sub: redo how -no-ass is handled

The -no-ass switch used to disable any use of libass for text subtitles.
This is not really the case anymore, because libass is now always
involved when rendering text. The only remaining use of -no-ass is
disabling styling or showing subtitles on the terminal. On the other
hand, the old subtitle rendering path is a big reason why the subtitle
code is still a big mess with an awful number of obscure special cases.

In order to simplify it, remove the old subtitle rendering code, and
always go through sd_ass.c. Basically, we use ASS_Track as central data
structure for storing text subtitles instead of struct sub_data. This
also makes libass mandatory for all text subs, even if they are printed
to the terminal in -no-video mode. (We could add something like sd_text
to avoid this, but it's not worth the trouble.)

struct sub_data and subreader.c are still around, even its ASS/SSA
reader. But struct sub_data is freed right after converting it to
ASS_Track. The internal ASS reader actually can handle some obscure
cases libass can't, like files encoded in UTF-16.

1 files changed, 51 insertions, 96 deletions

diff --git a/core/mplayer.c b/core/mplayer.c
index 52aa34058c..602d1f0616 100644
--- a/core/mplayer.c
+++ b/core/mplayer.c
@@ -74,6 +74,7 @@
 #include "sub/subreader.h"
 #include "sub/find_subfiles.h"
 #include "sub/dec_sub.h"
+#include "sub/sd.h"
 
 #include "core/mp_osd.h"
 #include "video/out/vo.h"
@@ -284,8 +285,6 @@ static void print_stream(struct MPContext *mpctx, struct track *t)
     const char *codec = s ? s->codec : NULL;
     if (!codec && t->sh_sub) // external subs hack
         codec = t->sh_sub->gsh->codec;
-    if (!codec && t->subdata)
-        codec = t->subdata->codec;
     mp_msg(MSGT_CPLAYER, MSGL_INFO, " (%s)", codec ? codec : "<unknown>");
     if (t->is_external)
         mp_msg(MSGT_CPLAYER, MSGL_INFO, " (external)");
@@ -1052,38 +1051,36 @@ struct track *mp_add_subtitles(struct MPContext *mpctx, char *filename,
                                float fps, int noerr)
 {
     struct MPOpts *opts = &mpctx->opts;
-    sub_data *subd = NULL;
     struct sh_sub *sh = NULL;
+    struct ass_track *asst = NULL;
+    const char *codec = NULL;
 
     if (filename == NULL)
         return NULL;
 
-    if (opts->ass_enabled) {
+    // Note: no text subtitles without libass. This is mainly because sd_ass is
+    // used for rendering. Even when showing subtitles with term-osd, going
+    // through sd_ass makes the code much simpler, as sd_ass can handle all
+    // the weird special-cases.
 #ifdef CONFIG_ASS
-        struct ass_track *asst = mp_ass_read_stream(mpctx->ass_library,
-                                                    filename, sub_cp);
-        bool is_native_ass = asst;
-        const char *codec = NULL;
-        if (!asst) {
-            subd = sub_read_file(filename, fps, &mpctx->opts);
-            if (subd) {
-                codec = subd->codec;
-                asst = mp_ass_read_subdata(mpctx->ass_library, opts, subd, fps);
-                talloc_free(subd);
-                subd = NULL;
-            }
-        }
-        if (asst) {
-            sh = sd_ass_create_from_track(asst, is_native_ass, opts);
-            if (codec)
-                sh->gsh->codec = codec;
+    if (opts->ass_enabled) {
+        asst = mp_ass_read_stream(mpctx->ass_library, filename, sub_cp);
+        codec = "ass";
+    }
+    if (!asst) {
+        sub_data *subd = sub_read_file(filename, fps, &mpctx->opts);
+        if (subd) {
+            codec = subd->codec;
+            asst = mp_ass_read_subdata(mpctx->ass_library, opts, subd, fps);
         }
+        talloc_free(subd);
+    }
+    if (asst)
+        sh = sd_ass_create_from_track(asst, codec, opts);
 #endif
-    } else
-        subd = sub_read_file(filename, fps, &mpctx->opts);
-
 
