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mpegtspacketizer: Handle rollover in offset calculations

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This commit is contained in:
Edward Hervey 2012-03-05 12:46:13 +01:00
parent d798cb7be3
commit 416b10b991
2 changed files with 29 additions and 8 deletions
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35
gst/mpegtsdemux/mpegtspacketizer.c
View file

@ -31,6 +31,10 @@
/* Skew calculation pameters */
#define MAX_TIME (2 * GST_SECOND)
/* maximal PCR time */
#define PCR_MAX_VALUE (((((guint64)1)<<33) * 300) + 298)
#define PTS_DTS_MAX_VALUE (((guint64)1) << 33)
#include "mpegtspacketizer.h"
#include "gstmpegdesc.h"
@ -89,8 +93,10 @@ struct _MpegTSPacketizerPrivate
/* FIXME : Replace this later on with a balanced tree or sequence */
guint64 first_offset;
guint64 first_pcr;
GstClockTime first_pcr_ts;
guint64 last_offset;
guint64 last_pcr;
GstClockTime last_pcr_ts;
/* Reference offset */
guint64 refoffset;
@ -206,8 +212,10 @@ mpegts_packetizer_init (MpegTSPacketizer2 * packetizer)
packetizer->priv->first_offset = -1;
packetizer->priv->first_pcr = -1;
packetizer->priv->first_pcr_ts = GST_CLOCK_TIME_NONE;
packetizer->priv->last_offset = -1;
packetizer->priv->last_pcr = -1;
packetizer->priv->last_pcr_ts = GST_CLOCK_TIME_NONE;
packetizer->priv->nb_seen_offsets = 0;
packetizer->priv->refoffset = -1;
}
@ -3140,6 +3148,7 @@ record_pcr (MpegTSPacketizer2 * packetizer, guint64 pcr, guint64 offset)
GST_DEBUG ("Recording first value. PCR:%" G_GUINT64_FORMAT " offset:%"
G_GUINT64_FORMAT, pcr, offset);
priv->first_pcr = pcr;
priv->first_pcr_ts = PCRTIME_TO_GSTTIME (pcr);
priv->first_offset = offset;
priv->nb_seen_offsets++;
} else
@ -3147,7 +3156,12 @@ record_pcr (MpegTSPacketizer2 * packetizer, guint64 pcr, guint64 offset)
if (priv->last_pcr == -1 || priv->last_offset < offset) {
GST_DEBUG ("Recording last value. PCR:%" G_GUINT64_FORMAT " offset:%"
G_GUINT64_FORMAT, pcr, offset);
if (G_UNLIKELY (priv->first_pcr != -1 && pcr < priv->first_pcr)) {
GST_DEBUG ("rollover detected");
pcr += PCR_MAX_VALUE;
}
priv->last_pcr = pcr;
priv->last_pcr_ts = PCRTIME_TO_GSTTIME (pcr);
priv->last_offset = offset;
priv->nb_seen_offsets++;
}
@ -3185,23 +3199,30 @@ mpegts_packetizer_offset_to_ts (MpegTSPacketizer2 * packetizer, guint64 offset)
}
GstClockTime
mpegts_packetizer_pts_to_ts (MpegTSPacketizer2 * packetizer, guint64 pts)
mpegts_packetizer_pts_to_ts (MpegTSPacketizer2 * packetizer, GstClockTime pts)
{
GstClockTime res = GST_CLOCK_TIME_NONE;
/* Use clock skew if present */
if (packetizer->calculate_skew
&& GST_CLOCK_TIME_IS_VALID (packetizer->base_time)) {
GST_DEBUG ("pts %" G_GUINT64_FORMAT " base_pcrtime:%" G_GUINT64_FORMAT
" base_time:%" GST_TIME_FORMAT, pts, packetizer->base_pcrtime,
GST_TIME_ARGS (packetizer->base_time));
return pts - packetizer->base_pcrtime + packetizer->base_time +
res = pts - packetizer->base_pcrtime + packetizer->base_time +
packetizer->skew;
} else
/* If not, use pcr observations */
if (packetizer->calculate_offset && packetizer->priv->first_pcr != -1) {
/* Rollover */
if (G_UNLIKELY (pts < packetizer->priv->first_pcr_ts))
pts += MPEGTIME_TO_GSTTIME (PTS_DTS_MAX_VALUE);
res = pts - packetizer->priv->first_pcr_ts;
}
/* If not, use pcr observations */
if (packetizer->calculate_offset && packetizer->priv->first_pcr != -1)
return pts - PCRTIME_TO_GSTTIME (packetizer->priv->first_pcr);
return GST_CLOCK_TIME_NONE;
GST_DEBUG ("Returning timestamp %" GST_TIME_FORMAT " for pts %"
GST_TIME_FORMAT, GST_TIME_ARGS (res), GST_TIME_ARGS (pts));
return res;
}
guint64

2
gst/mpegtsdemux/mpegtspacketizer.h
View file

@ -206,7 +206,7 @@ mpegts_packetizer_ts_to_offset (MpegTSPacketizer2 * packetizer,
GstClockTime ts);
GstClockTime
mpegts_packetizer_pts_to_ts (MpegTSPacketizer2 * packetizer,
guint64 pcr);
GstClockTime pts);
void
mpegts_packetizer_set_reference_offset (MpegTSPacketizer2 * packetizer,
guint64 refoffset);