Adding VP8 Alpha support in Media Source

media/webm/webm_video_client.cc

 // Copyright (c) 2013 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 "media/webm/webm_video_client.h"
 
 #include "media/base/video_decoder_config.h"
 #include "media/webm/webm_constants.h"
 
 namespace media {
 
 WebMVideoClient::WebMVideoClient(const LogCB& log_cb)
     : log_cb_(log_cb) {
   Reset();
 }
 
 WebMVideoClient::~WebMVideoClient() {
 }
 
 void WebMVideoClient::Reset() {
   pixel_width_ = -1;
   pixel_height_ = -1;
   crop_bottom_ = -1;
   crop_top_ = -1;
   crop_left_ = -1;
   crop_right_ = -1;
   display_width_ = -1;
   display_height_ = -1;
   display_unit_ = -1;
+  alpha_mode_ = -1;
 }
 
 bool WebMVideoClient::InitializeConfig(
     const std::string& codec_id, const std::vector<uint8>& codec_private,
     bool is_encrypted, VideoDecoderConfig* config) {
   DCHECK(config);
 
   VideoCodec video_codec = kUnknownVideoCodec;
   VideoCodecProfile profile = VIDEO_CODEC_PROFILE_UNKNOWN;
   if (codec_id == "V_VP8") {
     video_codec = kCodecVP8;
     profile = VP8PROFILE_MAIN;
   } else if (codec_id == "V_VP9") {
     video_codec = kCodecVP9;
     profile = VP9PROFILE_MAIN;
   } else {
     MEDIA_LOG(log_cb_) << "Unsupported video codec_id " << codec_id;
     return false;
   }
 
+  VideoFrame::Format format =
+      (alpha_mode_ == 1) ? VideoFrame::YV12A : VideoFrame::YV12;
+
   if (pixel_width_ <= 0 || pixel_height_ <= 0)
     return false;
 
   // Set crop and display unit defaults if these elements are not present.
   if (crop_bottom_ == -1)
     crop_bottom_ = 0;
 
   if (crop_top_ == -1)
     crop_top_ = 0;
 
@@ skipping 26 matching lines @@
     return false;
   }
   const uint8* extra_data = NULL;
   size_t extra_data_size = 0;
   if (codec_private.size() > 0) {
     extra_data = &codec_private[0];
     extra_data_size = codec_private.size();
   }
 
   config->Initialize(
-      video_codec, profile, VideoFrame::YV12, coded_size,
-      visible_rect, natural_size, extra_data, extra_data_size,
-      is_encrypted, true);
+      video_codec, profile, format, coded_size, visible_rect, natural_size,
+      extra_data, extra_data_size, is_encrypted, true);
   return config->IsValidConfig();
 }
 
 bool WebMVideoClient::OnUInt(int id, int64 val) {
   int64* dst = NULL;
 
   switch (id) {
     case kWebMIdPixelWidth:
       dst = &pixel_width_;
       break;
@@ skipping 14 matching lines @@
       break;
     case kWebMIdDisplayWidth:
       dst = &display_width_;
       break;
     case kWebMIdDisplayHeight:
       dst = &display_height_;
       break;
     case kWebMIdDisplayUnit:
       dst = &display_unit_;
       break;
+    case kWebMIdAlphaMode:
+      dst = &alpha_mode_;
+      break;
     default:
       return true;
   }
 
   if (*dst != -1) {
     MEDIA_LOG(log_cb_) << "Multiple values for id " << std::hex << id
                        << " specified (" << *dst << " and " << val << ")";
     return false;
   }
 
   *dst = val;
   return true;
 }
 
 bool WebMVideoClient::OnBinary(int id, const uint8* data, int size) {
   // Accept binary fields we don't care about for now.
   return true;
 }
 
 bool WebMVideoClient::OnFloat(int id, double val) {
   // Accept float fields we don't care about for now.
   return true;
 }
 
 }  // namespace media