aacenc: support extended channel layouts using PCEs

This commit implements support for PCE (Program Configuration Elements) in the
AAC encoder, and as such allows for encoding of channel layouts not present
in the presets defined by the spec (which only lists the 8 most common ones).

This has been a highly requested feature and is also the first open source encoder
to support this many layouts.

Many thanks to pkviet <pkv.stream@gmail.com> who implemented support for and
verified all channel layouts.

1 files changed, 285 insertions, 1 deletions

diff --git a/libavcodec/aacenc.h b/libavcodec/aacenc.h
index ea2d3b9628..5a015ca92e 100644
--- a/libavcodec/aacenc.h
+++ b/libavcodec/aacenc.h
@@ -45,6 +45,7 @@ typedef struct AACEncOptions {
     int pns;
     int tns;
     int ltp;
+    int pce;
     int pred;
     int mid_side;
     int intensity_stereo;
@@ -89,6 +90,286 @@ typedef struct AACQuantizeBandCostCacheEntry {
     uint16_t generation;
 } AACQuantizeBandCostCacheEntry;
 
+typedef struct AACPCEInfo {
+    int64_t layout;
+    int num_ele[4];                              ///< front, side, back, lfe
+    int pairing[3][8];                           ///< front, side, back
+    int index[4][8];                             ///< front, side, back, lfe
+    uint8_t config_map[16];                      ///< configs the encoder's channel specific settings
+    uint8_t reorder_map[16];                     ///< maps channels from lavc to aac order
+} AACPCEInfo;
+
+/**
+ * List of PCE (Program Configuration Element) for the channel layouts listed
+ * in channel_layout.h
+ *
+ * For those wishing in the future to add other layouts:
+ *
+ * - num_ele: number of elements in each group of front, side, back, lfe channels
+ *            (an element is of type SCE (single channel), CPE (channel pair) for
+ *            the first 3 groups; and is LFE for LFE group).
+ *
+ * - pairing: 0 for an SCE element or 1 for a CPE; does not apply to LFE group
+ *
+ * - index: there are three independent indices for SCE, CPE and LFE;
+ *     they are incremented irrespective of the group to which the element belongs;
+ *     they are not reset when going from one group to another
+ *
+ *     Example: for 7.0 channel layout,
+ *        .pairing = { { 1, 0 }, { 1 }, { 1 }, }, (3 CPE and 1 SCE in front group)
+ *        .index = { { 0, 0 }, { 1 }, { 2 }, },
+ *               (index is 0 for the single SCE but goes from 0 to 2 for the CPEs)
+ *
+ *     The index order impacts the channel ordering. But is otherwise arbitrary
+ *     (the sequence could have been 2, 0, 1 instead of 0, 1, 2).
+ *
+ *     Spec allows for discontinuous indices, e.g. if one has a total of two SCE,
+ *     SCE.0 SCE.15 is OK per spec; BUT it won't be decoded by our AAC decoder
+ *     which at this time requires that indices fully cover some range starting
+ *     from 0 (SCE.1 SCE.0 is OK but not SCE.0 SCE.15).
+ *
+ * - config_map: total number of elements and their types. Beware, the way the
+ *               types are ordered impacts the final channel ordering.
+ *
+ * - reorder_map: reorders the channels.
+ *
+ */
+static const AACPCEInfo aac_pce_configs[] = {
+    {
+        .layout = AV_CH_LAYOUT_MONO,
+        .num_ele = { 1, 0, 0, 0 },
