From 13944cf3ee871722efb6c81f9d066a23aadbcac8 Mon Sep 17 00:00:00 2001
From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Date: Fri, 28 Jan 2022 14:49:42 -0500
Subject: [PATCH] v4l2codecs: vp9: Make compressed hdr control optional

This is to supported by Mediatek VP9 driver. Mediatek handles
the forward probabilities in hardware hence does not need and
does not implement support for
V4L2_CID_STATELESS_VP9_COMPRESSED_HDR.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1600>
---
 .../sys/v4l2codecs/gstv4l2codecvp9dec.c            | 23 ++++++++++++++++------
 .../sys/v4l2codecs/gstv4l2decoder.c                |  6 ++++--
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/subprojects/gst-plugins-bad/sys/v4l2codecs/gstv4l2codecvp9dec.c b/subprojects/gst-plugins-bad/sys/v4l2codecs/gstv4l2codecvp9dec.c
index 19cd0a7..9aa2d86 100644
--- a/subprojects/gst-plugins-bad/sys/v4l2codecs/gstv4l2codecvp9dec.c
+++ b/subprojects/gst-plugins-bad/sys/v4l2codecs/gstv4l2codecvp9dec.c
@@ -369,6 +369,10 @@ gst_v4l2_codec_vp9_dec_open (GstVideoDecoder * decoder)
     return FALSE;
   }
 
+  vp9dec->parse_compressed_headers =
+      gst_v4l2_decoder_query_control_size (self->decoder,
+      V4L2_CID_STATELESS_VP9_COMPRESSED_HDR, NULL);
+
   /* V4L2 does not support non-keyframe resolution change, this will ask the
    * base class to drop frame until the next keyframe as a workaround. */
   gst_vp9_decoder_set_non_keyframe_format_change_support (vp9dec, FALSE);
@@ -623,7 +627,9 @@ gst_v4l2_codec_vp9_dec_new_sequence (GstVp9Decoder * decoder,
   }
 
   gst_v4l2_codec_vp9_dec_fill_dec_params (self, frame_hdr, NULL);
-  gst_v4l2_codec_vp9_dec_fill_prob_updates (self, frame_hdr);
+
+  if (decoder->parse_compressed_headers)
+    gst_v4l2_codec_vp9_dec_fill_prob_updates (self, frame_hdr);
 
   if (negotiation_needed) {
     self->need_negotiation = TRUE;
@@ -734,6 +740,7 @@ gst_v4l2_codec_vp9_dec_end_picture (GstVp9Decoder * decoder,
   GstV4l2Request *request = NULL;
   GstFlowReturn flow_ret;
   gsize bytesused;
+  guint num_controls = 1;
 
   /* *INDENT-OFF* */
   struct v4l2_ext_control decode_params_control[] = {
@@ -743,11 +750,17 @@ gst_v4l2_codec_vp9_dec_end_picture (GstVp9Decoder * decoder,
       .size = sizeof(self->v4l2_vp9_frame),
     },
     {
+      /* V4L2_CID_STATELESS_VP9_COMPRESSED_HDR */
+    },
+  };
+
+  if (decoder->parse_compressed_headers) {
+    decode_params_control[num_controls++] = (struct v4l2_ext_control) {
       .id = V4L2_CID_STATELESS_VP9_COMPRESSED_HDR,
       .ptr = &self->v4l2_delta_probs,
       .size = sizeof (self->v4l2_delta_probs),
-    },
-  };
+    };
+  }
   /* *INDENT-ON* */
 
   bytesused = self->bitstream_map.size;
@@ -782,7 +795,7 @@ gst_v4l2_codec_vp9_dec_end_picture (GstVp9Decoder * decoder,
   }
 
   if (!gst_v4l2_decoder_set_controls (self->decoder, request,
-          decode_params_control, G_N_ELEMENTS (decode_params_control))) {
+          decode_params_control, num_controls)) {
     GST_ELEMENT_ERROR (decoder, RESOURCE, WRITE,
         ("Driver did not accept the bitstream parameters."), (NULL));
     goto fail;
@@ -1025,8 +1038,6 @@ gst_v4l2_codec_vp9_dec_get_property (GObject * object, guint prop_id,
 static void
 gst_v4l2_codec_vp9_dec_init (GstV4l2CodecVp9Dec * self)
 {
-  GstVp9Decoder *parent = GST_VP9_DECODER (self);
-  parent->parse_compressed_headers = TRUE;
 }
 
 static void
diff --git a/subprojects/gst-plugins-bad/sys/v4l2codecs/gstv4l2decoder.c b/subprojects/gst-plugins-bad/sys/v4l2codecs/gstv4l2decoder.c
index e6e797a..ff43c75 100644
--- a/subprojects/gst-plugins-bad/sys/v4l2codecs/gstv4l2decoder.c
+++ b/subprojects/gst-plugins-bad/sys/v4l2codecs/gstv4l2decoder.c
@@ -739,7 +739,8 @@ gst_v4l2_decoder_query_control_size (GstV4l2Decoder * self,
     .id = control_id,
   };
 
-  *control_size = 0;
+  if (control_size)
+    *control_size = 0;
 
   ret = ioctl (self->video_fd, VIDIOC_QUERY_EXT_CTRL, &control);
   if (ret < 0)
@@ -749,7 +750,8 @@ gst_v4l2_decoder_query_control_size (GstV4l2Decoder * self,
      */
     return FALSE;
 
-  *control_size = control.elem_size;
+  if (control_size)
+    *control_size = control.elem_size;
   return TRUE;
 }
 
-- 
2.7.4