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https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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h264parse: compute timestamp
This commit is contained in:
Lin YANG
Sebastian Dröge
parent
9c08ece157
commit
d520e426b0
1 changed files with 125 additions and 5 deletions
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@ -1001,22 +1001,20 @@ gst_h264_parse_chain_forward (GstH264Parse * h264parse, gboolean discont,
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{
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{
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GstFlowReturn res = GST_FLOW_OK;
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GstFlowReturn res = GST_FLOW_OK;
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const guint8 *data;
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const guint8 *data;
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GstClockTime timestamp;
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if (discont) {
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if (discont) {
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gst_adapter_clear (h264parse->adapter);
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gst_adapter_clear (h264parse->adapter);
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h264parse->discont = TRUE;
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h264parse->discont = TRUE;
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}
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}
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timestamp = GST_BUFFER_TIMESTAMP (buffer);
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gst_adapter_push (h264parse->adapter, buffer);
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gst_adapter_push (h264parse->adapter, buffer);
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while (res == GST_FLOW_OK) {
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while (res == GST_FLOW_OK) {
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gint i;
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gint i;
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gint next_nalu_pos = -1;
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gint next_nalu_pos = -1;
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gint avail;
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gint avail;
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gboolean delta_unit = TRUE;
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gboolean delta_unit = FALSE;
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gboolean got_frame = FALSE;
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avail = gst_adapter_available (h264parse->adapter);
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avail = gst_adapter_available (h264parse->adapter);
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if (avail < h264parse->nal_length_size + 1)
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if (avail < h264parse->nal_length_size + 1)
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@ -1146,8 +1144,131 @@ gst_h264_parse_chain_forward (GstH264Parse * h264parse, gboolean discont,
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/* we have a packet */
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/* we have a packet */
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if (next_nalu_pos > 0) {
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if (next_nalu_pos > 0) {
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GstBuffer *outbuf;
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GstBuffer *outbuf;
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GstClockTime outbuf_dts = GST_CLOCK_TIME_NONE;
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outbuf = gst_adapter_take_buffer (h264parse->adapter, next_nalu_pos);
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outbuf = gst_adapter_take_buffer (h264parse->adapter, next_nalu_pos);
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outbuf_dts = gst_adapter_prev_timestamp (h264parse->adapter, NULL); /* Better value for the second parameter? */
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/* Ignore upstream dts that stalls or goes backward. Upstream elements
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* like filesrc would keep on writing timestamp=0. XXX: is this correct?
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* TODO: better way to detect whether upstream timstamps are useful */
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if (h264parse->last_outbuf_dts != GST_CLOCK_TIME_NONE
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&& outbuf_dts != GST_CLOCK_TIME_NONE
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&& outbuf_dts <= h264parse->last_outbuf_dts)
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outbuf_dts = GST_CLOCK_TIME_NONE;
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if (got_frame || delta_unit) {
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GstH264Sps *sps = h264parse->sps;
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gint duration = 1;
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if (!sps) {
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GST_DEBUG_OBJECT (h264parse, "referred SPS invalid");
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goto TIMESTAMP_FINISH;
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} else if (!sps->timing_info_present_flag) {
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GST_DEBUG_OBJECT (h264parse,
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"unable to compute timestamp: timing info not present");
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goto TIMESTAMP_FINISH;
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} else if (sps->time_scale == 0) {
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GST_DEBUG_OBJECT (h264parse,
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"unable to compute timestamp: time_scale = 0 "
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"(this is forbidden in spec; bitstream probably contains error)");
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goto TIMESTAMP_FINISH;
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}
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if (sps->pic_struct_present_flag
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&& h264parse->sei_pic_struct != (guint8) - 1) {
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/* Note that when h264parse->sei_pic_struct == -1 (unspecified), there
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* are ways to infer its value. This is related to computing the
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* TopFieldOrderCnt and BottomFieldOrderCnt, which looks
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* complicated and thus not implemented for the time being. Yet
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* the value we have here is correct for many applications
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*/
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switch (h264parse->sei_pic_struct) {
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case SEI_PIC_STRUCT_TOP_FIELD:
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case SEI_PIC_STRUCT_BOTTOM_FIELD:
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duration = 1;
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break;
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case SEI_PIC_STRUCT_FRAME:
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case SEI_PIC_STRUCT_TOP_BOTTOM:
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case SEI_PIC_STRUCT_BOTTOM_TOP:
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duration = 2;
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break;
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case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
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case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
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duration = 3;
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break;
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case SEI_PIC_STRUCT_FRAME_DOUBLING:
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duration = 4;
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break;
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case SEI_PIC_STRUCT_FRAME_TRIPLING:
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duration = 6;
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break;
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default:
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GST_DEBUG_OBJECT (h264parse,
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"h264parse->sei_pic_struct of unknown value %d. Not parsed",
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h264parse->sei_pic_struct);
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}
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} else {
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duration = h264parse->field_pic_flag ? 1 : 2;
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}
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/*
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* h264parse.264 C.1.2 Timing of coded picture removal (equivalent to DTS):
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* Tr,n(0) = initial_cpb_removal_delay[ SchedSelIdx ] / 90000
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* Tr,n(n) = Tr,n(nb) + Tc * cpb_removal_delay(n)
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* where
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* Tc = num_units_in_tick / time_scale
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*/
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if (h264parse->ts_trn_nb != GST_CLOCK_TIME_NONE) {
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/* buffering period is present */
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if (outbuf_dts != GST_CLOCK_TIME_NONE) {
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/* If upstream timestamp is valid, we respect it and adjust current
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* reference point */
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h264parse->ts_trn_nb = outbuf_dts -
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(GstClockTime) gst_util_uint64_scale_int
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(h264parse->sei_cpb_removal_delay * GST_SECOND,
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sps->num_units_in_tick, sps->time_scale);
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} else {
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/* If no upstream timestamp is given, we write in new timestamp */
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h264parse->dts = h264parse->ts_trn_nb +
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(GstClockTime) gst_util_uint64_scale_int
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(h264parse->sei_cpb_removal_delay * GST_SECOND,
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sps->num_units_in_tick, sps->time_scale);
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}
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} else {
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/* naive method: no removal delay specified, use best guess (add prev
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* frame duration) */
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if (outbuf_dts != GST_CLOCK_TIME_NONE)
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h264parse->dts = outbuf_dts;
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else if (h264parse->dts != GST_CLOCK_TIME_NONE)
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h264parse->dts +=
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(GstClockTime) gst_util_uint64_scale_int (h264parse->
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cur_duration * GST_SECOND, sps->num_units_in_tick,
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sps->time_scale);
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else
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h264parse->dts = 0; /* initialization */
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/* TODO: better approach: construct a buffer queue and put all these
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* NALs into the buffer. Wait until we are able to get any valid dts
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* or such like, and dump the buffer and estimate the timestamps of
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* the NALs by their duration.
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*/
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}
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h264parse->cur_duration = duration;
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h264parse->frame_cnt += 1;
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if (outbuf_dts != GST_CLOCK_TIME_NONE)
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h264parse->last_outbuf_dts = outbuf_dts;
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}
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if (outbuf_dts == GST_CLOCK_TIME_NONE)
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outbuf_dts = h264parse->dts;
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else
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h264parse->dts = outbuf_dts;
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TIMESTAMP_FINISH:
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GST_BUFFER_TIMESTAMP (outbuf) = outbuf_dts;
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GST_DEBUG_OBJECT (h264parse,
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GST_DEBUG_OBJECT (h264parse,
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"pushing buffer %p, size %u, ts %" GST_TIME_FORMAT, outbuf,
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"pushing buffer %p, size %u, ts %" GST_TIME_FORMAT, outbuf,
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@ -1164,7 +1285,6 @@ gst_h264_parse_chain_forward (GstH264Parse * h264parse, gboolean discont,
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GST_BUFFER_FLAG_UNSET (outbuf, GST_BUFFER_FLAG_DELTA_UNIT);
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GST_BUFFER_FLAG_UNSET (outbuf, GST_BUFFER_FLAG_DELTA_UNIT);
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gst_buffer_set_caps (outbuf, GST_PAD_CAPS (h264parse->srcpad));
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gst_buffer_set_caps (outbuf, GST_PAD_CAPS (h264parse->srcpad));
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GST_BUFFER_TIMESTAMP (outbuf) = timestamp;
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res = gst_pad_push (h264parse->srcpad, outbuf);
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res = gst_pad_push (h264parse->srcpad, outbuf);
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} else {
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} else {
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/* NALU can not be parsed yet, we wait for more data in the adapter. */
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/* NALU can not be parsed yet, we wait for more data in the adapter. */
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