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mpegtsparse: detect packetsize and don't just assume 188 bytes.

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This commit is contained in:
Zaheer Abbas Merali 2009-09-20 12:38:00 +01:00
parent de0ceb1178
commit bdf11016fa
2 changed files with 72 additions and 3 deletions
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65
gst/mpegdemux/mpegtspacketizer.c
View file

@ -167,6 +167,7 @@ mpegts_packetizer_init (MpegTSPacketizer * packetizer)
packetizer->adapter = gst_adapter_new ();
packetizer->streams = g_hash_table_new_full (g_direct_hash, g_direct_equal,
NULL, mpegts_packetizer_destroy_streams_value);
packetizer->know_packet_size = FALSE;
}
static void
@ -1965,10 +1966,61 @@ mpegts_packetizer_push (MpegTSPacketizer * packetizer, GstBuffer * buffer)
gst_adapter_push (packetizer->adapter, buffer);
}
void
mpegts_try_discover_packet_size (MpegTSPacketizer * packetizer)
{
guint8 *dest;
int i, pos, j;
const guint psizes[] = { MPEGTS_NORMAL_PACKETSIZE,
MPEGTS_M2TS_PACKETSIZE,
MPEGTS_DVB_ASI_PACKETSIZE,
MPEGTS_ATSC_PACKETSIZE
};
/* wait for 3 sync bytes */
/* so first return if there is not enough data for 4 * max packetsize */
if (gst_adapter_available_fast (packetizer->adapter) <
MPEGTS_MAX_PACKETSIZE * 4)
return;
/* check for sync bytes */
dest = g_malloc (MPEGTS_MAX_PACKETSIZE * 4);
gst_adapter_copy (packetizer->adapter, dest, 0, MPEGTS_MAX_PACKETSIZE * 4);
/* find first sync byte */
pos = -1;
for (i = 0; i < MPEGTS_MAX_PACKETSIZE; i++) {
if (dest[i] == 0x47) {
for (j = 0; j < 4; j++) {
guint packetsize = psizes[j];
/* check each of the packet size possibilities in turn */
if (dest[i] == 0x47 && dest[i + packetsize] == 0x47 &&
dest[i + packetsize * 2] == 0x47 &&
dest[i + packetsize * 3] == 0x47) {
packetizer->know_packet_size = TRUE;
packetizer->packet_size = packetsize;
pos = i;
break;
}
}
break;
}
}
GST_DEBUG ("have packetsize detected: %d of %u bytes",
packetizer->know_packet_size, packetizer->packet_size);
/* flush to sync byte */
if (pos > 0)
gst_adapter_flush (packetizer->adapter, pos);
g_free (dest);
}
gboolean
mpegts_packetizer_has_packets (MpegTSPacketizer * packetizer)
{
return gst_adapter_available (packetizer->adapter) >= 188;
if (G_UNLIKELY (packetizer->know_packet_size == FALSE)) {
mpegts_try_discover_packet_size (packetizer);
if (!packetizer->know_packet_size)
return FALSE;
}
return gst_adapter_available (packetizer->adapter) >= packetizer->packet_size;
}
MpegTSPacketizerPacketReturn
@ -1979,7 +2031,13 @@ mpegts_packetizer_next_packet (MpegTSPacketizer * packetizer,
guint avail;
packet->buffer = NULL;
while ((avail = gst_adapter_available (packetizer->adapter)) >= 188) {
if (G_UNLIKELY (!packetizer->know_packet_size)) {
mpegts_try_discover_packet_size (packetizer);
if (!packetizer->know_packet_size)
return PACKET_NEED_MORE;
}
while ((avail = gst_adapter_available (packetizer->adapter)) >=
packetizer->packet_size) {
sync_byte = *gst_adapter_peek (packetizer->adapter, 1);
if (G_UNLIKELY (sync_byte != 0x47)) {
GST_DEBUG ("lost sync %02x", sync_byte);
@ -1987,7 +2045,8 @@ mpegts_packetizer_next_packet (MpegTSPacketizer * packetizer,
continue;
}
packet->buffer = gst_adapter_take_buffer (packetizer->adapter, 188);
packet->buffer = gst_adapter_take_buffer (packetizer->adapter,
packetizer->packet_size);
packet->data_start = GST_BUFFER_DATA (packet->buffer);
packet->data_end =
GST_BUFFER_DATA (packet->buffer) + GST_BUFFER_SIZE (packet->buffer);

10
gst/mpegdemux/mpegtspacketizer.h
View file

@ -28,6 +28,14 @@
#include <gst/base/gstadapter.h>
#include <glib.h>
#define MPEGTS_NORMAL_PACKETSIZE 188
#define MPEGTS_M2TS_PACKETSIZE 192
#define MPEGTS_DVB_ASI_PACKETSIZE 204
#define MPEGTS_ATSC_PACKETSIZE 208
#define MPEGTS_MIN_PACKETSIZE MPEGTS_NORMAL_PACKETSIZE
#define MPEGTS_MAX_PACKETSIZE MPEGTS_ATSC_PACKETSIZE
G_BEGIN_DECLS
#define GST_TYPE_MPEGTS_PACKETIZER \
@ -52,6 +60,8 @@ struct _MpegTSPacketizer {
/* streams hashed by pid */
GHashTable *streams;
gboolean disposed;
gboolean know_packet_size;
guint16 packet_size;
};
struct _MpegTSPacketizerClass {