Use sps and pps to determine decodability of H.264 frames.

webrtc/modules/rtp_rtcp/source/rtp_format_h264.cc

 /*
  *  Copyright (c) 2014 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 466 matching lines @@
             RTC_HISTOGRAM_ENUMERATION(kSpsValidHistogramName,
                                       SpsValidEvent::kReceivedSpsParseFailure,
                                       SpsValidEvent::kSpsRewrittenMax);
             break;
         }
 
         if (sps) {
           parsed_payload->type.Video.width = sps->width;
           parsed_payload->type.Video.height = sps->height;
           nalu.sps_id = sps->id;
+        } else {
+          LOG(LS_WARNING) << "Failed to parse SPS id from SPS slice.";
         }
         parsed_payload->frame_type = kVideoFrameKey;
         break;
       }
       case H264::NaluType::kPps: {
         uint32_t pps_id;
         uint32_t sps_id;
         if (PpsParser::ParsePpsIds(&payload_data[start_offset],
                                     end_offset - start_offset, &pps_id,
                                     &sps_id)) {
           nalu.pps_id = pps_id;
           nalu.sps_id = sps_id;
         } else {
           LOG(LS_WARNING)
               << "Failed to parse PPS id and SPS id from PPS slice.";
         }
         break;
       }
       case H264::NaluType::kSei:
         FALLTHROUGH();
       case H264::NaluType::kIdr:
         parsed_payload->frame_type = kVideoFrameKey;
         FALLTHROUGH();
       default: {
         rtc::Optional<uint32_t> pps_id = PpsParser::ParsePpsIdFromSlice(
             &payload_data[start_offset], end_offset - start_offset);
-        if (pps_id)
+        if (pps_id) {
           nalu.pps_id = *pps_id;
+        } else {
+          LOG(LS_WARNING) << "Failed to parse PPS id from slice of type: "
+                          << static_cast<int>(nalu.type);
+        }
         break;
       }
     }
     RTPVideoHeaderH264* h264 = &parsed_payload->type.Video.codecHeader.H264;
     if (h264->nalus_length == kMaxNalusPerPacket) {
       LOG(LS_WARNING)
           << "Received packet containing more than " << kMaxNalusPerPacket
           << " NAL units. Will not keep track sps and pps ids for all of them.";
     } else {
       h264->nalus[h264->nalus_length++] = nalu;
@@ skipping 15 matching lines @@
   bool first_fragment = (payload_data[1] & kSBit) > 0;
   NaluInfo nalu;
   nalu.type = original_nal_type;
   nalu.sps_id = -1;
   nalu.pps_id = -1;
   if (first_fragment) {
     offset_ = 0;
     length_ -= kNalHeaderSize;
     rtc::Optional<uint32_t> pps_id = PpsParser::ParsePpsIdFromSlice(
         payload_data + 2 * kNalHeaderSize, length_ - kNalHeaderSize);
-    if (pps_id)
+    if (pps_id) {
       nalu.pps_id = *pps_id;
+    } else {
+      LOG(LS_WARNING) << "Failed to parse PPS from first fragment of FU-A NAL "
+                         "unit with original type: "
+                      << static_cast<int>(nalu.type);
+    }
     uint8_t original_nal_header = fnri | original_nal_type;
     modified_buffer_.reset(new rtc::Buffer());
     modified_buffer_->AppendData(payload_data + kNalHeaderSize, length_);
     (*modified_buffer_)[0] = original_nal_header;
   } else {
     offset_ = kFuAHeaderSize;
     length_ -= kFuAHeaderSize;
   }
 
   if (original_nal_type == H264::NaluType::kIdr) {
     parsed_payload->frame_type = kVideoFrameKey;
   } else {
     parsed_payload->frame_type = kVideoFrameDelta;
   }
   parsed_payload->type.Video.width = 0;
   parsed_payload->type.Video.height = 0;
   parsed_payload->type.Video.codec = kRtpVideoH264;
   parsed_payload->type.Video.isFirstPacket = first_fragment;
   RTPVideoHeaderH264* h264 = &parsed_payload->type.Video.codecHeader.H264;
   h264->packetization_type = kH264FuA;
   h264->nalu_type = original_nal_type;
-  h264->nalus[h264->nalus_length] = nalu;
-  h264->nalus_length = 1;
+  if (first_fragment) {
+    h264->nalus[h264->nalus_length] = nalu;
+    h264->nalus_length = 1;
+  }
   return true;
 }
 
 }  // namespace webrtc