aac: Split function to parse ADTS header data into public and private part

This makes the currently semi-public avpriv_aac_parse_header() function
private to libavcodec and adds a proper public API function to return
the parts of the ADTS header required in libavformat.

1 files changed, 50 insertions, 0 deletions

diff --git a/libavcodec/adts_header.h b/libavcodec/adts_header.h
new file mode 100644
index 0000000000..386aa0a331
--- /dev/null
+++ b/libavcodec/adts_header.h
@@ -0,0 +1,50 @@
+/*
+ * AAC ADTS header decoding prototypes and structures
+ * Copyright (c) 2003 Fabrice Bellard
+ * Copyright (c) 2003 Michael Niedermayer
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_ADTS_HEADER_H
+#define AVCODEC_ADTS_HEADER_H
+
+#include "get_bits.h"
+
+typedef struct AACADTSHeaderInfo {
+    uint32_t sample_rate;
+    uint32_t samples;
+    uint32_t bit_rate;
+    uint8_t  crc_absent;
+    uint8_t  object_type;
+    uint8_t  sampling_index;
+    uint8_t  chan_config;
+    uint8_t  num_aac_frames;
+} AACADTSHeaderInfo;
+
+/**
+ * Parse the ADTS frame header to the end of the variable header, which is
+ * the first 54 bits.
+ * @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 version element is invalid, -3 if the sample rate
+ * element is invalid, or -4 if the bit rate element is invalid.
+ */
+int ff_adts_header_parse(GetBitContext *gbc, AACADTSHeaderInfo *hdr);
+
+#endif /* AVCODEC_ADTS_HEADER_H */