oggdemux: improve push time seeking

Various tweaks to improve convergence, in particular for
the worst case, which is now cut in about half.

https://bugzilla.gnome.org/show_bug.cgi?id=662475
This commit is contained in:
Vincent Penquerc'h 2011-10-22 20:20:38 +01:00 committed by Sebastian Dröge
parent db21375406
commit e7079cd8d5
2 changed files with 136 additions and 20 deletions

View file

@ -1066,6 +1066,8 @@ gst_ogg_pad_stream_out (GstOggPad * pad, gint npackets)
break;
case 1:
GST_LOG_OBJECT (ogg, "packetout gave packet of size %ld", packet.bytes);
if (packet.bytes > ogg->max_packet_size)
ogg->max_packet_size = packet.bytes;
result = gst_ogg_pad_submit_packet (pad, &packet);
/* not linked is not a problem, it's possible that we are still
* collecting headers and that we don't have exposed the pads yet */
@ -1107,19 +1109,22 @@ gst_ogg_demux_setup_bisection_bounds (GstOggDemux * ogg)
GST_TIME_ARGS (ogg->push_last_seek_time - ogg->push_seek_time_target));
ogg->push_offset1 = ogg->push_last_seek_offset;
ogg->push_time1 = ogg->push_last_seek_time;
ogg->seek_undershot = FALSE;
} else {
GST_DEBUG_OBJECT (ogg, "We undershot by %" GST_TIME_FORMAT,
GST_TIME_ARGS (ogg->push_seek_time_target - ogg->push_last_seek_time));
ogg->push_offset0 = ogg->push_last_seek_offset;
ogg->push_time0 = ogg->push_last_seek_time;
ogg->seek_undershot = TRUE;
}
}
static gint64
gst_ogg_demux_estimate_bisection_target (GstOggDemux * ogg)
gst_ogg_demux_estimate_bisection_target (GstOggDemux * ogg, float seek_quality)
{
gint64 best;
gint64 segment_bitrate;
gint64 skew;
/* we might not know the length of the stream in time,
so push_time1 might not be set */
@ -1146,6 +1151,7 @@ gst_ogg_demux_estimate_bisection_target (GstOggDemux * ogg)
ogg->push_offset0 +
gst_util_uint64_scale (ogg->push_seek_time_target - ogg->push_time0,
segment_bitrate, 8 * GST_SECOND);
ogg->seek_secant = TRUE;
} else {
GST_DEBUG_OBJECT (ogg,
"New segment to consider: bytes %" G_GINT64_FORMAT " %" G_GINT64_FORMAT
@ -1162,20 +1168,63 @@ gst_ogg_demux_estimate_bisection_target (GstOggDemux * ogg)
"Local bitrate on the %" GST_TIME_FORMAT " - %" GST_TIME_FORMAT
" segment: %" G_GINT64_FORMAT, GST_TIME_ARGS (ogg->push_time0),
GST_TIME_ARGS (ogg->push_time1), segment_bitrate);
best =
ogg->push_offset0 +
gst_util_uint64_scale (ogg->push_seek_time_target - ogg->push_time0,
segment_bitrate, 8 * GST_SECOND);
if (seek_quality < 0.5f && ogg->seek_secant) {
gint64 new_best, best2 = (ogg->push_offset0 + ogg->push_offset1) / 2;
/* if dire result, give as much as 25% weight to a dumb bisection guess */
float secant_weight = 1.0f - ((0.5 - seek_quality) / 0.5f) * 0.25;
new_best = (best * secant_weight + best2 * (1.0f - secant_weight));
GST_DEBUG_OBJECT (ogg,
"Secant says %" G_GINT64_FORMAT ", straight is %" G_GINT64_FORMAT
", new best %" G_GINT64_FORMAT " with secant_weight %f", best,
best2, new_best, secant_weight);
best = new_best;
ogg->seek_secant = FALSE;
} else {
ogg->seek_secant = TRUE;
}
}
}
/* offset by typical page size */
best -= CHUNKSIZE;
GST_DEBUG_OBJECT (ogg, "Raw best guess: %" G_GINT64_FORMAT, best);
/* offset the guess down as we need to capture the start of the
page we are targetting - but only do so if we did not undershoot
last time, as we're likely to still do this time */
if (!ogg->seek_undershot) {
/* very small packets are packed on pages, so offset by at least
a value which is likely to get us at least one page where the
packet starts */
skew =
ogg->max_packet_size >
ogg->max_page_size ? ogg->max_packet_size : ogg->max_page_size;
GST_DEBUG_OBJECT (ogg, "Offsetting by %" G_GINT64_FORMAT, skew);
best -= skew;
}
/* do not seek too close to the bounds, as we stop seeking
when we get to within max_packet_size before the target */
if (best > ogg->push_offset1 - ogg->max_packet_size) {
best = ogg->push_offset1 - ogg->max_packet_size;
