sub: add name field to all sub decoders

Might help with debugging.

sub/dec_sub.c

@@ -115,6 +115,17 @@ void sub_set_ass_renderer(struct dec_sub *sub, struct ass_library *ass_library,
     sub->init_sd.ass_renderer = ass_renderer;
 }
 
+static void print_chain(struct dec_sub *sub)
+{
+    mp_msg(MSGT_OSD, MSGL_V, "Subtitle filter chain: ");
+    for (int n = 0; n < sub->num_sd; n++) {
+        struct sd *sd = sub->sd[n];
+        mp_msg(MSGT_OSD, MSGL_V, "%s%s (%s)", n > 0 ? " -> " : "", 
+               sd->driver->name, sd->codec);
+    }
+    mp_msg(MSGT_OSD, MSGL_V, "\n");
+}
+
 // Subtitles read with subreader.c
 static void read_sub_data(struct dec_sub *sub, struct sub_data *subdata)
 {
@@ -218,6 +229,7 @@ void sub_init_from_sh(struct dec_sub *sub, struct sh_sub *sh)
         sub->num_sd++;
         // Try adding new converters until a decoder is reached
         if (sd->driver->get_bitmaps || sd->driver->get_text) {
+            print_chain(sub);
             if (sh->sub_data)
                 read_sub_data(sub, sh->sub_data);
             return;

sub/sd.h

@@ -45,6 +45,7 @@ struct sd {
 };
 
 struct sd_functions {
+    const char *name;
     bool accept_packets_in_advance;
     bool (*supports_format)(const char *format);
     int  (*init)(struct sd *sd);

sub/sd_ass.c

@@ -300,6 +300,7 @@ static void uninit(struct sd *sd)
 }
 
 const struct sd_functions sd_ass = {
+    .name = "ass",
     .accept_packets_in_advance = true,
     .supports_format = supports_format,
     .init = init,

sub/sd_lavc.c

@@ -244,6 +244,7 @@ static void uninit(struct sd *sd)
 }
 
 const struct sd_functions sd_lavc = {
+    .name = "lavc",
     .supports_format = supports_format,
     .init = init,
     .decode = decode,

sub/sd_lavc_conv.c

@@ -155,6 +155,7 @@ static void uninit(struct sd *sd)
 }
 
 const struct sd_functions sd_lavc_conv = {
+    .name = "lavc_conv",
     .supports_format = supports_format,
     .init = init,
     .decode = decode,

sub/sd_microdvd.c

@@ -329,6 +329,7 @@ static void decode(struct sd *sd, struct demux_packet *packet)
 }
 
 const struct sd_functions sd_microdvd = {
+    .name = "microdvd",
     .supports_format = supports_format,
     .init = init,
     .decode = decode,

sub/sd_movtext.c

@@ -46,6 +46,7 @@ static void decode(struct sd *sd, struct demux_packet *packet)
 }
 
 const struct sd_functions sd_movtext = {
+    .name = "movtext",
     .supports_format = supports_format,
     .init = init,
     .decode = decode,

sub/sd_spu.c

@@ -92,6 +92,7 @@ static void uninit(struct sd *sd)
 }
 
 const struct sd_functions sd_spu = {
+    .name = "spu",
     .supports_format = supports_format,
     .init = init,
     .decode = decode,

sub/sd_srt.c

@@ -458,6 +458,7 @@ static void decode(struct sd *sd, struct demux_packet *packet)
 }
 
 const struct sd_functions sd_srt = {
+    .name = "srt",
     .supports_format = supports_format,
     .init = init,
     .decode = decode,