Another macOS std::list boost::thread SNAFU.
[dcpomatic.git] / src / lib / ffmpeg_decoder.cc
index 5352f176a91b58f784df14dcfb8426d31dbd3f79..77b608fa86b92a7c7734e9a0c1b835aa45c9d5bc 100644 (file)
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012-2016 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2012-2018 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -27,8 +27,9 @@
 #include "image.h"
 #include "util.h"
 #include "log.h"
+#include "dcpomatic_log.h"
 #include "ffmpeg_decoder.h"
-#include "subtitle_decoder.h"
+#include "text_decoder.h"
 #include "ffmpeg_audio_stream.h"
 #include "ffmpeg_subtitle_stream.h"
 #include "video_filter_graph.h"
 #include "raw_image_proxy.h"
 #include "video_decoder.h"
 #include "film.h"
-#include "md5_digester.h"
 #include "audio_decoder.h"
 #include "compose.hpp"
+#include "text_content.h"
+#include "audio_content.h"
+#include "frame_interval_checker.h"
 #include <dcp/subtitle_string.h>
 #include <sub/ssa_reader.h>
 #include <sub/subtitle.h>
@@ -57,11 +60,6 @@ extern "C" {
 
 #include "i18n.h"
 
-#define LOG_GENERAL(...) _log->log (String::compose (__VA_ARGS__), LogEntry::TYPE_GENERAL);
-#define LOG_ERROR(...) _log->log (String::compose (__VA_ARGS__), LogEntry::TYPE_ERROR);
-#define LOG_WARNING_NC(...) _log->log (__VA_ARGS__, LogEntry::TYPE_WARNING);
-#define LOG_WARNING(...) _log->log (String::compose (__VA_ARGS__), LogEntry::TYPE_WARNING);
-
 using std::cout;
 using std::string;
 using std::vector;
@@ -73,33 +71,36 @@ using std::map;
 using boost::shared_ptr;
 using boost::is_any_of;
 using boost::split;
+using boost::optional;
+using boost::dynamic_pointer_cast;
 using dcp::Size;
+using namespace dcpomatic;
 
-FFmpegDecoder::FFmpegDecoder (shared_ptr<const FFmpegContent> c, shared_ptr<Log> log, bool fast)
+FFmpegDecoder::FFmpegDecoder (shared_ptr<const Film> film, shared_ptr<const FFmpegContent> c, bool fast)
        : FFmpeg (c)
-       , _log (log)
+       , Decoder (film)
+       , _have_current_subtitle (false)
 {
-       if (c->video) {
-               video.reset (new VideoDecoder (this, c, log));
-               _pts_offset = pts_offset (c->ffmpeg_audio_streams(), c->first_video(), c->active_video_frame_rate());
+       if (c->video && c->video->use()) {
+               video.reset (new VideoDecoder (this, c));
+               _pts_offset = pts_offset (c->ffmpeg_audio_streams(), c->first_video(), c->active_video_frame_rate(film));
+               /* It doesn't matter what size or pixel format this is, it just needs to be black */
+               _black_image.reset (new Image (AV_PIX_FMT_RGB24, dcp::Size (128, 128), true));
+               _black_image->make_black ();
        } else {
                _pts_offset = ContentTime ();
        }
 
        if (c->audio) {
-               audio.reset (new AudioDecoder (this, c->audio, fast, log));
+               audio.reset (new AudioDecoder (this, c->audio, fast));
        }
 
-       if (c->subtitle) {
-               subtitle.reset (
-                       new SubtitleDecoder (
-                               this,
-                               c->subtitle,
-                               bind (&FFmpegDecoder::image_subtitles_during, this, _1, _2),
-                               bind (&FFmpegDecoder::text_subtitles_during, this, _1, _2)
-                               )
-                       );
+       if (c->only_text()) {
+               /* XXX: this time here should be the time of the first subtitle, not 0 */
+               text.push_back (shared_ptr<TextDecoder> (new TextDecoder (this, c->only_text(), ContentTime())));
        }
+
+       _next_time.resize (_format_context->nb_streams);
 }
 
 void
@@ -112,17 +113,58 @@ FFmpegDecoder::flush ()
 
