Merge remote-tracking branch 'qatar/master'

* qatar/master:
  avc: Add a function for converting mp4 style extradata to annex b
  pthread: free progress if buffer allocation failed.
  lavc/avconv: support changing frame sizes in codecs with frame mt.
  libavformat: Document who sets the AVStream.id field
  utvideo: mark output picture as keyframe.
  sunrast: Add support for negative linesize.
  vp8: fix update_lf_deltas in libavcodec/vp8.c
  ralf: read Huffman code lengths without GetBitContext

Conflicts:
	ffmpeg.c
	libavcodec/sunrastenc.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/avformat.h

@@ -558,7 +558,12 @@ typedef struct AVIndexEntry {
  */
 typedef struct AVStream {
     int index;    /**< stream index in AVFormatContext */
-    int id;       /**< format-specific stream ID */
+    /**
+     * Format-specific stream ID.
+     * decoding: set by libavformat
+     * encoding: set by the user
+     */
+    int id;
     AVCodecContext *codec; /**< codec context */
     /**
      * Real base framerate of the stream.