According to
https://github.com/google/spatial-media/blob/master/docs/spatial-audio-rfc.md
the first bit in ambisonic_type is a flag to signal the presence of
non-diegetic channels
in the audio track in addition to the ambisonic ones, so support this case too.
Signed-off-by: James Almer <jamr...@gmail.com>
---
Untested, and the spec could use some clarification/improvement for this field.
libavformat/mov.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/libavformat/mov.c b/libavformat/mov.c
index d0ee6201a5..e52a83c82e 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -7928,6 +7928,7 @@ static int mov_read_SA3D(MOVContext *c, AVIOContext *pb,
MOVAtom atom)
AVChannelLayout ch_layout = { 0 };
int ret, i, version, type;
int ambisonic_order, channel_order, normalization, channel_count;
+ int ambi_channels, non_diegetic_channels;
if (c->fc->nb_streams < 1)
return 0;
@@ -7946,11 +7947,12 @@ static int mov_read_SA3D(MOVContext *c, AVIOContext
*pb, MOVAtom atom)
}
type = avio_r8(pb);
- if (type) {
+ if (type & 0x7f) {
av_log(c->fc, AV_LOG_WARNING,
- "Unsupported ambisonic type %d\n", type);
+ "Unsupported ambisonic type %d\n", type & 0x7f);
return 0;
}
+ non_diegetic_channels = !!(type & 0x80) * 2;
ambisonic_order = avio_rb32(pb);
@@ -7969,12 +7971,14 @@ static int mov_read_SA3D(MOVContext *c, AVIOContext
*pb, MOVAtom atom)
}
channel_count = avio_rb32(pb);
- if (ambisonic_order < 0 || channel_count != (ambisonic_order + 1LL) *
(ambisonic_order + 1LL)) {
+ if (ambisonic_order < 0 || channel_count != ((ambisonic_order + 1LL) *
(ambisonic_order + 1LL) +
+ non_diegetic_channels)) {
av_log(c->fc, AV_LOG_ERROR,
"Invalid number of channels (%d / %d)\n",
channel_count, ambisonic_order);
return 0;
}
+ ambi_channels = channel_count - non_diegetic_channels;
ret = av_channel_layout_custom_init(&ch_layout, channel_count);
if (ret < 0)
@@ -7990,7 +7994,10 @@ static int mov_read_SA3D(MOVContext *c, AVIOContext *pb,
MOVAtom atom)
av_channel_layout_uninit(&ch_layout);
return 0;
}
- ch_layout.u.map[i].id = AV_CHAN_AMBISONIC_BASE + channel;
+ if (channel >= ambi_channels)
+ ch_layout.u.map[i].id = channel - ambi_channels;
+ else
+ ch_layout.u.map[i].id = AV_CHAN_AMBISONIC_BASE + channel;
}
ret = av_channel_layout_retype(&ch_layout, 0,
AV_CHANNEL_LAYOUT_RETYPE_FLAG_CANONICAL);
--
2.44.0
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