        /* XXX: should we reset _packet.data and size after each *_decode_* call? */
 
-       while (video && decode_video_packet ()) {}
+       while (video && decode_video_packet()) {}
 
        if (audio) {
                decode_audio_packet ();
+       }
+
+       /* Make sure all streams are the same length and round up to the next video frame */
+
+       FrameRateChange const frc = film()->active_frame_rate_change(_ffmpeg_content->position());
+       ContentTime full_length (_ffmpeg_content->full_length(film()), frc);
+       full_length = full_length.ceil (frc.source);
+       if (video) {
+               double const vfr = _ffmpeg_content->video_frame_rate().get();
+               Frame const f = full_length.frames_round (vfr);
+               Frame v = video->position(film()).get_value_or(ContentTime()).frames_round(vfr) + 1;
+               while (v < f) {
+                       video->emit (film(), shared_ptr<const ImageProxy> (new RawImageProxy (_black_image)), v);
+                       ++v;
+               }
+       }
+
+       BOOST_FOREACH (shared_ptr<FFmpegAudioStream> i, _ffmpeg_content->ffmpeg_audio_streams ()) {
+               ContentTime a = audio->stream_position(film(), i);
+               /* Unfortunately if a is 0 that really means that we don't know the stream position since
+                  there has been no data on it since the last seek.  In this case we'll just do nothing
+                  here.  I'm not sure if that's the right idea.
+               */
+               if (a > ContentTime()) {
+                       while (a < full_length) {
+                               ContentTime to_do = min (full_length - a, ContentTime::from_seconds (0.1));
+                               shared_ptr<AudioBuffers> silence (new AudioBuffers (i->channels(), to_do.frames_ceil (i->frame_rate())));
+                               silence->make_silent ();
+                               audio->emit (film(), i, silence, a);
+                               a += to_do;
+                       }
+               }
+       }
+
+       if (audio) {
                audio->flush ();
        }
 }
 
 bool
-FFmpegDecoder::pass (PassReason reason, bool accurate)
+FFmpegDecoder::pass ()
 {
+#ifdef DCPOMATIC_VARIANT_SWAROOP
+       if (_ffmpeg_content->encrypted() && !_ffmpeg_content->kdm()) {
+               return true;
+       }
+#endif
+
        int r = av_read_frame (_format_context, &_packet);
 
        /* AVERROR_INVALIDDATA can apparently be returned sometimes even when av_read_frame
@@ -134,7 +176,7 @@ FFmpegDecoder::pass (PassReason reason, bool accurate)
                        /* Maybe we should fail here, but for now we'll just finish off instead */
                        char buf[256];
                        av_strerror (r, buf, sizeof(buf));
-                       LOG_ERROR (N_("error on av_read_frame (%1) (%2)"), buf, r);
+                       LOG_ERROR (N_("error on av_read_frame (%1) (%2)"), &buf[0], r);
                }
 
                flush ();
@@ -144,11 +186,11 @@ FFmpegDecoder::pass (PassReason reason, bool accurate)
        int const si = _packet.stream_index;
        shared_ptr<const FFmpegContent> fc = _ffmpeg_content;
 
-       if (_video_stream && si == _video_stream.get() && !video->ignore() && (accurate || reason != PASS_REASON_SUBTITLE)) {
+       if (_video_stream && si == _video_stream.get() && video && !video->ignore()) {
                decode_video_packet ();
-       } else if (fc->subtitle_stream() && fc->subtitle_stream()->uses_index (_format_context, si)) {
+       } else if (fc->subtitle_stream() && fc->subtitle_stream()->uses_index(_format_context, si) && !only_text()->ignore()) {
                decode_subtitle_packet ();
-       } else if (accurate || reason != PASS_REASON_SUBTITLE) {
+       } else {
                decode_audio_packet ();
        }
 
