Implement actually decoding frames in VTVideoDecodeAccelerator.

content/common/gpu/media/vt_video_decode_accelerator.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 <CoreVideo/CoreVideo.h>
 #include <OpenGL/CGLIOSurface.h>
 
 #include "base/bind.h"
+#include "base/sys_byteorder.h"
 #include "base/thread_task_runner_handle.h"
 #include "content/common/gpu/media/vt_video_decode_accelerator.h"
 #include "media/filters/h264_parser.h"
+#include "ui/gl/scoped_binders.h"
+#include "ui/gl/scoped_cgl.h"
 
 using content_common_gpu_media::kModuleVt;
 using content_common_gpu_media::InitializeStubs;
 using content_common_gpu_media::IsVtInitialized;
 using content_common_gpu_media::StubPathMap;
 
 namespace content {
 
-// Size of length headers prepended to NALUs in MPEG-4 framing. (1, 2, or 4.)
+// Size of NALU length headers in AVCC/MPEG-4 format (can be 1, 2, or 4).
 static const int kNALUHeaderLength = 4;
 
+// We only request 5 picture buffers from the client which are used to hold the
+// decoded samples. These buffers are then reused when the client tells us that
+// it is done with the buffer.
+static const int kNumPictureBuffers = 5;
+
 // Route decoded frame callbacks back into the VTVideoDecodeAccelerator.
 static void OutputThunk(
     void* decompression_output_refcon,
     void* source_frame_refcon,
     OSStatus status,
     VTDecodeInfoFlags info_flags,
     CVImageBufferRef image_buffer,
     CMTime presentation_time_stamp,
     CMTime presentation_duration) {
+  // TODO(sandersd): Implement flush-before-delete to guarantee validity.
   VTVideoDecodeAccelerator* vda =
       reinterpret_cast<VTVideoDecodeAccelerator*>(decompression_output_refcon);
-  int32_t* bitstream_id_ptr = reinterpret_cast<int32_t*>(source_frame_refcon);
-  int32_t bitstream_id = *bitstream_id_ptr;
-  delete bitstream_id_ptr;
-  CFRetain(image_buffer);
-  vda->Output(bitstream_id, status, info_flags, image_buffer);
+  int32_t bitstream_id = reinterpret_cast<intptr_t>(source_frame_refcon);

[Pawel Osciak, 2014/08/03 04:26:30]

I meant reinterpret_cast<int32_t>...

+  vda->Output(bitstream_id, status, image_buffer);
+}
+
+VTVideoDecodeAccelerator::DecodedFrame::DecodedFrame(
+    int32_t bitstream_id,
+    CVImageBufferRef image_buffer)
+    : bitstream_id(bitstream_id),
+      image_buffer(image_buffer) {
+}
+
+VTVideoDecodeAccelerator::DecodedFrame::~DecodedFrame() {
 }
 
 VTVideoDecodeAccelerator::VTVideoDecodeAccelerator(CGLContextObj cgl_context)
     : cgl_context_(cgl_context),
       client_(NULL),
-      decoder_thread_("VTDecoderThread"),
       format_(NULL),
       session_(NULL),
-      weak_this_factory_(this) {
+      gpu_task_runner_(base::ThreadTaskRunnerHandle::Get()),
+      weak_this_factory_(this),
+      decoder_thread_("VTDecoderThread") {
   callback_.decompressionOutputCallback = OutputThunk;
   callback_.decompressionOutputRefCon = this;
 }
 
 VTVideoDecodeAccelerator::~VTVideoDecodeAccelerator() {
 }
 
 bool VTVideoDecodeAccelerator::Initialize(
     media::VideoCodecProfile profile,
     Client* client) {
   DCHECK(CalledOnValidThread());
   client_ = client;
 
   // Only H.264 is supported.
   if (profile < media::H264PROFILE_MIN || profile > media::H264PROFILE_MAX)
     return false;
 
