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midiparse: implement seeking

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Seek back to 0 for backward seeking and let things run and clip for forwards
seeking.
This commit is contained in:
Wim Taymans 2013-03-22 12:25:16 +01:00
parent 87041064f8
commit 803f564013
2 changed files with 169 additions and 6 deletions
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172
gst/midi/midiparse.c
View file

@ -103,6 +103,8 @@ static void gst_midi_parse_set_property (GObject * object, guint prop_id,
static void gst_midi_parse_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static void reset_track (GstMidiTrack * track, GstMidiParse * midiparse);
static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
@ -223,14 +225,162 @@ gst_midi_parse_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
return res;
}
static gboolean
gst_midi_parse_do_seek (GstMidiParse * midiparse, GstSegment * segment)
{
GST_DEBUG_OBJECT (midiparse, "seek to %" GST_TIME_FORMAT,
GST_TIME_ARGS (segment->position));
/* if seeking backwards, start from 0 else we just let things run and
* have it clip downstream */
if (segment->position < midiparse->segment.position) {
GST_DEBUG_OBJECT (midiparse, "seeking back to 0");
segment->position = 0;
g_list_foreach (midiparse->tracks, (GFunc) reset_track, midiparse);
midiparse->pulse = 0;
}
return TRUE;
}
static gboolean
gst_midi_parse_perform_seek (GstMidiParse * midiparse, GstEvent * event)
{
gboolean res = TRUE, tres;
gdouble rate;
GstFormat seek_format;
GstSeekFlags flags;
GstSeekType start_type, stop_type;
gint64 start, stop;
gboolean flush;
gboolean update;
GstSegment seeksegment;
guint32 seqnum;
GstEvent *tevent;
GST_DEBUG_OBJECT (midiparse, "doing seek: %" GST_PTR_FORMAT, event);
if (event) {
gst_event_parse_seek (event, &rate, &seek_format, &flags,
&start_type, &start, &stop_type, &stop);
if (seek_format != GST_FORMAT_TIME)
goto invalid_format;
flush = flags & GST_SEEK_FLAG_FLUSH;
seqnum = gst_event_get_seqnum (event);
} else {
flush = FALSE;
/* get next seqnum */
seqnum = gst_util_seqnum_next ();
}
/* send flush start */
if (flush) {
tevent = gst_event_new_flush_start ();
gst_event_set_seqnum (tevent, seqnum);
gst_pad_push_event (midiparse->srcpad, tevent);
} else
gst_pad_pause_task (midiparse->srcpad);
/* grab streaming lock, this should eventually be possible, either
* because the task is paused, our streaming thread stopped
* or because our peer is flushing. */
GST_PAD_STREAM_LOCK (midiparse->sinkpad);
if (G_UNLIKELY (midiparse->seqnum == seqnum)) {
/* we have seen this event before, issue a warning for now */
GST_WARNING_OBJECT (midiparse, "duplicate event found %" G_GUINT32_FORMAT,
seqnum);
} else {
midiparse->seqnum = seqnum;
GST_DEBUG_OBJECT (midiparse, "seek with seqnum %" G_GUINT32_FORMAT, seqnum);
}
/* Copy the current segment info into the temp segment that we can actually
* attempt the seek with. We only update the real segment if the seek succeeds. */
memcpy (&seeksegment, &midiparse->segment, sizeof (GstSegment));
/* now configure the final seek segment */
if (event) {
gst_segment_do_seek (&seeksegment, rate, seek_format, flags,
start_type, start, stop_type, stop, &update);
}
/* Else, no seek event passed, so we're just (re)starting the
current segment. */
GST_DEBUG_OBJECT (midiparse, "segment configured from %" G_GINT64_FORMAT
" to %" G_GINT64_FORMAT ", position %" G_GINT64_FORMAT,
seeksegment.start, seeksegment.stop, seeksegment.position);
/* do the seek, segment.position contains the new position. */
res = gst_midi_parse_do_seek (midiparse, &seeksegment);
/* and prepare to continue streaming */
if (flush) {
tevent = gst_event_new_flush_stop (TRUE);
gst_event_set_seqnum (tevent, seqnum);
/* send flush stop, peer will accept data and events again. We
* are not yet providing data as we still have the STREAM_LOCK. */
gst_pad_push_event (midiparse->srcpad, tevent);
}