@@ -174,8 +216,10 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
           of the block that do not form a complete sample or frame they will be dropped.
        */
        int const total_samples = size / bytes_per_audio_sample (stream);
-       int const frames = total_samples / stream->channels();
-       shared_ptr<AudioBuffers> audio (new AudioBuffers (stream->channels(), frames));
+       int const channels = stream->channels();
+       int const frames = total_samples / channels;
+       shared_ptr<AudioBuffers> audio (new AudioBuffers (channels, frames));
+       float** data = audio->data();
 
        switch (audio_sample_format (stream)) {
        case AV_SAMPLE_FMT_U8:
@@ -184,10 +228,10 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
                int sample = 0;
                int channel = 0;
                for (int i = 0; i < total_samples; ++i) {
-                       audio->data(channel)[sample] = float(*p++) / (1 << 23);
+                       data[channel][sample] = float(*p++) / (1 << 23);
 
                        ++channel;
-                       if (channel == stream->channels()) {
+                       if (channel == channels) {
                                channel = 0;
                                ++sample;
                        }
@@ -201,10 +245,10 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
                int sample = 0;
                int channel = 0;
                for (int i = 0; i < total_samples; ++i) {
-                       audio->data(channel)[sample] = float(*p++) / (1 << 15);
+                       data[channel][sample] = float(*p++) / (1 << 15);
 
                        ++channel;
-                       if (channel == stream->channels()) {
+                       if (channel == channels) {
                                channel = 0;
                                ++sample;
                        }
@@ -215,9 +259,9 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
        case AV_SAMPLE_FMT_S16P:
        {
                int16_t** p = reinterpret_cast<int16_t **> (_frame->data);
-               for (int i = 0; i < stream->channels(); ++i) {
+               for (int i = 0; i < channels; ++i) {
                        for (int j = 0; j < frames; ++j) {
-                               audio->data(i)[j] = static_cast<float>(p[i][j]) / (1 << 15);
+                               data[i][j] = static_cast<float>(p[i][j]) / (1 << 15);
                        }
                }
        }
@@ -229,10 +273,10 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
                int sample = 0;
                int channel = 0;
                for (int i = 0; i < total_samples; ++i) {
-                       audio->data(channel)[sample] = static_cast<float>(*p++) / 2147483648;
+                       data[channel][sample] = static_cast<float>(*p++) / 2147483648;
 
                        ++channel;
-                       if (channel == stream->channels()) {
+                       if (channel == channels) {
                                channel = 0;
                                ++sample;
                        }
@@ -243,9 +287,9 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
        case AV_SAMPLE_FMT_S32P:
        {
                int32_t** p = reinterpret_cast<int32_t **> (_frame->data);
-               for (int i = 0; i < stream->channels(); ++i) {
+               for (int i = 0; i < channels; ++i) {
                        for (int j = 0; j < frames; ++j) {
-                               audio->data(i)[j] = static_cast<float>(p[i][j]) / 2147483648;
+                               data[i][j] = static_cast<float>(p[i][j]) / 2147483648;
                        }
                }
        }
@@ -257,10 +301,10 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
                int sample = 0;
                int channel = 0;
                for (int i = 0; i < total_samples; ++i) {
-                       audio->data(channel)[sample] = *p++;
+                       data[channel][sample] = *p++;
 
                        ++channel;
-                       if (channel == stream->channels()) {
+                       if (channel == channels) {
                                channel = 0;
                                ++sample;
                        }
@@ -271,11 +315,12 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
        case AV_SAMPLE_FMT_FLTP:
        {
                float** p = reinterpret_cast<float**> (_frame->data);
+               DCPOMATIC_ASSERT (_frame->channels <= channels);
                /* Sometimes there aren't as many channels in the _frame as in the stream */
                for (int i = 0; i < _frame->channels; ++i) {
-                       memcpy (audio->data(i), p[i], frames * sizeof(float));
+                       memcpy (data[i], p[i], frames * sizeof(float));
                }
-               for (int i = _frame->channels; i < stream->channels(); ++i) {
+               for (int i = _frame->channels; i < channels; ++i) {
                        audio->make_silent (i);
                }
        }
@@ -303,17 +348,7 @@ FFmpegDecoder::bytes_per_audio_sample (shared_ptr<FFmpegAudioStream> stream) con
 void
 FFmpegDecoder::seek (ContentTime time, bool accurate)
 {
-       if (video) {
-               video->seek (time, accurate);
-       }
-
-       if (audio) {
-               audio->seek (time, accurate);
-       }
-
-       if (subtitle) {
-               subtitle->seek (time, accurate);
-       }
+       Decoder::seek (time, accurate);
 
