gstreamer/gst/videoparsers/gstvp9parse.c

/* GStreamer
 * Copyright (C) 2020 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <gst/codecparsers/gstvp9parser.h>
#include <gst/video/video.h>
#include "gstvp9parse.h"

#include <string.h>

GST_DEBUG_CATEGORY (vp9_parse_debug);
#define GST_CAT_DEFAULT vp9_parse_debug

typedef enum
{
  GST_VP9_PARSE_ALIGN_NONE = 0,
  GST_VP9_PARSE_ALIGN_SUPER_FRAME,
  GST_VP9_PARSE_ALIGN_FRAME,
} GstVp9ParseAligment;

struct _GstVp9Parse
{
  GstBaseParse parent;

  /* parsed from the last keyframe */
  gint width;
  gint height;
  gint subsampling_x;
  gint subsampling_y;
  GstVp9ColorSpace color_space;
  GstVp9ColorRange color_range;
  GstVP9Profile profile;
  GstVp9BitDepth bit_depth;

  GstVp9ParseAligment in_align;
  GstVp9ParseAligment align;

  GstVp9Parser *parser;
  gboolean update_caps;

  /* per frame status */
  gboolean discont;
};

static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-vp9"));

static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-vp9, parsed = (boolean) true, "
        "alignment=(string) { super-frame, frame }"));

#define parent_class gst_vp9_parse_parent_class
G_DEFINE_TYPE (GstVp9Parse, gst_vp9_parse, GST_TYPE_BASE_PARSE);

static gboolean gst_vp9_parse_start (GstBaseParse * parse);
static gboolean gst_vp9_parse_stop (GstBaseParse * parse);
static GstFlowReturn gst_vp9_parse_handle_frame (GstBaseParse * parse,
    GstBaseParseFrame * frame, gint * skipsize);
static gboolean gst_vp9_parse_set_sink_caps (GstBaseParse * parse,
    GstCaps * caps);
static GstCaps *gst_vp9_parse_get_sink_caps (GstBaseParse * parse,
    GstCaps * filter);
static void gst_vp9_parse_update_src_caps (GstVp9Parse * self, GstCaps * caps);
static GstFlowReturn gst_vp9_parse_parse_frame (GstVp9Parse * self,
    GstBaseParseFrame * frame, GstVp9FrameHdr * frame_hdr);

static void
gst_vp9_parse_class_init (GstVp9ParseClass * klass)
{
  GstBaseParseClass *parse_class = GST_BASE_PARSE_CLASS (klass);
  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);

  parse_class->start = GST_DEBUG_FUNCPTR (gst_vp9_parse_start);
  parse_class->stop = GST_DEBUG_FUNCPTR (gst_vp9_parse_stop);
  parse_class->handle_frame = GST_DEBUG_FUNCPTR (gst_vp9_parse_handle_frame);
  parse_class->set_sink_caps = GST_DEBUG_FUNCPTR (gst_vp9_parse_set_sink_caps);
  parse_class->get_sink_caps = GST_DEBUG_FUNCPTR (gst_vp9_parse_get_sink_caps);

  gst_element_class_add_static_pad_template (element_class, &srctemplate);
  gst_element_class_add_static_pad_template (element_class, &sinktemplate);

  gst_element_class_set_static_metadata (element_class, "VP9 parser",
      "Codec/Parser/Converter/Video",
      "Parses VP9 streams", "Seungha Yang <seungha@centricular.com>");

  GST_DEBUG_CATEGORY_INIT (vp9_parse_debug, "vp9parse", 0, "vp9 parser");
}

static void
gst_vp9_parse_init (GstVp9Parse * self)
{
  gst_base_parse_set_pts_interpolation (GST_BASE_PARSE (self), FALSE);
  gst_base_parse_set_infer_ts (GST_BASE_PARSE (self), FALSE);

