xa: fix timestamp calculation

The packet duration is always 28 samples.

libavformat/xa.c

@@ -38,7 +38,6 @@
 typedef struct MaxisXADemuxContext {
     uint32_t out_size;
     uint32_t sent_bytes;
-    uint32_t audio_frame_counter;
 } MaxisXADemuxContext;
 
 static int xa_probe(AVProbeData *p)
@@ -87,6 +86,7 @@ static int xa_read_header(AVFormatContext *s)
     st->codec->bits_per_coded_sample = avio_rl16(pb);
 
     avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
+    st->start_time = 0;
 
     return 0;
 }
@@ -111,9 +111,7 @@ static int xa_read_packet(AVFormatContext *s,
 
     pkt->stream_index = st->index;
     xa->sent_bytes += packet_size;
-    pkt->pts = xa->audio_frame_counter;
-    /* 14 bytes Samples per channel with 2 samples per byte */
-    xa->audio_frame_counter += 28 * st->codec->channels;
+    pkt->duration = 28;
 
     return ret;
 }

tests/ref/fate/maxis-xa

@@ -1,31 +1,31 @@
 #tb 0: 1/22050
-0,          0,          0,        0,       30, 0x51750711
-0,         56,         56,        0,       30, 0x9ca20c2a
-0,        112,        112,        0,       30, 0x7551081f
-0,        168,        168,        0,       30, 0x09540063
-0,        224,        224,        0,       30, 0x02c40018
-0,        280,        280,        0,       30, 0x0f6c0117
-0,        336,        336,        0,       30, 0x2aab0315
-0,        392,        392,        0,       30, 0x0e6d0117
-0,        448,        448,        0,       30, 0x04770036
-0,        504,        504,        0,       30, 0x939c090f
-0,        560,        560,        0,       30, 0xde511116
-0,        616,        616,        0,       30, 0x2f0f13f5
-0,        672,        672,        0,       30, 0x65bb0630
-0,        728,        728,        0,       30, 0x1f7a0333
-0,        784,        784,        0,       30, 0xa3d71008
-0,        840,        840,        0,       30, 0x69120801
-0,        896,        896,        0,       30, 0x1e7b0207
-0,        952,        952,        0,       30, 0x02c40018
-0,       1008,       1008,        0,       30, 0x0d050126
-0,       1064,       1064,        0,       30, 0x41c10333
-0,       1120,       1120,        0,       30, 0x16a10207
-0,       1176,       1176,        0,       30, 0x0f210207
-0,       1232,       1232,        0,       30, 0x4e4b073e
-0,       1288,       1288,        0,       30, 0xa6f20d1a
-0,       1344,       1344,        0,       30, 0xe1e40ff9
-0,       1400,       1400,        0,       30, 0x868b090f
-0,       1456,       1456,        0,       30, 0x8c85091e
-0,       1512,       1512,        0,       30, 0x5a21094b
-0,       1568,       1568,        0,       30, 0x993c0900
-0,       1624,       1624,        0,       30, 0x5b6b04e6
+0,          0,          0,       28,       30, 0x51750711
+0,         28,         28,       28,       30, 0x9ca20c2a
+0,         56,         56,       28,       30, 0x7551081f
+0,         84,         84,       28,       30, 0x09540063
+0,        112,        112,       28,       30, 0x02c40018
+0,        140,        140,       28,       30, 0x0f6c0117
+0,        168,        168,       28,       30, 0x2aab0315
+0,        196,        196,       28,       30, 0x0e6d0117
+0,        224,        224,       28,       30, 0x04770036
+0,        252,        252,       28,       30, 0x939c090f
+0,        280,        280,       28,       30, 0xde511116
+0,        308,        308,       28,       30, 0x2f0f13f5
+0,        336,        336,       28,       30, 0x65bb0630
+0,        364,        364,       28,       30, 0x1f7a0333
+0,        392,        392,       28,       30, 0xa3d71008
+0,        420,        420,       28,       30, 0x69120801
+0,        448,        448,       28,       30, 0x1e7b0207
+0,        476,        476,       28,       30, 0x02c40018
+0,        504,        504,       28,       30, 0x0d050126
+0,        532,        532,       28,       30, 0x41c10333
+0,        560,        560,       28,       30, 0x16a10207
+0,        588,        588,       28,       30, 0x0f210207
+0,        616,        616,       28,       30, 0x4e4b073e
+0,        644,        644,       28,       30, 0xa6f20d1a
+0,        672,        672,       28,       30, 0xe1e40ff9
+0,        700,        700,       28,       30, 0x868b090f
+0,        728,        728,       28,       30, 0x8c85091e
+0,        756,        756,       28,       30, 0x5a21094b
+0,        784,        784,       28,       30, 0x993c0900
+0,        812,        812,       28,       30, 0x5b6b04e6