[FFmpeg-devel] [PATCH 1/6] avcodec/ac3_parser{, _internal}: expose AC-3 bit_rate_code

[Jan Ekström]

From: Jan Ekström <jan.ekstrom at 24i.com>

Required by MP4's AC3SpecificBox and MPEG-TS AC-3 audio_descriptor,
of which the former is implemented in our MP4 writer.

Signed-off-by: Jan Ekström <jan.ekstrom at 24i.com>
---
 libavcodec/ac3_parser.c          | 3 +++
 libavcodec/ac3_parser_internal.h | 1 +
 2 files changed, 4 insertions(+)

diff --git a/libavcodec/ac3_parser.c b/libavcodec/ac3_parser.c
index 119b1598c5..852c9e6b0d 100644
--- a/libavcodec/ac3_parser.c
+++ b/libavcodec/ac3_parser.c
@@ -70,6 +70,7 @@ int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
         return AAC_AC3_PARSE_ERROR_BSID;
 
     hdr->num_blocks = 6;
+    hdr->ac3_bit_rate_code = -1;
 
     /* set default mix levels */
     hdr->center_mix_level   = 5;  // -4.5dB
@@ -89,6 +90,8 @@ int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
         if(frame_size_code > 37)
             return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
 
+        hdr->ac3_bit_rate_code = (frame_size_code >> 1);
+
         skip_bits(gbc, 5); // skip bsid, already got it
 
         hdr->bitstream_mode = get_bits(gbc, 3);
diff --git a/libavcodec/ac3_parser_internal.h b/libavcodec/ac3_parser_internal.h
index dd57dc95a6..bd4e1bbffb 100644
--- a/libavcodec/ac3_parser_internal.h
+++ b/libavcodec/ac3_parser_internal.h
@@ -60,6 +60,7 @@ typedef struct AC3HeaderInfo {
     uint8_t channels;
     uint16_t frame_size;
     uint64_t channel_layout;
+    int8_t ac3_bit_rate_code;
     /** @} */
 } AC3HeaderInfo;
 
-- 
2.36.1