamic_pointer_cast<FFmpegContent> (p.content)) {
+		s << "\tffmpeg     ";
+	} else if (dynamic_pointer_cast<ImageMagickContent> (p.content)) {
+		s << "\timagemagick";
+	} else if (dynamic_pointer_cast<SndfileContent> (p.content)) {
+		s << "\tsndfile    ";
+	}
+	
+	s << " at " << p.content->start() << " until " << p.content->end();
+	
+	return s;
+}
+#endif	
+
 Player::Player (shared_ptr<const Film> f, shared_ptr<const Playlist> p)
 	: _film (f)
 	, _playlist (p)
 	, _video (true)
 	, _audio (true)
-	, _subtitles (true)
-	, _have_valid_decoders (false)
-	, _ffmpeg_decoder_done (false)
-	, _video_sync (true)
+	, _have_valid_pieces (false)
+	, _video_position (0)
+	, _audio_position (0)
+	, _audio_buffers (f->dcp_audio_channels(), 0)
 {
 	_playlist->Changed.connect (bind (&Player::playlist_changed, this));
 	_playlist->ContentChanged.connect (bind (&Player::content_changed, this, _1, _2));
+	_film->Changed.connect (bind (&Player::film_changed, this, _1));
+	set_video_container_size (_film->container()->size (_film->full_frame ()));
 }
 
 void
@@ -56,230 +114,339 @@ Player::disable_audio ()
 	_audio = false;
 }
 
-void
-Player::disable_subtitles ()
-{
-	_subtitles = false;
-}
-
 bool
 Player::pass ()
 {
-	if (!_have_valid_decoders) {
-		setup_decoders ();
-		_have_valid_decoders = true;
+	if (!_have_valid_pieces) {
+		setup_pieces ();
+		_have_valid_pieces = true;
 	}
-	
-	bool done = true;
-	
-	if (_playlist->video_from() == Playlist::VIDEO_FFMPEG || _playlist->audio_from() == Playlist::AUDIO_FFMPEG) {
-		if (!_ffmpeg_decoder_done) {
-			if (_ffmpeg_decoder->pass ()) {
-				_ffmpeg_decoder_done = true;
-			} else {
-				done = false;
-			}
+
+#ifdef DEBUG_PLAYER
+	cout << "= PASS\n";
+#endif	
+
+        Time earliest_t = TIME_MAX;
+        shared_ptr<Piece> earliest;
+	enum {
+		VIDEO,
+		AUDIO
+	} type = VIDEO;
+
+	for (list<shared_ptr<Piece> >::iterator i = _pieces.begin(); i != _pieces.end(); ++i) {
+		if ((*i)->decoder->done ()) {
+			continue;
 		}
-	}
 
-	if (_playlist->video_from() == Playlist::VIDEO_IMAGEMAGICK) {
-		if (_imagemagick_decoder != _imagemagick_decoders.end ()) {
-			if ((*_imagemagick_decoder)->pass ()) {
-				_imagemagick_decoder++;
+		if (dynamic_pointer_cast<VideoDecoder> ((*i)->decoder)) {
+			if ((*i)->video_position < earliest_t) {
+				earliest_t = (*i)->video_position;
+				earliest = *i;
+				type = VIDEO;
 			}
+		}
 
-			if (_imagemagick_decoder != _imagemagick_decoders.end ()) {
-				done = false;
+		if (dynamic_pointer_cast<AudioDecoder> ((*i)->decoder)) {
+			if ((*i)->audio_position < earliest_t) {
+				earliest_t = (*i)->audio_position;
+				earliest = *i;
+				type = AUDIO;
 			}
 		}
 	}
 
-	/* XXX: sndfile */
-
-	return done;
-}
+	if (!earliest) {
+#ifdef DEBUG_PLAYER
+		cout << "no earliest piece.\n";
+#endif		
+		
+		flush ();
+		return true;
+	}
 
