avcodec/avcodec: Perform sub_charenc/iconv checks before AVCodec.init()

Also move them to ff_decode_preinit().

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index 5a00aeedae..cbd41c8cc8 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -2031,6 +2031,41 @@ FF_ENABLE_DEPRECATION_WARNINGS
                avctx->codec->max_lowres);
         avctx->lowres = avctx->codec->max_lowres;
     }
+    if (avctx->sub_charenc) {
+        if (avctx->codec_type != AVMEDIA_TYPE_SUBTITLE) {
+            av_log(avctx, AV_LOG_ERROR, "Character encoding is only "
+                   "supported with subtitles codecs\n");
+            return AVERROR(EINVAL);
+        } else if (avctx->codec_descriptor->props & AV_CODEC_PROP_BITMAP_SUB) {
+            av_log(avctx, AV_LOG_WARNING, "Codec '%s' is bitmap-based, "
+                   "subtitles character encoding will be ignored\n",
+                   avctx->codec_descriptor->name);
+            avctx->sub_charenc_mode = FF_SUB_CHARENC_MODE_DO_NOTHING;
+        } else {
+            /* input character encoding is set for a text based subtitle
+             * codec at this point */
+            if (avctx->sub_charenc_mode == FF_SUB_CHARENC_MODE_AUTOMATIC)
+                avctx->sub_charenc_mode = FF_SUB_CHARENC_MODE_PRE_DECODER;
+
+            if (avctx->sub_charenc_mode == FF_SUB_CHARENC_MODE_PRE_DECODER) {
+#if CONFIG_ICONV
+                iconv_t cd = iconv_open("UTF-8", avctx->sub_charenc);
+                if (cd == (iconv_t)-1) {
+                    ret = AVERROR(errno);
+                    av_log(avctx, AV_LOG_ERROR, "Unable to open iconv context "
+                           "with input character encoding \"%s\"\n", avctx->sub_charenc);
+                    return ret;
+                }
+                iconv_close(cd);
+#else
+                av_log(avctx, AV_LOG_ERROR, "Character encoding subtitles "
+                       "conversion needs a libavcodec built with iconv support "
+                       "for this codec\n");
+                return AVERROR(ENOSYS);
+#endif
+            }
+        }
+    }
 
     avctx->pts_correction_num_faulty_pts =
     avctx->pts_correction_num_faulty_dts = 0;