Allow H264 bitstream parser to fail gracefully

webrtc/common_video/h264/h264_bitstream_parser.cc

 /*
  *  Copyright (c) 2015 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.
  */
 #include "webrtc/common_video/h264/h264_bitstream_parser.h"
 
 #include <memory>
 #include <vector>
 
 #include "webrtc/base/bitbuffer.h"
 #include "webrtc/base/bytebuffer.h"
 #include "webrtc/base/checks.h"
 
 #include "webrtc/common_video/h264/h264_common.h"
 #include "webrtc/base/logging.h"
 
 namespace webrtc {
 
-#define RETURN_FALSE_ON_FAIL(x)       \
+#define RETURN_ON_FAIL(x, res)        \
   if (!(x)) {                         \
     LOG_F(LS_ERROR) << "FAILED: " #x; \
-    return false;                     \
+    return res;                       \
   }
 
+#define RETURN_INV_ON_FAIL(x) RETURN_ON_FAIL(x, kInvalidStream)

[pbos-webrtc, 2016/11/03 16:25:25]

I think you can s/INV/INVALID_STREAM/g

+
 H264BitstreamParser::H264BitstreamParser() {}
 H264BitstreamParser::~H264BitstreamParser() {}
 
-bool H264BitstreamParser::ParseNonParameterSetNalu(const uint8_t* source,
-                                                   size_t source_length,
-                                                   uint8_t nalu_type) {
-  RTC_CHECK(sps_);
-  RTC_CHECK(pps_);
+H264BitstreamParser::Result H264BitstreamParser::ParseNonParameterSetNalu(
+    const uint8_t* source,
+    size_t source_length,
+    uint8_t nalu_type) {
+  if (!sps_ || !pps_)
+    return kInvalidStream;
+
   last_slice_qp_delta_ = rtc::Optional<int32_t>();
   std::unique_ptr<rtc::Buffer> slice_rbsp(
       H264::ParseRbsp(source, source_length));
+  if (slice_rbsp->size() < H264::kNaluTypeSize)
+    return kInvalidStream;
+
   rtc::BitBuffer slice_reader(slice_rbsp->data() + H264::kNaluTypeSize,
                               slice_rbsp->size() - H264::kNaluTypeSize);
   // Check to see if this is an IDR slice, which has an extra field to parse
   // out.
   bool is_idr = (source[0] & 0x0F) == H264::NaluType::kIdr;
   uint8_t nal_ref_idc = (source[0] & 0x60) >> 5;
   uint32_t golomb_tmp;
   uint32_t bits_tmp;
 