-void
-Player::set_progress (shared_ptr<Job> job)
-{
-	/* Assume progress can be divined from how far through the video we are */
-	switch (_playlist->video_from ()) {
-	case Playlist::VIDEO_NONE:
-		break;
-	case Playlist::VIDEO_FFMPEG:
-		if (_playlist->video_length ()) {
-			job->set_progress (float(_ffmpeg_decoder->video_frame()) / _playlist->video_length ());
+	switch (type) {
+	case VIDEO:
+		if (earliest_t > _video_position) {
+#ifdef DEBUG_PLAYER
+			cout << "no video here; emitting black frame.\n";
+#endif
+			emit_black ();
+		} else {
+#ifdef DEBUG_PLAYER
+			cout << "Pass " << *earliest << "\n";
+#endif			
+			earliest->decoder->pass ();
 		}
 		break;
-	case Playlist::VIDEO_IMAGEMAGICK:
-	{
-		int n = 0;
-		for (list<shared_ptr<ImageMagickDecoder> >::iterator i = _imagemagick_decoders.begin(); i != _imagemagick_decoders.end(); ++i) {
-			if (_imagemagick_decoder == i) {
-				job->set_progress (float (n) / _imagemagick_decoders.size ());
-			}
-			++n;
+
+	case AUDIO:
+		if (earliest_t > _audio_position) {
+#ifdef DEBUG_PLAYER
+			cout << "no audio here; emitting silence.\n";
+#endif
+			emit_silence (_film->time_to_audio_frames (earliest_t - _audio_position));
+		} else {
+#ifdef DEBUG_PLAYER
+			cout << "Pass " << *earliest << "\n";
+#endif			
+			earliest->decoder->pass ();
 		}
 		break;
 	}
-	}
-}
 
-void
-Player::process_video (shared_ptr<Image> i, bool same, shared_ptr<Subtitle> s)
-{
-	Video (i, same, s);
+#ifdef DEBUG_PLAYER
+	cout << "\tpost pass " << _video_position << " " << _audio_position << "\n";
+#endif	
+
+        return false;
 }
 
 void
-Player::process_audio (shared_ptr<AudioBuffers> b)
+Player::process_video (weak_ptr<Piece> weak_piece, shared_ptr<const Image> image, bool same, VideoContent::Frame frame)
 {
-	Audio (b);
-}
+	shared_ptr<Piece> piece = weak_piece.lock ();
+	if (!piece) {
+		return;
+	}
 
-/** @return true on error */
-bool
-Player::seek (double t)
-{
-	if (!_have_valid_decoders) {
-		setup_decoders ();
-		_have_valid_decoders = true;
+	shared_ptr<VideoContent> content = dynamic_pointer_cast<VideoContent> (piece->content);
+	assert (content);
+
+	FrameRateConversion frc (content->video_frame_rate(), _film->dcp_video_frame_rate());
+	if (frc.skip && (frame % 2) == 1) {
+		return;
 	}
+
+	shared_ptr<Image> work_image = image->crop (content->crop(), true);
+
+	libdcp::Size const image_size = content->ratio()->size (_video_container_size);
 	
-	bool r = false;
+	work_image = work_image->scale_and_convert_to_rgb (image_size, _film->scaler(), true);
 
-	switch (_playlist->video_from()) {
-	case Playlist::VIDEO_NONE:
-		break;
-	case Playlist::VIDEO_FFMPEG:
-		if (!_ffmpeg_decoder || _ffmpeg_decoder->seek (t)) {
-			r = true;
-		}
-		/* We're seeking, so all `all done' bets are off */
-		_ffmpeg_decoder_done = false;
-		break;
-	case Playlist::VIDEO_IMAGEMAGICK:
-		/* Find the decoder that contains this position */
-		_imagemagick_decoder = _imagemagick_decoders.begin ();
-		while (_imagemagick_decoder != _imagemagick_decoders.end ()) {
-			double const this_length = (*_imagemagick_decoder)->video_length() / _film->video_frame_rate ();
-			if (t < this_length) {
-				break;
-			}
-			t -= this_length;
-			++_imagemagick_decoder;
-		}
+	Time time = content->start() + (frame * frc.factor() * TIME_HZ / _film->dcp_video_frame_rate());
+	
+	if (_film->with_subtitles () && _out_subtitle.image && time >= _out_subtitle.from && time <= _out_subtitle.to) {
+		work_image->alpha_blend (_out_subtitle.image, _out_subtitle.position);
+	}
 
-		if (_imagemagick_decoder != _imagemagick_decoders.end()) {
-			(*_imagemagick_decoder)->seek (t);
-		} else {
-			r = true;
-		}
-		break;
+	if (image_size != _video_container_size) {
+		assert (image_size.width <= _video_container_size.width);
+		assert (image_size.height <= _video_container_size.height);
+		shared_ptr<Image> im (new Image (PIX_FMT_RGB24, _video_container_size, true));
+		im->make_black ();
+		im->copy (work_image, Position<int> ((_video_container_size.width - image_size.width) / 2, (_video_container_size.height - image_size.height) / 2));
+		work_image = im;
 	}
 
