X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Fffmpeg_decoder.cc;h=bf094913082104a1392048f2b8003daf245c825e;hb=89115db77729a2c99f1a09ff6a461720e16f889e;hp=e1834d7f644fbc768e28c2b19a48c4dd687d9b6f;hpb=bfea14c1655bc4bbadbe3d9e89f4bd2ddf037659;p=dcpomatic.git

diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index e1834d7f6..bf0949130 100644
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -28,20 +28,13 @@
 #include <iostream>
 #include <stdint.h>
 #include <boost/lexical_cast.hpp>
+#include <sndfile.h>
 extern "C" {
-#include <tiffio.h>
 #include <libavcodec/avcodec.h>
 #include <libavformat/avformat.h>
-#include <libswscale/swscale.h>
-#include <libpostproc/postprocess.h>
 }
-#include <sndfile.h>
 #include "film.h"
-#include "format.h"
-#include "transcoder.h"
-#include "job.h"
 #include "filter.h"
-#include "options.h"
 #include "exceptions.h"
 #include "image.h"
 #include "util.h"
@@ -49,6 +42,7 @@ extern "C" {
 #include "ffmpeg_decoder.h"
 #include "filter_graph.h"
 #include "subtitle.h"
+#include "audio_buffers.h"
 
 #include "i18n.h"
 
@@ -57,172 +51,66 @@ using std::string;
 using std::vector;
 using std::stringstream;
 using std::list;
+using std::min;
 using boost::shared_ptr;
 using boost::optional;
 using boost::dynamic_pointer_cast;
 using libdcp::Size;
 
-FFmpegDecoder::FFmpegDecoder (shared_ptr<Film> f, DecodeOptions o)
-	: Decoder (f, o)
-	, VideoDecoder (f, o)
-	, AudioDecoder (f, o)
-	, _format_context (0)
-	, _video_stream (-1)
-	, _frame (0)
-	, _video_codec_context (0)
-	, _video_codec (0)
-	, _audio_codec_context (0)
-	, _audio_codec (0)
+FFmpegDecoder::FFmpegDecoder (shared_ptr<const Film> f, shared_ptr<const FFmpegContent> c, bool video, bool audio)
+	: Decoder (f)
+	, VideoDecoder (f)
+	, AudioDecoder (f)
+	, FFmpeg (c)
 	, _subtitle_codec_context (0)
 	, _subtitle_codec (0)
+	, _decode_video (video)
+	, _decode_audio (audio)
+	, _pts_offset (0)
 {
-	setup_general ();
-	setup_video ();
-	setup_audio ();
 	setup_subtitle ();
-}
-
-FFmpegDecoder::~FFmpegDecoder ()
-{
-	if (_audio_codec_context) {
-		avcodec_close (_audio_codec_context);
-	}
-	
-	if (_video_codec_context) {
-		avcodec_close (_video_codec_context);
-	}
-
-	if (_subtitle_codec_context) {
-		avcodec_close (_subtitle_codec_context);
-	}
-
-	av_free (_frame);
-	
-	avformat_close_input (&_format_context);
-}	
-
-void
-FFmpegDecoder::setup_general ()
-{
-	av_register_all ();
-
-	if (avformat_open_input (&_format_context, _film->content_path().c_str(), 0, 0) < 0) {
-		throw OpenFileError (_film->content_path ());
-	}
-
-	if (avformat_find_stream_info (_format_context, 0) < 0) {
-		throw DecodeError (_("could not find stream information"));
-	}
-
-	/* Find video, audio and subtitle streams and choose the first of each */
-
-	for (uint32_t i = 0; i < _format_context->nb_streams; ++i) {
-		AVStream* s = _format_context->streams[i];
-		if (s->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
-			_video_stream = i;
-		} else if (s->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
-
-			/* This is a hack; sometimes it seems that _audio_codec_context->channel_layout isn't set up,
-			   so bodge it here.  No idea why we should have to do this.
-			*/
-
-			if (s->codec->channel_layout == 0) {
-				s->codec->channel_layout = av_get_default_channel_layout (s->codec->channels);
-			}
-			
-			_audio_streams.push_back (
-				shared_ptr<AudioStream> (
-					new FFmpegAudioStream (stream_name (s), i, s->codec->sample_rate, s->codec->channel_layout)
-					)
-				);
-			
-		} else if (s->codec->codec_type == AVMEDIA_TYPE_SUBTITLE) {
-			_subtitle_streams.push_back (
-				shared_ptr<SubtitleStream> (
-					new SubtitleStream (stream_name (s), i)
-					)
-				);
-		}
-	}
-
-	if (_video_stream < 0) {
-		throw DecodeError (N_("could not find video stream"));
-	}
-
-	_frame = avcodec_alloc_frame ();
-	if (_frame == 0) {
-		throw DecodeError (N_("could not allocate frame"));
-	}
-}
-
-void
-FFmpegDecoder::setup_video ()
-{
-	_video_codec_context = _format_context->streams[_video_stream]->codec;
-	_video_codec = avcodec_find_decoder (_video_codec_context->codec_id);
-
-	if (_video_codec == 0) {
-		throw DecodeError (_("could not find video decoder"));
-	}
 