  GST_PAD_SET_ACCEPT_INTERSECT (GST_BASE_PARSE_SINK_PAD (self));
  GST_PAD_SET_ACCEPT_TEMPLATE (GST_BASE_PARSE_SINK_PAD (self));
}

static void
gst_vp9_parse_reset (GstVp9Parse * self)
{
  self->width = 0;
  self->height = 0;
  self->subsampling_x = -1;
  self->subsampling_y = -1;
  self->color_space = GST_VP9_CS_UNKNOWN;
  self->color_range = GST_VP9_CR_LIMITED;
  self->profile = GST_VP9_PROFILE_UNDEFINED;
  self->bit_depth = (GstVp9BitDepth) 0;
}

static gboolean
gst_vp9_parse_start (GstBaseParse * parse)
{
  GstVp9Parse *self = GST_VP9_PARSE (parse);

  GST_DEBUG_OBJECT (self, "start");

  self->parser = gst_vp9_parser_new ();
  gst_vp9_parse_reset (self);

  /* short frame header with one byte */
  gst_base_parse_set_min_frame_size (parse, 1);

  return TRUE;
}

static gboolean
gst_vp9_parse_stop (GstBaseParse * parse)
{
  GstVp9Parse *self = GST_VP9_PARSE (parse);

  GST_DEBUG_OBJECT (self, "stop");
  g_clear_pointer (&self->parser, gst_vp9_parser_free);

  return TRUE;
}

static const gchar *
gst_vp9_parse_profile_to_string (GstVP9Profile profile)
{
  switch (profile) {
    case GST_VP9_PROFILE_0:
      return "0";
    case GST_VP9_PROFILE_1:
      return "1";
    case GST_VP9_PROFILE_2:
      return "2";
    case GST_VP9_PROFILE_3:
      return "3";
    default:
      break;
  }

  return NULL;
}

static GstVP9Profile
gst_vp9_parse_profile_from_string (const gchar * profile)
{
  if (!profile)
    return GST_VP9_PROFILE_UNDEFINED;

  if (g_strcmp0 (profile, "0") == 0)
    return GST_VP9_PROFILE_0;
  else if (g_strcmp0 (profile, "1") == 0)
    return GST_VP9_PROFILE_1;
  else if (g_strcmp0 (profile, "2") == 0)
    return GST_VP9_PROFILE_2;
  else if (g_strcmp0 (profile, "3") == 0)
    return GST_VP9_PROFILE_3;

  return GST_VP9_PROFILE_UNDEFINED;
}

static const gchar *
gst_vp9_parse_alignment_to_string (GstVp9ParseAligment align)
{
  switch (align) {
    case GST_VP9_PARSE_ALIGN_SUPER_FRAME:
      return "super-frame";
    case GST_VP9_PARSE_ALIGN_FRAME:
      return "frame";
    default:
      break;
  }

  return NULL;
}

static GstVp9ParseAligment
gst_vp9_parse_alignment_from_string (const gchar * align)
{
  if (!align)
    return GST_VP9_PARSE_ALIGN_NONE;

  if (g_strcmp0 (align, "super-frame") == 0)
    return GST_VP9_PARSE_ALIGN_SUPER_FRAME;
  else if (g_strcmp0 (align, "frame") == 0)
    return GST_VP9_PARSE_ALIGN_FRAME;

  return GST_VP9_PARSE_ALIGN_NONE;
}

static void
gst_vp9_parse_alignment_from_caps (GstCaps * caps, GstVp9ParseAligment * align)
{
  *align = GST_VP9_PARSE_ALIGN_NONE;

  GST_DEBUG ("parsing caps: %" GST_PTR_FORMAT, caps);

  if (caps && gst_caps_get_size (caps) > 0) {
    GstStructure *s = gst_caps_get_structure (caps, 0);
    const gchar *str = NULL;

    if ((str = gst_structure_get_string (s, "alignment"))) {
      *align = gst_vp9_parse_alignment_from_string (str);
    }
  }
}

/* check downstream caps to configure format and alignment */
static void
gst_vp9_parse_negotiate (GstVp9Parse * self, GstVp9ParseAligment in_align,
    GstCaps * in_caps)
{
  GstCaps *caps;
  GstVp9ParseAligment align = self->align;

  caps = gst_pad_get_allowed_caps (GST_BASE_PARSE_SRC_PAD (self));
  GST_DEBUG_OBJECT (self, "allowed caps: %" GST_PTR_FORMAT, caps);