-	/* XXX: don't seek audio because we don't need to... */
+        Video (work_image, same, time);
+	time += TIME_HZ / _film->dcp_video_frame_rate();
 
-	return r;
+	if (frc.repeat) {
+		Video (work_image, true, time);
+		time += TIME_HZ / _film->dcp_video_frame_rate();
+	}
+
+	_video_position = piece->video_position = time;
 }
 
-bool
-Player::seek_to_last ()
+void
+Player::process_audio (weak_ptr<Piece> weak_piece, shared_ptr<const AudioBuffers> audio, AudioContent::Frame frame)
 {
-	if (!_have_valid_decoders) {
-		setup_decoders ();
-		_have_valid_decoders = true;
+	shared_ptr<Piece> piece = weak_piece.lock ();
+	if (!piece) {
+		return;
 	}
 
-	bool r = false;
-	
-	switch (_playlist->video_from ()) {
-	case Playlist::VIDEO_NONE:
-		break;
-	case Playlist::VIDEO_FFMPEG:
-		if (!_ffmpeg_decoder || _ffmpeg_decoder->seek_to_last ()) {
-			r = true;
-		}
+	shared_ptr<AudioContent> content = dynamic_pointer_cast<AudioContent> (piece->content);
+	assert (content);
 
-		/* We're seeking, so all `all done' bets are off */
-		_ffmpeg_decoder_done = false;
-		break;
-	case Playlist::VIDEO_IMAGEMAGICK:
-		if ((*_imagemagick_decoder)->seek_to_last ()) {
-			r = true;
+	/* Resample */
+	if (content->content_audio_frame_rate() != content->output_audio_frame_rate()) {
+		shared_ptr<Resampler> r = resampler (content);
+		audio = r->run (audio);
+	}
+
+	/* Remap channels */
+	shared_ptr<AudioBuffers> dcp_mapped (new AudioBuffers (_film->dcp_audio_channels(), audio->frames()));
+	dcp_mapped->make_silent ();
+	list<pair<int, libdcp::Channel> > map = content->audio_mapping().content_to_dcp ();
+	for (list<pair<int, libdcp::Channel> >::iterator i = map.begin(); i != map.end(); ++i) {
+		if (i->first < audio->channels() && i->second < dcp_mapped->channels()) {
+			dcp_mapped->accumulate_channel (audio.get(), i->first, i->second);
 		}
-		break;
 	}
 
-	/* XXX: don't seek audio because we don't need to... */
+	audio = dcp_mapped;
 
-	return r;
+	Time time = content->start() + (frame * TIME_HZ / _film->dcp_audio_frame_rate()) + (content->audio_delay() * TIME_HZ / 1000);
+
+	/* We must cut off anything that comes before the start of all time */
+	if (time < 0) {
+		int const frames = - time * _film->dcp_audio_frame_rate() / TIME_HZ;
+		if (frames >= audio->frames ()) {
+			return;
+		}
+
+		shared_ptr<AudioBuffers> trimmed (new AudioBuffers (audio->channels(), audio->frames() - frames));
+		trimmed->copy_from (audio.get(), audio->frames() - frames, frames, 0);
+
+		audio = trimmed;
+		time = 0;
+	}
+
+        /* The time of this audio may indicate that some of our buffered audio is not going to
+           be added to any more, so it can be emitted.
+        */
+
+        if (time > _audio_position) {
+                /* We can emit some audio from our buffers */
+                OutputAudioFrame const N = _film->time_to_audio_frames (time - _audio_position);
+		if (N > _audio_buffers.frames()) {
+			/* We need some extra silence before whatever is in the buffers */
+			_audio_buffers.ensure_size (N);
+			_audio_buffers.move (0, N - _audio_buffers.frames(), _audio_buffers.frames ());
+			_audio_buffers.make_silent (0, _audio_buffers.frames());
+			_audio_buffers.set_frames (N);
+		}
+			
+		if (N > _audio_buffers.frames()) {
+			cout << "N=" << N << ", ab=" << _audio_buffers.frames() << "\n";
+		}
+		assert (N <= _audio_buffers.frames());
+                shared_ptr<AudioBuffers> emit (new AudioBuffers (_audio_buffers.channels(), N));
+                emit->copy_from (&_audio_buffers, N, 0, 0);
+                Audio (emit, _audio_position);
+                _audio_position = piece->audio_position = time + _film->audio_frames_to_time (N);
+
+                /* And remove it from our buffers */
+                if (_audio_buffers.frames() > N) {
+                        _audio_buffers.move (N, 0, _audio_buffers.frames() - N);
+                }
+                _audio_buffers.set_frames (_audio_buffers.frames() - N);
+        }
+
+        /* Now accumulate the new audio into our buffers */
+        _audio_buffers.ensure_size (_audio_buffers.frames() + audio->frames());
+        _audio_buffers.accumulate_frames (audio.get(), 0, 0, audio->frames ());
+	_audio_buffers.set_frames (_audio_buffers.frames() + audio->frames());
 }
 