-	if (avcodec_open2 (_video_codec_context, _video_codec, 0) < 0) {
-		throw DecodeError (N_("could not open video decoder"));
+	if (video && audio && c->audio_stream() && c->first_video() && c->audio_stream()->first_audio) {
+		_pts_offset = compute_pts_offset (c->first_video().get(), c->audio_stream()->first_audio.get(), c->video_frame_rate());
 	}
 }
 
-void
-FFmpegDecoder::setup_audio ()
+double
+FFmpegDecoder::compute_pts_offset (double first_video, double first_audio, float video_frame_rate)
 {
-	if (!_audio_stream) {
-		return;
-	}
-
-	shared_ptr<FFmpegAudioStream> ffa = dynamic_pointer_cast<FFmpegAudioStream> (_audio_stream);
-	assert (ffa);
+	double const old_first_video = first_video;
 	
-	_audio_codec_context = _format_context->streams[ffa->id()]->codec;
-	_audio_codec = avcodec_find_decoder (_audio_codec_context->codec_id);
-
-	if (_audio_codec == 0) {
-		throw DecodeError (_("could not find audio decoder"));
+	/* Round the first video to a frame boundary */
+	if (fabs (rint (first_video * video_frame_rate) - first_video * video_frame_rate) > 1e-6) {
+		first_video = ceil (first_video * video_frame_rate) / video_frame_rate;
 	}
 
-	if (avcodec_open2 (_audio_codec_context, _audio_codec, 0) < 0) {
-		throw DecodeError (N_("could not open audio decoder"));
-	}
+	/* Compute the required offset (also removing any common start delay) */
+	return first_video - old_first_video - min (first_video, first_audio);
 }
 
-void
-FFmpegDecoder::setup_subtitle ()
+FFmpegDecoder::~FFmpegDecoder ()
 {
-	if (!_subtitle_stream || _subtitle_stream->id() >= int (_format_context->nb_streams)) {
-		return;
-	}
+	boost::mutex::scoped_lock lm (_mutex);
 
-	_subtitle_codec_context = _format_context->streams[_subtitle_stream->id()]->codec;
-	_subtitle_codec = avcodec_find_decoder (_subtitle_codec_context->codec_id);
-
-	if (_subtitle_codec == 0) {
-		throw DecodeError (_("could not find subtitle decoder"));
-	}
-	
-	if (avcodec_open2 (_subtitle_codec_context, _subtitle_codec, 0) < 0) {
-		throw DecodeError (N_("could not open subtitle decoder"));
+	if (_subtitle_codec_context) {
+		avcodec_close (_subtitle_codec_context);
 	}
-}
-
+}	
 
-bool
+void
 FFmpegDecoder::pass ()
 {
 	int r = av_read_frame (_format_context, &_packet);
-	
+
 	if (r < 0) {
 		if (r != AVERROR_EOF) {
 			/* Maybe we should fail here, but for now we'll just finish off instead */
 			char buf[256];
 			av_strerror (r, buf, sizeof(buf));
-			_film->log()->log (String::compose (N_("error on av_read_frame (%1) (%2)"), buf, r));
+			shared_ptr<const Film> film = _film.lock ();
+			assert (film);
+			film->log()->log (String::compose (N_("error on av_read_frame (%1) (%2)"), buf, r));
 		}
 
 		/* Get any remaining frames */
@@ -232,41 +120,28 @@ FFmpegDecoder::pass ()
 		
