message: fix memory leak in decode_video (ref:
diff: @@ -246,11 +246,15 @@ class FFmpegReadStreamMeta : public FFmpegReadStream {
  return errors::OutOfRange("EOF reached");
  }
  int ret;
  + av_init_packet(&packet_);
  do {
  ret = av_read_frame(format_context_.get(), &packet_);
  if (ret < 0) {
  break;
  }
  + if (packet_.stream_index != stream_index_) {
  + av_packet_unref(&packet_);
  + }
  } while (packet_.stream_index != stream_index_);
  int got_frame;
  // decode
  @@ -258,6 +262,7 @@ class FFmpegReadStreamMeta : public FFmpegReadStream {
  while (packet_.size > 0) {
  TF_RETURN_IF_ERROR(DecodeFrame(&got_frame));
  }
  + av_packet_unref(&packet_);
  return Status::OK();
  }
  // final cache clean up
  