        /* If we are doing an `accurate' seek, we need to use pre-roll, as
           we don't really know what the seek will give us.
@@ -326,7 +361,19 @@ FFmpegDecoder::seek (ContentTime time, bool accurate)
           http://www.mjbshaw.com/2012/04/seeking-in-ffmpeg-know-your-timestamp.html
        */
 
-       DCPOMATIC_ASSERT (_video_stream);
+       optional<int> stream;
+
+       if (_video_stream) {
+               stream = _video_stream;
+       } else {
+               DCPOMATIC_ASSERT (_ffmpeg_content->audio);
+               shared_ptr<FFmpegAudioStream> s = dynamic_pointer_cast<FFmpegAudioStream> (_ffmpeg_content->audio->stream ());
+               if (s) {
+                       stream = s->index (_format_context);
+               }
+       }
+
+       DCPOMATIC_ASSERT (stream);
 
        ContentTime u = time - _pts_offset;
        if (u < ContentTime ()) {
@@ -334,18 +381,32 @@ FFmpegDecoder::seek (ContentTime time, bool accurate)
        }
        av_seek_frame (
                _format_context,
-               _video_stream.get(),
-               u.seconds() / av_q2d (_format_context->streams[_video_stream.get()]->time_base),
+               stream.get(),
+               u.seconds() / av_q2d (_format_context->streams[stream.get()]->time_base),
                AVSEEK_FLAG_BACKWARD
                );
 
-       avcodec_flush_buffers (video_codec_context());
+       {
+               /* Force re-creation of filter graphs to reset them and hence to make sure
+                  they don't have any pre-seek frames knocking about.
+               */
+               boost::mutex::scoped_lock lm (_filter_graphs_mutex);
+               _filter_graphs.clear ();
+       }
+
+       if (video_codec_context ()) {
+               avcodec_flush_buffers (video_codec_context());
+       }
 
-       /* XXX: should be flushing audio buffers? */
+       BOOST_FOREACH (shared_ptr<FFmpegAudioStream> i, ffmpeg_content()->ffmpeg_audio_streams()) {
+               avcodec_flush_buffers (i->stream(_format_context)->codec);
+       }
 
        if (subtitle_codec_context ()) {
                avcodec_flush_buffers (subtitle_codec_context ());
        }
+
+       _have_current_subtitle = false;
 }
 
 void
@@ -356,11 +417,12 @@ FFmpegDecoder::decode_audio_packet ()
        */
 
        AVPacket copy_packet = _packet;
+       int const stream_index = copy_packet.stream_index;
 
        /* XXX: inefficient */
        vector<shared_ptr<FFmpegAudioStream> > streams = ffmpeg_content()->ffmpeg_audio_streams ();
        vector<shared_ptr<FFmpegAudioStream> >::const_iterator stream = streams.begin ();
-       while (stream != streams.end () && !(*stream)->uses_index (_format_context, copy_packet.stream_index)) {
+       while (stream != streams.end () && !(*stream)->uses_index (_format_context, stream_index)) {
                ++stream;
        }
 
@@ -376,7 +438,7 @@ FFmpegDecoder::decode_audio_packet ()
                if (decode_result < 0) {
                        /* avcodec_decode_audio4 can sometimes return an error even though it has decoded
                           some valid data; for example dca_subframe_footer can return AVERROR_INVALIDDATA
-                          if it overreads the auxiliary data.  ffplay carries on if frame_finished is true,
+                          if it overreads the auxiliary data.  ffplay carries on if frame_finished is true,
                           even in the face of such an error, so I think we should too.
 
