avoid initializing pts for not decoded streams

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@2284 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

ffmpeg.c

@@ -1121,6 +1121,7 @@ static int av_encode(AVFormatContext **output_files,
         ist = ist_table[i];
 	is = input_files[ist->file_index];
         ist->pts = 0;
+        if (ist->decoding_needed) {
             switch (ist->st->codec.codec_type) {
             case CODEC_TYPE_AUDIO:
                 av_frac_init(&ist->next_pts, 
@@ -1134,6 +1135,7 @@ static int av_encode(AVFormatContext **output_files,
                 break;
             }
         }
+    }
     
     /* compute buffer size max (should use a complete heuristic) */
     for(i=0;i<nb_input_files;i++) {