   // TODO(sandersd): Move VideoToolbox library loading to sandbox startup;
   // until then, --no-sandbox is required.
   if (!IsVtInitialized()) {
-    StubPathMap paths;
     // CoreVideo is also required, but the loader stops after the first
     // path is loaded. Instead we rely on the transitive dependency from
     // VideoToolbox to CoreVideo.
     // TODO(sandersd): Fallback to PrivateFrameworks for VideoToolbox.
+    StubPathMap paths;
     paths[kModuleVt].push_back(FILE_PATH_LITERAL(
         "/System/Library/Frameworks/VideoToolbox.framework/VideoToolbox"));
     if (!InitializeStubs(paths))
       return false;
   }
 
   // Spawn a thread to handle parsing and calling VideoToolbox.
   if (!decoder_thread_.Start())
     return false;
 
   // Note that --ignore-gpu-blacklist is still required to get here.
   return true;
 }
 
 // TODO(sandersd): Proper error reporting instead of CHECKs.
 void VTVideoDecodeAccelerator::ConfigureDecoder(
     const std::vector<const uint8_t*>& nalu_data_ptrs,
     const std::vector<size_t>& nalu_data_sizes) {
+  DCHECK(decoder_thread_.message_loop_proxy()->BelongsToCurrentThread());
+  // Construct a new format description from the parameter sets.
+  // TODO(sandersd): Replace this with custom code to support OS X < 10.9.
   format_.reset();
   CHECK(!CMVideoFormatDescriptionCreateFromH264ParameterSets(
       kCFAllocatorDefault,
       nalu_data_ptrs.size(),      // parameter_set_count
       &nalu_data_ptrs.front(),    // &parameter_set_pointers
       &nalu_data_sizes.front(),   // &parameter_set_sizes
       kNALUHeaderLength,          // nal_unit_header_length
-      format_.InitializeInto()
-  ));
+      format_.InitializeInto()));
+  CMVideoDimensions coded_dimensions =
+      CMVideoFormatDescriptionGetDimensions(format_);
 
-  // TODO(sandersd): Check if the size has changed and handle picture requests.
-  CMVideoDimensions coded_size = CMVideoFormatDescriptionGetDimensions(format_);
-  coded_size_.SetSize(coded_size.width, coded_size.height);
-
+  // Prepare VideoToolbox configuration dictionaries.
   base::ScopedCFTypeRef<CFMutableDictionaryRef> decoder_config(
       CFDictionaryCreateMutable(
           kCFAllocatorDefault,
           1,  // capacity
           &kCFTypeDictionaryKeyCallBacks,
           &kCFTypeDictionaryValueCallBacks));
 
   CFDictionarySetValue(
       decoder_config,
       // kVTVideoDecoderSpecification_EnableHardwareAcceleratedVideoDecoder
       CFSTR("EnableHardwareAcceleratedVideoDecoder"),
       kCFBooleanTrue);
 
   base::ScopedCFTypeRef<CFMutableDictionaryRef> image_config(
       CFDictionaryCreateMutable(
           kCFAllocatorDefault,
           4,  // capacity
           &kCFTypeDictionaryKeyCallBacks,
           &kCFTypeDictionaryValueCallBacks));
 
-  // TODO(sandersd): ARGB for video that is not 4:2:0.
-  int32_t pixel_format = '2vuy';
 #define CFINT(i) CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &i)
+  // TODO(sandersd): RGBA option for 4:4:4 video.
+  int32_t pixel_format = kCVPixelFormatType_422YpCbCr8;
   base::ScopedCFTypeRef<CFNumberRef> cf_pixel_format(CFINT(pixel_format));
-  base::ScopedCFTypeRef<CFNumberRef> cf_width(CFINT(coded_size.width));
-  base::ScopedCFTypeRef<CFNumberRef> cf_height(CFINT(coded_size.height));
+  base::ScopedCFTypeRef<CFNumberRef> cf_width(CFINT(coded_dimensions.width));
+  base::ScopedCFTypeRef<CFNumberRef> cf_height(CFINT(coded_dimensions.height));
 #undef CFINT
   CFDictionarySetValue(
       image_config, kCVPixelBufferPixelFormatTypeKey, cf_pixel_format);
   CFDictionarySetValue(image_config, kCVPixelBufferWidthKey, cf_width);
   CFDictionarySetValue(image_config, kCVPixelBufferHeightKey, cf_height);
   CFDictionarySetValue(
       image_config, kCVPixelBufferOpenGLCompatibilityKey, kCFBooleanTrue);
 