  /* concentrate on leading structure, since decodebin parser
   * capsfilter always includes parser template caps */
  if (caps) {
    caps = gst_caps_truncate (caps);
    GST_DEBUG_OBJECT (self, "negotiating with caps: %" GST_PTR_FORMAT, caps);
  }

  if (in_caps && caps) {
    if (gst_caps_can_intersect (in_caps, caps)) {
      GST_DEBUG_OBJECT (self, "downstream accepts upstream caps");
      gst_vp9_parse_alignment_from_caps (in_caps, &align);
      gst_clear_caps (&caps);
    }
  }

  /* FIXME We could fail the negotiation immediately if caps are empty */
  if (caps && !gst_caps_is_empty (caps)) {
    /* fixate to avoid ambiguity with lists when parsing */
    caps = gst_caps_fixate (caps);
    gst_vp9_parse_alignment_from_caps (caps, &align);
  }

  /* default */
  if (align == GST_VP9_PARSE_ALIGN_NONE)
    align = GST_VP9_PARSE_ALIGN_SUPER_FRAME;

  GST_DEBUG_OBJECT (self, "selected alignment %s",
      gst_vp9_parse_alignment_to_string (align));

  self->align = align;

  gst_clear_caps (&caps);
}

static gboolean
gst_vp9_parse_process_frame (GstVp9Parse * self, GstVp9FrameHdr * frame_hdr)
{
  GstVp9Parser *parser = self->parser;
  gint width, height;

  /* the resolution might be varying. Update our status per key frame */
  if (frame_hdr->frame_type != GST_VP9_KEY_FRAME) {
    return TRUE;
  }

  width = frame_hdr->width;
  height = frame_hdr->height;
  if (frame_hdr->display_size_enabled &&
      frame_hdr->display_width > 0 && frame_hdr->display_height) {
    width = frame_hdr->display_width;
    height = frame_hdr->display_height;
  }

  if (width != self->width || height != self->height) {
    GST_DEBUG_OBJECT (self, "resolution change from %dx%d to %dx%d",
        self->width, self->height, width, height);
    self->width = width;
    self->height = height;
    self->update_caps = TRUE;
  }

  if (self->subsampling_x != parser->subsampling_x ||
      self->subsampling_y != parser->subsampling_y) {
    GST_DEBUG_OBJECT (self,
        "subsampling changed from x: %d, y: %d to x: %d, y: %d",
        self->subsampling_x, self->subsampling_y,
        parser->subsampling_x, parser->subsampling_y);
    self->subsampling_x = parser->subsampling_x;
    self->subsampling_y = parser->subsampling_y;
    self->update_caps = TRUE;
  }

  if (parser->color_space != GST_VP9_CS_UNKNOWN &&
      parser->color_space != GST_VP9_CS_RESERVED_2 &&
      parser->color_space != self->color_space) {
    GST_DEBUG_OBJECT (self, "colorspace changed from %d to %d",
        self->color_space, parser->color_space);
    self->color_space = parser->color_space;
    self->update_caps = TRUE;
  }

  if (parser->color_range != self->color_range) {
    GST_DEBUG_OBJECT (self, "color range changed from %d to %d",
        self->color_range, parser->color_range);
    self->color_range = parser->color_range;
    self->update_caps = TRUE;
  }

  if (frame_hdr->profile != GST_VP9_PROFILE_UNDEFINED &&
      frame_hdr->profile != self->profile) {
    GST_DEBUG_OBJECT (self, "profile changed from %d to %d", self->profile,
        frame_hdr->profile);
    self->profile = frame_hdr->profile;
    self->update_caps = TRUE;
  }

  if (parser->bit_depth != self->bit_depth) {
    GST_DEBUG_OBJECT (self, "bit-depth changed from %d to %d",
        self->bit_depth, parser->bit_depth);
    self->bit_depth = parser->bit_depth;
    self->update_caps = TRUE;
  }

