gstreamer/sys/v4l2codecs/gstv4l2codecalphadecodebin.c
Nicolas Dufresne 4ac9f91921 alphadecodebin: Fix stall due to QoS
alphacombine element is a simple element that assumes buffers are always
paired, or at least that missing buffers are signalled with a GAP. The QoS
implementation in the GstVideoDecoder base class allow decoders dropping
frames independently and that could lead to stall in alphacombine.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2326>
2021-06-14 16:33:15 -04:00

231 lines
7.5 KiB
C

/* GStreamer
* Copyright (C) <2021> Collabora Ltd.
* Author: Daniel Almeida <daniel.almeida@collabora.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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/pbutils/pbutils.h>
#include "gstv4l2codecalphadecodebin.h"
#include "gstv4l2decoder.h"
GST_DEBUG_CATEGORY_STATIC (v4l2_codecalphadecodebin_debug);
#define GST_CAT_DEFAULT (v4l2_codecalphadecodebin_debug)
typedef struct
{
GstBin parent;
gboolean constructed;
const gchar *missing_element;
} GstV4l2CodecAlphaDecodeBinPrivate;
#define gst_v4l2_codec_alpha_decode_bin_parent_class parent_class
G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GstV4l2CodecAlphaDecodeBin,
gst_v4l2_codec_alpha_decode_bin, GST_TYPE_BIN,
G_ADD_PRIVATE (GstV4l2CodecAlphaDecodeBin);
GST_DEBUG_CATEGORY_INIT (v4l2_codecalphadecodebin_debug,
"v4l2codecs-alphadecodebin", 0, "V4L2 stateless alpha decode bin"));
static GstStaticPadTemplate gst_alpha_decode_bin_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("ANY")
);
static gboolean
gst_v4l2_codec_alpha_decode_bin_open (GstV4l2CodecAlphaDecodeBin * self)
{
GstV4l2CodecAlphaDecodeBinPrivate *priv =
gst_v4l2_codec_alpha_decode_bin_get_instance_private (self);
if (priv->missing_element) {
gst_element_post_message (GST_ELEMENT (self),
gst_missing_element_message_new (GST_ELEMENT (self),
priv->missing_element));
} else if (!priv->constructed) {
GST_ELEMENT_ERROR (self, CORE, FAILED,
("Failed to construct alpha decoder pipeline."), (NULL));
}
return priv->constructed;
}
static GstStateChangeReturn
gst_v4l2_codec_alpha_decode_bin_change_state (GstElement * element,
GstStateChange transition)
{
GstV4l2CodecAlphaDecodeBin *self = GST_V4L2_CODEC_ALPHA_DECODE_BIN (element);
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
if (!gst_v4l2_codec_alpha_decode_bin_open (self))
return GST_STATE_CHANGE_FAILURE;
break;
default:
break;
}
return GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
}
static void
gst_v4l2_codec_alpha_decode_bin_constructed (GObject * obj)
{
GstV4l2CodecAlphaDecodeBin *self = GST_V4L2_CODEC_ALPHA_DECODE_BIN (obj);
GstV4l2CodecAlphaDecodeBinPrivate *priv =
gst_v4l2_codec_alpha_decode_bin_get_instance_private (self);
GstV4l2CodecAlphaDecodeBinClass *klass =
GST_V4L2_CODEC_ALPHA_DECODE_BIN_GET_CLASS (self);
GstPad *src_gpad, *sink_gpad;
GstPad *src_pad = NULL, *sink_pad = NULL;
GstElement *alphademux = NULL;
GstElement *queue = NULL;
GstElement *alpha_queue = NULL;
GstElement *decoder = NULL;
GstElement *alpha_decoder = NULL;
GstElement *alphacombine = NULL;
/* setup ghost pads */
sink_gpad = gst_ghost_pad_new_no_target_from_template ("sink",
gst_element_class_get_pad_template (GST_ELEMENT_CLASS (klass), "sink"));
gst_element_add_pad (GST_ELEMENT (self), sink_gpad);
src_gpad = gst_ghost_pad_new_no_target_from_template ("src",
gst_element_class_get_pad_template (GST_ELEMENT_CLASS (klass), "src"));
gst_element_add_pad (GST_ELEMENT (self), src_gpad);
/* create elements */
alphademux = gst_element_factory_make ("codecalphademux", NULL);
