avcodec: add avpriv_dca_parse_core_frame_header()

There are 3 different places where DCA core frame header is parsed:
decoder, parser and demuxer. Each one uses ad-hoc code. Add common core
frame header parsing function that will be used in all places.

Signed-off-by: James Almer <jamrial@gmail.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/libavcodec/dca.c b/libavcodec/dca.c
index fb796191d6..39f8f3d81c 100644
--- a/libavcodec/dca.c
+++ b/libavcodec/dca.c
@@ -28,7 +28,9 @@
 #include "libavutil/error.h"
 
 #include "dca.h"
+#include "dca_core.h"
 #include "dca_syncwords.h"
+#include "get_bits.h"
 #include "put_bits.h"
 
 const uint32_t avpriv_dca_sample_rates[16] = {
@@ -85,3 +87,61 @@ int avpriv_dca_convert_bitstream(const uint8_t *src, int src_size, uint8_t *dst,
         return AVERROR_INVALIDDATA;
     }
 }
+
+int avpriv_dca_parse_core_frame_header(GetBitContext *gb, DCACoreFrameHeader *h)
+{
+    if (get_bits_long(gb, 32) != DCA_SYNCWORD_CORE_BE)
+        return DCA_PARSE_ERROR_SYNC_WORD;
+
+    h->normal_frame = get_bits1(gb);
+    h->deficit_samples = get_bits(gb, 5) + 1;
+    if (h->deficit_samples != DCA_PCMBLOCK_SAMPLES)
+        return DCA_PARSE_ERROR_DEFICIT_SAMPLES;
+
+    h->crc_present = get_bits1(gb);
+    h->npcmblocks = get_bits(gb, 7) + 1;
+    if (h->npcmblocks & (DCA_SUBBAND_SAMPLES - 1))
+        return DCA_PARSE_ERROR_PCM_BLOCKS;
+
+    h->frame_size = get_bits(gb, 14) + 1;
+    if (h->frame_size < 96)
+        return DCA_PARSE_ERROR_FRAME_SIZE;
+
+    h->audio_mode = get_bits(gb, 6);
+    if (h->audio_mode >= DCA_AMODE_COUNT)
+        return DCA_PARSE_ERROR_AMODE;
+
+    h->sr_code = get_bits(gb, 4);
+    if (!avpriv_dca_sample_rates[h->sr_code])
+        return DCA_PARSE_ERROR_SAMPLE_RATE;
+
+    h->br_code = get_bits(gb, 5);
+    if (get_bits1(gb))
+        return DCA_PARSE_ERROR_RESERVED_BIT;
+
+    h->drc_present = get_bits1(gb);
+    h->ts_present = get_bits1(gb);
+    h->aux_present = get_bits1(gb);
+    h->hdcd_master = get_bits1(gb);
+    h->ext_audio_type = get_bits(gb, 3);
+    h->ext_audio_present = get_bits1(gb);
+    h->sync_ssf = get_bits1(gb);
+    h->lfe_present = get_bits(gb, 2);
+    if (h->lfe_present == DCA_LFE_FLAG_INVALID)
+        return DCA_PARSE_ERROR_LFE_FLAG;
+
+    h->predictor_history = get_bits1(gb);
+    if (h->crc_present)
+        skip_bits(gb, 16);
+    h->filter_perfect = get_bits1(gb);
+    h->encoder_rev = get_bits(gb, 4);
+    h->copy_hist = get_bits(gb, 2);
+    h->pcmr_code = get_bits(gb, 3);
+    if (!ff_dca_bits_per_sample[h->pcmr_code])
+        return DCA_PARSE_ERROR_PCM_RES;
+
+    h->sumdiff_front = get_bits1(gb);
+    h->sumdiff_surround = get_bits1(gb);
+    h->dn_code = get_bits(gb, 4);
+    return 0;
+}