  return TRUE;
}

static GstFlowReturn
gst_vp9_parse_handle_frame (GstBaseParse * parse, GstBaseParseFrame * frame,
    gint * skipsize)
{
  GstVp9Parse *self = GST_VP9_PARSE (parse);
  GstBuffer *buffer = frame->buffer;
  GstFlowReturn ret = GST_FLOW_OK;
  GstVp9ParserResult parse_res = GST_VP9_PARSER_ERROR;
  GstMapInfo map;
  gsize offset = 0;
  GstVp9SuperframeInfo superframe_info;
  guint i;
  GstVp9FrameHdr frame_hdr;

  if (GST_BUFFER_FLAG_IS_SET (frame->buffer, GST_BUFFER_FLAG_DISCONT))
    self->discont = TRUE;
  else
    self->discont = FALSE;

  /* need to save buffer from invalidation upon _finish_frame */
  if (self->align == GST_VP9_PARSE_ALIGN_FRAME)
    buffer = gst_buffer_copy (frame->buffer);

  if (!gst_buffer_map (buffer, &map, GST_MAP_READ)) {
    GST_ELEMENT_ERROR (parse, CORE, NOT_IMPLEMENTED, (NULL),
        ("Couldn't map incoming buffer"));

    return GST_FLOW_ERROR;
  }

  GST_TRACE_OBJECT (self, "processing buffer of size %" G_GSIZE_FORMAT,
      map.size);

  /* superframe_info will be zero initialized by GstVp9Parser */
  parse_res = gst_vp9_parser_parse_superframe_info (self->parser,
      &superframe_info, map.data, map.size);

  if (parse_res != GST_VP9_PARSER_OK) {
    /* just finish this frame anyway, so that we don't too strict
     * regarding parsing vp9 stream.
     * Downstream might be able to handle this stream even though
     * it's very unlikely */
    GST_WARNING_OBJECT (self, "Couldn't parse superframe res: %d", parse_res);
    goto done;
  }

  for (i = 0; i < superframe_info.frames_in_superframe; i++) {
    guint32 frame_size;

    frame_size = superframe_info.frame_sizes[i];
    parse_res = gst_vp9_parser_parse_frame_header (self->parser,
        &frame_hdr, map.data + offset, frame_size);

    if (parse_res != GST_VP9_PARSER_OK) {
      GST_WARNING_OBJECT (self, "Parsing error %d", parse_res);
      break;
    }

    gst_vp9_parse_process_frame (self, &frame_hdr);

    if (self->align == GST_VP9_PARSE_ALIGN_FRAME) {
      GstBaseParseFrame subframe;

      gst_base_parse_frame_init (&subframe);
      subframe.flags |= frame->flags;
      subframe.offset = frame->offset;
      subframe.overhead = frame->overhead;
      subframe.buffer = gst_buffer_copy_region (buffer, GST_BUFFER_COPY_ALL,
          offset, frame_size);

      /* note we don't need to come up with a sub-buffer, since
       * subsequent code only considers input buffer's metadata.
       * Real data is either taken from input by baseclass or
       * a replacement output buffer is provided anyway. */
      gst_vp9_parse_parse_frame (self, &subframe, &frame_hdr);
      ret = gst_base_parse_finish_frame (parse, &subframe, frame_size);
    } else {
      /* FIXME: need to parse all frames belong to this superframe? */
      break;
    }

    offset += frame_size;
  }

done:
  gst_buffer_unmap (buffer, &map);

  if (self->align != GST_VP9_PARSE_ALIGN_FRAME) {
    if (parse_res == GST_VP9_PARSER_OK)
      gst_vp9_parse_parse_frame (self, frame, &frame_hdr);
    ret = gst_base_parse_finish_frame (parse, frame, map.size);
  } else {
    gst_buffer_unref (buffer);
    if (offset != map.size) {
      gsize left = map.size - offset;
      if (left != superframe_info.superframe_index_size) {
        GST_WARNING_OBJECT (parse,
            "Skipping leftover frame data %" G_GSIZE_FORMAT, left);
      }
      frame->flags |= GST_BASE_PARSE_FRAME_FLAG_DROP;
      ret = gst_base_parse_finish_frame (parse, frame, left);
    }
  }

