[FFmpeg-devel] [PATCH] libavformat/mov.c: Add parsing for DDTS atom for DTS audio

[Shawn Singh]

The DDTS atom is defined in ETSI TS 102 114, v1.4.1, Annex E.
This is useful for DTS-HD formats, some of which cannot be
decoded by dcadec.c or libdcadec.

Signed-off-by: Shawn Singh <shawnsingh at google.com>
---
 libavformat/mov.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index c57aaeb..da170a6 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -744,6 +744,61 @@ static int mov_read_dec3(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     return 0;
 }
 
+static int mov_read_ddts(MOVContext *c, AVIOContext *pb, MOVAtom atom)
+{
+    const uint32_t ddts_size = 20;
+    AVStream *st = NULL;
+    uint8_t *buf = NULL;
+    uint32_t frame_duration_code = 0;
+    uint32_t channel_layout_code = 0;
+    GetBitContext gb;
+
+    buf = av_malloc(ddts_size + FF_INPUT_BUFFER_PADDING_SIZE);
+    if (!buf) {
+        return AVERROR(ENOMEM);
+    }
+    if (avio_read(pb, buf, ddts_size) < ddts_size) {
+        av_free(buf);
+        return AVERROR_INVALIDDATA;
+    }
+
+    init_get_bits(&gb, buf, 8*ddts_size);
+
+    if (c->fc->nb_streams < 1) {
+        return 0;
+    }
+    st = c->fc->streams[c->fc->nb_streams-1];
+
+    st->codec->sample_rate = get_bits_long(&gb, 32);
+    skip_bits_long(&gb, 32); /* max bitrate */
+    st->codec->bit_rate = get_bits_long(&gb, 32);
+    st->codec->bits_per_coded_sample = get_bits(&gb, 8);
+    frame_duration_code = get_bits(&gb, 2);
+    skip_bits(&gb, 30); /* various fields */
+    channel_layout_code = get_bits(&gb, 16);
+
+    st->codec->frame_size =
+            (frame_duration_code == 0) ? 512 :
+            (frame_duration_code == 1) ? 1024 :
+            (frame_duration_code == 2) ? 2048 :
+            (frame_duration_code == 3) ? 4096 : 0;
+
+    if (channel_layout_code > 0xff) {
+        av_log(c->fc, AV_LOG_WARNING, "Unsupported DTS audio channel layout");
+    }
+    st->codec->channel_layout =
+            ((channel_layout_code & 0x1) ? AV_CH_FRONT_CENTER : 0) |
+            ((channel_layout_code & 0x2) ? AV_CH_FRONT_LEFT : 0) |
+            ((channel_layout_code & 0x2) ? AV_CH_FRONT_RIGHT : 0) |
+            ((channel_layout_code & 0x4) ? AV_CH_SIDE_LEFT : 0) |
+            ((channel_layout_code & 0x4) ? AV_CH_SIDE_RIGHT : 0) |
+            ((channel_layout_code & 0x8) ? AV_CH_LOW_FREQUENCY : 0);
+
+    st->codec->channels = av_get_channel_layout_nb_channels(st->codec->channel_layout);
+
+    return 0;
+}
+
 static int mov_read_chan(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 {
     AVStream *st;
@@ -3824,6 +3879,7 @@ static const MOVParseTableEntry mov_default_parse_table[] = {
 { MKTAG('e','s','d','s'), mov_read_esds },
 { MKTAG('d','a','c','3'), mov_read_dac3 }, /* AC-3 info */
 { MKTAG('d','e','c','3'), mov_read_dec3 }, /* EAC-3 info */
+{ MKTAG('d','d','t','s'), mov_read_ddts }, /* DTS audio descriptor */
 { MKTAG('w','i','d','e'), mov_read_wide }, /* place holder */
 { MKTAG('w','f','e','x'), mov_read_wfex },
 { MKTAG('c','m','o','v'), mov_read_cmov },
-- 
2.6.0.rc2.230.g3dd15c0