                           Returning from the method here caused mantis #352.
@@ -390,23 +452,48 @@ FFmpegDecoder::decode_audio_packet ()
                }
 
                if (frame_finished) {
-                       ContentTime ct = ContentTime::from_seconds (
-                               av_frame_get_best_effort_timestamp (_frame) *
-                               av_q2d ((*stream)->stream (_format_context)->time_base))
-                               + _pts_offset;
-
                        shared_ptr<AudioBuffers> data = deinterleave_audio (*stream);
 
+                       ContentTime ct;
+                       if (_frame->pts == AV_NOPTS_VALUE && _next_time[stream_index]) {
+                               /* In some streams we see not every frame coming through with a timestamp; for those
+                                  that have AV_NOPTS_VALUE we need to work out the timestamp ourselves.  This is
+                                  particularly noticeable with TrueHD streams (see #1111).
+                               */
+                               ct = *_next_time[stream_index];
+                       } else {
+                               ct = ContentTime::from_seconds (
+                                       av_frame_get_best_effort_timestamp (_frame) *
+                                       av_q2d ((*stream)->stream (_format_context)->time_base))
+                                       + _pts_offset;
+                       }
+
+                       _next_time[stream_index] = ct + ContentTime::from_frames(data->frames(), (*stream)->frame_rate());
+
                        if (ct < ContentTime ()) {
                                /* Discard audio data that comes before time 0 */
                                Frame const remove = min (int64_t (data->frames()), (-ct).frames_ceil(double((*stream)->frame_rate ())));
-                               data->move (remove, 0, data->frames() - remove);
+                               data->move (data->frames() - remove, remove, 0);
                                data->set_frames (data->frames() - remove);
                                ct += ContentTime::from_frames (remove, (*stream)->frame_rate ());
                        }
 
-                       if (data->frames() > 0) {
-                               audio->give (*stream, data, ct);
+                       if (ct < ContentTime()) {
+                               LOG_WARNING (
+                                       "Crazy timestamp %1 for %2 samples in stream %3 packet pts %4 (ts=%5 tb=%6, off=%7)",
+                                       to_string(ct),
+                                       data->frames(),
+                                       copy_packet.stream_index,
+                                       copy_packet.pts,
+                                       av_frame_get_best_effort_timestamp(_frame),
+                                       av_q2d((*stream)->stream(_format_context)->time_base),
+                                       to_string(_pts_offset)
+                                       );
+                       }
+
+                       /* Give this data provided there is some, and its time is sane */
+                       if (ct >= ContentTime() && data->frames() > 0) {
+                               audio->emit (film(), *stream, data, ct);
                        }
                }
 
@@ -435,7 +522,8 @@ FFmpegDecoder::decode_video_packet ()
        }
 
        if (i == _filter_graphs.end ()) {
-               graph.reset (new VideoFilterGraph (dcp::Size (_frame->width, _frame->height), (AVPixelFormat) _frame->format));
+               dcp::Fraction vfr (lrint(_ffmpeg_content->video_frame_rate().get() * 1000), 1000);
+               graph.reset (new VideoFilterGraph (dcp::Size (_frame->width, _frame->height), (AVPixelFormat) _frame->format, vfr));
                graph->setup (_ffmpeg_content->filters ());
                _filter_graphs.push_back (graph);
                LOG_GENERAL (N_("New graph for %1x%2, pixel format %3"), _frame->width, _frame->height, _frame->format);
@@ -451,9 +539,11 @@ FFmpegDecoder::decode_video_packet ()
 
                if (i->second != AV_NOPTS_VALUE) {
                        double const pts = i->second * av_q2d (_format_context->streams[_video_stream.get()]->time_base) + _pts_offset.seconds ();
-                       video->give (
+
+                       video->emit (
+                               film(),
                                shared_ptr<ImageProxy> (new RawImageProxy (image)),
-                               llrint (pts * _ffmpeg_content->active_video_frame_rate ())
+                               llrint(pts * _ffmpeg_content->active_video_frame_rate(film()))
                                );
                } else {
                        LOG_WARNING_NC ("Dropping frame without PTS");
@@ -472,10 +562,18 @@ FFmpegDecoder::decode_subtitle_packet ()
                return;
        }
 
