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>
23 #include <libavutil/pixfmt.h>
24 #include <libavutil/pixdesc.h>
26 #include "ffmpeg_examiner.h"
27 #include "ffmpeg_content.h"
29 #include "ffmpeg_audio_stream.h"
30 #include "ffmpeg_subtitle_stream.h"
32 #include "safe_stringstream.h"
39 using boost::shared_ptr;
40 using boost::optional;
42 /** @param job job that the examiner is operating in, or 0 */
43 FFmpegExaminer::FFmpegExaminer (shared_ptr<const FFmpegContent> c, shared_ptr<Job> job)
46 , _need_video_length (false)
48 /* Find audio and subtitle streams */
50 for (uint32_t i = 0; i < _format_context->nb_streams; ++i) {
51 AVStream* s = _format_context->streams[i];
52 if (s->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
54 /* This is a hack; sometimes it seems that _audio_codec_context->channel_layout isn't set up,
55 so bodge it here. No idea why we should have to do this.
58 if (s->codec->channel_layout == 0) {
59 s->codec->channel_layout = av_get_default_channel_layout (s->codec->channels);
62 _audio_streams.push_back (
63 shared_ptr<FFmpegAudioStream> (
64 new FFmpegAudioStream (audio_stream_name (s), s->id, s->codec->sample_rate, s->codec->channels)
68 } else if (s->codec->codec_type == AVMEDIA_TYPE_SUBTITLE) {
69 _subtitle_streams.push_back (shared_ptr<FFmpegSubtitleStream> (new FFmpegSubtitleStream (subtitle_stream_name (s), s->id)));
73 /* See if the header has duration information in it */
74 _need_video_length = _format_context->duration == AV_NOPTS_VALUE;
75 if (!_need_video_length) {
76 _video_length = (double (_format_context->duration) / AV_TIME_BASE) * video_frame_rate().get ();
78 job->sub (_("Finding length"));
79 job->set_progress_unknown ();
83 job->sub (_("Finding subtitles"));
86 /* Run through until we find:
88 * - the first audio for each stream.
89 * - the subtitle periods for each stream.
91 * We have to note subtitle periods as otherwise we have no way of knowing
92 * where we should look for subtitles (video and audio are always present,
96 int r = av_read_frame (_format_context, &_packet);
102 job->set_progress_unknown ();
105 AVCodecContext* context = _format_context->streams[_packet.stream_index]->codec;
107 if (_packet.stream_index == _video_stream) {
108 video_packet (context);
111 for (size_t i = 0; i < _audio_streams.size(); ++i) {
112 if (_audio_streams[i]->uses_index (_format_context, _packet.stream_index)) {
113 audio_packet (context, _audio_streams[i]);
117 for (size_t i = 0; i < _subtitle_streams.size(); ++i) {
118 if (_subtitle_streams[i]->uses_index (_format_context, _packet.stream_index)) {
119 subtitle_packet (context, _subtitle_streams[i]);
123 av_free_packet (&_packet);
128 FFmpegExaminer::video_packet (AVCodecContext* context)
130 if (_first_video && !_need_video_length) {
135 if (avcodec_decode_video2 (context, _frame, &frame_finished, &_packet) >= 0 && frame_finished) {
137 _first_video = frame_time (_format_context->streams[_video_stream]);
139 if (_need_video_length) {
140 _video_length = frame_time (
141 _format_context->streams[_video_stream]
142 ).get_value_or (ContentTime ()).frames (video_frame_rate().get ());
148 FFmpegExaminer::audio_packet (AVCodecContext* context, shared_ptr<FFmpegAudioStream> stream)
150 if (stream->first_audio) {
155 if (avcodec_decode_audio4 (context, _frame, &frame_finished, &_packet) >= 0 && frame_finished) {
156 stream->first_audio = frame_time (stream->stream (_format_context));
161 FFmpegExaminer::subtitle_packet (AVCodecContext* context, shared_ptr<FFmpegSubtitleStream> stream)
165 if (avcodec_decode_subtitle2 (context, &sub, &frame_finished, &_packet) >= 0 && frame_finished) {
166 FFmpegSubtitlePeriod const period = subtitle_period (sub);
167 if (sub.num_rects <= 0 && _last_subtitle_start) {
168 stream->add_subtitle (ContentTimePeriod (_last_subtitle_start.get (), period.from));
169 _last_subtitle_start = optional<ContentTime> ();
170 } else if (sub.num_rects == 1) {
172 stream->add_subtitle (ContentTimePeriod (period.from, period.to.get ()));
174 _last_subtitle_start = period.from;
177 avsubtitle_free (&sub);
181 optional<ContentTime>
182 FFmpegExaminer::frame_time (AVStream* s) const
184 optional<ContentTime> t;
186 int64_t const bet = av_frame_get_best_effort_timestamp (_frame);
187 if (bet != AV_NOPTS_VALUE) {
188 t = ContentTime::from_seconds (bet * av_q2d (s->time_base));
195 FFmpegExaminer::video_frame_rate () const
197 /* This use of r_frame_rate is debateable; there's a few different
198 * frame rates in the format context, but this one seems to be the most
201 return av_q2d (av_stream_get_r_frame_rate (_format_context->streams[_video_stream]));
205 FFmpegExaminer::video_size () const
207 return dcp::Size (video_codec_context()->width, video_codec_context()->height);
210 /** @return Length according to our content's header */
212 FFmpegExaminer::video_length () const
214 return max (Frame (1), _video_length);
218 FFmpegExaminer::sample_aspect_ratio () const
220 AVRational sar = av_guess_sample_aspect_ratio (_format_context, _format_context->streams[_video_stream], 0);
222 /* I assume this means that we don't know */
223 return optional<float> ();
225 return float (sar.num) / sar.den;
229 FFmpegExaminer::audio_stream_name (AVStream* s) const
233 n << stream_name (s);
235 if (!n.str().empty()) {
239 n << s->codec->channels << " channels";
245 FFmpegExaminer::subtitle_stream_name (AVStream* s) const
249 n << stream_name (s);
251 if (n.str().empty()) {
259 FFmpegExaminer::stream_name (AVStream* s) const
264 AVDictionaryEntry const * lang = av_dict_get (s->metadata, "language", 0, 0);
269 AVDictionaryEntry const * title = av_dict_get (s->metadata, "title", 0, 0);
271 if (!n.str().empty()) {
282 FFmpegExaminer::bits_per_pixel () const
284 return av_get_bits_per_pixel (av_pix_fmt_desc_get (video_codec_context()->pix_fmt));