Support for parsing CABAC coded bitstreams

webrtc/common_video/h264/pps_parser.cc

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 64 matching lines @@
     rtc::BitBuffer* bit_buffer) {
   PpsState pps;
 
   RETURN_EMPTY_ON_FAIL(ParsePpsIdsInternal(bit_buffer, &pps.id, &pps.sps_id));
 
   uint32_t bits_tmp;
   uint32_t golomb_ignored;
   // entropy_coding_mode_flag: u(1)
   uint32_t entropy_coding_mode_flag;
   RETURN_EMPTY_ON_FAIL(bit_buffer->ReadBits(&entropy_coding_mode_flag, 1));
-  // TODO(pbos): Implement CABAC support if spotted in the wild.
-  RTC_CHECK(entropy_coding_mode_flag == 0)
-      << "Don't know how to parse CABAC streams.";
+  pps.entropy_coding_mode_flag = !!entropy_coding_mode_flag;

[magjed_webrtc, 2016/09/28 15:13:01]

nit: !! is cute, but I would prefer != 0. I don't think the style guide mentions
this. I don't want to enforce my subjective style, so ignore this comment if you
want.

   // bottom_field_pic_order_in_frame_present_flag: u(1)
   uint32_t bottom_field_pic_order_in_frame_present_flag;
   RETURN_EMPTY_ON_FAIL(
       bit_buffer->ReadBits(&bottom_field_pic_order_in_frame_present_flag, 1));
   pps.bottom_field_pic_order_in_frame_present_flag =
       bottom_field_pic_order_in_frame_present_flag != 0;
 
   // num_slice_groups_minus1: ue(v)
   uint32_t num_slice_groups_minus1;
   RETURN_EMPTY_ON_FAIL(
@@ skipping 86 matching lines @@
   // pic_parameter_set_id: ue(v)
   if (!bit_buffer->ReadExponentialGolomb(pps_id))
     return false;
   // seq_parameter_set_id: ue(v)
   if (!bit_buffer->ReadExponentialGolomb(sps_id))
     return false;
   return true;
 }
 
 }  // namespace webrtc