+       /* Stop any current subtitle, either at the time it was supposed to stop, or now if now is sooner */
+       if (_have_current_subtitle) {
+               if (_current_subtitle_to) {
+                       only_text()->emit_stop (min(*_current_subtitle_to, subtitle_period(sub).from + _pts_offset));
+               } else {
+                       only_text()->emit_stop (subtitle_period(sub).from + _pts_offset);
+               }
+               _have_current_subtitle = false;
+       }
+
        if (sub.num_rects <= 0) {
-               /* Sometimes we get an empty AVSubtitle, which is used by some codecs to
-                  indicate that the previous subtitle should stop.  We can ignore it here.
-               */
+               /* Nothing new in this subtitle */
                return;
        }
 
@@ -483,14 +581,13 @@ FFmpegDecoder::decode_subtitle_packet ()
           source that we may have chopped off for the DCP).
        */
        FFmpegSubtitlePeriod sub_period = subtitle_period (sub);
-       ContentTimePeriod period;
-       period.from = sub_period.from + _pts_offset;
+       ContentTime from;
+       from = sub_period.from + _pts_offset;
        if (sub_period.to) {
-               /* We already know the subtitle period `to' time */
-               period.to = sub_period.to.get() + _pts_offset;
+               _current_subtitle_to = *sub_period.to + _pts_offset;
        } else {
-               /* We have to look up the `to' time in the stream's records */
-               period.to = ffmpeg_content()->subtitle_stream()->find_subtitle_to (subtitle_id (sub));
+               _current_subtitle_to = optional<ContentTime>();
+               _have_current_subtitle = true;
        }
 
        for (unsigned int i = 0; i < sub.num_rects; ++i) {
@@ -500,39 +597,31 @@ FFmpegDecoder::decode_subtitle_packet ()
                case SUBTITLE_NONE:
                        break;
                case SUBTITLE_BITMAP:
-                       decode_bitmap_subtitle (rect, period);
+                       decode_bitmap_subtitle (rect, from);
                        break;
                case SUBTITLE_TEXT:
                        cout << "XXX: SUBTITLE_TEXT " << rect->text << "\n";
                        break;
                case SUBTITLE_ASS:
-                       decode_ass_subtitle (rect->ass, period);
+                       decode_ass_subtitle (rect->ass, from);
                        break;
                }
        }
 
-       avsubtitle_free (&sub);
-}
-
-list<ContentTimePeriod>
-FFmpegDecoder::image_subtitles_during (ContentTimePeriod p, bool starting) const
-{
-       return _ffmpeg_content->image_subtitles_during (p, starting);
-}
+       if (_current_subtitle_to) {
+               only_text()->emit_stop (*_current_subtitle_to);
+       }
 
-list<ContentTimePeriod>
-FFmpegDecoder::text_subtitles_during (ContentTimePeriod p, bool starting) const
-{
-       return _ffmpeg_content->text_subtitles_during (p, starting);
+       avsubtitle_free (&sub);
 }
 
 void
-FFmpegDecoder::decode_bitmap_subtitle (AVSubtitleRect const * rect, ContentTimePeriod period)
+FFmpegDecoder::decode_bitmap_subtitle (AVSubtitleRect const * rect, ContentTime from)
 {
-       /* Note RGBA is expressed little-endian, so the first byte in the word is R, second
-          G, third B, fourth A.
+       /* Note BGRA is expressed little-endian, so the first byte in the word is B, second
+          G, third R, fourth A.
        */
-       shared_ptr<Image> image (new Image (AV_PIX_FMT_RGBA, dcp::Size (rect->w, rect->h), true));
+       shared_ptr<Image> image (new Image (AV_PIX_FMT_BGRA, dcp::Size (rect->w, rect->h), true));
 
