2 Copyright (C) 2013-2015 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.
21 #include <libavcodec/avcodec.h>
22 #include <libavformat/avformat.h>
24 #include "ffmpeg_examiner.h"
25 #include "ffmpeg_content.h"
26 #include "ffmpeg_audio_stream.h"
27 #include "ffmpeg_subtitle_stream.h"
29 #include "safe_stringstream.h"
36 using boost::shared_ptr;
37 using boost::optional;
39 FFmpegExaminer::FFmpegExaminer (shared_ptr<const FFmpegContent> c)
41 , _need_video_length (false)
43 /* Find audio and subtitle streams */
45 for (uint32_t i = 0; i < _format_context->nb_streams; ++i) {
46 AVStream* s = _format_context->streams[i];
47 if (s->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
49 /* This is a hack; sometimes it seems that _audio_codec_context->channel_layout isn't set up,
50 so bodge it here. No idea why we should have to do this.
53 if (s->codec->channel_layout == 0) {
54 s->codec->channel_layout = av_get_default_channel_layout (s->codec->channels);
57 _audio_streams.push_back (
58 shared_ptr<FFmpegAudioStream> (
59 new FFmpegAudioStream (audio_stream_name (s), s->id, s->codec->sample_rate, s->codec->channels)
63 } else if (s->codec->codec_type == AVMEDIA_TYPE_SUBTITLE) {
64 _subtitle_streams.push_back (shared_ptr<FFmpegSubtitleStream> (new FFmpegSubtitleStream (subtitle_stream_name (s), s->id)));
68 /* See if the header has duration information in it */
69 _need_video_length = _format_context->duration == AV_NOPTS_VALUE;
70 if (!_need_video_length) {
71 _video_length = ContentTime::from_seconds (double (_format_context->duration) / AV_TIME_BASE);
74 /* Run through until we find:
76 * - the first audio for each stream.
77 * - the subtitle periods for each stream.
79 * We have to note subtitle periods as otherwise we have no way of knowing
80 * where we should look for subtitles (video and audio are always present,
84 int r = av_read_frame (_format_context, &_packet);
89 AVCodecContext* context = _format_context->streams[_packet.stream_index]->codec;
91 if (_packet.stream_index == _video_stream) {
92 video_packet (context);
95 for (size_t i = 0; i < _audio_streams.size(); ++i) {
96 if (_audio_streams[i]->uses_index (_format_context, _packet.stream_index)) {
97 audio_packet (context, _audio_streams[i]);
101 for (size_t i = 0; i < _subtitle_streams.size(); ++i) {
102 if (_subtitle_streams[i]->uses_index (_format_context, _packet.stream_index)) {
103 subtitle_packet (context, _subtitle_streams[i]);
107 av_free_packet (&_packet);
112 FFmpegExaminer::video_packet (AVCodecContext* context)
114 if (_first_video && !_need_video_length) {
119 if (avcodec_decode_video2 (context, _frame, &frame_finished, &_packet) >= 0 && frame_finished) {
121 _first_video = frame_time (_format_context->streams[_video_stream]);
123 if (_need_video_length) {
124 _video_length = frame_time (_format_context->streams[_video_stream]).get_value_or (ContentTime ());
130 FFmpegExaminer::audio_packet (AVCodecContext* context, shared_ptr<FFmpegAudioStream> stream)
132 if (stream->first_audio) {
137 if (avcodec_decode_audio4 (context, _frame, &frame_finished, &_packet) >= 0 && frame_finished) {
138 stream->first_audio = frame_time (stream->stream (_format_context));
143 FFmpegExaminer::subtitle_packet (AVCodecContext* context, shared_ptr<FFmpegSubtitleStream> stream)
147 if (avcodec_decode_subtitle2 (context, &sub, &frame_finished, &_packet) >= 0 && frame_finished) {
148 ContentTimePeriod const period = subtitle_period (sub);
149 if (sub.num_rects == 0 && !stream->periods.empty () && stream->periods.back().to > period.from) {
150 /* Finish the last subtitle */
151 stream->periods.back().to = period.from;
152 } else if (sub.num_rects == 1) {
153 stream->periods.push_back (period);
158 optional<ContentTime>
159 FFmpegExaminer::frame_time (AVStream* s) const
161 optional<ContentTime> t;
163 int64_t const bet = av_frame_get_best_effort_timestamp (_frame);
164 if (bet != AV_NOPTS_VALUE) {
165 t = ContentTime::from_seconds (bet * av_q2d (s->time_base));
172 FFmpegExaminer::video_frame_rate () const
174 /* This use of r_frame_rate is debateable; there's a few different
175 * frame rates in the format context, but this one seems to be the most
178 return av_q2d (av_stream_get_r_frame_rate (_format_context->streams[_video_stream]));
182 FFmpegExaminer::video_size () const
184 return dcp::Size (video_codec_context()->width, video_codec_context()->height);
187 /** @return Length according to our content's header */
189 FFmpegExaminer::video_length () const
191 ContentTime const length = ContentTime::from_seconds (double (_format_context->duration) / AV_TIME_BASE);
192 return ContentTime (max (ContentTime (1), _video_length));
196 FFmpegExaminer::sample_aspect_ratio () const
198 AVRational sar = av_guess_sample_aspect_ratio (_format_context, _format_context->streams[_video_stream], 0);
200 /* I assume this means that we don't know */
201 return optional<float> ();
203 return float (sar.num) / sar.den;
207 FFmpegExaminer::audio_stream_name (AVStream* s) const
211 n << stream_name (s);
213 if (!n.str().empty()) {
217 n << s->codec->channels << " channels";
223 FFmpegExaminer::subtitle_stream_name (AVStream* s) const
227 n << stream_name (s);
229 if (n.str().empty()) {
237 FFmpegExaminer::stream_name (AVStream* s) const
242 AVDictionaryEntry const * lang = av_dict_get (s->metadata, "language", 0, 0);
247 AVDictionaryEntry const * title = av_dict_get (s->metadata, "title", 0, 0);
249 if (!n.str().empty()) {