-  // TODO(sandersd): Skip if the session is compatible.
-  // TODO(sandersd): Flush frames when resetting.
+  // TODO(sandersd): Check if the session is already compatible.
+  // TODO(sandersd): Flush.
   session_.reset();
   CHECK(!VTDecompressionSessionCreate(
       kCFAllocatorDefault,
       format_,              // video_format_description
       decoder_config,       // video_decoder_specification
       image_config,         // destination_image_buffer_attributes
       &callback_,           // output_callback
-      session_.InitializeInto()
-  ));
-  DVLOG(2) << "Created VTDecompressionSession";
+      session_.InitializeInto()));
+
+  // If the size has changed, trigger a request for new picture buffers.
+  gfx::Size new_coded_size(coded_dimensions.width, coded_dimensions.height);
+  if (coded_size_ != new_coded_size) {
+    coded_size_ = new_coded_size;
+    gpu_task_runner_->PostTask(FROM_HERE, base::Bind(
+        &VTVideoDecodeAccelerator::SizeChangedTask,
+        weak_this_factory_.GetWeakPtr(),
+        coded_size_));;
+  }
 }
 
 void VTVideoDecodeAccelerator::Decode(const media::BitstreamBuffer& bitstream) {
   DCHECK(CalledOnValidThread());
+  // TODO(sandersd): Test what happens if bitstream buffers are passed to VT out
+  // of order.
   decoder_thread_.message_loop_proxy()->PostTask(FROM_HERE, base::Bind(
       &VTVideoDecodeAccelerator::DecodeTask, base::Unretained(this),
       bitstream));
 }
 
+// TODO(sandersd): Proper error reporting instead of CHECKs.
 void VTVideoDecodeAccelerator::DecodeTask(
     const media::BitstreamBuffer bitstream) {
   DCHECK(decoder_thread_.message_loop_proxy()->BelongsToCurrentThread());
 
   // Map the bitstream buffer.
   base::SharedMemory memory(bitstream.handle(), true);
   size_t size = bitstream.size();
   CHECK(memory.Map(size));
   const uint8_t* buf = static_cast<uint8_t*>(memory.memory());
 
-  // Locate relevant NALUs in the buffer.
+  // NALUs are stored with Annex B format in the bitstream buffer (start codes),
+  // but VideoToolbox expects AVCC/MPEG-4 format (length headers), so we must
+  // rewrite the data.
+  //
+  // 1. Locate relevant NALUs and compute the size of the translated data.
+  //    Also record any parameter sets for VideoToolbox initialization.
   size_t data_size = 0;
   std::vector<media::H264NALU> nalus;
   std::vector<const uint8_t*> config_nalu_data_ptrs;
   std::vector<size_t> config_nalu_data_sizes;
   parser_.SetStream(buf, size);
   media::H264NALU nalu;
   while (true) {
     media::H264Parser::Result result = parser_.AdvanceToNextNALU(&nalu);
     if (result == media::H264Parser::kEOStream)
       break;
     CHECK_EQ(result, media::H264Parser::kOk);
+    // TODO(sandersd): Check that these are only at the start.
     if (nalu.nal_unit_type == media::H264NALU::kSPS ||
         nalu.nal_unit_type == media::H264NALU::kPPS ||
         nalu.nal_unit_type == media::H264NALU::kSPSExt) {
+      DVLOG(2) << "Parameter set " << nalu.nal_unit_type;
       config_nalu_data_ptrs.push_back(nalu.data);
       config_nalu_data_sizes.push_back(nalu.size);
+    } else {
+      nalus.push_back(nalu);
+      data_size += kNALUHeaderLength + nalu.size;
     }
-    nalus.push_back(nalu);
-    // Each NALU will have a 4-byte length header prepended.
-    data_size += kNALUHeaderLength + nalu.size;
   }
 
-  if (!config_nalu_data_ptrs.empty())
+  // 2. Initialize VideoToolbox.
+  // TODO(sandersd): Reinitialize when there are new parameter sets.
+  if (!session_)
     ConfigureDecoder(config_nalu_data_ptrs, config_nalu_data_sizes);
 
