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qtdemux: implement pull mode SNAP flag seeking

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This commit is contained in:
Mark Nauwelaerts 2016-12-29 12:25:35 +01:00
parent 494f4beb40
commit 867ce71922
1 changed files with 53 additions and 15 deletions
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68
gst/isomp4/qtdemux.c
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@ -1157,13 +1157,13 @@ parse_failed:
}
/* find the index of the keyframe needed to decode the sample at @index
* of stream @str.
* of stream @str, or of a subsequent keyframe (depending on @next)
*
* Returns the index of the keyframe.
*/
static guint32
gst_qtdemux_find_keyframe (GstQTDemux * qtdemux, QtDemuxStream * str,
guint32 index)
guint32 index, gboolean next)
{
guint32 new_index = index;
@ -1178,22 +1178,40 @@ gst_qtdemux_find_keyframe (GstQTDemux * qtdemux, QtDemuxStream * str,
goto beach;
}
/* else go back until we have a keyframe */
while (TRUE) {
/* else search until we have a keyframe */
while (new_index < str->n_samples) {
if (next && !qtdemux_parse_samples (qtdemux, str, new_index))
goto parse_failed;
if (str->samples[new_index].keyframe)
break;
if (new_index == 0)
break;
new_index--;
if (next)
new_index++;
else
new_index--;
}
if (new_index == str->n_samples) {
GST_DEBUG_OBJECT (qtdemux, "no next keyframe");
new_index = -1;
}
beach:
GST_DEBUG_OBJECT (qtdemux, "searching for keyframe index before index %u "
"gave %u", index, new_index);
GST_DEBUG_OBJECT (qtdemux, "searching for keyframe index %s index %u "
"gave %u", next ? "after" : "before", index, new_index);
return new_index;
/* ERRORS */
parse_failed:
{
GST_LOG_OBJECT (qtdemux, "Parsing of index %u failed!", new_index);
return -1;
}
}
/* find the segment for @time_position for @stream
@ -1262,7 +1280,7 @@ gst_qtdemux_move_stream (GstQTDemux * qtdemux, QtDemuxStream * str,
static void
gst_qtdemux_adjust_seek (GstQTDemux * qtdemux, gint64 desired_time,
gboolean use_sparse, gint64 * key_time, gint64 * key_offset)
gboolean use_sparse, gboolean next, gint64 * key_time, gint64 * key_offset)
{
guint64 min_offset;
gint64 min_byte_offset = -1;
@ -1321,9 +1339,18 @@ gst_qtdemux_adjust_seek (GstQTDemux * qtdemux, gint64 desired_time,
GST_TIME_ARGS (media_start), index, str->samples[index].offset,
empty_segment);
/* shift to next frame if we are looking for next keyframe */
if (next && QTSAMPLE_PTS (str, &str->samples[index]) < media_start &&
index < str->stbl_index)
index++;
if (!empty_segment) {
/* find previous keyframe */
kindex = gst_qtdemux_find_keyframe (qtdemux, str, index);
kindex = gst_qtdemux_find_keyframe (qtdemux, str, index, next);
/* we will settle for one before if none found after */
if (next && kindex == -1)
kindex = gst_qtdemux_find_keyframe (qtdemux, str, index, FALSE);
/* if the keyframe is at a different position, we need to update the
* requested seek time */
@ -1346,7 +1373,8 @@ gst_qtdemux_adjust_seek (GstQTDemux * qtdemux, gint64 desired_time,
/* this keyframe is inside the segment, convert back to
* segment time */
seg_time = (media_time - seg->media_start) + seg->time;
if (seg_time < min_offset)
if ((!next && (seg_time < min_offset)) ||
(next && (seg_time > min_offset)))
min_offset = seg_time;
}
}
@ -1427,7 +1455,9 @@ gst_qtdemux_do_push_seek (GstQTDemux * qtdemux, GstPad * pad, GstEvent * event)
/* find reasonable corresponding BYTE position,
* also try to mind about keyframes, since we can not go back a bit for them
* later on */
gst_qtdemux_adjust_seek (qtdemux, cur, FALSE, &key_cur, &byte_cur);
/* determining @next here based on SNAP_BEFORE/SNAP_AFTER should
* mostly just work, but let's not yet boldly go there ... */
gst_qtdemux_adjust_seek (qtdemux, cur, FALSE, FALSE, &key_cur, &byte_cur);
if (byte_cur == -1)
goto abort_seek;
@ -1511,8 +1541,16 @@ gst_qtdemux_perform_seek (GstQTDemux * qtdemux, GstSegment * segment,
* possibly flushing upstream */
if ((flags & GST_SEEK_FLAG_KEY_UNIT) && !qtdemux->fragmented) {
gint64 min_offset;
gboolean next, before, after;
gst_qtdemux_adjust_seek (qtdemux, desired_offset, TRUE, &min_offset, NULL);
before = ! !(flags & GST_SEEK_FLAG_SNAP_BEFORE);
after = ! !(flags & GST_SEEK_FLAG_SNAP_AFTER);
next = after && !before;
if (segment->rate < 0)
next = !next;
gst_qtdemux_adjust_seek (qtdemux, desired_offset, TRUE, next, &min_offset,
NULL);
GST_DEBUG_OBJECT (qtdemux, "keyframe seek, align to %"
GST_TIME_FORMAT, GST_TIME_ARGS (min_offset));
desired_offset = min_offset;
@ -4366,7 +4404,7 @@ gst_qtdemux_seek_to_previous_keyframe (GstQTDemux * qtdemux)
* that. For audio streams we do an arbitrary jump in the past (10 samples) */
if (ref_str->subtype == FOURCC_vide) {
k_index = gst_qtdemux_find_keyframe (qtdemux, ref_str,
ref_str->from_sample - 1);
ref_str->from_sample - 1, FALSE);
} else {
if (ref_str->from_sample >= 10)
k_index = ref_str->from_sample - 10;
@ -4467,7 +4505,7 @@ gst_qtdemux_seek_to_previous_keyframe (GstQTDemux * qtdemux)
GST_TIME_ARGS (seg_time), index);
/* find previous keyframe */
k_index = gst_qtdemux_find_keyframe (qtdemux, str, index);
k_index = gst_qtdemux_find_keyframe (qtdemux, str, index, FALSE);
}
/* Remember until where we want to go */
@ -4719,7 +4757,7 @@ gst_qtdemux_activate_segment (GstQTDemux * qtdemux, QtDemuxStream * stream,
}
/* find keyframe of the target index */
kf_index = gst_qtdemux_find_keyframe (qtdemux, stream, index);
kf_index = gst_qtdemux_find_keyframe (qtdemux, stream, index, FALSE);
/* *INDENT-OFF* */
/* indent does stupid stuff with stream->samples[].timestamp */