demux_lavf: remove --demuxer-lavf-cryptokey option

Was at least somewhat broken, and is misleading. I don't really have an
idea why FFmpeg has two AVOptions here anyway. We don't need to care,
and I'm only aware of 1 user trying this option ever.

See #4579.

DOCS/interface-changes.rst

@@ -52,6 +52,8 @@ Interface changes
       replacement
     - deprecate passing multiple arguments to -add/-pre options (affects the
       vf/af commands too)
+    - remove --demuxer-lavf-cryptokey. Use --demux-lavf-o=cryptokey=<hex> or
+      --demux-lavf-o=decryption_key=<hex> instead (whatever fits your situation).
  --- mpv 0.25.0 ---
     - remove opengl-cb dxva2 dummy hwdec interop
       (see git "vo_opengl: remove dxva2 dummy hwdec backend")

DOCS/man/options.rst

@@ -2687,10 +2687,6 @@ Demuxer
     libavformat might reallocate the buffer internally, or not fully use all
     of it.
 
-``--demuxer-lavf-cryptokey=<hexstring>``
-    Encryption key the demuxer should use. This is the raw binary data of
-    the key converted to a hexadecimal string.
-
 ``--demuxer-mkv-subtitle-preroll=<yes|index|no>``, ``--mkv-subtitle-preroll``
     Try harder to show embedded soft subtitles when seeking somewhere. Normally,
     it can happen that the subtitle at the seek target is not shown due to how

demux/demux_lavf.c

@@ -69,7 +69,6 @@ struct demux_lavf_opts {
     int buffersize;
     int allow_mimetype;
     char *format;
-    char *cryptokey;
     char **avopts;
     int hacks;
     int genptsmode;
@@ -90,7 +89,6 @@ const struct m_sub_options demux_lavf_conf = {
         OPT_FLAG("demuxer-lavf-allow-mimetype", allow_mimetype, 0),
         OPT_INTRANGE("demuxer-lavf-probescore", probescore, 0,
                      1, AVPROBE_SCORE_MAX),
-        OPT_STRING("demuxer-lavf-cryptokey", cryptokey, 0),
         OPT_FLAG("demuxer-lavf-hacks", hacks, 0),
         OPT_CHOICE("demuxer-lavf-genpts-mode", genptsmode, 0,
                    ({"lavf", 1}, {"no", 0})),
@@ -861,9 +859,6 @@ static int demux_open_lavf(demuxer_t *demuxer, enum demux_check check)
     if (priv->format_hack.fix_editlists)
         av_dict_set(&dopts, "advanced_editlist", "0", 0);
 
-    if (lavfdopts->cryptokey && lavfdopts->cryptokey[0])
-        av_dict_set(&dopts, "decryption_key", lavfdopts->cryptokey, 0);
-
     avfc->interrupt_callback = (AVIOInterruptCB){
         .callback = interrupt_cb,
         .opaque = demuxer,