Split the ADTS header decoder off of the ADTS parser.

The AAC decoder and ADTS-to-ASC BSF both require the header decoder
but not full parsing capabilities.

Originally committed as revision 24217 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 54 insertions, 0 deletions

diff --git a/libavcodec/aacadtsdec.h b/libavcodec/aacadtsdec.h
new file mode 100644
index 0000000000..bdc577179f
--- /dev/null
+++ b/libavcodec/aacadtsdec.h
@@ -0,0 +1,54 @@
+/*
+ * AAC ADTS header decoding prototypes and structures
+ * Copyright (c) 2003 Fabrice Bellard
+ * Copyright (c) 2003 Michael Niedermayer
+ *
+ * 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_AACADTSDEC_H
+#define AVCODEC_AACADTSDEC_H
+
+#include <stdint.h>
+#include "get_bits.h"
+
+#define AAC_ADTS_HEADER_SIZE 7
+
+typedef struct {
+    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 AAC frame header.
+ * Parse the ADTS frame header to the end of the variable header, which is
+ * the first 54 bits.
+ * @param gbc BitContext containing the first 54 bits of the frame.
+ * @param 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_aac_parse_header(GetBitContext *gbc, AACADTSHeaderInfo *hdr);
+
+#endif /* AVCODEC_AACADTSDEC_H */