 		/* XXX: should we reset _packet.data and size after each *_decode_* call? */
 		
-		int frame_finished;
-		
-		if (_opt.decode_video) {
-			while (avcodec_decode_video2 (_video_codec_context, _frame, &frame_finished, &_packet) >= 0 && frame_finished) {
-				filter_and_emit_video ();
-			}
+		if (_decode_video) {
+			while (decode_video_packet ());
 		}
-		
-		if (_audio_stream && _opt.decode_audio) {
+
+		if (_ffmpeg_content->audio_stream() && _decode_audio) {
 			decode_audio_packet ();
 		}
-			
-		return true;
+
+		/* Stop us being asked for any more data */
+		_video_position = _ffmpeg_content->video_length ();
+		_audio_position = _ffmpeg_content->audio_length ();
+		return;
 	}
 
 	avcodec_get_frame_defaults (_frame);
 
-	shared_ptr<FFmpegAudioStream> ffa = dynamic_pointer_cast<FFmpegAudioStream> (_audio_stream);
-
-	if (_packet.stream_index == _video_stream && _opt.decode_video) {
-
-		int frame_finished;
-		int const r = avcodec_decode_video2 (_video_codec_context, _frame, &frame_finished, &_packet);
-		if (r >= 0 && frame_finished) {
-
-			if (r != _packet.size) {
-				_film->log()->log (String::compose (N_("Used only %1 bytes of %2 in packet"), r, _packet.size));
-			}
-
-			filter_and_emit_video ();
-		}
-
-	} else if (ffa && _packet.stream_index == ffa->id() && _opt.decode_audio) {
+	if (_packet.stream_index == _video_stream && _decode_video) {
+		decode_video_packet ();
+	} else if (_ffmpeg_content->audio_stream() && _packet.stream_index == _ffmpeg_content->audio_stream()->id && _decode_audio) {
 		decode_audio_packet ();
-	} else if (_subtitle_stream && _packet.stream_index == _subtitle_stream->id() && _opt.decode_subtitles) {
+	} else if (_ffmpeg_content->subtitle_stream() && _packet.stream_index == _ffmpeg_content->subtitle_stream()->id) {
+#if 0		
 
 		int got_subtitle;
 		AVSubtitle sub;
@@ -277,19 +152,19 @@ FFmpegDecoder::pass ()
 			if (sub.num_rects > 0) {
 				shared_ptr<TimedSubtitle> ts;
 				try {
-					emit_subtitle (shared_ptr<TimedSubtitle> (new TimedSubtitle (sub)));
+					subtitle (shared_ptr<TimedSubtitle> (new TimedSubtitle (sub)));
 				} catch (...) {
 					/* some problem with the subtitle; we probably didn't understand it */
 				}
 			} else {
-				emit_subtitle (shared_ptr<TimedSubtitle> ());
+				subtitle (shared_ptr<TimedSubtitle> ());
 			}
 			avsubtitle_free (&sub);
 		}
+#endif		
 	}
-	
+
 	av_free_packet (&_packet);
-	return false;
 }
 
 /** @param data pointer to array of pointers to buffers.
@@ -298,19 +173,16 @@ FFmpegDecoder::pass ()
 shared_ptr<AudioBuffers>
 FFmpegDecoder::deinterleave_audio (uint8_t** data, int size)
 {
-	assert (_film->audio_channels());
+	assert (_ffmpeg_content->audio_channels());
 	assert (bytes_per_audio_sample());
 
-	shared_ptr<FFmpegAudioStream> ffa = dynamic_pointer_cast<FFmpegAudioStream> (_audio_stream);
-	assert (ffa);
-	
 	/* Deinterleave and convert to float */
 
-	assert ((size % (bytes_per_audio_sample() * ffa->channels())) == 0);
+	assert ((size % (bytes_per_audio_sample() * _ffmpeg_content->audio_channels())) == 0);
 
 	int const total_samples = size / bytes_per_audio_sample();
-	int const frames = total_samples / _film->audio_channels();
-	shared_ptr<AudioBuffers> audio (new AudioBuffers (ffa->channels(), frames));
+	int const frames = total_samples / _ffmpeg_content->audio_channels();
+	shared_ptr<AudioBuffers> audio (new AudioBuffers (_ffmpeg_content->audio_channels(), frames));
 
 	switch (audio_sample_format()) {
 	case AV_SAMPLE_FMT_S16:
@@ -322,7 +194,7 @@ FFmpegDecoder::deinterleave_audio (uint8_t** data, int size)
 			audio->data(channel)[sample] = float(*p++) / (1 << 15);
 
