2 Copyright (C) 2012 Carl Hetherington <cth@carlh.net>
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 /** @file src/lib/filter_graph.cc
21 * @brief A graph of FFmpeg filters.
25 #include <libavfilter/avfiltergraph.h>
26 #include <libavfilter/buffersrc.h>
27 #include <libavfilter/avcodec.h>
28 #include <libavfilter/buffersink.h>
29 #include <libavformat/avio.h>
32 #include "filter_graph.h"
34 #include "exceptions.h"
36 #include "ffmpeg_content.h"
37 #include "safe_stringstream.h"
46 using boost::shared_ptr;
47 using boost::weak_ptr;
50 /** Construct a FilterGraph for the settings in a piece of content.
51 * @param content Content.
52 * @param s Size of the images to process.
53 * @param p Pixel format of the images to process.
55 FilterGraph::FilterGraph (shared_ptr<const FFmpegContent> content, dcp::Size s, AVPixelFormat p)
57 , _buffer_src_context (0)
58 , _buffer_sink_context (0)
63 string const filters = Filter::ffmpeg_string (content->filters());
64 if (filters.empty ()) {
69 _frame = av_frame_alloc ();
71 AVFilterGraph* graph = avfilter_graph_alloc();
73 throw DecodeError (N_("could not create filter graph."));
76 AVFilter* buffer_src = avfilter_get_by_name(N_("buffer"));
77 if (buffer_src == 0) {
78 throw DecodeError (N_("could not find buffer src filter"));
81 AVFilter* buffer_sink = avfilter_get_by_name(N_("buffersink"));
82 if (buffer_sink == 0) {
83 throw DecodeError (N_("Could not create buffer sink filter"));
87 a << "video_size=" << _size.width << "x" << _size.height << ":"
88 << "pix_fmt=" << _pixel_format << ":"
90 << "pixel_aspect=1/1";
92 if (avfilter_graph_create_filter (&_buffer_src_context, buffer_src, "in", a.str().c_str(), 0, graph) < 0) {
93 throw DecodeError (N_("could not create buffer source"));
96 AVBufferSinkParams* sink_params = av_buffersink_params_alloc ();
97 PixelFormat* pixel_fmts = new PixelFormat[2];
98 pixel_fmts[0] = _pixel_format;
99 pixel_fmts[1] = PIX_FMT_NONE;
100 sink_params->pixel_fmts = pixel_fmts;
102 if (avfilter_graph_create_filter (&_buffer_sink_context, buffer_sink, N_("out"), 0, sink_params, graph) < 0) {
103 throw DecodeError (N_("could not create buffer sink."));
106 av_free (sink_params);
108 AVFilterInOut* outputs = avfilter_inout_alloc ();
109 outputs->name = av_strdup(N_("in"));
110 outputs->filter_ctx = _buffer_src_context;
111 outputs->pad_idx = 0;
114 AVFilterInOut* inputs = avfilter_inout_alloc ();
115 inputs->name = av_strdup(N_("out"));
116 inputs->filter_ctx = _buffer_sink_context;
120 if (avfilter_graph_parse (graph, filters.c_str(), inputs, outputs, 0) < 0) {
121 throw DecodeError (N_("could not set up filter graph."));
124 if (avfilter_graph_config (graph, 0) < 0) {
125 throw DecodeError (N_("could not configure filter graph."));
129 FilterGraph::~FilterGraph ()
132 av_frame_free (&_frame);
136 /** Take an AVFrame and process it using our configured filters, returning a
137 * set of Images. Caller handles memory management of the input frame.
139 list<pair<shared_ptr<Image>, int64_t> >
140 FilterGraph::process (AVFrame* frame)
142 list<pair<shared_ptr<Image>, int64_t> > images;
145 images.push_back (make_pair (shared_ptr<Image> (new Image (frame)), av_frame_get_best_effort_timestamp (frame)));
147 int r = av_buffersrc_write_frame (_buffer_src_context, frame);
149 throw DecodeError (String::compose (N_("could not push buffer into filter chain (%1)."), r));
153 if (av_buffersink_get_frame (_buffer_sink_context, _frame) < 0) {
157 images.push_back (make_pair (shared_ptr<Image> (new Image (_frame)), av_frame_get_best_effort_timestamp (_frame)));
158 av_frame_unref (_frame);
165 /** @param s Image size.
166 * @param p Pixel format.
167 * @return true if this chain can process images with `s' and `p', otherwise false.
170 FilterGraph::can_process (dcp::Size s, AVPixelFormat p) const
172 return (_size == s && _pixel_format == p);