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[xine-cvs] CVS: xine-lib/src/demuxers demux_ts.c,1.12,1.13
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From: James Courtier-D. <jcd...@us...> - 2001-09-10 00:55:51
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Update of /cvsroot/xine/xine-lib/src/demuxers
In directory usw-pr-cvs1:/tmp/cvs-serv8441/xine-lib/src/demuxers
Modified Files:
demux_ts.c
Log Message:
Re-wrote re-sync code so that it does not drop any packets.
Index: demux_ts.c
===================================================================
RCS file: /cvsroot/xine/xine-lib/src/demuxers/demux_ts.c,v
retrieving revision 1.12
retrieving revision 1.13
diff -u -r1.12 -r1.13
--- demux_ts.c 2001/09/04 16:19:27 1.12
+++ demux_ts.c 2001/09/10 00:55:48 1.13
@@ -34,6 +34,8 @@
*
* Date Author
* ---- ------
+ * 10-Sep-2001 James Courtier-Dutton <jcdutton>
+ * Re-wrote sync code so that it now does not loose any data.
* 27-Aug-2001 Hubert Matthews Reviewed by: n/a
* Added in synchronisation code.
*
@@ -72,6 +74,9 @@
#define PKT_SIZE 188
#define BODY_SIZE (188 - 4)
#define MAX_PIDS ((BODY_SIZE - 1 - 13) / 4)
+#define SYNC_BYTE 0x47
+#define MIN_SYNCS 5
+#define BUF_SIZE ((MIN_SYNCS+1) * PKT_SIZE)
#define NULL_PID 8191
#define INVALID_PID ((unsigned int)(-1))
@@ -617,114 +622,52 @@
}
}
-/*********************************************************************
- *
- * 2001/08/26 Hubert Matthews
- *
- * Added input synchronisation code. This code ensures synchronisation
- * where possible by checking that we have 5 sync bytes at 188 bytes apart.
- * On startup, it finds the first packet with a sync byte in it and starts
- * buffering after that. It starts to release packets to the demux when it
- * has found five synchronised packets in a row. If sync is broken at any
- * time (bit error or dropped multicast packet, for instance) it dumps all
- * its buffers and attempts to acquire sync again.
- *
- * Returns NULL when it is in buffering mode, and the address of an aligned
- * packet otherwise. NULL causes the calling function to go back around its
- * loop, so its harmless and easier than doing the packet looping internally.
- */
-
-#define SYNC_BYTE 0x47
-#define MIN_SYNCS 5
-#define BUF_SIZE ((MIN_SYNCS+1) * PKT_SIZE)
-#define WRAP_ADD(x, incr, limit) \
- (x) += (incr); \
- if ((x) >= (limit)) (x) -= (limit)
-#define BUMP(x) WRAP_ADD((x), PKT_SIZE, (BUF_SIZE - PKT_SIZE))
-
-/* When we've acquired sync, we need to set all of the continuity
- * counters to an invalid value to disable the sequence checking */
-
-static void resetAllCCs(demux_ts * this) {
- int i;
- for (i = 0; i != MAX_PIDS; ++i)
- this->media[i].counter = INVALID_CC;
-}
-
-/* Find the first sync byte in the packet pointed to by p */
+void correct_for_sync(demux_ts *this,uint8_t *buf) {
+ int32_t n, read_length;
+ if((buf[0] == SYNC_BYTE) && (buf[PKT_SIZE] == SYNC_BYTE) &&
+ (buf[PKT_SIZE*2] == SYNC_BYTE) && (buf[PKT_SIZE*3] == SYNC_BYTE)) {
+ return;
+ }
+ for(n=1;n<PKT_SIZE;n++) {
+ if((buf[n] == SYNC_BYTE) && (buf[n+PKT_SIZE] == SYNC_BYTE) &&
+ (buf[n+(PKT_SIZE*2)] == SYNC_BYTE) && (buf[n+(PKT_SIZE*3)] == SYNC_BYTE)) {
+ /* Found sync, fill in */
+ memmove(&buf[0],&buf[n],((PKT_SIZE*MIN_SYNCS)-n));
+ read_length = this->input->read(this->input, &buf[(PKT_SIZE*MIN_SYNCS)-n], n);
+ return;
+ }
+ }
+ printf("RE-Sync failed\n"); /* Sync up here */
+ return;
-static int searchForSyncByte(const unsigned char * p) {
- const unsigned char * start = p, * end = p + PKT_SIZE;
-
- while (p != end && *p != SYNC_BYTE)
- p++;
-
- if (p == end)
- return -1;
- else
- return p - start;
}
+
/* Main synchronisation routine.
