psx-str: fix audio pts

Each packet has 18 sectors with 224/channels samples in each sector.

libavformat/psxstr.c

@@ -224,7 +224,9 @@ static int str_read_packet(AVFormatContext *s,
             //    st->codec->bit_rate = 0; //FIXME;
                 st->codec->block_align = 128;
 
-                avpriv_set_pts_info(st, 64, 128, st->codec->sample_rate);
+                avpriv_set_pts_info(st, 64, 18 * 224 / st->codec->channels,
+                                    st->codec->sample_rate);
+                st->start_time = 0;
             }
             pkt = ret_pkt;
             if (av_new_packet(pkt, 2304))
@@ -233,6 +235,7 @@ static int str_read_packet(AVFormatContext *s,
 
             pkt->stream_index =
                 str->channels[channel].audio_stream_index;
+            pkt->duration = 1;
             return 0;
         default:
             av_log(s, AV_LOG_WARNING, "Unknown sector type %02X\n", sector[0x12]);