1 files changed, 300 insertions, 0 deletions
diff --git a/src/lib/decoder.cc b/src/lib/decoder.cc
new file mode 100644
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--- /dev/null
+++ b/src/lib/decoder.cc
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+/*
+    Copyright (C) 2012 Carl Hetherington <cth@carlh.net>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+/** @file  src/decoder.cc
+ *  @brief Parent class for decoders of content.
+ */
+
+#include <iostream>
+#include <stdint.h>
+extern "C" {
+#include <libavfilter/avfiltergraph.h>
+#include <libavfilter/buffersink.h>
+#include <libavfilter/avcodec.h>
+}
+#include "film.h"
+#include "format.h"
+#include "job.h"
+#include "film_state.h"
+#include "options.h"
+#include "exceptions.h"
+#include "image.h"
+#include "util.h"
+#include "log.h"
+#include "decoder.h"
+#include "filter.h"
+#include "delay_line.h"
+
+using namespace std;
+using namespace boost;
+
+/** @param s FilmState of the Film.
+ *  @param o Options.
+ *  @param j Job that we are running within, or 0
+ *  @param l Log to use.
+ *  @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<const FilmState> s, boost::shared_ptr<const Options> o, Job* j, Log* l, bool minimal, bool ignore_length)
+	: _fs (s)
+	, _opt (o)
+	, _job (j)
+	, _log (l)
+	, _minimal (minimal)
+	, _ignore_length (ignore_length)
+	, _video_frame (0)
+	, _buffer_src_context (0)
+	, _buffer_sink_context (0)
+	, _have_setup_video_filters (false)
+	, _delay_line (0)
+	, _delay_in_bytes (0)
+{
+	if (_opt->decode_video_frequency != 0 && _fs->length == 0) {
+		throw DecodeError ("cannot do a partial decode if length == 0");
+	}
+}
+
+Decoder::~Decoder ()
+{
+	delete _delay_line;
+}
+
+void
+Decoder::process_begin ()
+{
+	/* This assumes 2 bytes per sample */
+	_delay_in_bytes = _fs->audio_delay * _fs->audio_sample_rate * _fs->audio_channels * 2 / 1000;
+	delete _delay_line;
+	_delay_line = new DelayLine (_delay_in_bytes);
+}
+
+void
+Decoder::process_end ()
+{
+	if (_delay_in_bytes < 0) {
+		uint8_t remainder[-_delay_in_bytes];
+		_delay_line->get_remaining (remainder);
+		Audio (remainder, _delay_in_bytes);
+	}
+}
+
+/** Start decoding */
+void
+Decoder::go ()
+{
+	process_begin ();
+
+	if (_job && _ignore_length) {
+		_job->set_progress_unknown ();
+	}
+
+	while (pass () == false) {
+		if (_job && !_ignore_length) {
+			_job->set_progress (float (_video_frame) / decoding_frames ());
+		}
+	}
+
+	process_end ();
+}
+
+/** @return Number of frames that we will be decoding */
+int
+Decoder::decoding_frames () const
+{
+	if (_opt->num_frames > 0) {
+		return _opt->num_frames;
+	}
+	
+	return _fs->length;
+}
+
+/** 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 (!_have_setup_video_filters) {
+		setup_video_filters ();
+		_have_setup_video_filters = true;
+	}
+	
+	if (_opt->num_frames != 0 && _video_frame >= _opt->num_frames) {
+		return true;
+	}
+
+	return do_pass ();
+}
+
+/** Called by subclasses to tell the world that some audio data is ready */
+void
+Decoder::process_audio (uint8_t* data, int channels, int size)
+{
+	if (_fs->audio_gain != 0) {
+		float const linear_gain = pow (10, _fs->audio_gain / 20);
+		uint8_t* p = data;
+		int const samples = size / 2;
+		switch (_fs->audio_sample_format) {
+		case AV_SAMPLE_FMT_S16:
+			for (int i = 0; i < samples; ++i) {
+				/* XXX: assumes little-endian; also we should probably be dithering here */
+				int const ou = p[0] | (p[1] << 8);
+				int const os = ou >= 0x8000 ? (- 0x10000 + ou) : ou;
+				int const gs = int (os * linear_gain);
+				int const gu = gs > 0 ? gs : (0x10000 + gs);
+				p[0] = gu & 0xff;
+				p[1] = (gu & 0xff00) >> 8;
+				p += 2;
+			}
+			break;
+		default:
+			assert (false);
+		}
+	}
+
+	int available = _delay_line->feed (data, size);
+	Audio (data, available);
+}
+
+/** Called by subclasses to tell the world that some video data is ready.
