2 Copyright (C) 2015 Carl Hetherington <cth@carlh.net>
4 This file is part of DCP-o-matic.
6 DCP-o-matic is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 DCP-o-matic is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with DCP-o-matic. If not, see <http://www.gnu.org/licenses/>.
22 #include "audio_buffers.h"
23 #include "audio_filter_graph.h"
24 #include "compose.hpp"
26 #include <libavfilter/buffersink.h>
27 #include <libavfilter/buffersrc.h>
28 #include <libavutil/channel_layout.h>
29 #include <libavutil/opt.h>
37 using std::make_shared;
38 using std::shared_ptr;
42 AudioFilterGraph::AudioFilterGraph (int sample_rate, int channels)
43 : _sample_rate (sample_rate)
44 , _channels (channels)
46 /* FFmpeg doesn't know any channel layouts for any counts between 8 and 16,
47 so we need to tell it we're using 16 channels if we are using more than 8.
50 _channel_layout = av_get_default_channel_layout (16);
52 _channel_layout = av_get_default_channel_layout (_channels);
55 _in_frame = av_frame_alloc ();
58 AudioFilterGraph::~AudioFilterGraph()
60 av_frame_free (&_in_frame);
64 AudioFilterGraph::src_parameters () const
67 av_get_channel_layout_string (layout, sizeof(layout), 0, _channel_layout);
71 buffer, sizeof(buffer), "time_base=1/1:sample_rate=%d:sample_fmt=%s:channel_layout=%s",
72 _sample_rate, av_get_sample_fmt_name(AV_SAMPLE_FMT_FLTP), layout
80 AudioFilterGraph::set_parameters (AVFilterContext* context) const
82 AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_NONE };
83 int r = av_opt_set_int_list (context, "sample_fmts", sample_fmts, AV_SAMPLE_FMT_NONE, AV_OPT_SEARCH_CHILDREN);
84 DCPOMATIC_ASSERT (r >= 0);
86 int64_t channel_layouts[] = { _channel_layout, -1 };
87 r = av_opt_set_int_list (context, "channel_layouts", channel_layouts, -1, AV_OPT_SEARCH_CHILDREN);
88 DCPOMATIC_ASSERT (r >= 0);
90 int sample_rates[] = { _sample_rate, -1 };
91 r = av_opt_set_int_list (context, "sample_rates", sample_rates, -1, AV_OPT_SEARCH_CHILDREN);
92 DCPOMATIC_ASSERT (r >= 0);
97 AudioFilterGraph::src_name () const
103 AudioFilterGraph::sink_name () const
105 return "abuffersink";
109 AudioFilterGraph::process (shared_ptr<AudioBuffers> buffers)
111 DCPOMATIC_ASSERT (buffers->frames() > 0);
112 int const process_channels = av_get_channel_layout_nb_channels (_channel_layout);
113 DCPOMATIC_ASSERT (process_channels >= buffers->channels());
115 if (buffers->channels() < process_channels) {
116 /* We are processing more data than we actually have (see the hack in
117 the constructor) so we need to create new buffers with some extra
120 auto extended_buffers = make_shared<AudioBuffers>(process_channels, buffers->frames());
121 for (int i = 0; i < buffers->channels(); ++i) {
122 extended_buffers->copy_channel_from (buffers.get(), i, i);
124 for (int i = buffers->channels(); i < process_channels; ++i) {
125 extended_buffers->make_silent (i);
128 buffers = extended_buffers;
131 _in_frame->extended_data = new uint8_t*[process_channels];
132 for (int i = 0; i < buffers->channels(); ++i) {
133 if (i < AV_NUM_DATA_POINTERS) {
134 _in_frame->data[i] = reinterpret_cast<uint8_t*> (buffers->data(i));
136 _in_frame->extended_data[i] = reinterpret_cast<uint8_t*> (buffers->data(i));
139 _in_frame->nb_samples = buffers->frames ();
140 _in_frame->format = AV_SAMPLE_FMT_FLTP;
141 _in_frame->sample_rate = _sample_rate;
142 _in_frame->channel_layout = _channel_layout;
143 _in_frame->channels = process_channels;
145 int r = av_buffersrc_write_frame (_buffer_src_context, _in_frame);
147 delete[] _in_frame->extended_data;
148 /* Reset extended_data to its original value so that av_frame_free
149 does not try to free it.
151 _in_frame->extended_data = _in_frame->data;
155 av_strerror (r, buffer, sizeof(buffer));
156 throw DecodeError (String::compose (N_("could not push buffer into filter chain (%1)"), &buffer[0]));
160 if (av_buffersink_get_frame (_buffer_sink_context, _frame) < 0) {
164 /* We don't extract audio data here, since the only use of this class
168 av_frame_unref (_frame);