avcodec/avcodec: Nits

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/avcodec.h

@@ -4866,7 +4866,7 @@ int avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture,
  * If no subtitle could be decompressed, got_sub_ptr is zero.
  * Otherwise, the subtitle is stored in *sub.
  * Note that AV_CODEC_CAP_DR1 is not available for subtitle codecs. This is for
- * simplicity, because the performance difference is expect to be negligible
+ * simplicity, because the performance difference is expected to be negligible
  * and reusing a get_buffer written for video codecs would probably perform badly
  * due to a potentially very different allocation pattern.
  *
@@ -4882,7 +4882,7 @@ int avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture,
  * before packets may be fed to the decoder.
  *
  * @param avctx the codec context
- * @param[out] sub The Preallocated AVSubtitle in which the decoded subtitle will be stored,
+ * @param[out] sub The preallocated AVSubtitle in which the decoded subtitle will be stored,
  *                 must be freed with avsubtitle_free if *got_sub_ptr is set.
  * @param[in,out] got_sub_ptr Zero if no subtitle could be decompressed, otherwise, it is nonzero.
  * @param[in] avpkt The input AVPacket containing the input buffer.
@@ -5009,7 +5009,7 @@ int avcodec_send_frame(AVCodecContext *avctx, const AVFrame *frame);
  * @param avctx codec context
  * @param avpkt This will be set to a reference-counted packet allocated by the
  *              encoder. Note that the function will always call
- *              av_frame_unref(frame) before doing anything else.
+ *              av_packet_unref(avpkt) before doing anything else.
  * @return 0 on success, otherwise negative error code:
  *      AVERROR(EAGAIN):   output is not available in the current state - user
  *                         must try to send input