Don't force a full decoder reset on seek in VTVDA.

content/common/gpu/media/vt_video_decode_accelerator_mac.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/common/gpu/media/vt_video_decode_accelerator_mac.h"
 
 #include <CoreVideo/CoreVideo.h>
 #include <OpenGL/CGLIOSurface.h>
 #include <OpenGL/gl.h>
 #include <stddef.h>
@@ skipping 283 matching lines @@
     const BindGLImageCallback& bind_image_cb)
     : make_context_current_cb_(make_context_current_cb),
       bind_image_cb_(bind_image_cb),
       client_(nullptr),
       state_(STATE_DECODING),
       format_(nullptr),
       session_(nullptr),
       last_sps_id_(-1),
       last_pps_id_(-1),
       config_changed_(false),
+      waiting_for_idr_(true),
       missing_idr_logged_(false),
       gpu_task_runner_(base::ThreadTaskRunnerHandle::Get()),
       decoder_thread_("VTDecoderThread"),
       weak_this_factory_(this) {
   callback_.decompressionOutputCallback = OutputThunk;
   callback_.decompressionOutputRefCon = this;
   weak_this_ = weak_this_factory_.GetWeakPtr();
 }
 
 VTVideoDecodeAccelerator::~VTVideoDecodeAccelerator() {
@@ skipping 237 matching lines @@
         pps.assign(nalu.data, nalu.data + nalu.size);
         break;
 
       case media::H264NALU::kSliceDataA:
       case media::H264NALU::kSliceDataB:
       case media::H264NALU::kSliceDataC:
       case media::H264NALU::kNonIDRSlice:
       case media::H264NALU::kIDRSlice:
         // Compute the |pic_order_cnt| for the picture from the first slice.
         if (!has_slice) {
+          // Verify that we are not trying to decode a slice without an IDR.
+          if (waiting_for_idr_) {
+            if (nalu.nal_unit_type == media::H264NALU::kIDRSlice) {
+              waiting_for_idr_ = false;
+            } else {
+              // We can't compute anything yet, bail on this frame.
+              has_slice = true;
+              break;
+            }
+          }
+
           media::H264SliceHeader slice_hdr;
           result = parser_.ParseSliceHeader(nalu, &slice_hdr);
           if (result == media::H264Parser::kUnsupportedStream) {
             DLOG(ERROR) << "Unsupported slice header";
             NotifyError(PLATFORM_FAILURE, SFT_UNSUPPORTED_STREAM);
             return;
           }
           if (result != media::H264Parser::kOk) {
             DLOG(ERROR) << "Could not parse slice header";
             NotifyError(UNREADABLE_INPUT, SFT_INVALID_STREAM);
@@ skipping 68 matching lines @@
         return;
       }
 
       // ConfigureDecoder() calls NotifyError() on failure.
       if (!ConfigureDecoder())
         return;
     }
   }
 
   // If no IDR has been seen yet, skip decoding.
-  if (has_slice && !session_ && config_changed_) {
+  if (has_slice && (!session_ || waiting_for_idr_) && config_changed_) {
     if (!missing_idr_logged_) {
       LOG(ERROR) << "Illegal attempt to decode without IDR. "
                  << "Discarding decode requests until next IDR.";
       missing_idr_logged_ = true;
     }
     has_slice = false;
   }
 
   // If there is nothing to decode, drop the bitstream buffer by returning an
   // empty frame.
@@ skipping 275 matching lines @@
         pending_flush_tasks_.pop();
         client_->NotifyFlushDone();
         task_queue_.pop();
         return true;
       }
       return false;
 
     case TASK_RESET:
       DCHECK_EQ(task.type, pending_flush_tasks_.front());
       if (reorder_queue_.size() == 0) {
-        last_sps_id_ = -1;
-        last_pps_id_ = -1;
-        last_sps_.clear();
-        last_spsext_.clear();
-        last_pps_.clear();
-        poc_.Reset();
+        waiting_for_idr_ = true;
         pending_flush_tasks_.pop();
         client_->NotifyResetDone();
         task_queue_.pop();
         return true;
       }
       return false;
 
     case TASK_DESTROY:
       NOTREACHED() << "Can't destroy while in STATE_DECODING.";
       NotifyError(ILLEGAL_STATE, SFT_PLATFORM_ERROR);
@@ skipping 185 matching lines @@
     SupportedProfile profile;
     profile.profile = supported_profile;
     profile.min_resolution.SetSize(16, 16);
     profile.max_resolution.SetSize(4096, 2160);
     profiles.push_back(profile);
   }
   return profiles;
 }
 
 }  // namespace content