avi: Spin out the logic to position to the next non-interleaved stream

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

libavformat/avidec.c

@@ -1094,21 +1094,9 @@ start_sync:
     return AVERROR_EOF;
 }
 
-static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
+static int ni_prepare_read(AVFormatContext *s)
 {
     AVIContext *avi = s->priv_data;
-    AVIOContext *pb = s->pb;
-    int err;
-
-    if (CONFIG_DV_DEMUXER && avi->dv_demux) {
-        int size = avpriv_dv_get_packet(avi->dv_demux, pkt);
-        if (size >= 0)
-            return size;
-        else
-            goto resync;
-    }
-
-    if (avi->non_interleaved) {
     int best_stream_index = 0;
     AVStream *best_st     = NULL;
     AVIStream *best_ast;
@@ -1171,6 +1159,28 @@ static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
             best_ast->packet_size =
             best_ast->remaining   = best_st->index_entries[i].size;
     }
+
+    return 0;
+}
+
+static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    AVIContext *avi = s->priv_data;
+    AVIOContext *pb = s->pb;
+    int err;
+
+    if (CONFIG_DV_DEMUXER && avi->dv_demux) {
+        int size = avpriv_dv_get_packet(avi->dv_demux, pkt);
+        if (size >= 0)
+            return size;
+        else
+            goto resync;
+    }
+
+    if (avi->non_interleaved) {
+        err = ni_prepare_read(s);
+        if (err < 0)
+            return err;
     }
 
 resync: