Support for Ambisonics.

Signed-off-by: Jean-Marc Valin <jmvalin@jmvalin.ca>

src/opus_header.c

@@ -46,7 +46,8 @@
   - if (mapping != 0)
      - N = total number of streams (8 bits)
      - M = number of paired streams (8 bits)
-     - C times channel origin
+     - if (mapping != a projection family)
+       - C times channel origin
           - if (C<2*M)
              - stream = byte/2
              - if (byte&0x1 == 0)
@@ -55,6 +56,8 @@
                  - right
           - else
              - stream = byte-M
+    - else
+       - D demixing matrix (C*(N+M)*16 bits)
 */
 
 typedef struct {
@@ -101,7 +104,49 @@ static int write_chars(Packet *p, const unsigned char *str, int nb_chars)
    return 1;
 }
 
-int _ope_opus_header_to_packet(const OpusHeader *h, unsigned char *packet, int len)
+static int write_matrix_chars(Packet *p, const OpusGenericEncoder *st)
+{
+#ifdef OPUS_HAVE_OPUS_PROJECTION_H
+  opus_int32 size;
+  int ret;
+  ret=opeint_encoder_ctl(st, OPUS_PROJECTION_GET_DEMIXING_MATRIX_SIZE(&size));
+  if (ret != OPUS_OK) return 0;
+  if (size>p->maxlen-p->pos) return 0;
+  ret=opeint_encoder_ctl(st, OPUS_PROJECTION_GET_DEMIXING_MATRIX(&p->data[p->pos], size));
+  if (ret != OPUS_OK) return 0;
+  p->pos += size;
+  return 1;
+#else
+  (void)p;
+  (void)st;
+  return 0;
+#endif
+}
+
+int _ope_opus_header_get_size(const OpusHeader *h)
+{
+  int len=0;
+  if (opeint_use_projection(h->channel_mapping))
+  {
+    /* 19 bytes from fixed header,
+     * 2 bytes for nb_streams & nb_coupled,
+     * 2 bytes per cell of demixing matrix, where:
+     *    rows=channels, cols=nb_streams+nb_coupled
+     */
+    len=21+(h->channels*(h->nb_streams+h->nb_coupled)*2);
+  }
+  else
+  {
+    /* 19 bytes from fixed header,
+     * 2 bytes for nb_streams & nb_coupled,
+     * 1 byte per channel
+     */
+    len=21+h->channels;
+  }
+  return len;
+}
+
+int _ope_opus_header_to_packet(const OpusHeader *h, unsigned char *packet, int len, const OpusGenericEncoder *st)
 {
    int i;
    Packet p;
@@ -128,8 +173,24 @@ int _ope_opus_header_to_packet(const OpusHeader *h, unsigned char *packet, int l
    if (!write_uint32(&p, h->input_sample_rate))
       return 0;
 
-   if (!write_uint16(&p, h->gain))
+   if (opeint_use_projection(h->channel_mapping))
+   {
+#ifdef OPUS_HAVE_OPUS_PROJECTION_H
+      opus_int32 matrix_gain;
+      int ret;
+      ret=opeint_encoder_ctl(st, OPUS_PROJECTION_GET_DEMIXING_MATRIX_GAIN(&matrix_gain));
+      if (ret != OPUS_OK) return 0;
+      if (!write_uint16(&p, h->gain + matrix_gain))
+         return 0;
+#else
       return 0;
+#endif
+   }
+   else
+   {
+      if (!write_uint16(&p, h->gain))
+         return 0;
+   }
 
    ch = h->channel_mapping;
    if (!write_chars(&p, &ch, 1))
@@ -146,10 +207,18 @@ int _ope_opus_header_to_packet(const OpusHeader *h, unsigned char *packet, int l
          return 0;
 
       /* Multi-stream support */
-      for (i=0;i<h->channels;i++)
+      if (opeint_use_projection(h->channel_mapping))
+      {
+        if (!write_matrix_chars(&p, st))
+           return 0;
+      }
+      else
       {
-         if (!write_chars(&p, &h->stream_map[i], 1))
-            return 0;
+        for (i=0;i<h->channels;i++)
+        {
+          if (!write_chars(&p, &h->stream_map[i], 1))
+             return 0;
+        }
       }
    }
 

src/opus_header.h

@@ -31,6 +31,45 @@
 #include <stdlib.h>
 #include <opus.h>
 
+#include <opus_multistream.h>
+#ifdef OPUS_HAVE_OPUS_PROJECTION_H
+#include <opus_projection.h>
+#endif
+
+typedef struct OpusGenericEncoder OpusGenericEncoder;
+struct OpusGenericEncoder {
+  OpusMSEncoder *ms;
+#ifdef OPUS_HAVE_OPUS_PROJECTION_H
+  OpusProjectionEncoder *pr;
+#endif
+};
+
+int opeint_use_projection(int channel_mapping);
+
+int opeint_encoder_surround_init(OpusGenericEncoder *st, int Fs, int channels, int channel_mapping, int *nb_streams, int *nb_coupled, unsigned char *stream_map, int application);
+
+void opeint_encoder_cleanup(OpusGenericEncoder *st);
+
+int opeint_encoder_init(OpusGenericEncoder *st, opus_int32 Fs, int channels, int streams, int coupled_streams, const unsigned char *mapping, int application);
+
+int opeint_encode_float(OpusGenericEncoder *st, const float *pcm, int frame_size, unsigned char *data, opus_int32 max_data_bytes);
+
+#ifdef OPUS_HAVE_OPUS_PROJECTION_H
+# define opeint_encoder_ctl(st, request) \
+    ((st)->pr!=NULL ? \
+    opus_projection_encoder_ctl((st)->pr, request) : \
+    opus_multistream_encoder_ctl((st)->ms, request))
+# define opeint_encoder_ctl2(st, request, value) \
+    ((st)->pr!=NULL ? \
+    opus_projection_encoder_ctl((st)->pr, request, value) : \
+    opus_multistream_encoder_ctl((st)->ms, request, value))
+#else
+# define opeint_encoder_ctl(st, request) \
+    opus_multistream_encoder_ctl((st)->ms, request)
+# define opeint_encoder_ctl2(st, request, value) \
+    opus_multistream_encoder_ctl((st)->ms, request, value)
+#endif
+
 typedef struct {
    int version;
    int channels; /* Number of channels: 1..255 */
@@ -44,7 +83,9 @@ typedef struct {
    unsigned char stream_map[255];
 } OpusHeader;
 
-int _ope_opus_header_to_packet(const OpusHeader *h, unsigned char *packet, int len);
+int _ope_opus_header_get_size(const OpusHeader *h);
+
+int _ope_opus_header_to_packet(const OpusHeader *h, unsigned char *packet, int len, const OpusGenericEncoder *st);
 
 void _ope_comment_init(char **comments, int* length, const char *vendor_string);