if (!alphademux) {
priv->missing_element = "codecalphademux";
goto cleanup;
}
queue = gst_element_factory_make ("queue", NULL);
alpha_queue = gst_element_factory_make ("queue", NULL);
if (!queue || !alpha_queue) {
priv->missing_element = "queue";
goto cleanup;
}
decoder = gst_element_factory_make (klass->decoder_name, "maindec");
if (!decoder) {
priv->missing_element = klass->decoder_name;
goto cleanup;
}
alpha_decoder = gst_element_factory_make (klass->decoder_name, "alphadec");
if (!alpha_decoder) {
priv->missing_element = klass->decoder_name;
goto cleanup;
}
/* We disable QoS on decoders because we need to maintain frame pairing in
* order for alphacombine to work. */
g_object_set (decoder, "qos", FALSE, NULL);
g_object_set (alpha_decoder, "qos", FALSE, NULL);
alphacombine = gst_element_factory_make ("alphacombine", NULL);
if (!alphacombine) {
priv->missing_element = "alphacombine";
goto cleanup;
}
gst_bin_add_many (GST_BIN (self), alphademux, queue, alpha_queue, decoder,
alpha_decoder, alphacombine, NULL);
/* link elements */
sink_pad = gst_element_get_static_pad (alphademux, "sink");
gst_ghost_pad_set_target (GST_GHOST_PAD (sink_gpad), sink_pad);
gst_clear_object (&sink_pad);
gst_element_link_pads (alphademux, "src", queue, "sink");
gst_element_link_pads (queue, "src", decoder, "sink");
gst_element_link_pads (decoder, "src", alphacombine, "sink");
gst_element_link_pads (alphademux, "alpha", alpha_queue, "sink");
gst_element_link_pads (alpha_queue, "src", alpha_decoder, "sink");
gst_element_link_pads (alpha_decoder, "src", alphacombine, "alpha");
src_pad = gst_element_get_static_pad (alphacombine, "src");
gst_ghost_pad_set_target (GST_GHOST_PAD (src_gpad), src_pad);
gst_object_unref (src_pad);
g_object_set (queue, "max-size-bytes", 0, "max-size-time", 0,
"max-size-buffers", 1, NULL);
g_object_set (alpha_queue, "max-size-bytes", 0, "max-size-time", 0,
"max-size-buffers", 1, NULL);
/* signal success, we will handle this in NULL->READY transition */
priv->constructed = TRUE;
return;
cleanup:
gst_clear_object (&alphademux);
gst_clear_object (&queue);
gst_clear_object (&alpha_queue);
gst_clear_object (&decoder);
gst_clear_object (&alpha_decoder);
gst_clear_object (&alphacombine);
G_OBJECT_CLASS (parent_class)->constructed (obj);
}
static void
gst_v4l2_codec_alpha_decode_bin_class_init (GstV4l2CodecAlphaDecodeBinClass *
klass)
{
GstElementClass *element_class = (GstElementClass *) klass;
GObjectClass *obj_class = (GObjectClass *) klass;
/* This is needed to access the subclass class instance, otherwise we cannot
* read the class parameters */
obj_class->constructed = gst_v4l2_codec_alpha_decode_bin_constructed;
gst_element_class_add_static_pad_template (element_class,
&gst_alpha_decode_bin_src_template);
element_class->change_state =
GST_DEBUG_FUNCPTR (gst_v4l2_codec_alpha_decode_bin_change_state);
/* let's make the doc generator happy */
gst_type_mark_as_plugin_api (GST_TYPE_V4L2_CODEC_ALPHA_DECODE_BIN, 0);
}
static void
gst_v4l2_codec_alpha_decode_bin_init (GstV4l2CodecAlphaDecodeBin * self)
{
}
void
gst_v4l2_codec_alpha_decode_bin_register (GstPlugin * plugin,
GClassInitFunc class_init, gconstpointer class_data,
const gchar * element_name_tmpl, GstV4l2CodecDevice * device, guint rank)
{
/* TODO check that we have compatible src format */
gst_v4l2_decoder_register (plugin,
GST_TYPE_V4L2_CODEC_ALPHA_DECODE_BIN, class_init, class_data, NULL,
element_name_tmpl, device,
rank + GST_V4L2_CODEC_ALPHA_DECODE_BIN_RANK_OFFSET, NULL);
}