AAC bitstream format files support

Files with extension "aac" in ADTS or ADIF format are now playable.

Full credit goes to Igor Poretsky.

Change-Id: I413b34e15e5242fea60d3461966ae0984080f530

4 files changed, 127 insertions, 0 deletions

diff --git a/lib/rbcodec/metadata/aac.c b/lib/rbcodec/metadata/aac.c
new file mode 100644
index 0000000000..82adeacbde
--- /dev/null
+++ b/lib/rbcodec/metadata/aac.c
@@ -0,0 +1,122 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Parsing ADTS and ADIF headers
+ *
+ * Written by Igor B. Poretsky
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include "platform.h"
+
+#include "metadata.h"
+#include "metadata_common.h"
+#include "metadata_parsers.h"
+
+static const int sample_rates[] =
+{
+    96000, 88200, 64000, 48000,
+    44100, 32000, 24000, 22050,
+    16000, 12000, 11025, 8000,
+    7350, 0, 0, 0
+};
+
+static bool check_adts_syncword(int fd)
+{
+    uint16_t syncword;
+
+    read_uint16be(fd, &syncword);
+    return (syncword & 0xFFF6) == 0xFFF0;
+}
+
+bool get_aac_metadata(int fd, struct mp3entry *entry)
+{
+    unsigned char buf[5];
+
+    entry->title = NULL;
+    entry->tracknum = 0;
+    entry->discnum = 0;
+    entry->id3v1len = 0;
+    entry->id3v2len = getid3v2len(fd);
+    entry->first_frame_offset = entry->id3v2len;
+    entry->filesize = filesize(fd) - entry->first_frame_offset;
+    entry->needs_upsampling_correction = false;
+
+    if (entry->id3v2len)
+        setid3v2title(fd, entry);
+
+    if (-1 == lseek(fd, entry->first_frame_offset, SEEK_SET))
+        return false;
+
+    if (check_adts_syncword(fd))
+    {
+        int frames;
+        int stat_length;
+        uint64_t total;
+        if (read(fd, buf, 5) != 5)
+            return false;
+        entry->frequency = sample_rates[(buf[0] >> 2) & 0x0F];
+        entry->vbr = ((buf[3] & 0x1F) == 0x1F)
+          && ((buf[4] & 0xFC) == 0xFC);
+        stat_length = entry->frequency >> ((entry->vbr) ? 5 : 7);
+        for (frames = 1, total = 0; frames < stat_length; frames++)
+        {
+            unsigned int frame_length = (((unsigned int)buf[1] & 0x3) << 11)
+              | ((unsigned int)buf[2] << 3)
+              | ((unsigned int)buf[3] >> 5);
+            total += frame_length;
+            if (frame_length < 7)
+                break;
+            if (-1 == lseek(fd, frame_length - 7, SEEK_CUR))
+                break;
+            if (!check_adts_syncword(fd))
+                break;
+            if (read(fd, buf, 5) != 5)
+                break;
+        }
+        entry->bitrate = (unsigned int)((total * entry->frequency / frames + 64000) / 128000);
+        if (entry->frequency <= 24000)
+        {
+            entry->frequency <<= 1;
+            entry->needs_upsampling_correction = true;
+        }
+    }
+    else
+    {
+        uint32_t bitrate;
+        if (-1 == lseek(fd, entry->first_frame_offset, SEEK_SET))
+            return false;
+        if (read(fd, buf, 5) != 5)
+            return false;
+        if (memcmp(buf, "ADIF", 4))
+            return false;
+        if (-1 == lseek(fd, (buf[4] & 0x80) ? (entry->first_frame_offset + 9) : entry->first_frame_offset, SEEK_SET))
+            return false;
+        read_uint32be(fd, &bitrate);
+        entry->vbr = (bitrate & 0x10000000) != 0;
+        entry->bitrate = ((bitrate & 0xFFFFFE0) + 16000) / 32000;
+        read_uint32be(fd, (uint32_t*)(&(entry->frequency)));
+        entry->frequency = sample_rates[(entry->frequency >> (entry->vbr ? 23 : 3)) & 0x0F];
+    }
+    entry->length = (unsigned long)((entry->filesize * 8LL + (entry->bitrate >> 1)) / entry->bitrate);
+
+    return true;
+}
diff --git a/lib/rbcodec/metadata/metadata.c b/lib/rbcodec/metadata/metadata.c
index 7ca4b1afd2..c24a27df2b 100644
--- a/lib/rbcodec/metadata/metadata.c
+++ b/lib/rbcodec/metadata/metadata.c
@@ -235,6 +235,9 @@ const struct afmt_entry audio_formats[AFMT_NUM_CODECS] =
     /* Opus */
     [AFMT_OPUS] =
         AFMT_ENTRY("Opus", "opus", NULL, get_ogg_metadata,   "opus\0"),
+    /* AAC bitstream format */
+    [AFMT_AAC_BSF] =
+        AFMT_ENTRY("AAC", "aac_bsf", NULL, get_aac_metadata,   "aac\0"),
 #endif
 };
 
diff --git a/lib/rbcodec/metadata/metadata.h b/lib/rbcodec/metadata/metadata.h
index 18cfce7523..a7ebcf16e5 100644
--- a/lib/rbcodec/metadata/metadata.h
+++ b/lib/rbcodec/metadata/metadata.h
@@ -90,6 +90,7 @@ enum
     AFMT_VGM,         /* VGM (Video Game Music Format) */
     AFMT_KSS,          /* KSS (MSX computer KSS Music File) */
     AFMT_OPUS,         /* Opus (see http://www.opus-codec.org ) */
+    AFMT_AAC_BSF,
 #endif
 
     /* add new formats at any index above this line to have a sensible order -
diff --git a/lib/rbcodec/metadata/metadata_parsers.h b/lib/rbcodec/metadata/metadata_parsers.h
index 304e393538..9f03c79bb5 100644
--- a/lib/rbcodec/metadata/metadata_parsers.h
+++ b/lib/rbcodec/metadata/metadata_parsers.h
@@ -56,4 +56,5 @@ bool get_hes_metadata(int fd, struct mp3entry* id3);
 bool get_sgc_metadata(int fd, struct mp3entry* id3);
 bool get_vgm_metadata(int fd, struct mp3entry* id3);
 bool get_kss_metadata(int fd, struct mp3entry* id3);
+bool get_aac_metadata(int fd, struct mp3entry* id3);
 #endif /* CONFIG_CODEC == SWCODEC */