-  // TODO(sandersd): Rewrite slice NALU headers and send for decoding.
+  // 3. Allocate a memory-backed CMBlockBuffer for the translated data.
+  base::ScopedCFTypeRef<CMBlockBufferRef> data;
+  CHECK(!CMBlockBufferCreateWithMemoryBlock(
+      kCFAllocatorDefault,
+      NULL,                 // &memory_block
+      data_size,            // block_length
+      kCFAllocatorDefault,  // block_allocator
+      NULL,                 // &custom_block_source
+      0,                    // offset_to_data
+      data_size,            // data_length
+      0,                    // flags
+      data.InitializeInto()));
+
+  // 4. Copy NALU data, inserting length headers.
+  size_t offset = 0;
+  for (size_t i = 0; i < nalus.size(); i++) {
+    media::H264NALU& nalu = nalus[i];
+    uint32_t header = base::HostToNet32(checked_cast<uint32_t>(nalu.size));
+    CHECK(!CMBlockBufferReplaceDataBytes(
+        &header, data, offset, kNALUHeaderLength));
+    offset += kNALUHeaderLength;
+    CHECK(!CMBlockBufferReplaceDataBytes(nalu.data, data, offset, nalu.size));
+    offset += nalu.size;
+  }
+
+  // 5. Package the data for VideoToolbox and request decoding.
+  base::ScopedCFTypeRef<CMSampleBufferRef> frame;
+  CHECK(!CMSampleBufferCreate(
+      kCFAllocatorDefault,
+      data,                 // data_buffer
+      true,                 // data_ready
+      NULL,                 // make_data_ready_callback
+      NULL,                 // make_data_ready_refcon
+      format_,              // format_description
+      1,                    // num_samples
+      0,                    // num_sample_timing_entries
+      NULL,                 // &sample_timing_array
+      0,                    // num_sample_size_entries
+      NULL,                 // &sample_size_array
+      frame.InitializeInto()));
+
+  // Asynchronous Decompression allows for parallel submission of frames
+  // (without it, DecodeFrame() does not return until the frame has been
+  // decoded). We don't enable Temporal Processing so that frames are always
+  // returned in decode order; this makes it easier to avoid deadlock.
+  VTDecodeFrameFlags decode_flags =
+      kVTDecodeFrame_EnableAsynchronousDecompression;
+
+  intptr_t bitstream_id = bitstream.id();
+  CHECK(!VTDecompressionSessionDecodeFrame(
+      session_,
+      frame,                                  // sample_buffer
+      decode_flags,                           // decode_flags
+      reinterpret_cast<void*>(bitstream_id),  // source_frame_refcon
+      NULL));                                 // &info_flags_out
 }
 
 // This method may be called on any VideoToolbox thread.
+// TODO(sandersd): Proper error reporting instead of CHECKs.
 void VTVideoDecodeAccelerator::Output(
     int32_t bitstream_id,
     OSStatus status,
-    VTDecodeInfoFlags info_flags,
     CVImageBufferRef image_buffer) {
-  // TODO(sandersd): Store the frame in a queue.
-  CFRelease(image_buffer);
+  CHECK(!status);
+  CHECK_EQ(CFGetTypeID(image_buffer), CVPixelBufferGetTypeID());
+  CFRetain(image_buffer);
+  gpu_task_runner_->PostTask(FROM_HERE, base::Bind(
+      &VTVideoDecodeAccelerator::OutputTask,
+      weak_this_factory_.GetWeakPtr(),
+      DecodedFrame(bitstream_id, image_buffer)));
+}
+
+void VTVideoDecodeAccelerator::OutputTask(DecodedFrame frame) {
+  DCHECK(CalledOnValidThread());
+  decoded_frames_.push(frame);
+  SendPictures();
+}
+
+void VTVideoDecodeAccelerator::SizeChangedTask(gfx::Size coded_size) {
+  DCHECK(CalledOnValidThread());
+  texture_size_ = coded_size;
+  // TODO(sandersd): Dismiss existing picture buffers.
+  client_->ProvidePictureBuffers(
+      kNumPictureBuffers, texture_size_, GL_TEXTURE_RECTANGLE_ARB);
 }
 
 void VTVideoDecodeAccelerator::AssignPictureBuffers(
     const std::vector<media::PictureBuffer>& pictures) {
   DCHECK(CalledOnValidThread());
+
+  for (size_t i = 0; i < pictures.size(); i++) {
+    CHECK(!available_picture_ids_.count(pictures[i].id()));

[Pawel Osciak, 2014/08/03 04:26:30]

Nice, pretty crafty!