+        .pairing = { { 0 }, },
+        .index = { { 0 }, },
+        .config_map = { 1, TYPE_SCE, },
+        .reorder_map = { 0 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_STEREO,
+        .num_ele = { 1, 0, 0, 0 },
+        .pairing = { { 1 }, },
+        .index = { { 0 }, },
+        .config_map = { 1, TYPE_CPE, },
+        .reorder_map = { 0, 1 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_2POINT1,
+        .num_ele = { 1, 0, 0, 1 },
+        .pairing = { { 1 }, },
+        .index = { { 0 },{ 0 },{ 0 },{ 0 } },
+        .config_map = { 2, TYPE_CPE, TYPE_LFE },
+        .reorder_map = { 0, 1, 2 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_2_1,
+        .num_ele = { 1, 0, 1, 0 },
+        .pairing = { { 1 },{ 0 },{ 0 } },
+        .index = { { 0 },{ 0 },{ 0 }, },
+        .config_map = { 2, TYPE_CPE, TYPE_SCE },
+        .reorder_map = { 0, 1, 2 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_SURROUND,
+        .num_ele = { 2, 0, 0, 0 },
+        .pairing = { { 1, 0 }, },
+        .index = { { 0, 0 }, },
+        .config_map = { 2, TYPE_CPE, TYPE_SCE, },
+        .reorder_map = { 0, 1, 2 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_3POINT1,
+        .num_ele = { 2, 0, 0, 1 },
+        .pairing = { { 1, 0 }, },
+        .index = { { 0, 0 }, { 0 }, { 0 }, { 0 }, },
+        .config_map = { 3, TYPE_CPE, TYPE_SCE, TYPE_LFE },
+        .reorder_map = { 0, 1, 2, 3 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_4POINT0,
+        .num_ele = { 2, 0, 1, 0 },
+        .pairing = { { 1, 0 }, { 0 }, { 0 }, },
+        .index = { { 0, 0 }, { 0 }, { 1 } },
+        .config_map = { 3, TYPE_CPE, TYPE_SCE, TYPE_SCE },
+        .reorder_map = {  0, 1, 2, 3 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_4POINT1,
+        .num_ele = { 2, 1, 1, 0 },
+        .pairing = { { 1, 0 }, { 0 }, { 0 }, },
+        .index = { { 0, 0 }, { 1 }, { 2 }, { 0 } },
+        .config_map = { 4, TYPE_CPE, TYPE_SCE, TYPE_SCE, TYPE_SCE },
+        .reorder_map = { 0, 1, 2, 3, 4 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_2_2,
+        .num_ele = { 1, 1, 0, 0 },
+        .pairing = { { 1 }, { 1 }, },
+        .index = { { 0 }, { 1 }, },
+        .config_map = { 2, TYPE_CPE, TYPE_CPE },
+        .reorder_map = { 0, 1, 2, 3 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_QUAD,
+        .num_ele = { 1, 0, 1, 0 },
+        .pairing = { { 1 }, { 0 }, { 1 }, },
+        .index = { { 0 }, { 0 }, { 1 } },
+        .config_map = { 2, TYPE_CPE, TYPE_CPE },
+        .reorder_map = { 0, 1, 2, 3 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_5POINT0,
+        .num_ele = { 2, 1, 0, 0 },
+        .pairing = { { 1, 0 }, { 1 }, },
+        .index = { { 0, 0 }, { 1 } },
+        .config_map = { 3, TYPE_CPE, TYPE_SCE, TYPE_CPE },
+        .reorder_map = { 0, 1, 2, 3, 4 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_5POINT1,
+        .num_ele = { 2, 1, 1, 0 },
+        .pairing = { { 1, 0 }, { 0 }, { 1 }, },
+        .index = { { 0, 0 }, { 1 }, { 1 } },
+        .config_map = { 4, TYPE_CPE, TYPE_SCE, TYPE_SCE, TYPE_CPE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_5POINT0_BACK,
+        .num_ele = { 2, 0, 1, 0 },
+        .pairing = { { 1, 0 }, { 0 }, { 1 } },