  return ret;
}

static void
gst_vp9_parse_update_src_caps (GstVp9Parse * self, GstCaps * caps)
{
  GstCaps *sink_caps, *src_caps;
  GstCaps *final_caps = NULL;
  GstStructure *s = NULL;
  gint width, height;
  gint par_n = 0, par_d = 0;
  gint fps_n = 0, fps_d = 0;
  gint bitdepth = 0;
  gchar *colorimetry = NULL;
  const gchar *chroma_format = NULL;
  const gchar *profile = NULL;

  if (!self->update_caps)
    return;

  /* if this is being called from the first _setcaps call, caps on the sinkpad
   * aren't set yet and so they need to be passed as an argument */
  if (caps)
    sink_caps = gst_caps_ref (caps);
  else
    sink_caps = gst_pad_get_current_caps (GST_BASE_PARSE_SINK_PAD (self));

  /* carry over input caps as much as possible; override with our own stuff */
  if (!sink_caps)
    sink_caps = gst_caps_new_empty_simple ("video/x-vp9");
  else
    s = gst_caps_get_structure (sink_caps, 0);

  final_caps = gst_caps_copy (sink_caps);

  /* frame header should give this but upstream overrides */
  if (s && gst_structure_has_field (s, "width") &&
      gst_structure_has_field (s, "height")) {
    gst_structure_get_int (s, "width", &width);
    gst_structure_get_int (s, "height", &height);
  } else {
    width = self->width;
    height = self->height;
  }

  if (width > 0 && height > 0)
    gst_caps_set_simple (final_caps, "width", G_TYPE_INT, width,
        "height", G_TYPE_INT, height, NULL);

  if (s && gst_structure_get_fraction (s, "pixel-aspect-ratio", &par_n, &par_d)) {
    if (par_n != 0 && par_d != 0) {
      gst_caps_set_simple (final_caps, "pixel-aspect-ratio",
          GST_TYPE_FRACTION, par_n, par_d, NULL);
    }
  }

  if (s && gst_structure_has_field (s, "framerate")) {
    gst_structure_get_fraction (s, "framerate", &fps_n, &fps_d);
  }

  if (fps_n > 0 && fps_d > 0) {
    gst_caps_set_simple (final_caps, "framerate",
        GST_TYPE_FRACTION, fps_n, fps_d, NULL);
    gst_base_parse_set_frame_rate (GST_BASE_PARSE (self), fps_n, fps_d, 0, 0);
  }

  if (self->color_space != GST_VP9_CS_UNKNOWN &&
      self->color_space != GST_VP9_CS_RESERVED_2) {
    GstVideoColorimetry cinfo;
    gboolean have_cinfo = TRUE;

    memset (&cinfo, 0, sizeof (GstVideoColorimetry));

    switch (self->parser->color_space) {
      case GST_VP9_CS_BT_601:
        gst_video_colorimetry_from_string (&cinfo, GST_VIDEO_COLORIMETRY_BT601);
        break;
      case GST_VP9_CS_BT_709:
        gst_video_colorimetry_from_string (&cinfo, GST_VIDEO_COLORIMETRY_BT709);
        break;
      case GST_VP9_CS_SMPTE_170:
        gst_video_colorimetry_from_string (&cinfo, GST_VIDEO_COLORIMETRY_BT601);
        break;
      case GST_VP9_CS_SMPTE_240:
        gst_video_colorimetry_from_string (&cinfo,
            GST_VIDEO_COLORIMETRY_SMPTE240M);
        break;
      case GST_VP9_CS_BT_2020:
        if (self->parser->bit_depth == GST_VP9_BIT_DEPTH_12) {
          gst_video_colorimetry_from_string (&cinfo,
              GST_VIDEO_COLORIMETRY_BT2020);
        } else {
          gst_video_colorimetry_from_string (&cinfo,
              GST_VIDEO_COLORIMETRY_BT2020_10);
        }
        break;
      case GST_VP9_CS_SRGB:
        gst_video_colorimetry_from_string (&cinfo, GST_VIDEO_COLORIMETRY_SRGB);
        break;
      default:
        have_cinfo = FALSE;
        break;
    }

