Add support for Workgroup 4 (WG4) channel mapping

This is the channel ordering used in DVD Audio, and is the standard
used internally in the VLC media player.

libAACenc/src/aacenc.h

@@ -174,7 +174,8 @@ typedef enum {
 typedef enum {
 
   CH_ORDER_MPEG = 0,  /*!< MPEG channel ordering (e. g. 5.1: C, L, R, SL, SR, LFE)           */
-  CH_ORDER_WAV        /*!< WAV fileformat channel ordering (e. g. 5.1: L, R, C, LFE, SL, SR) */
+  CH_ORDER_WAV,       /*!< WAV fileformat channel ordering (e. g. 5.1: L, R, C, LFE, SL, SR) */
+  CH_ORDER_WG4        /*!< WG4 fileformat channel ordering (e. g. 5.1: L, R, SL, SR, C, LFE) */
 
 } CHANNEL_ORDER;
 

libAACenc/src/aacenc_lib.cpp

@@ -1657,7 +1657,7 @@ AACENC_ERROR aacEncoder_SetParam(
         break;
     case AACENC_CHANNELORDER:
         if (hAacEncoder->aacConfig.channelOrder != (CHANNEL_ORDER)value) {
-            if (! ((value==0) || (value==1)) ) {
+            if (! ((value==0) || (value==1) || (value==2)) ) {
                 err = AACENC_INVALID_CONFIG;
                 break;
             }

libAACenc/src/channel_map.cpp

@@ -153,6 +153,18 @@ static const CHANNEL_ASSIGNMENT_INFO_TAB assignmentInfoTabWav[] =
      { MODE_1_2_2_2_1,               { 2, 0, 1, 6, 7, 4, 5, 3,-1,-1,-1,-1} },  /*  7.1ch     */
 };
 
+static const CHANNEL_ASSIGNMENT_INFO_TAB assignmentInfoTabWg4[] =
+{
+     { MODE_INVALID,                 {-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1} },  /*  invalid   */
+     { MODE_1,                       { 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1} },  /*  mono      */
+     { MODE_2,                       { 0, 1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1} },  /*  stereo    */
+     { MODE_1_2,                     { 2, 0, 1,-1,-1,-1,-1,-1,-1,-1,-1,-1} },  /*  3ch       */
+     { MODE_1_2_1,                   { 3, 0, 1, 2,-1,-1,-1,-1,-1,-1,-1,-1} },  /*  4ch       */
+     { MODE_1_2_2,                   { 4, 0, 1, 2, 3,-1,-1,-1,-1,-1,-1,-1} },  /*  5ch       */
+     { MODE_1_2_2_1,                 { 4, 0, 1, 2, 3, 5,-1,-1,-1,-1,-1,-1} },  /*  5.1ch     */
+     { MODE_1_2_2_2_1,               { 6, 0, 1, 2, 3, 4, 5, 7,-1,-1,-1,-1} },  /*  7.1ch     */
+};
+
 /* Channel mode configuration tab provides,
    corresponding number of channels and elements
 */
@@ -176,8 +188,10 @@ const INT* FDKaacEnc_getChannelAssignment(CHANNEL_MODE encMode, CHANNEL_ORDER co
 
   if (co == CH_ORDER_MPEG)
     pTab = assignmentInfoTabMpeg;
-  else
+  else if (co == CH_ORDER_WAV)
     pTab = assignmentInfoTabWav;
+  else
+    pTab = assignmentInfoTabWg4;
 
   for(i=MAX_MODES-1; i>0; i--) {
     if (encMode== pTab[i].encoderMode) {