 #ifdef DCPOMATIC_HAVE_AVSUBTITLERECT_PICT
        /* Start of the first line in the subtitle */
@@ -544,18 +633,18 @@ FFmpegDecoder::decode_bitmap_subtitle (AVSubtitleRect const * rect, ContentTimeP
 #else
        /* Start of the first line in the subtitle */
        uint8_t* sub_p = rect->data[0];
-       /* sub_p looks up into a BGRA palette which is here
-          (i.e. first byte B, second G, third R, fourth A)
+       /* sub_p looks up into a BGRA palette which is at rect->data[1].
+          (first byte B, second G, third R, fourth A)
        */
-       uint32_t const * palette = (uint32_t *) rect->data[1];
 #endif
        /* And the stream has a map of those palette colours to colours
           chosen by the user; created a `mapped' palette from those settings.
        */
        map<RGBA, RGBA> colour_map = ffmpeg_content()->subtitle_stream()->colours ();
        vector<RGBA> mapped_palette (rect->nb_colors);
+       uint8_t const * palette = rect->data[1];
        for (int i = 0; i < rect->nb_colors; ++i) {
-               RGBA c ((palette[i] & 0xff0000) >> 16, (palette[i] & 0xff00) >> 8, palette[i] & 0xff, (palette[i] & 0xff000000) >> 24);
+               RGBA c (palette[2], palette[1], palette[0], palette[3]);
                map<RGBA, RGBA>::const_iterator j = colour_map.find (c);
                if (j != colour_map.end ()) {
                        mapped_palette[i] = j->second;
@@ -566,101 +655,83 @@ FFmpegDecoder::decode_bitmap_subtitle (AVSubtitleRect const * rect, ContentTimeP
                        */
                        mapped_palette[i] = c;
                }
+               palette += 4;
        }
 
        /* Start of the output data */
-       uint32_t* out_p = (uint32_t *) image->data()[0];
+       uint8_t* out_p = image->data()[0];
 
        for (int y = 0; y < rect->h; ++y) {
                uint8_t* sub_line_p = sub_p;
-               uint32_t* out_line_p = out_p;
+               uint8_t* out_line_p = out_p;
                for (int x = 0; x < rect->w; ++x) {
                        RGBA const p = mapped_palette[*sub_line_p++];
-                       /* XXX: this seems to be wrong to me (isn't the output image RGBA?) but it looks right on screen */
-                       *out_line_p++ = (p.a << 24) | (p.r << 16) | (p.g << 8) | p.b;
+                       *out_line_p++ = p.b;
+                       *out_line_p++ = p.g;
+                       *out_line_p++ = p.r;
+                       *out_line_p++ = p.a;
                }
 #ifdef DCPOMATIC_HAVE_AVSUBTITLERECT_PICT
                sub_p += rect->pict.linesize[0];
 #else
                sub_p += rect->linesize[0];
 #endif
-               out_p += image->stride()[0] / sizeof (uint32_t);
+               out_p += image->stride()[0];
        }
 
-       dcp::Size const vs = _ffmpeg_content->video->size ();
+       int target_width = subtitle_codec_context()->width;
+       if (target_width == 0 && video_codec_context()) {
+               /* subtitle_codec_context()->width == 0 has been seen in the wild but I don't
+                  know if it's supposed to mean something from FFmpeg's point of view.
+               */
+               target_width = video_codec_context()->width;
+       }
+       int target_height = subtitle_codec_context()->height;
+       if (target_height == 0 && video_codec_context()) {
+               target_height = video_codec_context()->height;
+       }
+       DCPOMATIC_ASSERT (target_width);
+       DCPOMATIC_ASSERT (target_height);
        dcpomatic::Rect<double> const scaled_rect (
-               static_cast<double> (rect->x) / vs.width,
-               static_cast<double> (rect->y) / vs.height,
-               static_cast<double> (rect->w) / vs.width,
-               static_cast<double> (rect->h) / vs.height
+               static_cast<double> (rect->x) / target_width,
+               static_cast<double> (rect->y) / target_height,
+               static_cast<double> (rect->w) / target_width,
+               static_cast<double> (rect->h) / target_height
                );
 