+        .index = { { 0, 0 }, { 0 }, { 1 } },
+        .config_map = { 3, TYPE_CPE, TYPE_SCE, TYPE_CPE },
+        .reorder_map = { 0, 1, 2, 3, 4 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_5POINT1_BACK,
+        .num_ele = { 2, 1, 1, 0 },
+        .pairing = { { 1, 0 }, { 0 }, { 1 }, },
+        .index = { { 0, 0 }, { 1 }, { 1 } },
+        .config_map = { 4, TYPE_CPE, TYPE_SCE, TYPE_SCE, TYPE_CPE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_6POINT0,
+        .num_ele = { 2, 1, 1, 0 },
+        .pairing = { { 1, 0 }, { 1 }, { 0 }, },
+        .index = { { 0, 0 }, { 1 }, { 1 } },
+        .config_map = { 4, TYPE_CPE, TYPE_SCE, TYPE_CPE, TYPE_SCE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_6POINT0_FRONT,
+        .num_ele = { 2, 1, 0, 0 },
+        .pairing = { { 1, 1 }, { 1 } },
+        .index = { { 1, 0 }, { 2 }, },
+        .config_map = { 3, TYPE_CPE, TYPE_CPE, TYPE_CPE, },
+        .reorder_map = { 0, 1, 2, 3, 4, 5 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_HEXAGONAL,
+        .num_ele = { 2, 0, 2, 0 },
+        .pairing = { { 1, 0 },{ 0 },{ 1, 0 }, },
+        .index = { { 0, 0 },{ 0 },{ 1, 1 } },
+        .config_map = { 4, TYPE_CPE, TYPE_SCE, TYPE_CPE, TYPE_SCE, },
+        .reorder_map = { 0, 1, 2, 3, 4, 5 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_6POINT1,
+        .num_ele = { 2, 1, 2, 0 },
+        .pairing = { { 1, 0 },{ 0 },{ 1, 0 }, },
+        .index = { { 0, 0 },{ 1 },{ 1, 2 } },
+        .config_map = { 5, TYPE_CPE, TYPE_SCE, TYPE_SCE, TYPE_CPE, TYPE_SCE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_6POINT1_BACK,
+        .num_ele = { 2, 1, 2, 0 },
+        .pairing = { { 1, 0 }, { 0 }, { 1, 0 }, },
+        .index = { { 0, 0 }, { 1 }, { 1, 2 } },
+        .config_map = { 5, TYPE_CPE, TYPE_SCE, TYPE_SCE, TYPE_CPE, TYPE_SCE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_6POINT1_FRONT,
+        .num_ele = { 2, 1, 2, 0 },
+        .pairing = { { 1, 0 }, { 0 }, { 1, 0 }, },
+        .index = { { 0, 0 }, { 1 }, { 1, 2 } },
+        .config_map = { 5, TYPE_CPE, TYPE_SCE, TYPE_SCE, TYPE_CPE, TYPE_SCE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_7POINT0,
+        .num_ele = { 2, 1, 1, 0 },
+        .pairing = { { 1, 0 }, { 1 }, { 1 }, },
+        .index = { { 0, 0 }, { 1 }, { 2 }, },
+        .config_map = { 4, TYPE_CPE, TYPE_SCE, TYPE_CPE, TYPE_CPE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_7POINT0_FRONT,
+        .num_ele = { 2, 1, 1, 0 },
+        .pairing = { { 1, 0 }, { 1 }, { 1 }, },
+        .index = { { 0, 0 }, { 1 }, { 2 }, },
+        .config_map = { 4, TYPE_CPE, TYPE_SCE, TYPE_CPE, TYPE_CPE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_7POINT1,
+        .num_ele = { 2, 1, 2, 0 },
+        .pairing = { { 1, 0 }, { 0 }, { 1, 1 }, },
+        .index = { { 0, 0 }, { 1 }, { 1, 2 }, { 0 } },
+        .config_map = { 5, TYPE_CPE, TYPE_SCE,  TYPE_SCE, TYPE_CPE, TYPE_CPE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6, 7 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_7POINT1_WIDE,
+        .num_ele = { 2, 1, 2, 0 },
+        .pairing = { { 1, 0 }, { 0 },{  1, 1 }, },
+        .index = { { 0, 0 }, { 1 }, { 1, 2 }, { 0 } },