    if (have_cinfo) {
      if (self->parser->color_range == GST_VP9_CR_LIMITED)
        cinfo.range = GST_VIDEO_COLOR_RANGE_16_235;
      else
        cinfo.range = GST_VIDEO_COLOR_RANGE_0_255;

      colorimetry = gst_video_colorimetry_to_string (&cinfo);
    }
  }

  if (self->color_space != GST_VP9_CS_SRGB) {
    if (self->parser->subsampling_x == 1 && self->parser->subsampling_y == 1)
      chroma_format = "4:2:0";
    else if (self->parser->subsampling_x == 1 &&
        self->parser->subsampling_y == 0)
      chroma_format = "4:2:2";
    else if (self->parser->subsampling_x == 0 &&
        self->parser->subsampling_y == 1)
      chroma_format = "4:4:0";
    else if (self->parser->subsampling_x == 1 &&
        self->parser->subsampling_y == 1)
      chroma_format = "4:4:4";

    if (chroma_format)
      gst_caps_set_simple (final_caps,
          "chroma-format", G_TYPE_STRING, chroma_format, NULL);
  }

  switch (self->bit_depth) {
    case GST_VP9_BIT_DEPTH_8:
      bitdepth = 8;
      break;
    case GST_VP9_BIT_DEPTH_10:
      bitdepth = 10;
      break;
    case GST_VP9_BIT_DEPTH_12:
      bitdepth = 12;
      break;
    default:
      break;
  }

  if (bitdepth) {
    gst_caps_set_simple (final_caps,
        "bit-depth-luma", G_TYPE_UINT, bitdepth,
        "bit-depth-chroma", G_TYPE_UINT, bitdepth, NULL);
  }

  if (colorimetry && (!s || !gst_structure_has_field (s, "colorimetry"))) {
    gst_caps_set_simple (final_caps,
        "colorimetry", G_TYPE_STRING, colorimetry, NULL);
  }

  g_free (colorimetry);

  gst_caps_set_simple (final_caps, "parsed", G_TYPE_BOOLEAN, TRUE,
      "alignment", G_TYPE_STRING,
      gst_vp9_parse_alignment_to_string (self->align), NULL);

  profile = gst_vp9_parse_profile_to_string (self->profile);
  if (profile)
    gst_caps_set_simple (final_caps, "profile", G_TYPE_STRING, profile, NULL);

  src_caps = gst_pad_get_current_caps (GST_BASE_PARSE_SRC_PAD (self));

  if (!(src_caps && gst_caps_is_strictly_equal (src_caps, final_caps))) {
    GST_DEBUG_OBJECT (self, "Update src caps %" GST_PTR_FORMAT, final_caps);
    gst_pad_set_caps (GST_BASE_PARSE_SRC_PAD (self), final_caps);
  }

  gst_clear_caps (&src_caps);
  gst_caps_unref (final_caps);
  gst_caps_unref (sink_caps);

  self->update_caps = FALSE;
}

static GstFlowReturn
gst_vp9_parse_parse_frame (GstVp9Parse * self, GstBaseParseFrame * frame,
    GstVp9FrameHdr * frame_hdr)
{
  GstBuffer *buffer;

  buffer = frame->buffer;

  gst_vp9_parse_update_src_caps (self, NULL);

  if (frame_hdr->frame_type == GST_VP9_KEY_FRAME)
    GST_BUFFER_FLAG_UNSET (buffer, GST_BUFFER_FLAG_DELTA_UNIT);
  else
    GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DELTA_UNIT);

  if (self->align == GST_VP9_PARSE_ALIGN_FRAME) {
    if (!frame_hdr->show_frame)
      GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DECODE_ONLY);
    else
      GST_BUFFER_FLAG_UNSET (buffer, GST_BUFFER_FLAG_DECODE_ONLY);
  }

