avformat/matroskadec, mov: Fix declaration-after-statement warnings

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavformat/matroskadec.c

@@ -4542,14 +4542,13 @@ static int64_t webm_dash_manifest_compute_bandwidth(AVFormatContext *s, int64_t
         int64_t pre_bytes, pre_ns;
         double pre_sec, prebuffer, bits_per_second;
         CueDesc desc_beg = get_cue_desc(s, time_ns, cues_start);
+        // Start with the first Cue.
+        CueDesc desc_end = desc_beg;
 
         if (time_ns > INT64_MAX - prebuffer_ns)
             return -1;
         prebuffered_ns = time_ns + prebuffer_ns;
 
-        // Start with the first Cue.
-        CueDesc desc_end = desc_beg;
-
         // Figure out how much data we have downloaded for the prebuffer. This will
         // be used later to adjust the bits per sample to try.
         while (desc_end.start_time_ns != -1 && desc_end.end_time_ns < prebuffered_ns) {

libavformat/mov.c

@@ -4903,9 +4903,9 @@ static int avif_add_stream(MOVContext *c, int item_id)
 {
     MOVStreamContext *sc;
     AVStream *st;
+    int item_index = -1;
     if (c->fc->nb_streams)
         return AVERROR_INVALIDDATA;
-    int item_index = -1;
     for (int i = 0; i < c->avif_info_size; i++)
         if (c->avif_info[i].item_id == item_id) {
             item_index = i;