 			++channel;
-			if (channel == _film->audio_channels()) {
+			if (channel == _ffmpeg_content->audio_channels()) {
 				channel = 0;
 				++sample;
 			}
@@ -333,7 +205,7 @@ FFmpegDecoder::deinterleave_audio (uint8_t** data, int size)
 	case AV_SAMPLE_FMT_S16P:
 	{
 		int16_t** p = reinterpret_cast<int16_t **> (data);
-		for (int i = 0; i < _film->audio_channels(); ++i) {
+		for (int i = 0; i < _ffmpeg_content->audio_channels(); ++i) {
 			for (int j = 0; j < frames; ++j) {
 				audio->data(i)[j] = static_cast<float>(p[i][j]) / (1 << 15);
 			}
@@ -350,7 +222,7 @@ FFmpegDecoder::deinterleave_audio (uint8_t** data, int size)
 			audio->data(channel)[sample] = static_cast<float>(*p++) / (1 << 31);
 
 			++channel;
-			if (channel == _film->audio_channels()) {
+			if (channel == _ffmpeg_content->audio_channels()) {
 				channel = 0;
 				++sample;
 			}
@@ -367,7 +239,7 @@ FFmpegDecoder::deinterleave_audio (uint8_t** data, int size)
 			audio->data(channel)[sample] = *p++;
 
 			++channel;
-			if (channel == _film->audio_channels()) {
+			if (channel == _ffmpeg_content->audio_channels()) {
 				channel = 0;
 				++sample;
 			}
@@ -378,7 +250,7 @@ FFmpegDecoder::deinterleave_audio (uint8_t** data, int size)
 	case AV_SAMPLE_FMT_FLTP:
 	{
 		float** p = reinterpret_cast<float**> (data);
-		for (int i = 0; i < _film->audio_channels(); ++i) {
+		for (int i = 0; i < _ffmpeg_content->audio_channels(); ++i) {
 			memcpy (audio->data(i), p[i], frames * sizeof(float));
 		}
 	}
@@ -391,283 +263,225 @@ FFmpegDecoder::deinterleave_audio (uint8_t** data, int size)
 	return audio;
 }
 
-float
-FFmpegDecoder::frames_per_second () const
-{
-	AVStream* s = _format_context->streams[_video_stream];
-
-	if (s->avg_frame_rate.num && s->avg_frame_rate.den) {
-		return av_q2d (s->avg_frame_rate);
-	}
-
-	return av_q2d (s->r_frame_rate);
-}
-
 AVSampleFormat
 FFmpegDecoder::audio_sample_format () const
 {
-	if (_audio_codec_context == 0) {
+	if (!_ffmpeg_content->audio_stream()) {
 		return (AVSampleFormat) 0;
 	}
 	
-	return _audio_codec_context->sample_fmt;
-}
-
-libdcp::Size
-FFmpegDecoder::native_size () const
-{
-	return libdcp::Size (_video_codec_context->width, _video_codec_context->height);
-}
-
-PixelFormat
-FFmpegDecoder::pixel_format () const
-{
-	return _video_codec_context->pix_fmt;
+	return audio_codec_context()->sample_fmt;
 }
 
 int
-FFmpegDecoder::time_base_numerator () const
+FFmpegDecoder::bytes_per_audio_sample () const
 {
-	return _video_codec_context->time_base.num;
+	return av_get_bytes_per_sample (audio_sample_format ());
 }
 
-int
-FFmpegDecoder::time_base_denominator () const
+void
+FFmpegDecoder::seek (VideoContent::Frame frame)
 {
-	return _video_codec_context->time_base.den;
+	do_seek (frame, false, false);
 }
 
-int
-FFmpegDecoder::sample_aspect_ratio_numerator () const
+void
+FFmpegDecoder::seek_back ()
 {
-	return _video_codec_context->sample_aspect_ratio.num;
+	if (_video_position == 0) {
+		return;
+	}
+	
+	do_seek (_video_position - 1, true, true);
 }
 
