gstreamer/subprojects/gst-plugins-bad/gst/codectimestamper/gsth265timestamper.c

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/* GStreamer
* Copyright (C) 2022 Seungha Yang <seungha@centricular.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:element-h265timestamper
* @title: h265timestamper
* @short_description: A timestamp correction element for H.265 streams
*
* `h265timestamper` updates the DTS (Decoding Time Stamp) of each frame
* based on H.265 SPS codec setup data, specifically the frame reordering
* information written in the SPS indicating the maximum number of B-frames
* allowed.
*
* In order to determine the DTS of each frame, this element may need to hold
* back a few frames in case the codec data indicates that frame reordering is
* allowed for the given stream. That means this element may introduce additional
* latency for the DTS decision.
*
* This element can be useful if downstream elements require correct DTS
* information but upstream elements either do not provide it at all or the
* upstream DTS information is unreliable.
*
* For example, mp4 muxers typically require both DTS and PTS on the input
* buffers, but in case where the input H.265 data comes from Matroska files or
* RTP/RTSP streams DTS timestamps may be absent and this element may need to
* be used to clean up the DTS timestamps before handing it to the mp4 muxer.
*
* This is particularly the case where the H.265 stream contains B-frames
* (i.e. frame reordering is required), as streams without correct DTS information
* will confuse the muxer element and will result in unexpected (or bogus)
* duration/framerate/timestamp values in the muxed container stream.
*
* ## Example launch line
* ```
* gst-launch-1.0 filesrc location=video.mkv ! matroskademux ! h265parse ! h265timestamper ! mp4mux ! filesink location=output.mp4
* ```
*
* Since: 1.22
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/base/base.h>
#include <gst/codecparsers/gsth265parser.h>
#include "gsth265timestamper.h"
GST_DEBUG_CATEGORY_STATIC (gst_h265_timestamper_debug);
#define GST_CAT_DEFAULT gst_h265_timestamper_debug
static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("video/x-h265, alignment=(string) au"));
static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("video/x-h265, alignment=(string) au"));
struct _GstH265Timestamper
{
GstCodecTimestamper parent;
GstH265Parser *parser;
gboolean packetized;
guint nal_length_size;
};
static gboolean gst_h265_timestamper_start (GstCodecTimestamper * timestamper);
static gboolean gst_h265_timestamper_stop (GstCodecTimestamper * timestamper);
static gboolean gst_h265_timestamper_set_caps (GstCodecTimestamper *
timestamper, GstCaps * caps);
static GstFlowReturn gst_h265_timestamper_handle_buffer (GstCodecTimestamper *
timestamper, GstBuffer * buffer);
static void gst_h265_timestamper_process_nal (GstH265Timestamper * self,
GstH265NalUnit * nalu);
G_DEFINE_TYPE (GstH265Timestamper,
gst_h265_timestamper, GST_TYPE_CODEC_TIMESTAMPER);
GST_ELEMENT_REGISTER_DEFINE (h265timestamper, "h265timestamper",
GST_RANK_NONE, GST_TYPE_H265_TIMESTAMPER);
static void
gst_h265_timestamper_class_init (GstH265TimestamperClass * klass)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
GstCodecTimestamperClass *timestamper_class =
GST_CODEC_TIMESTAMPER_CLASS (klass);
gst_element_class_add_static_pad_template (element_class, &sinktemplate);
gst_element_class_add_static_pad_template (element_class, &srctemplate);
gst_element_class_set_static_metadata (element_class, "H.265 timestamper",
"Codec/Video", "Timestamp H.265 streams",
"Seungha Yang <seungha@centricular.com>");
timestamper_class->start = GST_DEBUG_FUNCPTR (gst_h265_timestamper_start);
timestamper_class->stop = GST_DEBUG_FUNCPTR (gst_h265_timestamper_stop);
timestamper_class->set_caps =
GST_DEBUG_FUNCPTR (gst_h265_timestamper_set_caps);
timestamper_class->handle_buffer =
GST_DEBUG_FUNCPTR (gst_h265_timestamper_handle_buffer);
GST_DEBUG_CATEGORY_INIT (gst_h265_timestamper_debug, "h265timestamper", 0,
"h265timestamper");
}
static void
gst_h265_timestamper_init (GstH265Timestamper * self)
{
}
static gboolean
gst_h265_timestamper_set_caps (GstCodecTimestamper * timestamper,
GstCaps * caps)
{
GstH265Timestamper *self = GST_H265_TIMESTAMPER (timestamper);
GstStructure *s = gst_caps_get_structure (caps, 0);
const gchar *str;
gboolean found_format = FALSE;
const GValue *codec_data_val;
self->packetized = FALSE;
self->nal_length_size = 4;