+ *  We do some post-processing / filtering then emit it for listeners.
+ *  @param frame to decode; caller manages memory.
+ */
+void
+Decoder::process_video (AVFrame* frame)
+{
+	if (_minimal) {
+		++_video_frame;
+		return;
+	}
+
+	/* Use FilmState::length here as our one may be wrong */
+
+	int gap = 0;
+	if (_opt->decode_video_frequency != 0) {
+		gap = _fs->length / _opt->decode_video_frequency;
+	}
+	
+	if (_opt->decode_video_frequency != 0 && gap != 0 && (_video_frame % gap) != 0) {
+		++_video_frame;
+		return;
+	}
+
+	if (av_vsrc_buffer_add_frame (_buffer_src_context, frame, 0) < 0) {
+		throw DecodeError ("could not push buffer into filter chain.");
+	}
+	
+	while (avfilter_poll_frame (_buffer_sink_context->inputs[0])) {
+		AVFilterBufferRef* filter_buffer;
+		if (av_buffersink_get_buffer_ref (_buffer_sink_context, &filter_buffer, 0) >= 0) {
+			
+			/* This takes ownership of filter_buffer */
+			shared_ptr<Image> image (new FilterBufferImage ((PixelFormat) frame->format, filter_buffer));
+
+			if (_opt->black_after > 0 && _video_frame > _opt->black_after) {
+				image->make_black ();
+			}
+
+			Video (image, _video_frame);
+			++_video_frame;
+		}
+	}
+}
+
+void
+Decoder::setup_video_filters ()
+{
+	stringstream fs;
+	Size size_after_crop;
+	
+	if (_opt->apply_crop) {
+		size_after_crop = _fs->cropped_size (native_size ());
+		fs << crop_string (Position (_fs->left_crop, _fs->top_crop), size_after_crop);
+	} else {
+		size_after_crop = native_size ();
+		fs << crop_string (Position (0, 0), size_after_crop);
+	}
+
+	string filters = Filter::ffmpeg_strings (_fs->filters).first;
+	if (!filters.empty ()) {
+		filters += ",";
+	}
+
+	filters += fs.str ();
+
+	avfilter_register_all ();
+	
+	AVFilterGraph* graph = avfilter_graph_alloc();
+	if (graph == 0) {
+		throw DecodeError ("Could not create filter graph.");
+	}
+	
+	AVFilter* buffer_src = avfilter_get_by_name("buffer");
+	if (buffer_src == 0) {
+		throw DecodeError ("Could not create buffer src filter");
+	}
+	
+	AVFilter* buffer_sink = avfilter_get_by_name("buffersink");
+	if (buffer_sink == 0) {
+		throw DecodeError ("Could not create buffer sink filter");
+	}
+	
+	stringstream a;
+	a << native_size().width << ":"
+	  << native_size().height << ":"
+	  << pixel_format() << ":"
+	  << time_base_numerator() << ":"
+	  << time_base_denominator() << ":"
+	  << sample_aspect_ratio_numerator() << ":"
+	  << sample_aspect_ratio_denominator();
+
+	int r;
+	if ((r = avfilter_graph_create_filter (&_buffer_src_context, buffer_src, "in", a.str().c_str(), 0, graph)) < 0) {
+		throw DecodeError ("could not create buffer source");
+	}
+
+	enum PixelFormat pixel_formats[] = { pixel_format(), PIX_FMT_NONE };
+	if (avfilter_graph_create_filter (&_buffer_sink_context, buffer_sink, "out", 0, pixel_formats, graph) < 0) {
+		throw DecodeError ("could not create buffer sink.");
+	}
+
+	AVFilterInOut* outputs = avfilter_inout_alloc ();
+	outputs->name = av_strdup("in");
+	outputs->filter_ctx = _buffer_src_context;
+	outputs->pad_idx = 0;
+	outputs->next = 0;
+
+	AVFilterInOut* inputs = avfilter_inout_alloc ();
+	inputs->name = av_strdup("out");
+	inputs->filter_ctx = _buffer_sink_context;
+	inputs->pad_idx = 0;
+	inputs->next = 0;
+
+	_log->log ("Using filter chain `" + filters + "'");
+	if (avfilter_graph_parse (graph, filters.c_str(), &inputs, &outputs, 0) < 0) {
+		throw DecodeError ("could not set up filter graph.");
+	}
+
+	if (avfilter_graph_config (graph, 0) < 0) {
+		throw DecodeError ("could not configure filter graph.");
+	}
+}
+