---
libavcodec/ac3dec.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c
index fcb52e1..df66ce1 100644
--- a/libavcodec/ac3dec.c
+++ b/libavcodec/ac3dec.c
@@ -31,6 +31,7 @@
#include "libavutil/channel_layout.h"
#include "libavutil/crc.h"
+#include "libavutil/downmix_info.h"
#include "libavutil/opt.h"
#include "internal.h"
#include "aac_ac3_parser.h"
@@ -77,6 +78,42 @@ static const float gain_levels[9] = {
LEVEL_MINUS_9DB
};
+/** Adjustments in dB gain (LFE, +10 to -21 dB) */
+static const float gain_levels_lfe[32] = {
+ 3.162275,
+ 2.818382,
+ 2.511886,
+ 2.238719,
+ 1.995261,
+ 1.778278,
+ 1.584893,
+ 1.412536,
+ 1.258924,
+ 1.122018,
+ 1.000000,
+ 0.891251,
+ 0.794328,
+ 0.707946,
+ 0.630957,
+ 0.562341,
+ 0.501187,
+ 0.446683,
+ 0.398107,
+ 0.354813,
+ 0.316227,
+ 0.281838,
+ 0.251188,
+ 0.223872,
+ 0.199526,
+ 0.177828,
+ 0.158489,
+ 0.141253,
+ 0.125892,
+ 0.112201,
+ 0.100000,
+ 0.089125
+};
+
/**
* Table for default stereo downmixing coefficients
* reference: Section 7.8.2 Downmixing Into Two Channels
@@ -1308,6 +1345,7 @@ static int ac3_decode_frame(AVCodecContext * avctx, void
*data,
const uint8_t *channel_map;
const float *output[AC3_MAX_CHANNELS];
enum AVMatrixEncoding matrix_encoding;
+ AVDownmixInfo *downmix_info;
/* copy input buffer to decoder context to avoid reading past the end
of the buffer, which can be caused by a damaged input stream. */
@@ -1478,6 +1516,33 @@ static int ac3_decode_frame(AVCodecContext * avctx, void
*data,
if ((ret = ff_side_data_update_matrix_encoding(frame, matrix_encoding)) <
0)
return ret;
+ /* AVDownmixInfo */
+ if ((downmix_info = av_downmix_info_update_side_data(frame))) {
+ switch (s->preferred_downmix) {
+ case AC3_DMIXMOD_LTRT:
+ downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_LTRT;
+ break;
+ case AC3_DMIXMOD_LORO:
+ downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_LORO;
+ break;
+ case AC3_DMIXMOD_DPLII:
+ downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_DPLII;
+ break;
+ default:
+ downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_UNKNOWN;
+ break;
+ }
+ downmix_info->center_mix_level = gain_levels[s->
center_mix_level];
+ downmix_info->center_mix_level_ltrt = gain_levels[s->
center_mix_level_ltrt];
+ downmix_info->surround_mix_level = gain_levels[s->
surround_mix_level];
+ downmix_info->surround_mix_level_ltrt =
gain_levels[s->surround_mix_level_ltrt];
+ if (s->lfe_mix_level_exists)
+ downmix_info->lfe_mix_level =
gain_levels_lfe[s->lfe_mix_level];
+ else
+ downmix_info->lfe_mix_level = 0.0; // -inf dB
+ } else
+ return AVERROR(ENOMEM);
+
*got_frame_ptr = 1;
return FFMIN(buf_size, s->frame_size);
--
1.8.3.4 (Apple Git-47)
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