str = gst_structure_get_string (s, "stream-format");
if (g_strcmp0 (str, "hvc1") == 0 || g_strcmp0 (str, "hev1") == 0) {
self->packetized = TRUE;
found_format = TRUE;
} else if (g_strcmp0 (str, "byte-stream") == 0) {
found_format = TRUE;
}
codec_data_val = gst_structure_get_value (s, "codec_data");
if (codec_data_val && GST_VALUE_HOLDS_BUFFER (codec_data_val)) {
GstBuffer *codec_data = gst_value_get_buffer (codec_data_val);
GstH265Parser *parser = self->parser;
GstMapInfo map;
GstH265NalUnit nalu;
GstH265ParserResult pres;
guint num_nal_arrays;
guint off;
guint num_nals, i, j;
guint8 *data;
gsize size;
if (!gst_buffer_map (codec_data, &map, GST_MAP_READ)) {
GST_ERROR_OBJECT (self, "Unable to map codec-data buffer");
return FALSE;
}
data = map.data;
size = map.size;
/* parse the hvcC data */
if (size < 23) {
GST_WARNING_OBJECT (self, "hvcC too small");
goto unmap;
}
/* wrong hvcC version */
if (data[0] != 0 && data[0] != 1) {
goto unmap;
}
self->nal_length_size = (data[21] & 0x03) + 1;
GST_DEBUG_OBJECT (self, "nal length size %u", self->nal_length_size);
num_nal_arrays = data[22];
off = 23;
for (i = 0; i < num_nal_arrays; i++) {
if (off + 3 >= size) {
GST_WARNING_OBJECT (self, "hvcC too small");
goto unmap;
}
num_nals = GST_READ_UINT16_BE (data + off + 1);
off += 3;
for (j = 0; j < num_nals; j++) {
pres = gst_h265_parser_identify_nalu_hevc (parser,
data, off, size, 2, &nalu);
if (pres != GST_H265_PARSER_OK) {
GST_WARNING_OBJECT (self, "hvcC too small");
goto unmap;
}
gst_h265_timestamper_process_nal (self, &nalu);
off = nalu.offset + nalu.size;
}
}
/* codec_data would mean packetized format */
if (!found_format)
self->packetized = TRUE;
unmap:
gst_buffer_unmap (codec_data, &map);
}
return TRUE;
}
static void
gst_h265_timestamper_process_sps (GstH265Timestamper * self, GstH265SPS * sps)
{
guint max_reorder_frames =
sps->max_num_reorder_pics[sps->max_sub_layers_minus1];
GST_DEBUG_OBJECT (self, "Max num reorder frames %d", max_reorder_frames);
gst_codec_timestamper_set_window_size (GST_CODEC_TIMESTAMPER_CAST (self),
max_reorder_frames);
}
static void
gst_h265_timestamper_process_nal (GstH265Timestamper * self,
GstH265NalUnit * nalu)
{
GstH265ParserResult ret;
switch (nalu->type) {
case GST_H265_NAL_VPS:{
GstH265VPS vps;
ret = gst_h265_parser_parse_vps (self->parser, nalu, &vps);
if (ret != GST_H265_PARSER_OK)
GST_WARNING_OBJECT (self, "Failed to parse SPS");
break;
}
case GST_H265_NAL_SPS:{
GstH265SPS sps;
ret = gst_h265_parser_parse_sps (self->parser, nalu, &sps, FALSE);
if (ret != GST_H265_PARSER_OK) {
GST_WARNING_OBJECT (self, "Failed to parse SPS");
break;
}
gst_h265_timestamper_process_sps (self, &sps);
break;
}
/* TODO: parse PPS/SLICE and correct PTS based on POC if needed */
default:
break;
}
}
static GstFlowReturn
gst_h265_timestamper_handle_buffer (GstCodecTimestamper * timestamper,
GstBuffer * buffer)
{
GstH265Timestamper *self = GST_H265_TIMESTAMPER (timestamper);
GstMapInfo map;
/* Ignore any error while parsing NAL */
if (gst_buffer_map (buffer, &map, GST_MAP_READ)) {
GstH265ParserResult ret;
GstH265NalUnit nalu;
if (self->packetized) {
ret = gst_h265_parser_identify_nalu_hevc (self->parser,
map.data, 0, map.size, self->nal_length_size, &nalu);
while (ret == GST_H265_PARSER_OK) {
gst_h265_timestamper_process_nal (self, &nalu);
ret = gst_h265_parser_identify_nalu_hevc (self->parser,
map.data, nalu.offset + nalu.size, map.size, self->nal_length_size,
&nalu);
}
} else {
ret = gst_h265_parser_identify_nalu (self->parser,
map.data, 0, map.size, &nalu);
if (ret == GST_H265_PARSER_NO_NAL_END)
ret = GST_H265_PARSER_OK;
while (ret == GST_H265_PARSER_OK) {
gst_h265_timestamper_process_nal (self, &nalu);
ret = gst_h265_parser_identify_nalu (self->parser,
map.data, nalu.offset + nalu.size, map.size, &nalu);
if (ret == GST_H265_PARSER_NO_NAL_END)
ret = GST_H265_PARSER_OK;
}
}
gst_buffer_unmap (buffer, &map);
}
return GST_FLOW_OK;
}
static void
gst_h265_timestamper_reset (GstH265Timestamper * self)
{
g_clear_pointer (&self->parser, gst_h265_parser_free);
}
static gboolean
gst_h265_timestamper_start (GstCodecTimestamper * timestamper)
{
GstH265Timestamper *self = GST_H265_TIMESTAMPER (timestamper);
gst_h265_timestamper_reset (self);
self->parser = gst_h265_parser_new ();
return TRUE;
}
static gboolean
gst_h265_timestamper_stop (GstCodecTimestamper * timestamper)
{
GstH265Timestamper *self = GST_H265_TIMESTAMPER (timestamper);
gst_h265_timestamper_reset (self);
return TRUE;
}