From e6d9fa66f12cf5a3024c9bc7c4c608f7fc59207e Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Thu, 2 Feb 2012 22:27:27 -0500
Subject: [PATCH] ac3dec: Move center and surround mix level tables to the
parser.
That way all mix levels as exported by avpriv_ac3_parse_header()
will have the same meaning.
Previously the 3-bit center mix level for E-AC-3 was used to index in a
4-entry table, leading to out-of-array reads.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Justin Ruggles <justin.ruggles@gmail.com>
Signed-off-by: Alex Converse <alex.converse@gmail.com>
---
libavcodec/ac3_parser.c | 20 ++++++++++++++++----
libavcodec/ac3dec.c | 16 ++--------------
2 files changed, 18 insertions(+), 18 deletions(-)
diff --git a/libavcodec/ac3_parser.c b/libavcodec/ac3_parser.c
index e3c46fd332a..067b4f98792 100644
--- a/libavcodec/ac3_parser.c
+++ b/libavcodec/ac3_parser.c
@@ -34,6 +34,18 @@ static const uint8_t eac3_blocks[4] = {
1, 2, 3, 6
};
+/**
+ * Table for center mix levels
+ * reference: Section 5.4.2.4 cmixlev
+ */
+static const uint8_t center_levels[4] = { 4, 5, 6, 5 };
+
+/**
+ * Table for surround mix levels
+ * reference: Section 5.4.2.5 surmixlev
+ */
+static const uint8_t surround_levels[4] = { 4, 6, 7, 6 };
+
int avpriv_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
{
@@ -53,8 +65,8 @@ int avpriv_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
hdr->num_blocks = 6;
/* set default mix levels */
- hdr->center_mix_level = 1; // -4.5dB
- hdr->surround_mix_level = 1; // -6.0dB
+ hdr->center_mix_level = 5; // -4.5dB
+ hdr->surround_mix_level = 6; // -6.0dB
if(hdr->bitstream_id <= 10) {
/* Normal AC-3 */
@@ -76,9 +88,9 @@ int avpriv_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
skip_bits(gbc, 2); // skip dsurmod
} else {
if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO)
- hdr->center_mix_level = get_bits(gbc, 2);
+ hdr-> center_mix_level = center_levels[get_bits(gbc, 2)];
if(hdr->channel_mode & 4)
- hdr->surround_mix_level = get_bits(gbc, 2);
+ hdr->surround_mix_level = surround_levels[get_bits(gbc, 2)];
}
hdr->lfe_on = get_bits1(gbc);
diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c
index b50ec2abe62..66a9ea62998 100644
--- a/libavcodec/ac3dec.c
+++ b/libavcodec/ac3dec.c
@@ -76,18 +76,6 @@ static const float gain_levels[9] = {
LEVEL_MINUS_9DB
};
-/**
- * Table for center mix levels
- * reference: Section 5.4.2.4 cmixlev
- */
-static const uint8_t center_levels[4] = { 4, 5, 6, 5 };
-
-/**
- * Table for surround mix levels
- * reference: Section 5.4.2.5 surmixlev
- */
-static const uint8_t surround_levels[4] = { 4, 6, 7, 6 };
-
/**
* Table for default stereo downmixing coefficients
* reference: Section 7.8.2 Downmixing Into Two Channels
@@ -315,8 +303,8 @@ static int parse_frame_header(AC3DecodeContext *s)
static void set_downmix_coeffs(AC3DecodeContext *s)
{
int i;
- float cmix = gain_levels[center_levels[s->center_mix_level]];
- float smix = gain_levels[surround_levels[s->surround_mix_level]];
+ float cmix = gain_levels[s-> center_mix_level];
+ float smix = gain_levels[s->surround_mix_level];
float norm0, norm1;
for (i = 0; i < s->fbw_channels; i++) {
--
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