[SCM] libav/experimental: Document that and why subtitle decoders do not support direct-rendering.

[siretart at users.alioth.debian.org]

The following commit has been merged in the experimental branch:
commit 1f96d868363e9c6a22575d2306ebb3708b8d38dd
Author: Reimar Döffinger <Reimar.Doeffinger at gmx.de>
Date:   Sat Jul 10 23:35:15 2010 +0000

    Document that and why subtitle decoders do not support direct-rendering.
    
    Originally committed as revision 24177 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 495d679..9ae98b5 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -3542,6 +3542,10 @@ attribute_deprecated int avcodec_decode_subtitle(AVCodecContext *avctx, AVSubtit
  * Return a negative value on error, otherwise return the number of bytes used.
  * If no subtitle could be decompressed, got_sub_ptr is zero.
  * Otherwise, the subtitle is stored in *sub.
+ * Note that CODEC_CAP_DR1 is not available for subtitle codecs. This is for
+ * simplicity, because the performance difference is expect to be negligible
+ * and reusing a get_buffer written for video codecs would probably perform badly
+ * due to a potentially very different allocation pattern.
  *
  * @param avctx the codec context
  * @param[out] sub The AVSubtitle in which the decoded subtitle will be stored.

-- 
Libav/FFmpeg packaging