Configuration - compilation error when building with FFmpeg 2.8

When building OCCT (7.4.0.beta2) with Clang 6.0 on Ubuntu 16.04, I get these errors:

[ 32%] Building CXX object src/TKService/CMakeFiles/TKService.dir/__/Media/Media_CodecContext.cxx.o
[user path removed]/occt/src/Media/Media_CodecContext.cxx:93:60: error: no member named 'codecpar' in 'AVStream'
  if (avcodec_parameters_to_context (myCodecCtx, theStream.codecpar) < 0)
                                                 ~~~~~~~~~ ^
[user path removed]/occt/src/Media/Media_CodecContext.cxx:104:98: error: no member named 'codecpar' in 'AVStream'
  const AVCodecID aCodecId = theCodecId != AV_CODEC_ID_NONE ? (AVCodecID )theCodecId : theStream.codecpar->code...
                                                                                       ~~~~~~~~~ ^
[user path removed]/occt/src/Media/Media_CodecContext.cxx:116:17: error: no member named 'codecpar' in 'AVStream'
  if (theStream.codecpar->codec_type == AVMEDIA_TYPE_VIDEO)
      ~~~~~~~~~ ^
[user path removed]/occt/src/Media/Media_CodecContext.cxx:146:17: error: no member named 'codecpar' in 'AVStream'
  if (theStream.codecpar->codec_type == AVMEDIA_TYPE_VIDEO
      ~~~~~~~~~ ^
[user path removed]/occt/src/Media/Media_CodecContext.cxx:241:20: error: use of undeclared identifier
      'avcodec_send_packet'
  const int aRes = avcodec_send_packet (myCodecCtx, thePacket->Packet());
                   ^
[user path removed]/occt/src/Media/Media_CodecContext.cxx:264:21: error: use of undeclared identifier
      'avcodec_receive_frame'
  const int aRes2 = avcodec_receive_frame (myCodecCtx, theFrame->ChangeFrame());
                    ^
6 errors generated.

I have FFmpeg 2.8.15-0ubuntu0.16.04.1