GST_DEBUG_OBJECT (ogg,
"Too close to high bound, pushing back to %" G_GINT64_FORMAT, best);
} else if (best < ogg->push_offset0 + ogg->max_packet_size) {
best = ogg->push_offset0 + ogg->max_packet_size;
GST_DEBUG_OBJECT (ogg,
"Too close to low bound, pushing forth to %" G_GINT64_FORMAT, best);
}
/* keep within bounds */
if (best > ogg->push_offset1)
best = ogg->push_offset1;
if (best < ogg->push_offset0)
best = ogg->push_offset0;
if (best < 0)
best = 0;
GST_DEBUG_OBJECT (ogg, "Choosing target %" G_GINT64_FORMAT, best);
return best;
}
@ -1252,6 +1301,38 @@ gst_ogg_demux_seek_back_after_push_duration_check_unlock (GstOggDemux * ogg)
return GST_FLOW_OK;
}
static float
gst_ogg_demux_estimate_seek_quality (GstOggDemux * ogg)
{
gint64 diff; /* how far from the goal we ended up */
gint64 dist; /* how far we moved this iteration */
float seek_quality;
if (ogg->push_prev_seek_time == GST_CLOCK_TIME_NONE) {
/* for the first seek, we pretend we got a good seek,
as we don't have a previous seek yet */
return 1.0f;
}
/* We take a guess at how good the last seek was at guessing
the byte target by comparing the amplitude of the last
seek to the error */
diff = ogg->push_seek_time_target - ogg->push_last_seek_time;
if (diff < 0)
diff = -diff;
dist = ogg->push_last_seek_time - ogg->push_prev_seek_time;
if (dist < 0)
dist = -dist;
seek_quality = (dist == 0) ? 0.0f : 1.0f / (1.0f + diff / (float) dist);
GST_DEBUG_OBJECT (ogg,
"We moved %" GST_TIME_FORMAT ", we're off by %" GST_TIME_FORMAT
", seek quality %f", GST_TIME_ARGS (dist), GST_TIME_ARGS (diff),
seek_quality);
return seek_quality;
}
static gboolean
gst_ogg_pad_handle_push_mode_state (GstOggPad * pad, ogg_page * page)
{
@ -1327,6 +1408,7 @@ gst_ogg_pad_handle_push_mode_state (GstOggPad * pad, ogg_page * page)
GstEvent *sevent;
int res;
gboolean close_enough;
float seek_quality;
/* ignore -1 granpos when seeking, we want to sync on a real granpos */
if (granpos < 0) {
@ -1364,14 +1446,18 @@ gst_ogg_pad_handle_push_mode_state (GstOggPad * pad, ogg_page * page)
GST_TIME_ARGS (ogg->push_seek_time_target));
if (ogg->push_time1 != GST_CLOCK_TIME_NONE) {
seek_quality = gst_ogg_demux_estimate_seek_quality (ogg);
GST_DEBUG_OBJECT (ogg,
"Interval was %" G_GINT64_FORMAT " - %" G_GINT64_FORMAT " (%"
G_GINT64_FORMAT "), time %" GST_TIME_FORMAT " - %" GST_TIME_FORMAT
" (%" GST_TIME_FORMAT ")", ogg->push_offset0, ogg->push_offset1,
ogg->push_offset1 - ogg->push_offset0,
" (%" GST_TIME_FORMAT "), seek quality %f", ogg->push_offset0,
ogg->push_offset1, ogg->push_offset1 - ogg->push_offset0,
GST_TIME_ARGS (ogg->push_time0), GST_TIME_ARGS (ogg->push_time1),
GST_TIME_ARGS (ogg->push_time1 - ogg->push_time0));
GST_TIME_ARGS (ogg->push_time1 - ogg->push_time0), seek_quality);
} else {
/* in a open ended seek, we can't do bisection, so we pretend
we like our result so far */
seek_quality = 1.0f;
GST_DEBUG_OBJECT (ogg,
"Interval was %" G_GINT64_FORMAT " - %" G_GINT64_FORMAT " (%"
G_GINT64_FORMAT "), time %" GST_TIME_FORMAT " - unknown",
@ -1379,30 +1465,39 @@ gst_ogg_pad_handle_push_mode_state (GstOggPad * pad, ogg_page * page)
ogg->push_offset1 - ogg->push_offset0,
GST_TIME_ARGS (ogg->push_time0));
}
ogg->push_prev_seek_time = ogg->push_last_seek_time;
gst_ogg_demux_setup_bisection_bounds (ogg);
best = gst_ogg_demux_estimate_bisection_target (ogg);
best = gst_ogg_demux_estimate_bisection_target (ogg, seek_quality);
if (ogg->push_seek_time_target == 0) {
GST_DEBUG_OBJECT (ogg, "Seeking to 0, deemed close enough");
close_enough = (ogg->push_last_seek_time == 0);
} else {
/* TODO: make this dependent on framerate ? */
GstClockTime threshold = GST_SECOND / 2;
GstClockTime time_threshold = GST_SECOND / 2;
guint64 byte_threshold =
(ogg->max_packet_size >
64 * 1024 ? ogg->max_packet_size : 64 * 1024);
/* We want to be within half a second before the target */
