Merge commit '50a1c66cf6ab7eb683daaa9e2da3869fa3a54609'

* commit '50a1c66cf6ab7eb683daaa9e2da3869fa3a54609':
  ac3_parser: add a public function for parsing the data required by the demuxer

avpriv_ac3_parse_header() is left in place but without the
GetBitContext parameter, as the mov muxer requires a lot more fields
than just bitstream_id and frame_size from the AC3HeaderInfo struct.

Merged-by: James Almer <jamrial@gmail.com>

libavcodec/ac3_parser_internal.h

@@ -0,0 +1,42 @@
+/*
+ * AC-3 parser internal code
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_AC3_PARSER_INTERNAL_H
+#define AVCODEC_AC3_PARSER_INTERNAL_H
+
+#include "ac3.h"
+#include "get_bits.h"
+
+/**
+ * Parse AC-3 frame header.
+ * Parse the header up to the lfeon element, which is the first 52 or 54 bits
+ * depending on the audio coding mode.
+ * @param[in]  gbc BitContext containing the first 54 bits of the frame.
+ * @param[out] hdr Pointer to struct where header info is written.
+ * @return Returns 0 on success, -1 if there is a sync word mismatch,
+ * -2 if the bsid (version) element is invalid, -3 if the fscod (sample rate)
+ * element is invalid, or -4 if the frmsizecod (bit rate) element is invalid.
+ */
+int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr);
+
+int avpriv_ac3_parse_header(AC3HeaderInfo **hdr, const uint8_t *buf,
+                            size_t size);
+
+#endif /* AVCODEC_AC3_PARSER_INTERNAL_H */