- * Returns NULL when it is in buffering mode, and the address of an aligned
- * packet otherwise. NULL causes the calling function to go back around its
- * loop, so its harmless and easier than doing the packet looping internally.
*/
static unsigned char * demux_synchronise(demux_ts * this) {
- static int in, out, count; /* statics are zeroed */
- static unsigned char buf[BUF_SIZE];
-
- int syncByte, syncBytePosn;
- unsigned char * retPtr = NULL;
-
- if (this->input->read(this->input, &buf[in], PKT_SIZE) != PKT_SIZE) {
- if (count > 0) {
- int oldOut = out; /* drain pipeline on end of stream */
- BUMP(out);
- count--;
- retPtr = &buf[oldOut];
- } else {
- this->status = DEMUX_FINISHED;
- }
- return retPtr;
- }
-
- syncBytePosn = out;
- WRAP_ADD(syncBytePosn, count * PKT_SIZE, BUF_SIZE - PKT_SIZE);
- syncByte = buf[syncBytePosn];
-
- if (syncByte != SYNC_BYTE) { /* new packet not in sync */
- int syncPosn = searchForSyncByte(&buf[in]);
- if (syncPosn > 0) {
- memmove(&buf[0], &buf[in + syncPosn], PKT_SIZE - syncPosn);
- in = PKT_SIZE - syncPosn;
- } else {
- in = 0; /* no sync byte in packet, so start again */
- }
- out = count = 0;
- } else { /* this packet extends the sync run */
- BUMP(in);
- count++;
- if (count > MIN_SYNCS) { /* sync acquired */
- int oldOut = out;
- resetAllCCs(this);
- BUMP(out);
- count--;
- retPtr = &buf[oldOut];
+ static int32_t packet_number=MIN_SYNCS;
+ static uint8_t buf[BUF_SIZE]; /* This should change to a malloc. */
+ uint8_t *return_pointer = NULL;
+ int32_t n, read_length;
+
+ if (packet_number == MIN_SYNCS) {
+ for(n=0;n<MIN_SYNCS;n++) {
+ read_length = this->input->read(this->input, &buf[n*PKT_SIZE], PKT_SIZE);
+ if(read_length != PKT_SIZE) {
+ this->status = DEMUX_FINISHED;
+ return NULL;
+ }
}
- }
-
- return retPtr;
+ packet_number=0;
+ correct_for_sync(this,&buf[0]);
+ }
+ return_pointer=&buf[PKT_SIZE*packet_number];
+ packet_number++;
+ return return_pointer;
}
-
-#undef BUMP
-#undef WRAP_ADD
-#undef MIN_SYNCS
-#undef BUF_SIZE
-#undef SYNC_BYTE
-
-
+
/* transport stream packet layer */
static void demux_ts_parse_packet (demux_ts *this) {
@@ -757,7 +700,6 @@
/*
* Discard packets that are obviously bad.
- * FIXME: maybe search for 0x47 is the first 188 bytes[packet size] of stream.
*/
if (sync_byte != 0x47) {
fprintf (stderr, "demux error! invalid ts sync byte %02x\n",originalPkt[0]);
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