[FFmpeg-devel] [PATCH 7/7] avcodec/aacdec_template: add support for 22.2 / channel_config 13

[Jan Ekström]

---
 libavcodec/aacdec_template.c | 89 +++++++++++++++++++++++++++++++-----
 1 file changed, 78 insertions(+), 11 deletions(-)

diff --git a/libavcodec/aacdec_template.c b/libavcodec/aacdec_template.c
index 21db12fdab..8c5048cc13 100644
--- a/libavcodec/aacdec_template.c
+++ b/libavcodec/aacdec_template.c
@@ -387,17 +387,77 @@ static uint64_t sniff_channel_order(uint8_t (*layout_map)[3], int tags)
         i++;
     }
 
-    // Must choose a stable sort
+    // The previous checks would end up at 8 at this point for 22.2
+    if (tags == 16 && i == 8) {
+        e2c_vec[i] = (struct elem_to_channel) {
+            .av_position  = AV_CH_TOP_FRONT_CENTER,
+            .syn_ele      = layout_map[i][0],
+            .elem_id      = layout_map[i][1],
+            .aac_position = layout_map[i][2]
+        }; i++;
+        i += assign_pair(e2c_vec, layout_map, i,
+                         AV_CH_TOP_FRONT_LEFT,
+                         AV_CH_TOP_FRONT_RIGHT,
+                         AAC_CHANNEL_FRONT);
+        i += assign_pair(e2c_vec, layout_map, i,
+                         AV_CH_TOP_SIDE_LEFT,
+                         AV_CH_TOP_SIDE_RIGHT,
+                         AAC_CHANNEL_SIDE);
+        e2c_vec[i] = (struct elem_to_channel) {
+            .av_position  = AV_CH_TOP_CENTER,
+            .syn_ele      = layout_map[i][0],
+            .elem_id      = layout_map[i][1],
+            .aac_position = layout_map[i][2]
+        }; i++;
+        i += assign_pair(e2c_vec, layout_map, i,
+                         AV_CH_TOP_BACK_LEFT,
+                         AV_CH_TOP_BACK_RIGHT,
+                         AAC_CHANNEL_BACK);
+        e2c_vec[i] = (struct elem_to_channel) {
+            .av_position  = AV_CH_TOP_BACK_CENTER,
+            .syn_ele      = layout_map[i][0],
+            .elem_id      = layout_map[i][1],
+            .aac_position = layout_map[i][2]
+        }; i++;
+        e2c_vec[i] = (struct elem_to_channel) {
+            .av_position  = AV_CH_BOTTOM_FRONT_CENTER,
+            .syn_ele      = layout_map[i][0],
+            .elem_id      = layout_map[i][1],
+            .aac_position = layout_map[i][2]
+        }; i++;
+        i += assign_pair(e2c_vec, layout_map, i,
+                         AV_CH_BOTTOM_FRONT_LEFT,
+                         AV_CH_BOTTOM_FRONT_RIGHT,
+                         AAC_CHANNEL_FRONT);
+    }
+
     total_non_cc_elements = n = i;
-    do {
-        int next_n = 0;
-        for (i = 1; i < n; i++)
-            if (e2c_vec[i - 1].av_position > e2c_vec[i].av_position) {
-                FFSWAP(struct elem_to_channel, e2c_vec[i - 1], e2c_vec[i]);
-                next_n = i;
-            }
-        n = next_n;
-    } while (n > 0);
+
+    if (tags == 16 && total_non_cc_elements == 16) {
+        // For 22.2 reorder the result as needed
+        FFSWAP(struct elem_to_channel, e2c_vec[2], e2c_vec[0]);   // FL & FR first (final), FC third
+        FFSWAP(struct elem_to_channel, e2c_vec[2], e2c_vec[1]);   // FC second (final), FLc & FRc third
+        FFSWAP(struct elem_to_channel, e2c_vec[6], e2c_vec[2]);   // LFE1 third (final), FLc & FRc seventh
+        FFSWAP(struct elem_to_channel, e2c_vec[4], e2c_vec[3]);   // BL & BR fourth (final), SiL & SiR fifth
+        FFSWAP(struct elem_to_channel, e2c_vec[6], e2c_vec[4]);   // FLc & FRc fifth (final), SiL & SiR seventh
+        FFSWAP(struct elem_to_channel, e2c_vec[7], e2c_vec[6]);   // LFE2 seventh (final), SiL & SiR eight (final)
+        FFSWAP(struct elem_to_channel, e2c_vec[9], e2c_vec[8]);   // TpFL & TpFR ninth (final), TFC tenth (final)
+        FFSWAP(struct elem_to_channel, e2c_vec[11], e2c_vec[10]); // TC eleventh (final), TpSiL & TpSiR twelth
+        FFSWAP(struct elem_to_channel, e2c_vec[12], e2c_vec[11]); // TpBL & TpBR twelth (final), TpSiL & TpSiR thirteenth (final)
+    } else {
+        // For everything else, utilize the AV channel position define as a
+        // stable sort.
+        do {
+            int next_n = 0;
+            for (i = 1; i < n; i++)
+                if (e2c_vec[i - 1].av_position > e2c_vec[i].av_position) {
+                    FFSWAP(struct elem_to_channel, e2c_vec[i - 1], e2c_vec[i]);
+                    next_n = i;
+                }
+            n = next_n;
+        } while (n > 0);
+
+    }
 
     layout = 0;
     for (i = 0; i < total_non_cc_elements; i++) {
@@ -535,7 +595,7 @@ static int set_default_channel_config(AACContext *ac, AVCodecContext *avctx,
                                       int channel_config)
 {
     if (channel_config < 1 || (channel_config > 7 && channel_config < 11) ||
-        channel_config > 12) {
+        channel_config > 13) {
         av_log(avctx, AV_LOG_ERROR,
                "invalid default channel configuration (%d)\n",
                channel_config);
@@ -615,6 +675,13 @@ static ChannelElement *get_che(AACContext *ac, int type, int elem_id)
     /* For indexed channel configurations map the channels solely based
      * on position. */
     switch (ac->oc[1].m4ac.chan_config) {
+    case 13:
+        if (ac->tags_mapped > 3 && ((type == TYPE_CPE && elem_id < 8) ||
+                                    (type == TYPE_SCE && elem_id < 6) ||
+                                    (type == TYPE_LFE && elem_id < 2))) {
+            ac->tags_mapped++;
+            return ac->tag_che_map[type][elem_id] = ac->che[type][elem_id];
+        }
     case 12:
     case 7:
         if (ac->tags_mapped == 3 && type == TYPE_CPE) {
-- 
2.26.2