-int
-FFmpegDecoder::sample_aspect_ratio_denominator () const
+void
+FFmpegDecoder::do_seek (VideoContent::Frame frame, bool backwards, bool accurate)
 {
-	return _video_codec_context->sample_aspect_ratio.den;
-}
+	int64_t const vt = frame * _ffmpeg_content->video_frame_rate() / av_q2d (_format_context->streams[_video_stream]->time_base);
+	av_seek_frame (_format_context, _video_stream, vt, backwards ? AVSEEK_FLAG_BACKWARD : 0);
+	_video_position = frame;
 
-string
-FFmpegDecoder::stream_name (AVStream* s) const
-{
-	stringstream n;
-	
-	AVDictionaryEntry const * lang = av_dict_get (s->metadata, N_("language"), 0, 0);
-	if (lang) {
-		n << lang->value;
-	}
-	
-	AVDictionaryEntry const * title = av_dict_get (s->metadata, N_("title"), 0, 0);
-	if (title) {
-		if (!n.str().empty()) {
-			n << N_(" ");
-		}
-		n << title->value;
+	avcodec_flush_buffers (video_codec_context());
+	if (_subtitle_codec_context) {
+		avcodec_flush_buffers (_subtitle_codec_context);
 	}
 
-	if (n.str().empty()) {
-		n << N_("unknown");
+	if (accurate) {
+		while (1) {
+			int r = av_read_frame (_format_context, &_packet);
+			if (r < 0) {
+				return;
+			}
+			
+			avcodec_get_frame_defaults (_frame);
+			
+			if (_packet.stream_index == _video_stream) {
+				int finished = 0;
+				int const r = avcodec_decode_video2 (video_codec_context(), _frame, &finished, &_packet);
+				if (r >= 0 && finished) {
+					int64_t const bet = av_frame_get_best_effort_timestamp (_frame);
+					if (bet > vt) {
+						_video_position = (bet * av_q2d (_format_context->streams[_video_stream]->time_base) + _pts_offset)
+							* _ffmpeg_content->video_frame_rate();
+						break;
+					}
+				}
+			}
+			
+			av_free_packet (&_packet);
+		}
 	}
-
-	return n.str ();
-}
-
-int
-FFmpegDecoder::bytes_per_audio_sample () const
-{
-	return av_get_bytes_per_sample (audio_sample_format ());
 }
 
 void
-FFmpegDecoder::set_audio_stream (shared_ptr<AudioStream> s)
+FFmpegDecoder::decode_audio_packet ()
 {
-	AudioDecoder::set_audio_stream (s);
-	setup_audio ();
-}
+	/* Audio packets can contain multiple frames, so we may have to call avcodec_decode_audio4
+	   several times.
+	*/
+	
+	AVPacket copy_packet = _packet;
 
-void
-FFmpegDecoder::set_subtitle_stream (shared_ptr<SubtitleStream> s)
-{
-	VideoDecoder::set_subtitle_stream (s);
-	setup_subtitle ();
-	OutputChanged ();
+	while (copy_packet.size > 0) {
+
+		int frame_finished;
+		int const decode_result = avcodec_decode_audio4 (audio_codec_context(), _frame, &frame_finished, &copy_packet);
+		if (decode_result >= 0) {
+			if (frame_finished) {
+
+				if (_audio_position == 0) {
+					/* Where we are in the source, in seconds */
+					double const pts = av_q2d (_format_context->streams[copy_packet.stream_index]->time_base)
+						* av_frame_get_best_effort_timestamp(_frame) - _pts_offset;
+
+					if (pts > 0) {
+						/* Emit some silence */
+						shared_ptr<AudioBuffers> silence (
+							new AudioBuffers (
+								_ffmpeg_content->audio_channels(),
+								pts * _ffmpeg_content->content_audio_frame_rate()
+								)
+							);
+						
+						silence->make_silent ();
+						audio (silence, _audio_position);
+					}
+				}
+					
+				copy_packet.data += decode_result;
+				copy_packet.size -= decode_result;
+			}
+		}
+	}
 }
 
-void
-FFmpegDecoder::filter_and_emit_video ()
+bool
+FFmpegDecoder::decode_video_packet ()
 {
+	int frame_finished;
+	if (avcodec_decode_video2 (video_codec_context(), _frame, &frame_finished, &_packet) < 0 || !frame_finished) {
+		return false;
+	}
+		
 	boost::mutex::scoped_lock lm (_filter_graphs_mutex);
-	
-	shared_ptr<FilterGraph> graph;
 
