Only parse PPS up to PPS and SPS ids in the depacketizater.

webrtc/common_video/h264/pps_parser.cc

Index: webrtc/common_video/h264/pps_parser.cc
diff --git a/webrtc/common_video/h264/pps_parser.cc b/webrtc/common_video/h264/pps_parser.cc
index 01a6c76d911ed4670016cf439ae1d8dd01cae52f..a48d27bfc7fd8c2706b78dc7b72b41a12d429ac4 100644
--- a/webrtc/common_video/h264/pps_parser.cc
+++ b/webrtc/common_video/h264/pps_parser.cc
@@ -38,6 +38,20 @@ rtc::Optional<PpsParser::PpsState> PpsParser::ParsePps(const uint8_t* data,
   return ParseInternal(&bit_buffer);
 }
 
+bool PpsParser::ParsePpsIds(const uint8_t* data,
+                            size_t length,
+                            uint32_t* pps_id,
+                            uint32_t* sps_id) {
+  RTC_DCHECK(pps_id);
+  RTC_DCHECK(sps_id);
+  // First, parse out rbsp, which is basically the source buffer minus emulation
+  // bytes (the last byte of a 0x00 0x00 0x03 sequence). RBSP is defined in
+  // section 7.3.1 of the H.264 standard.
+  std::unique_ptr<rtc::Buffer> unpacked_buffer = H264::ParseRbsp(data, length);
+  rtc::BitBuffer bit_buffer(unpacked_buffer->data(), unpacked_buffer->size());
+  return ParsePpsIdsInternal(&bit_buffer, pps_id, sps_id);
+}
+
 rtc::Optional<uint32_t> PpsParser::ParsePpsIdFromSlice(const uint8_t* data,
                                                        size_t length) {
   std::unique_ptr<rtc::Buffer> slice_rbsp(H264::ParseRbsp(data, length));
@@ -61,12 +75,10 @@ rtc::Optional<PpsParser::PpsState> PpsParser::ParseInternal(
     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;
-  // pic_parameter_set_id: ue(v)
-  RETURN_EMPTY_ON_FAIL(bit_buffer->ReadExponentialGolomb(&pps.id));
-  // seq_parameter_set_id: ue(v)
-  RETURN_EMPTY_ON_FAIL(bit_buffer->ReadExponentialGolomb(&pps.sps_id));
   // entropy_coding_mode_flag: u(1)
   uint32_t entropy_coding_mode_flag;
   RETURN_EMPTY_ON_FAIL(bit_buffer->ReadBits(&entropy_coding_mode_flag, 1));
@@ -166,4 +178,16 @@ rtc::Optional<PpsParser::PpsState> PpsParser::ParseInternal(
   return rtc::Optional<PpsParser::PpsState>(pps);
 }
 
+bool PpsParser::ParsePpsIdsInternal(rtc::BitBuffer* bit_buffer,
+                                    uint32_t* pps_id,
+                                    uint32_t* sps_id) {
+  // 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