if (threshold > ogg->push_seek_time_target)
threshold = ogg->push_seek_time_target;
/* We want to be within half a second before the target,
or before the target and half less or equal to the max
packet size left to search in */
if (time_threshold > ogg->push_seek_time_target)
time_threshold = ogg->push_seek_time_target;
close_enough = ogg->push_last_seek_time < ogg->push_seek_time_target
&& ogg->push_last_seek_time >=
ogg->push_seek_time_target - threshold;
&& (ogg->push_last_seek_time >=
ogg->push_seek_time_target - time_threshold
|| ogg->push_offset1 <= ogg->push_offset0 + byte_threshold);
GST_DEBUG_OBJECT (ogg,
"testing if we're close enough: %" GST_TIME_FORMAT " <= %"
GST_TIME_FORMAT " < %" GST_TIME_FORMAT " ? %s",
GST_TIME_ARGS (ogg->push_seek_time_target - threshold),
GST_TIME_FORMAT " < %" GST_TIME_FORMAT ", or %" G_GUINT64_FORMAT
" <= %" G_GUINT64_FORMAT " ? %s",
GST_TIME_ARGS (ogg->push_seek_time_target - time_threshold),
GST_TIME_ARGS (ogg->push_last_seek_time),
GST_TIME_ARGS (ogg->push_seek_time_target),
ogg->push_offset1 - ogg->push_offset0, byte_threshold,
close_enough ? "Yes" : "No");
}
@ -1432,7 +1527,7 @@ gst_ogg_pad_handle_push_mode_state (GstOggPad * pad, ogg_page * page)
GST_TIME_ARGS (ogg->push_seek_time_original_target));
ogg->push_state = PUSH_LINEAR2;
} else {
GST_DEBUG_OBJECT (ogg, "Seek to keyframe done, playing");
GST_INFO_OBJECT (ogg, "Seek to keyframe done, playing");
/* we're synced to the seek target, so flush stream and stuff
any queued pages into the stream so we start decoding there */
@ -1466,14 +1561,22 @@ gst_ogg_pad_handle_push_mode_state (GstOggPad * pad, ogg_page * page)
GST_TIME_ARGS (pad->push_kf_time));
earliest_keyframe_time = gst_ogg_demux_get_earliest_keyframe_time (ogg);
if (earliest_keyframe_time != GST_CLOCK_TIME_NONE) {
GST_DEBUG_OBJECT (ogg,
GST_INFO_OBJECT (ogg,
"All non sparse streams now have a previous keyframe time,"
"bisecting again to %" GST_TIME_FORMAT,
GST_TIME_ARGS (earliest_keyframe_time));
ogg->push_seek_time_target = earliest_keyframe_time;
ogg->push_offset0 = 0;
ogg->push_time0 = ogg->push_start_time;
ogg->push_offset1 = ogg->push_last_seek_offset;
ogg->push_time1 = ogg->push_last_seek_time;
ogg->push_prev_seek_time = GST_CLOCK_TIME_NONE;
ogg->seek_secant = FALSE;
ogg->seek_undershot = FALSE;
ogg->push_state = PUSH_BISECT2;
best = gst_ogg_demux_estimate_bisection_target (ogg);
best = gst_ogg_demux_estimate_bisection_target (ogg, 1.0f);
}
}
}
@ -1578,6 +1681,9 @@ gst_ogg_pad_submit_page (GstOggPad * pad, ogg_page * page)
return result;
}
if (page->header_len + page->body_len > ogg->max_page_size)
ogg->max_page_size = page->header_len + page->body_len;
if (ogg_stream_pagein (&pad->map.stream, page) != 0)
goto choked;
@ -3289,8 +3395,11 @@ gst_ogg_demux_perform_seek_push (GstOggDemux * ogg, GstEvent * event)
ogg->push_time0 = ogg->push_start_time;
ogg->push_time1 = ogg->push_time_length;
ogg->push_seek_time_target = start;
ogg->push_prev_seek_time = GST_CLOCK_TIME_NONE;
ogg->push_seek_time_original_target = start;
ogg->push_state = PUSH_BISECT1;
ogg->seek_secant = FALSE;
ogg->seek_undershot = FALSE;
/* reset pad push mode seeking state */
for (i = 0; i < chain->streams->len; i++) {

View file

@ -145,6 +145,10 @@ struct _GstOggDemux
gboolean need_chains;
gboolean resync;
/* keep track of how large pages and packets are,
useful for skewing when seeking */
guint64 max_packet_size, max_page_size;
/* state */
GMutex *chain_lock; /* we need the lock to protect the chains */
GArray *chains; /* list of chains we know */
@ -186,6 +190,9 @@ struct _GstOggDemux
GstSeekFlags push_seek_flags;
GstEvent *push_mode_seek_delayed_event;
gboolean push_disable_seeking;
gboolean seek_secant;
gboolean seek_undershot;
GstClockTime push_prev_seek_time;
gint push_bisection_steps[2];
gint stats_bisection_steps[2];