+        .config_map = { 5, TYPE_CPE, TYPE_SCE, TYPE_SCE, TYPE_CPE, TYPE_CPE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6, 7 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_7POINT1_WIDE_BACK,
+        .num_ele = { 2, 1, 2, 0 },
+        .pairing = { { 1, 0 }, { 0 }, { 1, 1 }, },
+        .index = { { 0, 0 }, { 1 }, { 1, 2 }, { 0 } },
+        .config_map = { 5, TYPE_CPE, TYPE_SCE, TYPE_SCE, TYPE_CPE, TYPE_CPE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6, 7 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_OCTAGONAL,
+        .num_ele = { 2, 1, 2, 0 },
+        .pairing = { { 1, 0 }, { 1 }, { 1, 0 }, },
+        .index = { { 0, 0 }, { 1 }, { 2, 1 } },
+        .config_map = { 5, TYPE_CPE, TYPE_SCE, TYPE_CPE, TYPE_CPE, TYPE_SCE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6, 7 },
+    },
+    {   /* Meant for order 2/mixed ambisonics */
+        .layout = AV_CH_LAYOUT_OCTAGONAL | AV_CH_TOP_CENTER,
+        .num_ele = { 2, 2, 2, 0 },
+        .pairing = { { 1, 0 }, { 1, 0 }, { 1, 0 }, },
+        .index = { { 0, 0 }, { 1, 1 }, { 2, 2 } },
+        .config_map = { 6, TYPE_CPE, TYPE_SCE, TYPE_CPE, TYPE_SCE, TYPE_CPE, TYPE_SCE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6, 7, 8 },
+    },
+    {   /* Meant for order 2/mixed ambisonics */
+        .layout = AV_CH_LAYOUT_6POINT0_FRONT | AV_CH_BACK_CENTER |
+                  AV_CH_BACK_LEFT | AV_CH_BACK_RIGHT | AV_CH_TOP_CENTER,
+        .num_ele = { 2, 2, 2, 0 },
+        .pairing = { { 1, 1 }, { 1, 0 }, { 1, 0 }, },
+        .index = { { 0, 1 }, { 2, 0 }, { 3, 1 } },
+        .config_map = { 6, TYPE_CPE, TYPE_CPE, TYPE_CPE, TYPE_SCE, TYPE_CPE, TYPE_SCE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
+    },
+    {
+        .layout = AV_CH_LAYOUT_HEXADECAGONAL,
+        .num_ele = { 4, 2, 4, 0 },
+        .pairing = { { 1, 0, 1, 0 }, { 1, 1 }, { 1, 0, 1, 0 }, },
+        .index = { { 0, 0, 1, 1 }, { 2, 3 }, { 4, 2, 5, 3 } },
+        .config_map = { 10, TYPE_CPE, TYPE_SCE, TYPE_CPE, TYPE_SCE, TYPE_CPE, TYPE_CPE, TYPE_CPE, TYPE_SCE, TYPE_CPE, TYPE_SCE },
+        .reorder_map = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
+    },
+};
+
 /**
  * AAC encoder context
  */
@@ -99,12 +380,15 @@ typedef struct AACEncContext {
     FFTContext mdct1024;                         ///< long (1024 samples) frame transform context
     FFTContext mdct128;                          ///< short (128 samples) frame transform context
     AVFloatDSPContext *fdsp;
-    float *planar_samples[8];                    ///< saved preprocessed input
+    AACPCEInfo pce;                              ///< PCE data, if needed
+    float *planar_samples[16];                   ///< saved preprocessed input
 
     int profile;                                 ///< copied from avctx
+    int needs_pce;                               ///< flag for non-standard layout
     LPCContext lpc;                              ///< used by TNS
     int samplerate_index;                        ///< MPEG-4 samplerate index
     int channels;                                ///< channel count
+    const uint8_t *reorder_map;                  ///< lavc to aac reorder map
     const uint8_t *chan_map;                     ///< channel configuration map
 
     ChannelElement *cpe;                         ///< channel elements