[FFmpeg-devel] [PATCH v2 1/4] avcodec/eac3dec: add detection of Atmos spatial extension profile

[Marth64 <marth64@proxyid.net>]

Signed-off-by: Marth64 <marth64@proxyid.net>
---
 libavcodec/ac3dec.c     |  3 +++
 libavcodec/ac3dec.h     |  1 +
 libavcodec/avcodec.h    |  2 ++
 libavcodec/codec_desc.c |  1 +
 libavcodec/eac3dec.c    | 11 ++++++++++-
 libavcodec/profiles.c   |  5 +++++
 libavcodec/profiles.h   |  1 +
 7 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c
index 0b120e6140..8cede139b8 100644
--- a/libavcodec/ac3dec.c
+++ b/libavcodec/ac3dec.c
@@ -1714,6 +1714,9 @@ skip:
     if (!err) {
         avctx->sample_rate = s->sample_rate;
         avctx->bit_rate    = s->bit_rate + s->prev_bit_rate;
+
+        if (s->eac3_extension_type_a == 1)
+            avctx->profile = FF_PROFILE_EAC3_DDP_ATMOS;
     }
 
     if (!avctx->sample_rate) {
diff --git a/libavcodec/ac3dec.h b/libavcodec/ac3dec.h
index 138b462abb..0829f4b40d 100644
--- a/libavcodec/ac3dec.h
+++ b/libavcodec/ac3dec.h
@@ -102,6 +102,7 @@ typedef struct AC3DecodeContext {
     int eac3;                               ///< indicates if current frame is E-AC-3
     int eac3_frame_dependent_found;         ///< bitstream has E-AC-3 dependent frame(s)
     int eac3_subsbtreamid_found;            ///< bitstream has E-AC-3 additional substream(s)
+    int eac3_extension_type_a;              ///< bitstream has E-AC-3 extension type A enabled frame(s)
     int dolby_surround_mode;                ///< dolby surround mode                    (dsurmod)
     int dolby_surround_ex_mode;             ///< dolby surround ex mode                 (dsurexmod)
     int dolby_headphone_mode;               ///< dolby headphone mode                   (dheadphonmod)
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 39881a1d2b..0e85dd50a4 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -1591,6 +1591,8 @@ typedef struct AVCodecContext {
 #define FF_PROFILE_DTS_HD_MA   60
 #define FF_PROFILE_DTS_EXPRESS 70
 
+#define FF_PROFILE_EAC3_DDP_ATMOS         30
+
 #define FF_PROFILE_MPEG2_422    0
 #define FF_PROFILE_MPEG2_HIGH   1
 #define FF_PROFILE_MPEG2_SS     2
diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
index 199f62df15..4098d4f5a5 100644
--- a/libavcodec/codec_desc.c
+++ b/libavcodec/codec_desc.c
@@ -2931,6 +2931,7 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .name      = "eac3",
         .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52B (AC-3, E-AC-3)"),
         .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
+        .profiles  = NULL_IF_CONFIG_SMALL(ff_eac3_profiles),
     },
     {
         .id        = AV_CODEC_ID_SIPR,
diff --git a/libavcodec/eac3dec.c b/libavcodec/eac3dec.c
index deca51dd3d..5c71751a0c 100644
--- a/libavcodec/eac3dec.c
+++ b/libavcodec/eac3dec.c
@@ -464,7 +464,16 @@ static int ff_eac3_parse_header(AC3DecodeContext *s)
     if (get_bits1(gbc)) {
         int addbsil = get_bits(gbc, 6);
         for (i = 0; i < addbsil + 1; i++) {
-            skip_bits(gbc, 8); // skip additional bit stream info
+            if (i == 0) {
+                /* In this 8 bit chunk, the LSB is equal to flag_ec3_extension_type_a
+                   which can be used to detect Atmos presence */
+                skip_bits(gbc, 7);
+                if (get_bits1(gbc)) {
+                    s->eac3_extension_type_a = 1;
+                }
+            } else {
+                skip_bits(gbc, 8); // skip additional bit stream info
+            }
         }
     }
 
diff --git a/libavcodec/profiles.c b/libavcodec/profiles.c
index 7af7fbeb13..343b08f363 100644
--- a/libavcodec/profiles.c
+++ b/libavcodec/profiles.c
@@ -45,6 +45,11 @@ const AVProfile ff_dca_profiles[] = {
     { FF_PROFILE_UNKNOWN },
 };
 
+const AVProfile ff_eac3_profiles[] = {
+  { FF_PROFILE_EAC3_DDP_ATMOS, "Dolby Digital Plus + Dolby Atmos"},
+  { FF_PROFILE_UNKNOWN },
+};
+
 const AVProfile ff_dnxhd_profiles[] = {
   { FF_PROFILE_DNXHD,      "DNXHD"},
   { FF_PROFILE_DNXHR_LB,   "DNXHR LB"},
diff --git a/libavcodec/profiles.h b/libavcodec/profiles.h
index 41a19aa9ad..6ebedbd03f 100644
--- a/libavcodec/profiles.h
+++ b/libavcodec/profiles.h
@@ -58,6 +58,7 @@
 
 extern const AVProfile ff_aac_profiles[];
 extern const AVProfile ff_dca_profiles[];
+extern const AVProfile ff_eac3_profiles[];
 extern const AVProfile ff_dnxhd_profiles[];
 extern const AVProfile ff_h264_profiles[];
 extern const AVProfile ff_hevc_profiles[];
-- 
2.25.1

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