add libaribb24 ARIB STD-B24 caption decoder

* Outputs ASS lines with basic coloring and font scaling for each
  given region.
* Sets the default style to the resolution of the subtitle plane
  (for example, 960x540 / 36pt font for profile A).
* Has options to:
  * Disable ruby text (which is coded as regions which have
    half-height text in libaribb24).
    Enabled by default as without positioning ruby text only
    confuses as it is usually coded in the beginning of the decoded
    subtitle line.
  * Set the working directory, in which libaribb24 will read
    configuration as well as into which it may save broadcast extra
    symbols as PNG.
    Unset by default.

The unconventional library check can be explained by the library's
current master branch being licensed as LGPLv3, but at the time of
writing the latest official release is still licensed under GPLv3.

Thus, one either has to wait for the following release, or enable
GPLv3.

1 files changed, 4 insertions, 0 deletions

diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index f554c53f0e..0ce22ec4fa 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -677,6 +677,7 @@ enum AVCodecID {
     AV_CODEC_ID_ASS,
     AV_CODEC_ID_HDMV_TEXT_SUBTITLE,
     AV_CODEC_ID_TTML,
+    AV_CODEC_ID_ARIB_CAPTION,
 
     /* other specific kind of codecs (generally used for attachments) */
     AV_CODEC_ID_FIRST_UNKNOWN = 0x18000,           ///< A dummy ID pointing at the start of various fake codecs.
@@ -2993,6 +2994,9 @@ typedef struct AVCodecContext {
 #define FF_PROFILE_PRORES_4444      4
 #define FF_PROFILE_PRORES_XQ        5
 
+#define FF_PROFILE_ARIB_PROFILE_A 0
+#define FF_PROFILE_ARIB_PROFILE_C 1
+
     /**
      * level
      * - encoding: Set by user.