 void
-Player::setup_decoders ()
+Player::flush ()
 {
-	if ((_video && _playlist->video_from() == Playlist::VIDEO_FFMPEG) || (_audio && _playlist->audio_from() == Playlist::AUDIO_FFMPEG)) {
-		_ffmpeg_decoder.reset (
-			new FFmpegDecoder (
-				_film,
-				_playlist->ffmpeg(),
-				_video && _playlist->video_from() == Playlist::VIDEO_FFMPEG,
-				_audio && _playlist->audio_from() == Playlist::AUDIO_FFMPEG,
-				_subtitles && _film->with_subtitles(),
-				_video_sync
-				)
-			);
+	if (_audio_buffers.frames() > 0) {
+		shared_ptr<AudioBuffers> emit (new AudioBuffers (_audio_buffers.channels(), _audio_buffers.frames()));
+		emit->copy_from (&_audio_buffers, _audio_buffers.frames(), 0, 0);
+		Audio (emit, _audio_position);
+		_audio_position += _film->audio_frames_to_time (_audio_buffers.frames ());
+		_audio_buffers.set_frames (0);
 	}
-	
-	if (_video && _playlist->video_from() == Playlist::VIDEO_FFMPEG) {
-		_ffmpeg_decoder->connect_video (shared_from_this ());
+
+	while (_video_position < _audio_position) {
+		emit_black ();
 	}
 
-	if (_audio && _playlist->audio_from() == Playlist::AUDIO_FFMPEG) {
-		_ffmpeg_decoder->connect_audio (shared_from_this ());
+	while (_audio_position < _video_position) {
+		emit_silence (_film->time_to_audio_frames (_video_position - _audio_position));
 	}
+	
+}
 
-	if (_video && _playlist->video_from() == Playlist::VIDEO_IMAGEMAGICK) {
-		list<shared_ptr<const ImageMagickContent> > ic = _playlist->imagemagick ();
-		for (list<shared_ptr<const ImageMagickContent> >::iterator i = ic.begin(); i != ic.end(); ++i) {
-			shared_ptr<ImageMagickDecoder> d (new ImageMagickDecoder (_film, *i));
-			_imagemagick_decoders.push_back (d);
-			d->connect_video (shared_from_this ());
-		}
+/** @return true on error */
+void
+Player::seek (Time t, bool accurate)
+{
+	if (!_have_valid_pieces) {
+		setup_pieces ();
+		_have_valid_pieces = true;
+	}
 
-		_imagemagick_decoder = _imagemagick_decoders.begin ();
+	if (_pieces.empty ()) {
+		return;
 	}
 
-	if (_audio && _playlist->audio_from() == Playlist::AUDIO_SNDFILE) {
-		list<shared_ptr<const SndfileContent> > sc = _playlist->sndfile ();
-		for (list<shared_ptr<const SndfileContent> >::iterator i = sc.begin(); i != sc.end(); ++i) {
-			shared_ptr<SndfileDecoder> d (new SndfileDecoder (_film, *i));
-			_sndfile_decoders.push_back (d);
-			d->connect_audio (shared_from_this ());
+	for (list<shared_ptr<Piece> >::iterator i = _pieces.begin(); i != _pieces.end(); ++i) {
+		shared_ptr<VideoContent> vc = dynamic_pointer_cast<VideoContent> ((*i)->content);
+		if (!vc) {
+			continue;
 		}
+		
+		Time s = t - vc->start ();
+		s = max (static_cast<Time> (0), s);
+		s = min (vc->length(), s);
+
+		FrameRateConversion frc (vc->video_frame_rate(), _film->dcp_video_frame_rate());
+		VideoContent::Frame f = s * vc->video_frame_rate() / (frc.factor() * TIME_HZ);
+		dynamic_pointer_cast<VideoDecoder>((*i)->decoder)->seek (f, accurate);
 	}
+
+	/* XXX: don't seek audio because we don't need to... */
 }
 
 void
-Player::disable_video_sync ()
+Player::setup_pieces ()
 {
-	_video_sync = false;
-}
+	list<shared_ptr<Piece> > old_pieces = _pieces;
 
