[gst-devel] Framestepping backwards doesn't work with MPEG2 PS files.
wl2776
wl2776 at gmail.com
Wed May 19 14:40:05 CEST 2010
The playbin2 doesn't react on the new_step events when paused.
Current playing position, reported by _query_position doesn't change. The
displayed picture doesn't change also.
Framestepping forward is OK.
0. GStreamer is initialized with the keys --gst-debug=player:5,mpegpsdemux:3
where player is my private debug category.
1. My application creates the playbin2 instance to play the file.
It successfully opens and plays.
2. I pause the playbin2.
3. I position a playbin2 somewhere in the movie by clicking on a movie
progress bar on my form.
This issues the call
r=gst_element_seek_simple(GST_ELEMENT(m_player),
GST_FORMAT_TIME,
(GstSeekFlags)(GST_SEEK_FLAG_FLUSH|GST_SEEK_FLAG_KEY_UNIT),
pos*GST_MSECOND);
where pos is the seek position.
GST_DEBUG rigth after this shows that r=1 (seek is successful), I also
observe the changing picture.
Debug shows the following.
0:00:11.316272000 3952 003D9118 INFO mpegpsdemux
gstmpegdemux.c:1060:gst_flups_demux_do_seek:<mpegpsdemux0> sink segment
configured 0409D880, trying to go at SCR: 5535000
0:00:11.326286000 3952 003D9118 INFO mpegpsdemux
gstmpegdemux.c:1082:gst_flups_demux_do_seek:<mpegpsdemux0> doing seek at
offset 42065920 SCR: 5534990 0:01:01.499888888
0:00:11.346315000 3952 003D9118 DEBUG player
gst_player.cpp:911:gst_player::set_position: direction=1, seek to 61500
msec, r=1
0:00:11.356329000 3952 040A06C0 INFO mpegpsdemux
gstmpegdemux.c:533:gst_flups_demux_send_data:<mpegpsdemux0> sending new
segment: rate 1 applied_rate 1 start: 0:01:01.500011111, stop:
99:99:99.999999999, time: 0:01:01.500000000 to pad 0401E668
0:00:11.356329000 3952 040A06C0 INFO mpegpsdemux
gstmpegdemux.c:533:gst_flups_demux_send_data:<mpegpsdemux0> sending new
segment: rate 1 applied_rate 1 start: 0:01:01.500011111, stop:
99:99:99.999999999, time: 0:01:01.500000000 to pad 0401EA50
0:00:11.486517000 3952 0404AEE0 DEBUG player
gst_player.cpp:330:gst_player::bus_watch: message async-done(2097152) from
playbin0
0:00:11.486517000 3952 0404AEE0 DEBUG player
gst_player.cpp:334:gst_player::bus_watch: current player position 61500ms
0:00:11.526574000 3952 0404AEE0 DEBUG player
gst_player.cpp:341:gst_player::bus_watch: current segment: rate 1.000000 fmt
3 start 61500011111 stop -1 direction 1
4. I press "step left" button on my player's window.
This issues the call to my step_left() function
void gst_player::step_left(void)
{GstFormat fmt=GST_FORMAT_TIME;
gboolean rb;
if(m_player){
if(m_current_position>=40*GST_MSECOND){
if(m_direction>0) {
m_direction=-1;
flag_set(FLAG_STEP_LEFT1);
rb=gst_element_seek(m_player,-1.0,GST_FORMAT_TIME,
(GstSeekFlags)(GST_SEEK_FLAG_FLUSH|GST_SEEK_FLAG_ACCURATE),
GST_SEEK_TYPE_SET,0,GST_SEEK_TYPE_SET,m_current_position);
GST_DEBUG("seek backwards: %d",rb);
}else{
rb=gst_element_send_event (m_player,
gst_event_new_step (GST_FORMAT_BUFFERS, 1,
1.0, TRUE, FALSE));
GST_DEBUG("send step event: %d",rb);
}
}
}
}
This function tracks current playback direction, if it doesn't match, it
sends the seek event to turn the player to backwards playback.
The bus_watch watches for the async-done messages, checks the application's
internal flags and basing on them decides what caused the async-done message
and what to do next.
Here is the relevant code from my bus-watch.
