From 158b39126d59f07069e0da07e0658111967c6179 Mon Sep 17 00:00:00 2001
From: Robert Swain <robert.swain@gmail.com>
Date: Wed, 7 Jan 2009 22:09:21 +0000
Subject: Support ADTS AAC files in the ffaac decoder (limited to streams
 containing one raw_data_block() per ADTS frame)

Patch by Alex Converse ( alex converse gmail com) based on a patch by Robert
Swain ( robert swain gmail com )

Originally committed as revision 16485 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/aac_parser.c | 86 +++++++++++++++++++++++++++++++------------------
 1 file changed, 54 insertions(+), 32 deletions(-)

(limited to 'libavcodec/aac_parser.c')

diff --git a/libavcodec/aac_parser.c b/libavcodec/aac_parser.c
index 3ff14163da..e38b5ecf01 100644
--- a/libavcodec/aac_parser.c
+++ b/libavcodec/aac_parser.c
@@ -22,16 +22,64 @@
 
 #include "parser.h"
 #include "aac_ac3_parser.h"
+#include "aac_parser.h"
 #include "bitstream.h"
 #include "mpeg4audio.h"
 
 #define AAC_HEADER_SIZE 7
 
+int ff_aac_parse_header(GetBitContext *gbc, AACADTSHeaderInfo *hdr)
+{
+    int size, rdb, ch, sr;
+    int aot, crc_abs;
+
+    if(get_bits(gbc, 12) != 0xfff)
+        return AAC_AC3_PARSE_ERROR_SYNC;
+
+    skip_bits1(gbc);             /* id */
+    skip_bits(gbc, 2);           /* layer */
+    crc_abs = get_bits1(gbc);    /* protection_absent */
+    aot     = get_bits(gbc, 2);  /* profile_objecttype */
+    sr      = get_bits(gbc, 4);  /* sample_frequency_index */
+    if(!ff_mpeg4audio_sample_rates[sr])
+        return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
+    skip_bits1(gbc);             /* private_bit */
+    ch      = get_bits(gbc, 3);  /* channel_configuration */
+
+    if(!ff_mpeg4audio_channels[ch])
+        return AAC_AC3_PARSE_ERROR_CHANNEL_CFG;
+
+    skip_bits1(gbc);             /* original/copy */
+    skip_bits1(gbc);             /* home */
+
+    /* adts_variable_header */
+    skip_bits1(gbc);             /* copyright_identification_bit */
+    skip_bits1(gbc);             /* copyright_identification_start */
+    size    = get_bits(gbc, 13); /* aac_frame_length */
+    if(size < AAC_HEADER_SIZE)
+        return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
+
+    skip_bits(gbc, 11);          /* adts_buffer_fullness */
+    rdb = get_bits(gbc, 2);      /* number_of_raw_data_blocks_in_frame */
+
+    hdr->object_type    = aot;
+    hdr->chan_config    = ch;
+    hdr->crc_absent     = crc_abs;
+    hdr->num_aac_frames = rdb + 1;
+    hdr->sampling_index = sr;
+    hdr->sample_rate    = ff_mpeg4audio_sample_rates[sr];
+    hdr->samples        = (rdb + 1) * 1024;
+    hdr->bit_rate       = size * 8 * hdr->sample_rate / hdr->samples;
+
+    return size;
+}
+
 static int aac_sync(uint64_t state, AACAC3ParseContext *hdr_info,
         int *need_next_header, int *new_frame_start)
 {
     GetBitContext bits;
-    int size, rdb, ch, sr;
+    AACADTSHeaderInfo hdr;
+    int size;
     union {
         uint64_t u64;
         uint8_t  u8[8];
@@ -40,40 +88,14 @@ static int aac_sync(uint64_t state, AACAC3ParseContext *hdr_info,
     tmp.u64 = be2me_64(state);
     init_get_bits(&bits, tmp.u8+8-AAC_HEADER_SIZE, AAC_HEADER_SIZE * 8);
 
-    if(get_bits(&bits, 12) != 0xfff)
-        return 0;
-
-    skip_bits1(&bits);          /* id */
-    skip_bits(&bits, 2);        /* layer */
-    skip_bits1(&bits);          /* protection_absent */
-    skip_bits(&bits, 2);        /* profile_objecttype */
-    sr = get_bits(&bits, 4);    /* sample_frequency_index */
-    if(!ff_mpeg4audio_sample_rates[sr])
-        return 0;
-    skip_bits1(&bits);          /* private_bit */
-    ch = get_bits(&bits, 3);    /* channel_configuration */
-    if(!ff_mpeg4audio_channels[ch])
+    if ((size = ff_aac_parse_header(&bits, &hdr)) < 0)
         return 0;
-    skip_bits1(&bits);          /* original/copy */
-    skip_bits1(&bits);          /* home */
-
-    /* adts_variable_header */
-    skip_bits1(&bits);          /* copyright_identification_bit */
-    skip_bits1(&bits);          /* copyright_identification_start */
-    size = get_bits(&bits, 13); /* aac_frame_length */
-    if(size < AAC_HEADER_SIZE)
-        return 0;
-
-    skip_bits(&bits, 11);       /* adts_buffer_fullness */
-    rdb = get_bits(&bits, 2);   /* number_of_raw_data_blocks_in_frame */
-
-    hdr_info->channels = ff_mpeg4audio_channels[ch];
-    hdr_info->sample_rate = ff_mpeg4audio_sample_rates[sr];
-    hdr_info->samples = (rdb + 1) * 1024;
-    hdr_info->bit_rate = size * 8 * hdr_info->sample_rate / hdr_info->samples;
-
     *need_next_header = 0;
     *new_frame_start  = 1;
+    hdr_info->sample_rate = hdr.sample_rate;
+    hdr_info->channels    = ff_mpeg4audio_channels[hdr.chan_config];
+    hdr_info->samples     = hdr.samples;
+    hdr_info->bit_rate    = hdr.bit_rate;
     return size;
 }
 
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