splitmuxsrc: Keep streams aligned during adjustments

When calculating the timestamp offset to apply to
media streams in a fragment, ensure that all fragments
are offset "together" to preserve alignment in cases
where there might gaps in a recording at a fragment boundary.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7053>
This commit is contained in:
Jan Schmidt 2024-05-10 00:48:11 +10:00
parent 682db96a41
commit 1294264ab9
2 changed files with 30 additions and 9 deletions

View file

@ -141,19 +141,38 @@ handle_buffer_measuring (GstSplitMuxPartReader * reader,
if (reader->prep_state == PART_STATE_PREPARING_COLLECT_STREAMS &&
!part_pad->seen_buffer) {
/* If this is the first buffer on the pad in the collect_streams state,
* then calculate initial offset based on running time of this segment */
* then calculate initial offset based on running time of this segment
* that will put this stream's timestamps on a common zero base */
part_pad->initial_ts_offset =
part_pad->orig_segment.start + part_pad->orig_segment.base -
part_pad->orig_segment.time;
part_pad->orig_segment.start - part_pad->orig_segment.base;
GST_DEBUG_OBJECT (reader,
"Initial TS offset for pad %" GST_PTR_FORMAT " now %" GST_TIME_FORMAT,
part_pad, GST_TIME_ARGS (part_pad->initial_ts_offset));
"Initial TS offset for pad %" GST_PTR_FORMAT " now %" GST_TIME_FORMAT
" from seg %" GST_SEGMENT_FORMAT,
part_pad, GST_TIME_ARGS (part_pad->initial_ts_offset),
&part_pad->orig_segment);
/* And check if this is the 'earliest' stream in the set that
* will be used to move the entire presentation back to 0 */
GstClockTime smallest_offset = part_pad->orig_segment.base;
if (!GST_CLOCK_TIME_IS_VALID (reader->smallest_ts_offset) ||
smallest_offset < reader->smallest_ts_offset) {
reader->smallest_ts_offset = smallest_offset;
GST_DEBUG_OBJECT (reader,
"Overall TS offset for all pads %" GST_PTR_FORMAT " now %"
GST_TIME_FORMAT, part_pad,
GST_TIME_ARGS (reader->smallest_ts_offset));
}
}
part_pad->seen_buffer = TRUE;
/* Adjust buffer timestamps */
offset = reader->info.start_offset + part_pad->segment.base;
offset -= part_pad->initial_ts_offset;
offset = reader->info.start_offset - part_pad->initial_ts_offset;
offset -= reader->smallest_ts_offset;
/* We don't add the ts_offset here, because we
* want to measure the logical length of the stream,
* not to generate output timestamps */
@ -245,8 +264,8 @@ splitmux_part_pad_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
}
/* Adjust buffer timestamps */
offset = reader->info.start_offset + part_pad->segment.base;
offset -= part_pad->initial_ts_offset;
offset = reader->info.start_offset - part_pad->initial_ts_offset;
offset -= reader->smallest_ts_offset;
offset += reader->ts_offset;
if (GST_BUFFER_PTS_IS_VALID (buf))
@ -699,6 +718,7 @@ gst_splitmux_part_reader_init (GstSplitMuxPartReader * reader)
reader->need_duration_measuring = TRUE;
reader->active = FALSE;
reader->smallest_ts_offset = GST_CLOCK_TIME_NONE;
reader->info.start_offset = GST_CLOCK_TIME_NONE;
reader->info.duration = GST_CLOCK_TIME_NONE;

View file

@ -82,6 +82,7 @@ struct _GstSplitMuxPartReader
GstSplitMuxPartReaderInfo info;
GstClockTime smallest_ts_offset;
GstClockTime ts_offset;
GstClockTime end_offset;