player: add always to --subs-fallback-forced

In general, forced tracks should only be shown if they match the
language of the audio. However some people do want them no matter what,
so add an always option to this so such tracks are always selected.

DOCS/interface-changes.rst

@@ -46,6 +46,7 @@ Interface changes
     - change `slang` default back to NULL
     - remove special handling of the `auto` value from `--alang/slang/vlang` options
     - add `--subs-match-os-language` as a replacement for `--slang=auto`
+    - add `always` option to `--subs-fallback-forced`
  --- mpv 0.36.0 ---
     - add `--target-contrast`
     - Target luminance value is now also applied when ICC profile is used.

DOCS/man/options.rst

@@ -150,9 +150,11 @@ Track Selection
     select a full track even if it doesn't match your preferred subtitle language (default: default).
     Setting this to `default` means that only streams flagged as `default` will be selected.
 
-``--subs-fallback-forced=<yes|no>``
+``--subs-fallback-forced=<yes|no|always>``
     When autoselecting a subtitle track, if no tracks match your preferred languages,
     select a forced track that matches the language of the selected audio track (default: yes).
+    `always` will always select a forced track if possible, regardles if the language matches the
+    selected audio track or not.
 
 
 Playback Control

options/options.c

@@ -524,7 +524,8 @@ static const m_option_t mp_opts[] = {
     {"subs-with-matching-audio", OPT_BOOL(subs_with_matching_audio)},
     {"subs-match-os-language", OPT_BOOL(subs_match_os_language)},
     {"subs-fallback", OPT_CHOICE(subs_fallback, {"no", 0}, {"default", 1}, {"yes", 2})},
-    {"subs-fallback-forced", OPT_BOOL(subs_fallback_forced)},
+    {"subs-fallback-forced", OPT_CHOICE(subs_fallback_forced, {"no", 0},
+        {"yes", 1}, {"always", 2})},
 
     {"lavfi-complex", OPT_STRING(lavfi_complex), .flags = UPDATE_LAVFI_COMPLEX},
 
@@ -1047,7 +1048,7 @@ static const struct MPOpts mp_default_opts = {
     .subs_with_matching_audio = true,
     .subs_match_os_language = true,
     .subs_fallback = 1,
-    .subs_fallback_forced = true,
+    .subs_fallback_forced = 1,
     .audio_display = 1,
     .audio_output_format = 0,  // AF_FORMAT_UNKNOWN
     .playback_speed = 1.,

options/options.h

@@ -270,7 +270,7 @@ typedef struct MPOpts {
     bool subs_with_matching_audio;
     bool subs_match_os_language;
     int subs_fallback;
-    bool subs_fallback_forced;
+    int subs_fallback_forced;
     int audio_display;
     char **display_tags;
 

player/loadfile.c

@@ -646,8 +646,10 @@ struct track *select_default_track(struct MPContext *mpctx, int order,
         if (!pick || compare_track(track, pick, langs, os_langs, mpctx->opts, preferred_program))
             pick = track;
 
-        // We only try to autoselect forced tracks if they match the audio language and are subs
-        if (fallback_forced && track->forced_track && mp_match_lang_single(audio_lang, track->lang) &&
+        // We only try to autoselect forced tracks if they match the audio language and are subs or
+        // if the user always wants forced sub tracks
+        if (fallback_forced && track->forced_track &&
+            (mp_match_lang_single(audio_lang, track->lang) || opts->subs_fallback_forced == 2) &&
             (!forced_pick || compare_track(track, forced_pick, langs, os_langs, mpctx->opts, preferred_program)))
             forced_pick = track;
     }