+	shared_ptr<FilterGraph> graph;
+	
 	list<shared_ptr<FilterGraph> >::iterator i = _filter_graphs.begin();
 	while (i != _filter_graphs.end() && !(*i)->can_process (libdcp::Size (_frame->width, _frame->height), (AVPixelFormat) _frame->format)) {
 		++i;
 	}
 
 	if (i == _filter_graphs.end ()) {
-		graph.reset (new FilterGraph (_film, this, libdcp::Size (_frame->width, _frame->height), (AVPixelFormat) _frame->format));
+		shared_ptr<const Film> film = _film.lock ();
+		assert (film);
+
+		graph.reset (new FilterGraph (_ffmpeg_content, libdcp::Size (_frame->width, _frame->height), (AVPixelFormat) _frame->format));
 		_filter_graphs.push_back (graph);
-		_film->log()->log (String::compose (N_("New graph for %1x%2, pixel format %3"), _frame->width, _frame->height, _frame->format));
+
+		film->log()->log (String::compose (N_("New graph for %1x%2, pixel format %3"), _frame->width, _frame->height, _frame->format));
 	} else {
 		graph = *i;
 	}
 
 	list<shared_ptr<Image> > images = graph->process (_frame);
 
+	string post_process = Filter::ffmpeg_strings (_ffmpeg_content->filters()).second;
+	
 	for (list<shared_ptr<Image> >::iterator i = images.begin(); i != images.end(); ++i) {
+
+		shared_ptr<Image> image = *i;
+		if (!post_process.empty ()) {
+			image = image->post_process (post_process, true);
+		}
+		
 		int64_t const bet = av_frame_get_best_effort_timestamp (_frame);
 		if (bet != AV_NOPTS_VALUE) {
-			emit_video (*i, bet * av_q2d (_format_context->streams[_video_stream]->time_base));
+
+			double const pts = bet * av_q2d (_format_context->streams[_video_stream]->time_base) - _pts_offset;
+			double const next = _video_position / _ffmpeg_content->video_frame_rate();
+			double const one_frame = 1 / _ffmpeg_content->video_frame_rate ();
+			double delta = pts - next;
+
+			while (delta > one_frame) {
+				/* This PTS is more than one frame forward in time of where we think we should be; emit
+				   a black frame.
+				*/
+				boost::shared_ptr<Image> black (
+					new SimpleImage (
+						static_cast<AVPixelFormat> (_frame->format),
+						libdcp::Size (video_codec_context()->width, video_codec_context()->height),
+						true
+						)
+					);
+				
+				black->make_black ();
+				video (image, false, _video_position);
+				delta -= one_frame;
+			}
+
+			if (delta > -one_frame) {
+				/* This PTS is within a frame of being right; emit this (otherwise it will be dropped) */
+				video (image, false, _video_position);
+			}
 		} else {
-			_film->log()->log ("Dropping frame without PTS");
+			shared_ptr<const Film> film = _film.lock ();
+			assert (film);
+			film->log()->log ("Dropping frame without PTS");
 		}
 	}
-}
 
-bool
-FFmpegDecoder::seek (double p)
-{
-	return do_seek (p, false);
+	return true;
 }
 
-bool
-FFmpegDecoder::seek_to_last ()
-{
-	/* This AVSEEK_FLAG_BACKWARD in do_seek is a bit of a hack; without it, if we ask for a seek to the same place as last time
-	   (used when we change decoder parameters and want to re-fetch the frame) we end up going forwards rather than
-	   staying in the same place.
-	*/
-	return do_seek (last_source_time(), true);
-}
-
-bool
-FFmpegDecoder::do_seek (double p, bool backwards)
-{
-	int64_t const vt = p / av_q2d (_format_context->streams[_video_stream]->time_base);
-
-	int const r = av_seek_frame (_format_context, _video_stream, vt, backwards ? AVSEEK_FLAG_BACKWARD : 0);
 	
-	avcodec_flush_buffers (_video_codec_context);
-	if (_subtitle_codec_context) {
-		avcodec_flush_buffers (_subtitle_codec_context);
-	}
-	
-	return r < 0;
-}
-
-shared_ptr<FFmpegAudioStream>
-FFmpegAudioStream::create (string t, optional<int> v)
-{
-	if (!v) {
-		/* version < 1; no type in the string, and there's only FFmpeg streams anyway */
-		return shared_ptr<FFmpegAudioStream> (new FFmpegAudioStream (t, v));
-	}
-
-	stringstream s (t);
-	string type;
-	s >> type;
-	if (type != N_("ffmpeg")) {
-		return shared_ptr<FFmpegAudioStream> ();
-	}
-
-	return shared_ptr<FFmpegAudioStream> (new FFmpegAudioStream (t, v));
-}
-
-FFmpegAudioStream::FFmpegAudioStream (string t, optional<int> version)
+void
+FFmpegDecoder::setup_subtitle ()
 {
-	stringstream n (t);
+	boost::mutex::scoped_lock lm (_mutex);
 	
