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qtmux: autodetect out-of-order input timestamps and determine DTS accordingly

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Favour using input buffer timestamps for DTS, but fallback to using buffer
duration (accumulation) if input ts detected out-of-order.

Fixes #624212.
This commit is contained in:
Mark Nauwelaerts 2010-08-16 12:36:24 +02:00 committed by Tim-Philipp Müller
parent 9e79307431
commit 365b419216
1 changed files with 56 additions and 12 deletions
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68
gst/quicktime/gstqtmux.c
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@ -1545,6 +1545,14 @@ ftyp_error:
}
}
/* check whether @a differs from @b by order of @magn */
static gboolean inline
gst_qtmux_check_difference (GstQTMux * qtmux, GstClockTime a,
GstClockTime b, GstClockTime magn)
{
return ((a - b >= (magn >> 1)) || (b - a >= (magn >> 1)));
}
/*
* Here we push the buffer and update the tables in the track atoms
*/
@ -1585,14 +1593,42 @@ gst_qt_mux_add_buffer (GstQTMux * qtmux, GstQTPad * pad, GstBuffer * buf)
} else
gst_buffer_ref (last_buf);
/* fall back to duration if:
* - last bufer
* - the buffers are out of order,
* - lack of valid time forces fall back */
if (buf == NULL ||
!GST_BUFFER_TIMESTAMP_IS_VALID (last_buf) ||
!GST_BUFFER_TIMESTAMP_IS_VALID (buf) ||
GST_BUFFER_TIMESTAMP (buf) < GST_BUFFER_TIMESTAMP (last_buf)) {
/* nasty heuristic mess to guestimate dealing with DTS/PTS,
* while also trying to stay close to input ts to preserve sync, so:
* - prefer using input ts where possible
* - if those detected out-of-order (*), and input duration available,
* mark as out-of-order and fallback to duration
* - if in out-of-order, need to preserve sync between streams, and adding
* durations might drift, so try to resync when we expect
* input ts == (sum of durations), which is at some keyframe input frame.
*
* (*) if input ts out-of-order, or if ts differs from (sum of durations)
* by an (approx) order-of-duration magnitude
*/
if (G_LIKELY (buf) && !pad->is_out_of_order) {
if (G_LIKELY (GST_BUFFER_TIMESTAMP_IS_VALID (last_buf) &&
GST_BUFFER_TIMESTAMP_IS_VALID (buf))) {
if ((GST_BUFFER_TIMESTAMP (buf) < GST_BUFFER_TIMESTAMP (last_buf)) ||
(!GST_CLOCK_TIME_IS_VALID (pad->first_ts) &&
GST_BUFFER_DURATION_IS_VALID (last_buf) &&
gst_qtmux_check_difference (qtmux,
GST_BUFFER_TIMESTAMP (last_buf) +
GST_BUFFER_DURATION (last_buf), GST_BUFFER_TIMESTAMP (buf),
GST_BUFFER_DURATION (last_buf)))) {
GST_DEBUG_OBJECT (qtmux, "detected out-of-order input");
pad->is_out_of_order = TRUE;
}
} else {
/* this is pretty bad */
GST_WARNING_OBJECT (qtmux, "missing input timestamp");
/* fall back to durations */
pad->is_out_of_order = TRUE;
}
}
/* fall back to duration if last buffer or
* out-of-order (determined previously), otherwise use input ts */
if (buf == NULL || pad->is_out_of_order) {
if (!GST_BUFFER_DURATION_IS_VALID (last_buf)) {
/* be forgiving for some possibly last upstream flushed buffer */
if (buf)
@ -1602,6 +1638,18 @@ gst_qt_mux_add_buffer (GstQTMux * qtmux, GstQTPad * pad, GstBuffer * buf)
duration = 0;
} else {
duration = GST_BUFFER_DURATION (last_buf);
/* avoid drift in sum timestamps,
* so use input timestamp for suitable keyframe */
if (buf && !GST_BUFFER_FLAG_IS_SET (buf, GST_BUFFER_FLAG_DELTA_UNIT) &&
GST_BUFFER_TIMESTAMP (buf) >= pad->last_dts &&
!gst_qtmux_check_difference (qtmux, pad->last_dts + duration,
GST_BUFFER_TIMESTAMP (buf), duration)) {
GST_DEBUG_OBJECT (qtmux, "resyncing out-of-order input to ts; "
"replacing %" GST_TIME_FORMAT " by %" GST_TIME_FORMAT,
GST_TIME_ARGS (pad->last_dts + duration),
GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)));
duration = GST_BUFFER_TIMESTAMP (buf) - pad->last_dts;
}
}
} else {
duration = GST_BUFFER_TIMESTAMP (buf) - GST_BUFFER_TIMESTAMP (last_buf);
@ -2317,7 +2365,6 @@ gst_qt_mux_video_sink_set_caps (GstPad * pad, GstCaps * caps)
}
} else if (strcmp (mimetype, "video/x-h264") == 0) {
entry.fourcc = FOURCC_avc1;
qtpad->is_out_of_order = TRUE;
if (qtpad->avg_bitrate == 0) {
gint avg_bitrate = 0;
gst_structure_get_int (structure, "bitrate", &avg_bitrate);
@ -2342,7 +2389,6 @@ gst_qt_mux_video_sink_set_caps (GstPad * pad, GstCaps * caps)
entry.fourcc = FOURCC_SVQ3;
entry.version = 3;
entry.depth = 32;
qtpad->is_out_of_order = TRUE;
seqh_value = gst_structure_get_value (structure, "seqh");
if (seqh_value) {
@ -2441,14 +2487,12 @@ gst_qt_mux_video_sink_set_caps (GstPad * pad, GstCaps * caps)
gst_structure_get_fourcc (structure, "format", &fourcc);
entry.fourcc = fourcc;
qtpad->is_out_of_order = TRUE;
qtpad->have_dts = TRUE;
} else if (strcmp (mimetype, "video/x-mp4-part") == 0) {
guint32 fourcc;
gst_structure_get_fourcc (structure, "format", &fourcc);
entry.fourcc = fourcc;
qtpad->is_out_of_order = TRUE;
qtpad->have_dts = TRUE;
}