/* if the seek was successful, we update our real segment and push
* out the new segment. */
if (res) {
GST_OBJECT_LOCK (midiparse);
memcpy (&midiparse->segment, &seeksegment, sizeof (GstSegment));
GST_OBJECT_UNLOCK (midiparse);
if (seeksegment.flags & GST_SEGMENT_FLAG_SEGMENT) {
GstMessage *message;
message = gst_message_new_segment_start (GST_OBJECT (midiparse),
seeksegment.format, seeksegment.position);
gst_message_set_seqnum (message, seqnum);
gst_element_post_message (GST_ELEMENT (midiparse), message);
}
/* for deriving a stop position for the playback segment from the seek
* segment, we must take the duration when the stop is not set */
if ((stop = seeksegment.stop) == -1)
stop = seeksegment.duration;
midiparse->segment_pending = TRUE;
}
midiparse->discont = TRUE;
/* and restart the task in case it got paused explicitly or by
* the FLUSH_START event we pushed out. */
tres =
gst_pad_start_task (midiparse->sinkpad,
(GstTaskFunction) gst_midi_parse_loop, midiparse->sinkpad, NULL);
if (res && !tres)
res = FALSE;
/* and release the lock again so we can continue streaming */
GST_PAD_STREAM_UNLOCK (midiparse->sinkpad);
return res;
/* ERROR */
invalid_format:
{
GST_DEBUG_OBJECT (midiparse, "Unsupported seek format %s",
gst_format_get_name (seek_format));
return FALSE;
}
}
static gboolean
gst_midi_parse_src_event (GstPad * pad, GstObject * parent, GstEvent * event)
{
gboolean res = FALSE;
GstMidiParse *midiparse = GST_MIDI_PARSE (parent);
GST_DEBUG_OBJECT (pad, "%s event received", GST_EVENT_TYPE_NAME (event));
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_SEEK:
res = gst_midi_parse_perform_seek (midiparse, event);
break;
default:
break;
}
@ -239,7 +389,6 @@ gst_midi_parse_src_event (GstPad * pad, GstObject * parent, GstEvent * event)
return res;
}
static gboolean
gst_midi_parse_activate (GstPad * sinkpad, GstObject * parent)
{
@ -646,7 +795,7 @@ unhandled_event:
}
static void
reset_track (GstMidiParse * midiparse, GstMidiTrack * track)
reset_track (GstMidiTrack * track, GstMidiParse * midiparse)
{
GST_DEBUG_OBJECT (midiparse, "reset track");
track->offset = 0;
@ -669,7 +818,7 @@ parse_MTrk (GstMidiParse * midiparse, guint8 * data, guint size)
track = g_slice_new (GstMidiTrack);
track->data = data;
track->size = size;
reset_track (midiparse, track);
reset_track (track, midiparse);
midiparse->tracks = g_list_append (midiparse->tracks, track);
midiparse->track_count++;
@ -688,7 +837,7 @@ parse_MTrk (GstMidiParse * midiparse, guint8 * data, guint size)
if (duration > midiparse->segment.duration)
midiparse->segment.duration = duration;
reset_track (midiparse, track);
reset_track (track, midiparse);
return TRUE;
}
@ -859,8 +1008,8 @@ gst_midi_parse_parse_song (GstMidiParse * midiparse)
gst_pad_set_caps (midiparse->srcpad, outcaps);
gst_caps_unref (outcaps);
gst_pad_push_event (midiparse->srcpad,
gst_event_new_segment (&midiparse->segment));
midiparse->segment_pending = TRUE;
midiparse->discont = TRUE;
GST_DEBUG_OBJECT (midiparse, "Parsing song done");
@ -902,6 +1051,11 @@ play_push_func (GstMidiParse * midiparse, GstMidiTrack * track,
GST_DEBUG_OBJECT (midiparse, "pushing %" GST_TIME_FORMAT,
GST_TIME_ARGS (position));
if (midiparse->discont) {
GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_DISCONT);
midiparse->discont = FALSE;
}
return gst_pad_push (midiparse->srcpad, outbuf);
}
@ -917,6 +1071,12 @@ gst_midi_parse_do_play (GstMidiParse * midiparse)
pulse = midiparse->pulse;
position = midiparse->segment.position;
if (midiparse->segment_pending) {
gst_pad_push_event (midiparse->srcpad,
gst_event_new_segment (&midiparse->segment));
midiparse->segment_pending = FALSE;
}
GST_DEBUG_OBJECT (midiparse, "pulse %" G_GUINT64_FORMAT ", position %"
GST_TIME_FORMAT, pulse, GST_TIME_ARGS (position));

3
gst/midi/midiparse.h
View file

@ -72,6 +72,9 @@ struct _GstMidiParse
/* output data */
gboolean discont;
GstSegment segment;
gboolean segment_pending;
guint32 seqnum;
guint64 pulse;
};