Make ffprobe show stream->nb_frames if that info is known.

Patch by Robert Krüger $(echo kru3g3r@signal7.d3 | sed -e 's/3/e/g').

Originally committed as revision 22964 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffprobe.c

@@ -190,6 +190,8 @@ static void show_stream(AVFormatContext *fmt_ctx, int stream_idx)
                                                   &stream->time_base));
     printf("duration=%s\n",     time_value_string(val_str, sizeof(val_str), stream->duration,
                                                   &stream->time_base));
+    if (stream->nb_frames)
+        printf("nb_frames=%"PRId64"\n",    stream->nb_frames);
 
     while ((tag = av_metadata_get(stream->metadata, "", tag, AV_METADATA_IGNORE_SUFFIX)))
         printf("TAG:%s=%s\n", tag->key, tag->value);