-    if (!sh && !subd) {
+    if (!sh) {
+        // Used with image subtitles.
         struct track *ext = open_external_file(mpctx, filename, NULL, 0,
                                                STREAM_SUB);
         if (ext)
@@ -1101,7 +1098,6 @@ struct track *mp_add_subtitles(struct MPContext *mpctx, char *filename,
         .demuxer_id = -1,
         .is_external = true,
         .sh_sub = talloc_steal(track, sh),
-        .subdata = talloc_steal(track, subd),
         .external_filename = talloc_strdup(track, filename),
     };
     MP_TARRAY_APPEND(mpctx, mpctx->tracks, mpctx->num_tracks, track);
@@ -1545,23 +1541,16 @@ void set_osd_function(struct MPContext *mpctx, int osd_function)
 /**
  * \brief Display text subtitles on the OSD
  */
-void set_osd_subtitle(struct MPContext *mpctx, subtitle *subs)
-{
-    int i;
-    vo_sub = subs;
-    vo_osd_changed(OSDTYPE_SUBTITLE);
-    if (!mpctx->sh_video) {
-        // reverse order, since newest set_osd_msg is displayed first
-        for (i = SUB_MAX_TEXT - 1; i >= 0; i--) {
-            if (!subs || i >= subs->lines || !subs->text[i])
-                rm_osd_msg(mpctx, OSD_MSG_SUB_BASE + i);
-            else {
-                // HACK: currently display time for each sub line
-                // except the last is set to 2 seconds.
-                int display_time = i == subs->lines - 1 ? 180000 : 2000;
-                set_osd_msg(mpctx, OSD_MSG_SUB_BASE + i, 1, display_time,
-                            "%s", subs->text[i]);
-            }
+static void set_osd_subtitle(struct MPContext *mpctx, const char *text)
+{
+    if (!text)
+        text = "";
+    if (strcmp(mpctx->osd->sub_text, text) != 0) {
+        osd_set_sub(mpctx->osd, text);
+        if (!mpctx->sh_video) {
+            rm_osd_msg(mpctx, OSD_MSG_SUB_BASE);
+            if (text && text[0])
+                set_osd_msg(mpctx, OSD_MSG_SUB_BASE, 1, INT_MAX, "%s", text);
         }
     }
 }
@@ -1877,9 +1866,7 @@ static void reset_subtitles(struct MPContext *mpctx)
 {
     if (mpctx->sh_sub)
         sub_reset(mpctx->sh_sub, mpctx->osd);
-    sub_clear_text(&mpctx->subs, MP_NOPTS_VALUE);
-    if (vo_sub)
-        set_osd_subtitle(mpctx, NULL);
+    set_osd_subtitle(mpctx, NULL);
     if (vo_spudec) {
         spudec_reset(vo_spudec);
         vo_osd_changed(OSDTYPE_SPU);
@@ -1888,33 +1875,22 @@ static void reset_subtitles(struct MPContext *mpctx)
 
 static void update_subtitles(struct MPContext *mpctx, double refpts_tl)
 {
-    struct MPOpts *opts = &mpctx->opts;
-    struct sh_video *sh_video = mpctx->sh_video;
     struct sh_sub *sh_sub = mpctx->sh_sub;
     struct demux_stream *d_sub = sh_sub ? sh_sub->ds : NULL;
     unsigned char *packet = NULL;
     int len;
     const char *type = sh_sub ? sh_sub->gsh->codec : NULL;
 
-    mpctx->osd->sub_offset = mpctx->video_offset;
-
     struct track *track = mpctx->current_track[STREAM_SUB];
     if (!track)
         return;
 
-    if (!track->under_timeline)
-        mpctx->osd->sub_offset = 0;
+    double video_offset = track->under_timeline ? mpctx->video_offset : 0;
 
-    double refpts_s = refpts_tl - mpctx->osd->sub_offset;
-    double curpts_s = refpts_s + sub_delay;
+    mpctx->osd->sub_offset = video_offset - sub_delay;
 
-    // find sub
-    if (track->subdata) {
-        if (sub_fps == 0)
-            sub_fps = sh_video ? sh_video->fps : 25;
-        find_sub(mpctx, track->subdata, curpts_s *
-                 (track->subdata->sub_uses_time ? 100. : sub_fps));
-    }
+    double curpts_s = refpts_tl - mpctx->osd->sub_offset;
+    double refpts_s = refpts_tl - video_offset;
 
