sub: remove subtitle filter chain concept

It was stupid. The only thing that still effectively used it was
sd_lavc_conv - all other "filters" were the subtitle decoder/renderers
for text (sd_ass) and bitmap (sd_lavc) subtitles.

While having a subtitle filter chain was interesting (and actually
worked in almost the same way as the audio/video ones), I didn't
manage to use it in a meaningful way, and I couldn't e.g. factor
secondary features like fixing subtitle timing into filters.

Refactor the shit and drop unneeded things as it goes.

1 files changed, 30 insertions, 15 deletions

diff --git a/sub/sd_ass.c b/sub/sd_ass.c
index dc045996cd..baf35b5d30 100644
--- a/sub/sd_ass.c
+++ b/sub/sd_ass.c
@@ -40,6 +40,7 @@ struct sd_ass_priv {
     struct ass_track *ass_track;
     struct ass_track *shadow_track; // for --sub-ass=no rendering
     bool is_converted;
+    struct lavc_conv *converter;
     bool on_top;
     struct sub_bitmap *parts;
     char last_text[500];
@@ -79,21 +80,31 @@ static void mp_ass_add_default_styles(ASS_Track *track, struct MPOpts *opts)
 
 static bool supports_format(const char *format)
 {
-    // "ssa" is used for the FFmpeg subtitle converter output
-    return format && (strcmp(format, "ass") == 0 ||
-                      strcmp(format, "ssa") == 0);
+    return (format && strcmp(format, "ass") == 0) ||
+           lavc_conv_supports_format(format);
 }
 
 static int init(struct sd *sd)
 {
     struct MPOpts *opts = sd->opts;
-    if (!sd->ass_library || !sd->ass_renderer || !sd->ass_lock || !sd->codec)
+    if (!sd->ass_library || !sd->ass_renderer || !sd->ass_lock)
         return -1;
 
-    struct sd_ass_priv *ctx = talloc_zero(NULL, struct sd_ass_priv);
+    struct sd_ass_priv *ctx = talloc_zero(sd, struct sd_ass_priv);
     sd->priv = ctx;
 
-    ctx->is_converted = sd->converted_from != NULL;
+    char *extradata = sd->sh->extradata;
+    int extradata_size = sd->sh->extradata_size;
+
+    if (strcmp(sd->sh->codec, "ass") != 0) {
+        ctx->is_converted = true;
+        ctx->converter = lavc_conv_create(sd->log, sd->sh->codec, extradata,
+                                          extradata_size);
+        if (!ctx->converter)
+            return -1;
+        extradata = lavc_conv_get_extradata(ctx->converter);
+        extradata_size = extradata ? strlen(extradata) : 0;
+    }
 
     pthread_mutex_lock(sd->ass_lock);
 
@@ -106,10 +117,8 @@ static int init(struct sd *sd)
     ctx->shadow_track->PlayResY = 288;
     mp_ass_add_default_styles(ctx->shadow_track, opts);
 
-    if (sd->extradata) {
-        ass_process_codec_private(ctx->ass_track, sd->extradata,
-                                  sd->extradata_len);
-    }
+    if (extradata)
+        ass_process_codec_private(ctx->ass_track, extradata, extradata_size);
 
     mp_ass_add_default_styles(ctx->ass_track, opts);
 
@@ -158,15 +167,18 @@ static void decode(struct sd *sd, struct demux_packet *packet)
 {
     struct sd_ass_priv *ctx = sd->priv;
     ASS_Track *track = ctx->ass_track;
-    if (strcmp(sd->codec, "ass") == 0) {
+    if (ctx->converter) {
+        if (check_packet_seen(sd, packet->pos))
+            return;
+        char **r = lavc_conv_decode(ctx->converter, packet);
+        for (int n = 0; r && r[n]; n++)
+            ass_process_data(track, r[n], strlen(r[n]));
+    } else {
         // Note that for this packet format, libass has an internal mechanism
         // for discarding duplicate (already seen) packets.
         ass_process_chunk(track, packet->buffer, packet->len,
                           lrint(packet->pts * 1000),
                           lrint(packet->duration * 1000));
-    } else {
-        if (!check_packet_seen(sd, packet->pos))
-            ass_process_data(track, packet->buffer, packet->len);
     }
 }
 
@@ -505,14 +517,17 @@ static void reset(struct sd *sd)
     struct sd_ass_priv *ctx = sd->priv;
     if (sd->opts->sub_clear_on_seek)
         ass_flush_events(ctx->ass_track);
+    if (ctx->converter)
+        lavc_conv_reset(ctx->converter);
 }
 
 static void uninit(struct sd *sd)
 {
     struct sd_ass_priv *ctx = sd->priv;
 
+    if (ctx->converter)
+        lavc_conv_uninit(ctx->converter);
     ass_free_track(ctx->ass_track);
-    talloc_free(ctx);
 }
 
 static int control(struct sd *sd, enum sd_ctrl cmd, void *arg)