-       subtitle->give_image (period, image, scaled_rect);
+       only_text()->emit_bitmap_start (from, image, scaled_rect);
 }
 
 void
-FFmpegDecoder::decode_ass_subtitle (string ass, ContentTimePeriod period)
+FFmpegDecoder::decode_ass_subtitle (string ass, ContentTime from)
 {
        /* We have no styles and no Format: line, so I'm assuming that FFmpeg
           produces a single format of Dialogue: lines...
        */
 
-       vector<string> bits;
-       split (bits, ass, is_any_of (","));
-       if (bits.size() < 10) {
+       int commas = 0;
+       string text;
+       for (size_t i = 0; i < ass.length(); ++i) {
+               if (commas < 9 && ass[i] == ',') {
+                       ++commas;
+               } else if (commas == 9) {
+                       text += ass[i];
+               }
+       }
+
+       if (text.empty ()) {
                return;
        }
 
        sub::RawSubtitle base;
-       list<sub::RawSubtitle> raw = sub::SSAReader::parse_line (base, bits[9]);
-       list<sub::Subtitle> subs = sub::collect<list<sub::Subtitle> > (raw);
-
-       /* XXX: lots of this is copied from TextSubtitle; there should probably be some sharing */
-
-       /* Highest line index in this subtitle */
-       int highest = 0;
-       BOOST_FOREACH (sub::Subtitle i, subs) {
-               BOOST_FOREACH (sub::Line j, i.lines) {
-                       DCPOMATIC_ASSERT (j.vertical_position.reference && j.vertical_position.reference.get() == sub::TOP_OF_SUBTITLE);
-                       DCPOMATIC_ASSERT (j.vertical_position.line);
-                       highest = max (highest, j.vertical_position.line.get());
-               }
-       }
+       list<sub::RawSubtitle> raw = sub::SSAReader::parse_line (
+               base,
+               text,
+               _ffmpeg_content->video->size().width,
+               _ffmpeg_content->video->size().height
+               );
 
-       list<dcp::SubtitleString> ss;
-
-       BOOST_FOREACH (sub::Subtitle i, sub::collect<list<sub::Subtitle> > (sub::SSAReader::parse_line (base, bits[9]))) {
-               BOOST_FOREACH (sub::Line j, i.lines) {
-                       BOOST_FOREACH (sub::Block k, j.blocks) {
-                               ss.push_back (
-                                       dcp::SubtitleString (
-                                               boost::optional<string> (),
-                                               k.italic,
-                                               k.bold,
-                                               dcp::Colour (255, 255, 255),
-                                               /* 48pt is 1/22nd of the screen height */
-                                               48,
-                                               1,
-                                               dcp::Time (i.from.seconds(), 1000),
-                                               dcp::Time (i.to.seconds(), 1000),
-                                               0,
-                                               dcp::HALIGN_CENTER,
-                                               /* This 1.015 is an arbitrary value to lift the bottom sub off the bottom
-                                                  of the screen a bit to a pleasing degree.
-                                               */
-                                               1.015 - ((1 + highest - j.vertical_position.line.get()) * 1.5 / 22),
-                                               dcp::VALIGN_TOP,
-                                               dcp::DIRECTION_LTR,
-                                               k.text,
-                                               static_cast<dcp::Effect> (0),
-                                               dcp::Colour (255, 255, 255),
-                                               dcp::Time (),
-                                               dcp::Time ()
-                                               )
-                                       );
-                       }
-               }
+       BOOST_FOREACH (sub::Subtitle const & i, sub::collect<list<sub::Subtitle> > (raw)) {
+               only_text()->emit_plain_start (from, i);
        }
-
-       subtitle->give_text (period, ss);
 }