-double
-Player::last_video_time () const
-{
-	switch (_playlist->video_from ()) {
-	case Playlist::VIDEO_NONE:
-		return 0;
-	case Playlist::VIDEO_FFMPEG:
-		return _ffmpeg_decoder->last_source_time ();
-	case Playlist::VIDEO_IMAGEMAGICK:
-		return (*_imagemagick_decoder)->last_source_time ();
+	_pieces.clear ();
+
+	Playlist::ContentList content = _playlist->content ();
+	sort (content.begin(), content.end(), ContentSorter ());
+
+	for (Playlist::ContentList::iterator i = content.begin(); i != content.end(); ++i) {
+
+		shared_ptr<Piece> piece (new Piece (*i));
+
+                /* XXX: into content? */
+
+		shared_ptr<const FFmpegContent> fc = dynamic_pointer_cast<const FFmpegContent> (*i);
+		if (fc) {
+			shared_ptr<FFmpegDecoder> fd (new FFmpegDecoder (_film, fc, _video, _audio));
+			
+			fd->Video.connect (bind (&Player::process_video, this, piece, _1, _2, _3));
+			fd->Audio.connect (bind (&Player::process_audio, this, piece, _1, _2));
+			fd->Subtitle.connect (bind (&Player::process_subtitle, this, piece, _1, _2, _3, _4));
+
+			piece->decoder = fd;
+		}
+		
+		shared_ptr<const ImageMagickContent> ic = dynamic_pointer_cast<const ImageMagickContent> (*i);
+		if (ic) {
+			shared_ptr<ImageMagickDecoder> id;
+			
+			/* See if we can re-use an old ImageMagickDecoder */
+			for (list<shared_ptr<Piece> >::const_iterator j = old_pieces.begin(); j != old_pieces.end(); ++j) {
+				shared_ptr<ImageMagickDecoder> imd = dynamic_pointer_cast<ImageMagickDecoder> ((*j)->decoder);
+				if (imd && imd->content() == ic) {
+					id = imd;
+				}
+			}
+
+			if (!id) {
+				id.reset (new ImageMagickDecoder (_film, ic));
+				id->Video.connect (bind (&Player::process_video, this, piece, _1, _2, _3));
+			}
+
+			piece->decoder = id;
+		}
+
+		shared_ptr<const SndfileContent> sc = dynamic_pointer_cast<const SndfileContent> (*i);
+		if (sc) {
+			shared_ptr<AudioDecoder> sd (new SndfileDecoder (_film, sc));
+			sd->Audio.connect (bind (&Player::process_audio, this, piece, _1, _2));
+
+			piece->decoder = sd;
+		}
+
+		_pieces.push_back (piece);
 	}
 
-	return 0;
+#ifdef DEBUG_PLAYER
+	cout << "=== Player setup:\n";
+	for (list<shared_ptr<Piece> >::iterator i = _pieces.begin(); i != _pieces.end(); ++i) {
+		cout << *(i->get()) << "\n";
+	}
+#endif	
 }
 
 void
@@ -290,15 +457,132 @@ Player::content_changed (weak_ptr<Content> w, int p)
 		return;
 	}
 
-	if (p == VideoContentProperty::VIDEO_LENGTH) {
-		if (dynamic_pointer_cast<FFmpegContent> (c)) {
-			_have_valid_decoders = false;
-		}
+	if (
+		p == ContentProperty::START || p == ContentProperty::LENGTH ||
+		p == VideoContentProperty::VIDEO_CROP || p == VideoContentProperty::VIDEO_RATIO
+		) {
+		
+		_have_valid_pieces = false;
+		Changed ();
+
+	} else if (p == SubtitleContentProperty::SUBTITLE_OFFSET || p == SubtitleContentProperty::SUBTITLE_SCALE) {
+		update_subtitle ();
+		Changed ();
 	}
 }
 