   // first_mb_in_slice: ue(v)
-  RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
+  RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
   // slice_type: ue(v)
   uint32_t slice_type;
-  RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(&slice_type));
+  RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&slice_type));
   // slice_type's 5..9 range is used to indicate that all slices of a picture
   // have the same value of slice_type % 5, we don't care about that, so we map
   // to the corresponding 0..4 range.
   slice_type %= 5;
   // pic_parameter_set_id: ue(v)
-  RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
+  RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
   if (sps_->separate_colour_plane_flag == 1) {
     // colour_plane_id
-    RETURN_FALSE_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 2));
+    RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 2));
   }
   // frame_num: u(v)
   // Represented by log2_max_frame_num_minus4 + 4 bits.
-  RETURN_FALSE_ON_FAIL(
+  RETURN_INV_ON_FAIL(
       slice_reader.ReadBits(&bits_tmp, sps_->log2_max_frame_num_minus4 + 4));
   uint32_t field_pic_flag = 0;
   if (sps_->frame_mbs_only_flag == 0) {
     // field_pic_flag: u(1)
-    RETURN_FALSE_ON_FAIL(slice_reader.ReadBits(&field_pic_flag, 1));
+    RETURN_INV_ON_FAIL(slice_reader.ReadBits(&field_pic_flag, 1));
     if (field_pic_flag != 0) {
       // bottom_field_flag: u(1)
-      RETURN_FALSE_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 1));
+      RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 1));
     }
   }
   if (is_idr) {
     // idr_pic_id: ue(v)
-    RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
+    RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
   }
   // pic_order_cnt_lsb: u(v)
   // Represented by sps_.log2_max_pic_order_cnt_lsb_minus4 + 4 bits.
   if (sps_->pic_order_cnt_type == 0) {
-    RETURN_FALSE_ON_FAIL(slice_reader.ReadBits(
+    RETURN_INV_ON_FAIL(slice_reader.ReadBits(
         &bits_tmp, sps_->log2_max_pic_order_cnt_lsb_minus4 + 4));
     if (pps_->bottom_field_pic_order_in_frame_present_flag &&
         field_pic_flag == 0) {
       // delta_pic_order_cnt_bottom: se(v)
-      RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
+      RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
     }
   }
   if (sps_->pic_order_cnt_type == 1 &&
       !sps_->delta_pic_order_always_zero_flag) {
     // delta_pic_order_cnt[0]: se(v)
-    RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
+    RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
     if (pps_->bottom_field_pic_order_in_frame_present_flag && !field_pic_flag) {
       // delta_pic_order_cnt[1]: se(v)
-      RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
+      RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
     }
   }
   if (pps_->redundant_pic_cnt_present_flag) {
     // redundant_pic_cnt: ue(v)
-    RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
+    RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
   }
   if (slice_type == H264::SliceType::kB) {
     // direct_spatial_mv_pred_flag: u(1)
-    RETURN_FALSE_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 1));
+    RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 1));
   }
   switch (slice_type) {
     case H264::SliceType::kP:
     case H264::SliceType::kB:
     case H264::SliceType::kSp:
       uint32_t num_ref_idx_active_override_flag;
       // num_ref_idx_active_override_flag: u(1)
-      RETURN_FALSE_ON_FAIL(
+      RETURN_INV_ON_FAIL(
           slice_reader.ReadBits(&num_ref_idx_active_override_flag, 1));
       if (num_ref_idx_active_override_flag != 0) {
         // num_ref_idx_l0_active_minus1: ue(v)
-        RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
+        RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
         if (slice_type == H264::SliceType::kB) {
           // num_ref_idx_l1_active_minus1: ue(v)
-          RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
+          RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
         }
       }
       break;
     default:
       break;
   }
   // assume nal_unit_type != 20 && nal_unit_type != 21:
-  RTC_CHECK_NE(nalu_type, 20);
-  RTC_CHECK_NE(nalu_type, 21);
+  if (nalu_type == 20 || nalu_type == 21) {
+    LOG(LS_ERROR) << "Unsupported nal unit type.";
+    return kUnsupportedStream;
+  }
   // if (nal_unit_type == 20 || nal_unit_type == 21)
   //   ref_pic_list_mvc_modification()
   // else
   {
     // ref_pic_list_modification():
     // |slice_type| checks here don't use named constants as they aren't named
     // in the spec for this segment. Keeping them consistent makes it easier to
     // verify that they are both the same.
     if (slice_type % 5 != 2 && slice_type % 5 != 4) {
       // ref_pic_list_modification_flag_l0: u(1)
       uint32_t ref_pic_list_modification_flag_l0;
-      RETURN_FALSE_ON_FAIL(
+      RETURN_INV_ON_FAIL(
           slice_reader.ReadBits(&ref_pic_list_modification_flag_l0, 1));
       if (ref_pic_list_modification_flag_l0) {
         uint32_t modification_of_pic_nums_idc;
         do {
           // modification_of_pic_nums_idc: ue(v)
-          RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(
+          RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(
               &modification_of_pic_nums_idc));
           if (modification_of_pic_nums_idc == 0 ||
               modification_of_pic_nums_idc == 1) {
             // abs_diff_pic_num_minus1: ue(v)
-            RETURN_FALSE_ON_FAIL(
-                slice_reader.ReadExponentialGolomb(&golomb_tmp));
+            RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
           } else if (modification_of_pic_nums_idc == 2) {
             // long_term_pic_num: ue(v)
-            RETURN_FALSE_ON_FAIL(
-                slice_reader.ReadExponentialGolomb(&golomb_tmp));
+            RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
           }
         } while (modification_of_pic_nums_idc != 3);
       }
     }
     if (slice_type % 5 == 1) {
       // ref_pic_list_modification_flag_l1: u(1)
       uint32_t ref_pic_list_modification_flag_l1;
-      RETURN_FALSE_ON_FAIL(
+      RETURN_INV_ON_FAIL(
           slice_reader.ReadBits(&ref_pic_list_modification_flag_l1, 1));
       if (ref_pic_list_modification_flag_l1) {
         uint32_t modification_of_pic_nums_idc;
         do {
           // modification_of_pic_nums_idc: ue(v)
-          RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(
+          RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(
               &modification_of_pic_nums_idc));
           if (modification_of_pic_nums_idc == 0 ||
               modification_of_pic_nums_idc == 1) {
             // abs_diff_pic_num_minus1: ue(v)
-            RETURN_FALSE_ON_FAIL(
-                slice_reader.ReadExponentialGolomb(&golomb_tmp));
+            RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
           } else if (modification_of_pic_nums_idc == 2) {
             // long_term_pic_num: ue(v)
-            RETURN_FALSE_ON_FAIL(
-                slice_reader.ReadExponentialGolomb(&golomb_tmp));
+            RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
           }
         } while (modification_of_pic_nums_idc != 3);
       }
     }
   }
   // TODO(pbos): Do we need support for pred_weight_table()?
-  RTC_CHECK(
-      !((pps_->weighted_pred_flag && (slice_type == H264::SliceType::kP ||
-                                      slice_type == H264::SliceType::kSp)) ||
-        (pps_->weighted_bipred_idc != 0 && slice_type == H264::SliceType::kB)))
-      << "Missing support for pred_weight_table().";
+  if ((pps_->weighted_pred_flag && (slice_type == H264::SliceType::kP ||
+                                    slice_type == H264::SliceType::kSp)) ||
+      (pps_->weighted_bipred_idc == 1 && slice_type == H264::SliceType::kB)) {
+    LOG(LS_ERROR) << "Streams with pred_weight_table unsupported.";
+    return kUnsupportedStream;
+  }
   // if ((weighted_pred_flag && (slice_type == P || slice_type == SP)) ||
   //    (weighted_bipred_idc == 1 && slice_type == B)) {
   //  pred_weight_table()
   // }
   if (nal_ref_idc != 0) {
     // dec_ref_pic_marking():
     if (is_idr) {
       // no_output_of_prior_pics_flag: u(1)
       // long_term_reference_flag: u(1)
-      RETURN_FALSE_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 2));
+      RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 2));
     } else {
       // adaptive_ref_pic_marking_mode_flag: u(1)
       uint32_t adaptive_ref_pic_marking_mode_flag;
-      RETURN_FALSE_ON_FAIL(
+      RETURN_INV_ON_FAIL(
           slice_reader.ReadBits(&adaptive_ref_pic_marking_mode_flag, 1));
       if (adaptive_ref_pic_marking_mode_flag) {
         uint32_t memory_management_control_operation;
         do {
           // memory_management_control_operation: ue(v)
-          RETURN_FALSE_ON_FAIL(slice_reader.ReadExponentialGolomb(
+          RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(
               &memory_management_control_operation));
           if (memory_management_control_operation == 1 ||
               memory_management_control_operation == 3) {
             // difference_of_pic_nums_minus1: ue(v)
-            RETURN_FALSE_ON_FAIL(
-                slice_reader.ReadExponentialGolomb(&golomb_tmp));
+            RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
           }
           if (memory_management_control_operation == 2) {
             // long_term_pic_num: ue(v)
-            RETURN_FALSE_ON_FAIL(
-                slice_reader.ReadExponentialGolomb(&golomb_tmp));
+            RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
           }
           if (memory_management_control_operation == 3 ||
               memory_management_control_operation == 6) {
             // long_term_frame_idx: ue(v)
-            RETURN_FALSE_ON_FAIL(
-                slice_reader.ReadExponentialGolomb(&golomb_tmp));
+            RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
           }
           if (memory_management_control_operation == 4) {
             // max_long_term_frame_idx_plus1: ue(v)
-            RETURN_FALSE_ON_FAIL(
-                slice_reader.ReadExponentialGolomb(&golomb_tmp));
+            RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
           }
         } while (memory_management_control_operation != 0);
       }
     }
   }
   // cabac not supported: entropy_coding_mode_flag == 0 asserted above.
   // if (entropy_coding_mode_flag && slice_type != I && slice_type != SI)
   //   cabac_init_idc
   int32_t last_slice_qp_delta;
-  RETURN_FALSE_ON_FAIL(
+  RETURN_INV_ON_FAIL(
       slice_reader.ReadSignedExponentialGolomb(&last_slice_qp_delta));
   last_slice_qp_delta_ = rtc::Optional<int32_t>(last_slice_qp_delta);
-  return true;
+  return kOk;
 }
 