     // DVD sub:
     if (is_dvd_sub(type) && !(sh_sub && sh_sub->active)) {
@@ -1955,7 +1931,7 @@ static void update_subtitles(struct MPContext *mpctx, double refpts_tl)
             if (timestamp >= 0)
                 spudec_assemble(vo_spudec, packet, len, timestamp);
         }
-    } else if (d_sub && (is_text_sub(type) || (sh_sub && sh_sub->active))) {
+    } else if (d_sub && sh_sub && sh_sub->active) {
         bool non_interleaved = is_non_interleaved(mpctx, track);
         if (non_interleaved)
             ds_get_next_pts(d_sub);
@@ -1967,7 +1943,7 @@ static void update_subtitles(struct MPContext *mpctx, double refpts_tl)
                        "Sub early: c_pts=%5.3f s_pts=%5.3f\n",
                        curpts_s, subpts_s);
                 // Libass handled subs can be fed to it in advance
-                if (!opts->ass_enabled || !is_text_sub(type))
+                if (!sub_accept_packets_in_advance(sh_sub))
                     break;
                 // Try to avoid demuxing whole file at once
                 if (non_interleaved && subpts_s > curpts_s + 1)
@@ -1984,41 +1960,19 @@ static void update_subtitles(struct MPContext *mpctx, double refpts_tl)
                 len = FFMIN(len - 2, AV_RB16(packet));
                 packet += 2;
             }
-            if (sh_sub && sh_sub->active) {
-                sub_decode(sh_sub, mpctx->osd, packet, len, subpts_s, duration);
-            } else if (subpts_s != MP_NOPTS_VALUE) {
-                // text sub
-                if (duration < 0)
-                    sub_clear_text(&mpctx->subs, MP_NOPTS_VALUE);
-                if (is_ass_sub(type)) { // ssa/ass subs without libass => convert to plaintext
-                    int i;
-                    unsigned char *p = packet;
-                    for (i = 0; i < 8 && *p != '\0'; p++)
-                        if (*p == ',')
-                            i++;
-                    if (*p == '\0')  /* Broken line? */
-                        continue;
-                    len -= p - packet;
-                    packet = p;
-                }
-                double endpts_s = MP_NOPTS_VALUE;
-                if (subpts_s != MP_NOPTS_VALUE && duration >= 0)
-                    endpts_s = subpts_s + duration;
-                sub_add_text(&mpctx->subs, packet, len, endpts_s);
-                set_osd_subtitle(mpctx, &mpctx->subs);
-            }
+            sub_decode(sh_sub, mpctx->osd, packet, len, subpts_s, duration);
             if (non_interleaved)
                 ds_get_next_pts(d_sub);
         }
-        if (!opts->ass_enabled)
-            if (sub_clear_text(&mpctx->subs, curpts_s))
-                set_osd_subtitle(mpctx, &mpctx->subs);
     }
     if (vo_spudec) {
         spudec_heartbeat(vo_spudec, 90000 * curpts_s);
         if (spudec_changed(vo_spudec))
             vo_osd_changed(OSDTYPE_SPU);
     }
+
+    if (!mpctx->osd->render_bitmap_subs)
+        set_osd_subtitle(mpctx, sub_get_text(mpctx->osd, curpts_s));
 }
 
 static int check_framedrop(struct MPContext *mpctx, double frame_time)
@@ -2130,12 +2084,8 @@ static void reinit_subs(struct MPContext *mpctx)
 
     mpctx->initialized_flags |= INITIALIZED_SUB;
 
-    if (track->subdata || track->sh_sub) {
-#ifdef CONFIG_ASS
-        if (opts->ass_enabled && track->sh_sub)
-            sub_init(track->sh_sub, mpctx->osd);
-#endif
-        vo_osd_changed(OSDTYPE_SUBTITLE);
+    if (track->sh_sub) {
+        sub_init(track->sh_sub, mpctx->osd);
     } else if (track->stream) {
         struct stream *s = track->demuxer ? track->demuxer->stream : NULL;
         if (s && s->type == STREAMTYPE_DVD)
@@ -2153,6 +2103,12 @@ static void reinit_subs(struct MPContext *mpctx)
         else
             sub_init(mpctx->sh_sub, mpctx->osd);
     }
+
+    // Decides whether to use OSD path or normal subtitle rendering path.
+    mpctx->osd->render_bitmap_subs = true;
+    struct sh_sub *sh_sub = mpctx->osd->sh_sub;
+    if (sh_sub && sh_sub->active && sh_sub->sd_driver->get_text)
+        mpctx->osd->render_bitmap_subs = opts->ass_enabled;
 }
 
 static char *track_layout_hash(struct MPContext *mpctx)
@@ -4551,7 +4507,6 @@ terminate_playback:  // don't jump here after ao/vo/getch initialization!
     talloc_free(mpctx->resolve_result);
     mpctx->resolve_result = NULL;
 
-    vo_sub = NULL;
 #ifdef CONFIG_ASS
     if (mpctx->osd->ass_renderer)
         ass_renderer_done(mpctx->osd->ass_renderer);