  if (self->discont) {
    GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DISCONT);
    self->discont = FALSE;
  }

  return GST_FLOW_OK;
}

static gboolean
gst_vp9_parse_set_sink_caps (GstBaseParse * parse, GstCaps * caps)
{
  GstVp9Parse *self = GST_VP9_PARSE (parse);
  GstStructure *str;
  GstVp9ParseAligment align;
  GstCaps *in_caps = NULL;
  const gchar *profile;

  str = gst_caps_get_structure (caps, 0);

  /* accept upstream info if provided */
  gst_structure_get_int (str, "width", &self->width);
  gst_structure_get_int (str, "height", &self->height);
  profile = gst_structure_get_string (str, "profile");
  if (profile)
    self->profile = gst_vp9_parse_profile_from_string (profile);

  /* get upstream align from caps */
  gst_vp9_parse_alignment_from_caps (caps, &align);

  /* default */
  if (align == GST_VP9_PARSE_ALIGN_NONE)
    align = GST_VP9_PARSE_ALIGN_SUPER_FRAME;

  /* prefer alignment type determined above */
  in_caps = gst_caps_copy (caps);
  gst_caps_set_simple (in_caps, "alignment", G_TYPE_STRING,
      gst_vp9_parse_alignment_to_string (align), NULL);

  /* negotiate with downstream, set output align */
  gst_vp9_parse_negotiate (self, align, in_caps);

  self->update_caps = TRUE;

  /* if all of decoder's capability related values are provided
   * by upstream, update src caps now */
  if (self->width > 0 && self->height > 0 && profile)
    gst_vp9_parse_update_src_caps (self, in_caps);

  gst_caps_unref (in_caps);

  self->in_align = align;

  return TRUE;
}

static void
remove_fields (GstCaps * caps, gboolean all)
{
  guint i, n;

  n = gst_caps_get_size (caps);
  for (i = 0; i < n; i++) {
    GstStructure *s = gst_caps_get_structure (caps, i);

    if (all) {
      gst_structure_remove_field (s, "alignment");
    }
    gst_structure_remove_field (s, "parsed");
  }
}

static GstCaps *
gst_vp9_parse_get_sink_caps (GstBaseParse * parse, GstCaps * filter)
{
  GstCaps *peercaps, *templ;
  GstCaps *res, *tmp, *pcopy;

  templ = gst_pad_get_pad_template_caps (GST_BASE_PARSE_SINK_PAD (parse));
  if (filter) {
    GstCaps *fcopy = gst_caps_copy (filter);
    /* Remove the fields we convert */
    remove_fields (fcopy, TRUE);
    peercaps = gst_pad_peer_query_caps (GST_BASE_PARSE_SRC_PAD (parse), fcopy);
    gst_caps_unref (fcopy);
  } else {
    peercaps = gst_pad_peer_query_caps (GST_BASE_PARSE_SRC_PAD (parse), NULL);
  }

  pcopy = gst_caps_copy (peercaps);
  remove_fields (pcopy, TRUE);

  res = gst_caps_intersect_full (pcopy, templ, GST_CAPS_INTERSECT_FIRST);
  gst_caps_unref (pcopy);
  gst_caps_unref (templ);

  if (filter) {
    GstCaps *tmp = gst_caps_intersect_full (res, filter,
        GST_CAPS_INTERSECT_FIRST);
    gst_caps_unref (res);
    res = tmp;
  }

  /* Try if we can put the downstream caps first */
  pcopy = gst_caps_copy (peercaps);
  remove_fields (pcopy, FALSE);
  tmp = gst_caps_intersect_full (pcopy, res, GST_CAPS_INTERSECT_FIRST);
  gst_caps_unref (pcopy);
  if (!gst_caps_is_empty (tmp))
    res = gst_caps_merge (tmp, res);
  else
    gst_caps_unref (tmp);

  gst_caps_unref (peercaps);

  return res;
}