 void H264BitstreamParser::ParseSlice(const uint8_t* slice, size_t length) {
   H264::NaluType nalu_type = H264::ParseNaluType(slice[0]);
   switch (nalu_type) {
     case H264::NaluType::kSps: {
       sps_ = SpsParser::ParseSps(slice + H264::kNaluTypeSize,
                                  length - H264::kNaluTypeSize);
       if (!sps_)
-        FATAL() << "Unable to parse SPS from H264 bitstream.";
+        LOG(LS_WARNING) << "Unable to parse SPS from H264 bitstream.";
       break;
     }
     case H264::NaluType::kPps: {
       pps_ = PpsParser::ParsePps(slice + H264::kNaluTypeSize,
                                  length - H264::kNaluTypeSize);
       if (!pps_)
-        FATAL() << "Unable to parse PPS from H264 bitstream.";
+        LOG(LS_WARNING) << "Unable to parse PPS from H264 bitstream.";
       break;
     }
     default:
-      RTC_CHECK(ParseNonParameterSetNalu(slice, length, nalu_type))
-          << "Failed to parse picture slice.";
+      Result res = ParseNonParameterSetNalu(slice, length, nalu_type);
+      if (res != kOk)
+        LOG(LS_INFO) << "Failed to parse bitstream. Error: " << res;

[magjed_webrtc, 2016/11/03 21:27:48]

nit: I think we should do at least LS_WARNING here.

       break;
   }
 }
 
 void H264BitstreamParser::ParseBitstream(const uint8_t* bitstream,
                                          size_t length) {
   std::vector<H264::NaluIndex> nalu_indices =
       H264::FindNaluIndices(bitstream, length);
-  RTC_CHECK(!nalu_indices.empty());
   for (const H264::NaluIndex& index : nalu_indices)
     ParseSlice(&bitstream[index.payload_start_offset], index.payload_size);
 }
 
 bool H264BitstreamParser::GetLastSliceQp(int* qp) const {
   if (!last_slice_qp_delta_ || !pps_)
     return false;
   *qp = 26 + pps_->pic_init_qp_minus26 + *last_slice_qp_delta_;
   return true;
 }
 
 }  // namespace webrtc