-	int name_index = 4;
-	if (!version) {
-		name_index = 2;
-		int channels;
-		n >> _id >> channels;
-		_channel_layout = av_get_default_channel_layout (channels);
-		_sample_rate = 0;
-	} else {
-		string type;
-		/* Current (marked version 1) */
-		n >> type >> _id >> _sample_rate >> _channel_layout;
-		assert (type == N_("ffmpeg"));
-	}
-
-	for (int i = 0; i < name_index; ++i) {
-		size_t const s = t.find (' ');
-		if (s != string::npos) {
-			t = t.substr (s + 1);
-		}
+	if (!_ffmpeg_content->subtitle_stream() || _ffmpeg_content->subtitle_stream()->id >= int (_format_context->nb_streams)) {
+		return;
 	}
 
-	_name = t;
-}
-
-string
-FFmpegAudioStream::to_string () const
-{
-	return String::compose (N_("ffmpeg %1 %2 %3 %4"), _id, _sample_rate, _channel_layout, _name);
-}
+	_subtitle_codec_context = _format_context->streams[_ffmpeg_content->subtitle_stream()->id]->codec;
+	_subtitle_codec = avcodec_find_decoder (_subtitle_codec_context->codec_id);
 
-void
-FFmpegDecoder::film_changed (Film::Property p)
-{
-	switch (p) {
-	case Film::CROP:
-	case Film::FILTERS:
-	{
-		boost::mutex::scoped_lock lm (_filter_graphs_mutex);
-		_filter_graphs.clear ();
+	if (_subtitle_codec == 0) {
+		throw DecodeError (_("could not find subtitle decoder"));
 	}
-	OutputChanged ();
-	break;
-
-	default:
-		break;
+	
+	if (avcodec_open2 (_subtitle_codec_context, _subtitle_codec, 0) < 0) {
+		throw DecodeError (N_("could not open subtitle decoder"));
 	}
 }
 
-/** @return Length (in video frames) according to our content's header */
-SourceFrame
-FFmpegDecoder::length () const
+bool
+FFmpegDecoder::done () const
 {
-	return (double(_format_context->duration) / AV_TIME_BASE) * frames_per_second();
+	bool const vd = !_decode_video || (_video_position >= _ffmpeg_content->video_length());
+	bool const ad = !_decode_audio || !_ffmpeg_content->audio_stream() || (_audio_position >= _ffmpeg_content->audio_length());
+	return vd && ad;
 }
-
-void
-FFmpegDecoder::decode_audio_packet ()
-{
-	shared_ptr<FFmpegAudioStream> ffa = dynamic_pointer_cast<FFmpegAudioStream> (_audio_stream);
-	assert (ffa);
-
-	/* Audio packets can contain multiple frames, so we may have to call avcodec_decode_audio4
-	   several times.
-	*/
 	
-	AVPacket copy_packet = _packet;
-
-	while (copy_packet.size > 0) {
-
-		int frame_finished;
-		int const decode_result = avcodec_decode_audio4 (_audio_codec_context, _frame, &frame_finished, &copy_packet);
-		if (decode_result >= 0) {
-			if (frame_finished) {
-			
-				/* Where we are in the source, in seconds */
-				double const source_pts_seconds = av_q2d (_format_context->streams[copy_packet.stream_index]->time_base)
-					* av_frame_get_best_effort_timestamp(_frame);
-				
-				int const data_size = av_samples_get_buffer_size (
-					0, _audio_codec_context->channels, _frame->nb_samples, audio_sample_format (), 1
-					);
-				
-				assert (_audio_codec_context->channels == _film->audio_channels());
-				Audio (deinterleave_audio (_frame->data, data_size), source_pts_seconds);
-			}
-			
-			copy_packet.data += decode_result;
-			copy_packet.size -= decode_result;
-		}
-	}
-}