[sandersd (OOO until July 31), 2014/08/04 19:24:20]

Turns out to be wrong to :-(

+    available_picture_ids_.push(pictures[i].id());
+    texture_ids_[pictures[i].id()] = pictures[i].texture_id();

[Pawel Osciak, 2014/08/03 04:26:30]

Should probably check this is empty too though...?

[sandersd (OOO until July 31), 2014/08/04 19:24:20]

This is a better plan.

+  }
+
+  // Pictures are not marked as uncleared until this method returns. They will
+  // become broken if they are used before that happens.
+  gpu_task_runner_->PostTask(FROM_HERE, base::Bind(
+      &VTVideoDecodeAccelerator::SendPictures,
+      weak_this_factory_.GetWeakPtr()));
 }
 
 void VTVideoDecodeAccelerator::ReusePictureBuffer(int32_t picture_id) {
   DCHECK(CalledOnValidThread());
+  DCHECK_EQ(CFGetRetainCount(picture_bindings_[picture_id]), 1);
+  picture_bindings_.erase(picture_id);
+  available_picture_ids_.push(picture_id);
+  SendPictures();
+}
+
+// TODO(sandersd): Proper error reporting instead of CHECKs.
+void VTVideoDecodeAccelerator::SendPictures() {
+  DCHECK(CalledOnValidThread());
+  if (available_picture_ids_.empty() || decoded_frames_.empty())
+    return;
+
+  gfx::ScopedCGLSetCurrentContext scoped_set_current_context(cgl_context_);
+  glEnable(GL_TEXTURE_RECTANGLE_ARB);
+
+  while (!available_picture_ids_.empty() && !decoded_frames_.empty()) {
+    int32_t picture_id = available_picture_ids_.front();
+    available_picture_ids_.pop();
+    DecodedFrame frame = decoded_frames_.front();
+    decoded_frames_.pop();
+    IOSurfaceRef surface = CVPixelBufferGetIOSurface(frame.image_buffer);
+
+    gfx::ScopedTextureBinder
+        texture_binder(GL_TEXTURE_RECTANGLE_ARB, texture_ids_[picture_id]);
+    CHECK(!CGLTexImageIOSurface2D(
+        cgl_context_,                 // ctx
+        GL_TEXTURE_RECTANGLE_ARB,     // target
+        GL_RGB,                       // internal_format
+        texture_size_.width(),        // width
+        texture_size_.height(),       // height
+        GL_YCBCR_422_APPLE,           // format
+        GL_UNSIGNED_SHORT_8_8_APPLE,  // type
+        surface,                      // io_surface
+        0));                          // plane
+
+    picture_bindings_[picture_id] = frame.image_buffer;
+    client_->PictureReady(media::Picture(picture_id, frame.bitstream_id));
+    client_->NotifyEndOfBitstreamBuffer(frame.bitstream_id);
+  }
+
+  glDisable(GL_TEXTURE_RECTANGLE_ARB);
 }
 
 void VTVideoDecodeAccelerator::Flush() {
   DCHECK(CalledOnValidThread());
   // TODO(sandersd): Trigger flush, sending frames.
 }
 
 void VTVideoDecodeAccelerator::Reset() {
   DCHECK(CalledOnValidThread());
   // TODO(sandersd): Trigger flush, discarding frames.
 }
 
 void VTVideoDecodeAccelerator::Destroy() {
   DCHECK(CalledOnValidThread());
   // TODO(sandersd): Trigger flush, discarding frames, and wait for them.
   delete this;
 }
 
 bool VTVideoDecodeAccelerator::CanDecodeOnIOThread() {
   return false;
 }
 
 }  // namespace content