From 75549414927212d4d1666730133805b33447de79 Mon Sep 17 00:00:00 2001
From: John Stebbins <jstebbins.hb@gmail.com>
Date: Tue, 3 Nov 2015 10:16:01 -0800
Subject: [PATCH] muxavformat: add support for mp4 fallback audio signalling

---
diff --git a/libhb/muxavformat.c b/libhb/muxavformat.c
index 0d70597..373c2ab 100644
--- a/libhb/muxavformat.c
+++ b/libhb/muxavformat.c
@@ -121,7 +121,7 @@ static int avformatInit( hb_mux_object_t * m )
     hb_mux_data_t * track;
     int meta_mux;
     int max_tracks;
-    int ii, ret;
+    int ii, jj, ret;
 
     int clock_min, clock_max, clock;
     hb_video_framerate_get_limits(&clock_min, &clock_max, &clock);
@@ -589,6 +589,56 @@ static int avformatInit( hb_mux_object_t * m )
         }
     }
 
+    // Check for audio track associations
+    for (ii = 0; ii < hb_list_count(job->list_audio); ii++)
+    {
+        audio = hb_list_item(job->list_audio, ii);
+        switch (audio->config.out.codec & HB_ACODEC_MASK)
+        {
+            case HB_ACODEC_FFAAC:
+            case HB_ACODEC_CA_AAC:
+            case HB_ACODEC_CA_HAAC:
+            case HB_ACODEC_FDK_AAC:
+            case HB_ACODEC_FDK_HAAC:
+                break;
+
+            default:
+            {
+                // Mark associated fallback audio tracks for any non-aac track
+                for(jj = 0; jj < hb_list_count( job->list_audio ); jj++ )
+                {
+                    hb_audio_t    * fallback;
+                    int             codec;
+
+                    if (ii == jj) continue;
+
+                    fallback = hb_list_item( job->list_audio, jj );
+                    codec = fallback->config.out.codec & HB_ACODEC_MASK;
+                    if (fallback->config.in.track == audio->config.in.track &&
+                        (codec == HB_ACODEC_FFAAC ||
+                         codec == HB_ACODEC_CA_AAC ||
+                         codec == HB_ACODEC_CA_HAAC ||
+                         codec == HB_ACODEC_FDK_AAC ||
+                         codec == HB_ACODEC_FDK_HAAC))
+                    {
+                        hb_mux_data_t * fallback_track;
+                        int           * sd;
+
+                        track = audio->priv.mux_data;
+                        fallback_track = fallback->priv.mux_data;
+                        sd = (int*)av_stream_new_side_data(track->st,
+                                                     AV_PKT_DATA_FALLBACK_TRACK,
+                                                     sizeof(int));
+                        if (sd != NULL)
+                        {
+                            *sd = fallback_track->st->index;
+                        }
+                    }
+                }
+            } break;
+        }
+    }
+
     char * subidx_fmt =
         "size: %dx%d\n"
         "org: %d, %d\n"