case GST_MESSAGE_ASYNC_DONE:{
GST_DEBUG("message %s(%d) from %s",
GST_MESSAGE_TYPE_NAME(msg),GST_MESSAGE_TYPE(msg),GST_MESSAGE_SRC_NAME(msg));
GstFormat fmt=GST_FORMAT_TIME;
gst_element_query_position(m_player,&fmt,&m_current_position);
GST_DEBUG("current player position
%dms",GST_TIME_AS_MSECONDS(m_current_position));
GstQuery *query=gst_query_new_segment(GST_FORMAT_TIME);
gst_element_query(GST_ELEMENT(m_player),query);
gdouble rate;
gint64 start=-1,stop=-1;
gst_query_parse_segment(query,&rate,&fmt,&start,&stop);
GST_DEBUG("current segment: rate %lf fmt %d start %"G_GINT64_FORMAT
" stop %"G_GINT64_FORMAT" direction
%d",rate,fmt,start,stop,m_direction);
gst_query_unref(query);
if(m_flags & FLAG_GO_END){
flag_unset(FLAG_GO_END);
/* ... */
}else if(m_flags & FLAG_STEP_LEFT1){
flag_unset(FLAG_STEP_LEFT1);
GST_DEBUG("flag_unset(FLAG_STEP_LEFT1);");
rb=gst_element_send_event (m_player,
gst_event_new_step (GST_FORMAT_BUFFERS, 1, 1.0, TRUE,
FALSE));
GST_DEBUG("send step event: %d",rb);
}
}
Here is the debug output, resulted by several presses of the step_left
button
0:10:32.509504000 3952 003D9118 INFO mpegpsdemux
gstmpegdemux.c:1060:gst_flups_demux_do_seek:<mpegpsdemux0> sink segment
configured 0409D880, trying to go at SCR: 5535000
0:10:32.519518000 3952 003D9118 INFO mpegpsdemux
gstmpegdemux.c:1082:gst_flups_demux_do_seek:<mpegpsdemux0> doing seek at
offset 42065920 SCR: 5534990 0:01:01.499888888
0:10:32.519518000 3952 003D9118 DEBUG player
gst_player.cpp:940:gst_player::step_left: seek backwards: 1
0:10:32.519518000 3952 040A06C0 INFO mpegpsdemux
gstmpegdemux.c:533:gst_flups_demux_send_data:<mpegpsdemux0> sending new
segment: rate -1 applied_rate 1 start: 0:00:00.000011111, stop:
0:01:01.500011111, time: 0:00:00.000000000 to pad 0401E668
0:10:32.990195000 3952 0404AEE0 DEBUG player
gst_player.cpp:330:gst_player::bus_watch: message async-done(2097152) from
playbin0
0:10:32.990195000 3952 0404AEE0 DEBUG player
gst_player.cpp:334:gst_player::bus_watch: current player position 61500ms
0:10:32.990195000 3952 0404AEE0 DEBUG player
gst_player.cpp:341:gst_player::bus_watch: current segment: rate -1.000000
fmt 3 start 11111 stop 61500011111 direction -1
0:10:32.990195000 3952 0404AEE0 DEBUG player
gst_player.cpp:354:gst_player::bus_watch: flag_unset(FLAG_STEP_LEFT1);
0:10:32.990195000 3952 0404AEE0 DEBUG player
gst_player.cpp:356:gst_player::bus_watch: send step event: 1
0:10:33.000209000 3952 0404AEE0 DEBUG player
gst_player.cpp:330:gst_player::bus_watch: message async-done(2097152) from
playbin0
0:10:33.000209000 3952 0404AEE0 DEBUG player
gst_player.cpp:334:gst_player::bus_watch: current player position 61500ms
0:10:33.000209000 3952 0404AEE0 DEBUG player
gst_player.cpp:341:gst_player::bus_watch: current segment: rate -1.000000
fmt 3 start 11111 stop 61500011111 direction -1
0:14:59.793840000 3952 003D9118 DEBUG player
gst_player.cpp:943:gst_player::step_left: send step event: 1
0:14:59.803854000 3952 0404AEE0 DEBUG player
gst_player.cpp:330:gst_player::bus_watch: message async-done(2097152) from
playbin0
0:14:59.803854000 3952 0404AEE0 DEBUG player
gst_player.cpp:334:gst_player::bus_watch: current player position 61500ms
0:14:59.803854000 3952 0404AEE0 DEBUG player
gst_player.cpp:341:gst_player::bus_watch: current segment: rate -1.000000
fmt 3 start 11111 stop 61500011111 direction -1
0:15:02.467685000 3952 003D9118 DEBUG player
gst_player.cpp:943:gst_player::step_left: send step event: 1
0:15:02.467685000 3952 0404AEE0 DEBUG player
gst_player.cpp:330:gst_player::bus_watch: message async-done(2097152) from
playbin0
0:15:02.467685000 3952 0404AEE0 DEBUG player
gst_player.cpp:334:gst_player::bus_watch: current player position 61500ms
0:15:02.467685000 3952 0404AEE0 DEBUG player
gst_player.cpp:341:gst_player::bus_watch: current segment: rate -1.000000
fmt 3 start 11111 stop 61500011111 direction -1
0:15:05.191601000 3952 003D9118 DEBUG player
gst_player.cpp:943:gst_player::step_left: send step event: 1
0:15:05.191601000 3952 0404AEE0 DEBUG player
gst_player.cpp:330:gst_player::bus_watch: message async-done(2097152) from
playbin0
0:15:05.191601000 3952 0404AEE0 DEBUG player
gst_player.cpp:334:gst_player::bus_watch: current player position 61500ms
0:15:05.191601000 3952 0404AEE0 DEBUG player
gst_player.cpp:341:gst_player::bus_watch: current segment: rate -1.000000
fmt 3 start 11111 stop 61500011111 direction -1
As can be seen, current position remains at 61500ms, the displayed picture
doesn't change. I repeat, m_player is the playbin2, and is paused.
--
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