Fix large timebases.

Fixed issue1633

Originally committed as revision 21636 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h264.c

@@ -1781,11 +1781,11 @@ static int decode_slice_header(H264Context *h, H264Context *h0){
         }
 
         if(h->sps.timing_info_present_flag){
-            s->avctx->time_base= (AVRational){h->sps.num_units_in_tick, h->sps.time_scale};
+            int64_t den= h->sps.time_scale;
             if(h->x264_build > 0 && h->x264_build < 44)
-                s->avctx->time_base.den *= 2;
+                den *= 2;
             av_reduce(&s->avctx->time_base.num, &s->avctx->time_base.den,
-                      s->avctx->time_base.num, s->avctx->time_base.den, 1<<30);
+                      h->sps.num_units_in_tick, den, 1<<30);
         }
         s->avctx->pix_fmt = s->avctx->get_format(s->avctx, s->avctx->codec->pix_fmts);
         s->avctx->hwaccel = ff_find_hwaccel(s->avctx->codec->id, s->avctx->pix_fmt);

libavcodec/h264_ps.c

@@ -176,7 +176,7 @@ static inline int decode_vui_parameters(H264Context *h, SPS *sps){
     if(sps->timing_info_present_flag){
         sps->num_units_in_tick = get_bits_long(&s->gb, 32);
         sps->time_scale = get_bits_long(&s->gb, 32);
-        if(sps->num_units_in_tick-1 > 0x7FFFFFFEU || sps->time_scale-1 > 0x7FFFFFFEU){
+        if(!sps->num_units_in_tick || !sps->time_scale){
             av_log(h->s.avctx, AV_LOG_ERROR, "time_scale/num_units_in_tick invalid or unsupported (%d/%d)\n", sps->time_scale, sps->num_units_in_tick);
             return -1;
         }