Fixing seek in fMP4 files.

Author: srikanth-descript

libavformat/mov.c

@@ -85,6 +85,7 @@ typedef struct MOVParseTableEntry {
 static int mov_read_default(MOVContext *c, AVIOContext *pb, MOVAtom atom);
 static int mov_read_mfra(MOVContext *c, AVIOContext *f);
 static void mov_free_stream_context(AVFormatContext *s, AVStream *st);
+static int mov_switch_root(AVFormatContext *s, int64_t target, int index);
 static int64_t add_ctts_entry(MOVCtts** ctts_data, unsigned int* ctts_count, unsigned int* allocated_size,
                               int count, int duration);
 
@@ -1653,6 +1654,31 @@ static int64_t get_frag_time(AVFormatContext *s, AVStream *dst_st,
         return frag_stream_info->sidx_pts;
     }
 
+
+    // Check if the requested stream is present in the fragment
+    int exists = 0;
+    for (i = 0; i < frag_index->item[index].nb_stream_info; i++) {
+        if (dst_st->id != frag_index->item[index].stream_info[i].id) {
+            continue;
+        }
+
+        if ( get_stream_info_time(&frag_index->item[index].stream_info[i]) != AV_NOPTS_VALUE) {
+            exists = 1;
+            break;
+        }
+        if ( mov_switch_root(s,-1,index) < 0)
+            return AV_NOPTS_VALUE;
+
+        if ( get_stream_info_time(&frag_index->item[index].stream_info[i]) != AV_NOPTS_VALUE) {
+            exists = 1;
+            break;
+        }
+    }
+
+    if (!exists)
+        return AV_NOPTS_VALUE;
+
+
     for (i = 0; i < frag_index->item[index].nb_stream_info; i++) {
         AVStream *frag_stream = NULL;
         frag_stream_info = &frag_index->item[index].stream_info[i];