 void
 Player::playlist_changed ()
 {
-	_have_valid_decoders = false;
+	_have_valid_pieces = false;
+	Changed ();
+}
+
+void
+Player::set_video_container_size (libdcp::Size s)
+{
+	_video_container_size = s;
+	_black_frame.reset (new Image (PIX_FMT_RGB24, _video_container_size, true));
+	_black_frame->make_black ();
+}
+
+shared_ptr<Resampler>
+Player::resampler (shared_ptr<AudioContent> c)
+{
+	map<shared_ptr<AudioContent>, shared_ptr<Resampler> >::iterator i = _resamplers.find (c);
+	if (i != _resamplers.end ()) {
+		return i->second;
+	}
+	
+	shared_ptr<Resampler> r (new Resampler (c->content_audio_frame_rate(), c->output_audio_frame_rate(), c->audio_channels()));
+	_resamplers[c] = r;
+	return r;
+}
+
+void
+Player::emit_black ()
+{
+	/* XXX: use same here */
+	Video (_black_frame, false, _video_position);
+	_video_position += _film->video_frames_to_time (1);
+}
+
+void
+Player::emit_silence (OutputAudioFrame most)
+{
+	OutputAudioFrame N = min (most, _film->dcp_audio_frame_rate() / 2);
+	shared_ptr<AudioBuffers> silence (new AudioBuffers (_film->dcp_audio_channels(), N));
+	silence->make_silent ();
+	Audio (silence, _audio_position);
+	_audio_position += _film->audio_frames_to_time (N);
+}
+
+void
+Player::film_changed (Film::Property p)
+{
+	/* Here we should notice Film properties that affect our output, and
+	   alert listeners that our output now would be different to how it was
+	   last time we were run.
+	*/
+
+	if (p == Film::SCALER || p == Film::WITH_SUBTITLES || p == Film::CONTAINER) {
+		Changed ();
+	}
+}
+
+void
+Player::process_subtitle (weak_ptr<Piece> weak_piece, shared_ptr<Image> image, dcpomatic::Rect<double> rect, Time from, Time to)
+{
+	_in_subtitle.piece = weak_piece;
+	_in_subtitle.image = image;
+	_in_subtitle.rect = rect;
+	_in_subtitle.from = from;
+	_in_subtitle.to = to;
+
+	update_subtitle ();
+}
+
+void
+Player::update_subtitle ()
+{
+	shared_ptr<Piece> piece = _in_subtitle.piece.lock ();
+	if (!piece) {
+		return;
+	}
+
+	if (!_in_subtitle.image) {
+		_out_subtitle.image.reset ();
+		return;
+	}
+
+	shared_ptr<SubtitleContent> sc = dynamic_pointer_cast<SubtitleContent> (piece->content);
+	assert (sc);
+
+	dcpomatic::Rect<double> in_rect = _in_subtitle.rect;
+	libdcp::Size scaled_size;
+
+	in_rect.y += sc->subtitle_offset ();
+
+	/* We will scale the subtitle up to fit _video_container_size, and also by the additional subtitle_scale */
+	scaled_size.width = in_rect.width * _video_container_size.width * sc->subtitle_scale ();
+	scaled_size.height = in_rect.height * _video_container_size.height * sc->subtitle_scale ();
+
+	/* Then we need a corrective translation, consisting of two parts:
+	 *
+	 * 1.  that which is the result of the scaling of the subtitle by _video_container_size; this will be
+	 *     rect.x * _video_container_size.width and rect.y * _video_container_size.height.
+	 *
+	 * 2.  that to shift the origin of the scale by subtitle_scale to the centre of the subtitle; this will be
+	 *     (width_before_subtitle_scale * (1 - subtitle_scale) / 2) and
+	 *     (height_before_subtitle_scale * (1 - subtitle_scale) / 2).
+	 *
+	 * Combining these two translations gives these expressions.
+	 */
+	
+	_out_subtitle.position.x = rint (_video_container_size.width * (in_rect.x + (in_rect.width * (1 - sc->subtitle_scale ()) / 2)));
+	_out_subtitle.position.y = rint (_video_container_size.height * (in_rect.y + (in_rect.height * (1 - sc->subtitle_scale ()) / 2)));
+	
+	_out_subtitle.image = _in_subtitle.image->scale (libdcp::Size (scaled_size.width, scaled_size.height), Scaler::from_id ("bicubic"), true);
+	_out_subtitle.from = _in_subtitle.from + piece->content->start ();
+	_out_subtitle.to = _in_subtitle.to + piece->content->start ();
 }