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QUdpSocket does not trigger ReadyRead signal

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  • O onurcevik

    @jsulm I deleted sleep and for loop it still did not work. I did take a look couple of examples even tried to run it. A pinpoint to what wrongs with my code would be really helpful. Since removing sleep and for did not work either.

    Edit: I will switch to QWidget application and try to send through a button click.

    aha_1980A Offline
    aha_1980A Offline
    aha_1980
    Lifetime Qt Champion
    wrote on last edited by
    #12

    Hi @onurcevik,

    • On which platform are you?
    • Which Qt version do you use?
    • Do you have multiple network adapters in your computer?

    Regards

    Qt has to stay free or it will die.

    O 1 Reply Last reply
    0
    • aha_1980A aha_1980

      Hi @onurcevik,

      • On which platform are you?
      • Which Qt version do you use?
      • Do you have multiple network adapters in your computer?

      Regards

      O Offline
      O Offline
      onurcevik
      wrote on last edited by
      #13

      @aha_1980

      • I am on Kubuntu
      • I use Qt Creator 4.6.2 Based on Qt 5.11.1 (GCC 8.1.0, 64 bit)
      • I only have 1 modem.
      aha_1980A 1 Reply Last reply
      0
      • O onurcevik

        @aha_1980

        • I am on Kubuntu
        • I use Qt Creator 4.6.2 Based on Qt 5.11.1 (GCC 8.1.0, 64 bit)
        • I only have 1 modem.
        aha_1980A Offline
        aha_1980A Offline
        aha_1980
        Lifetime Qt Champion
        wrote on last edited by aha_1980
        #14

        @onurcevik

        Can you please post the output of ifconfig -a?

        It is likely that your packet is not even send out. You can check that with Wireshark.

        Edit:

        I use Qt Creator 4.6.2 Based on Qt 5.11.1 (GCC 8.1.0, 64 bit)

        That is the Creator version, not the Qt version I asked for.

        Qt has to stay free or it will die.

        O 1 Reply Last reply
        0
        • aha_1980A aha_1980

          @onurcevik

          Can you please post the output of ifconfig -a?

          It is likely that your packet is not even send out. You can check that with Wireshark.

          Edit:

          I use Qt Creator 4.6.2 Based on Qt 5.11.1 (GCC 8.1.0, 64 bit)

          That is the Creator version, not the Qt version I asked for.

          O Offline
          O Offline
          onurcevik
          wrote on last edited by
          #15

          @aha_1980

          That is the Creator version, not the Qt version I asked for.

          I use Qt Creator 4.6.2 Based on Qt 5.11.1 (GCC 8.1.0, 64 bit)

          QT version is next to the QT Creator Version which is 5.11.1

          the output of ifconfig -a :

          enp27s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
                  inet 192.168.2.44  netmask 255.255.255.0  broadcast 192.168.2.255
                  inet6 fe80::a98d:26da:2afd:3299  prefixlen 64  scopeid 0x20<link>
                  ether 00:d8:61:15:7d:b8  txqueuelen 1000  (Ethernet)
                  RX packets 37659  bytes 41459688 (41.4 MB)
                  RX errors 0  dropped 0  overruns 0  frame 0
                  TX packets 27301  bytes 2684010 (2.6 MB)
                  TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
          
          lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
                  inet 127.0.0.1  netmask 255.0.0.0
                  inet6 ::1  prefixlen 128  scopeid 0x10<host>
                  loop  txqueuelen 1000  (Local Loopback)
                  RX packets 1963  bytes 180145 (180.1 KB)
                  RX errors 0  dropped 0  overruns 0  frame 0
                  TX packets 1963  bytes 180145 (180.1 KB)
                  TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
          
          

          @aha_1980 said in QUdpSocket does not trigger ReadyRead signal:

          aha_1980A 1 Reply Last reply
          0
          • O onurcevik

            @aha_1980

            That is the Creator version, not the Qt version I asked for.

            I use Qt Creator 4.6.2 Based on Qt 5.11.1 (GCC 8.1.0, 64 bit)

            QT version is next to the QT Creator Version which is 5.11.1

            the output of ifconfig -a :

            enp27s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
                    inet 192.168.2.44  netmask 255.255.255.0  broadcast 192.168.2.255
                    inet6 fe80::a98d:26da:2afd:3299  prefixlen 64  scopeid 0x20<link>
                    ether 00:d8:61:15:7d:b8  txqueuelen 1000  (Ethernet)
                    RX packets 37659  bytes 41459688 (41.4 MB)
                    RX errors 0  dropped 0  overruns 0  frame 0
                    TX packets 27301  bytes 2684010 (2.6 MB)
                    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
            
            lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
                    inet 127.0.0.1  netmask 255.0.0.0
                    inet6 ::1  prefixlen 128  scopeid 0x10<host>
                    loop  txqueuelen 1000  (Local Loopback)
                    RX packets 1963  bytes 180145 (180.1 KB)
                    RX errors 0  dropped 0  overruns 0  frame 0
                    TX packets 1963  bytes 180145 (180.1 KB)
                    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
            
            

            @aha_1980 said in QUdpSocket does not trigger ReadyRead signal:

            aha_1980A Offline
            aha_1980A Offline
            aha_1980
            Lifetime Qt Champion
            wrote on last edited by
            #16

            @onurcevik said in QUdpSocket does not trigger ReadyRead signal:

            QT version is next to the QT Creator Version which is 5.11.1

            That is the Qt version Creator is built with, which is not necessarily the version you are using to compile your program.

            From you ifconfig I see, that there is only one physical interface., so bind should select the correct one.

            Please check with wireshark that the packet is sent out.

            Qt has to stay free or it will die.

            O 1 Reply Last reply
            1
            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #17

              Just for the sake of simplification, did you take a look at the examples linked in the QUdpSocket documentation ?

              Thinking about:

              Broadcast Sender
              Broadcast Receiver
              Multicast Sender
              Multicast Receiver

              Interested in AI ? www.idiap.ch
              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

              1 Reply Last reply
              4
              • aha_1980A aha_1980

                @onurcevik said in QUdpSocket does not trigger ReadyRead signal:

                QT version is next to the QT Creator Version which is 5.11.1

                That is the Qt version Creator is built with, which is not necessarily the version you are using to compile your program.

                From you ifconfig I see, that there is only one physical interface., so bind should select the correct one.

                Please check with wireshark that the packet is sent out.

                O Offline
                O Offline
                onurcevik
                wrote on last edited by onurcevik
                #18

                @aha_1980 I now realized that I can't even send the socket due to large size which is 1 mb. Do you know how can I divide it into chunks of bytes ? Or should I create new topic?

                1 Reply Last reply
                0
                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #19

                  What exactly is the goal of your application ?

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                  O 1 Reply Last reply
                  1
                  • SGaistS SGaist

                    What exactly is the goal of your application ?

                    O Offline
                    O Offline
                    onurcevik
                    wrote on last edited by
                    #20

                    @SGaist I want to take pictures from camera then send and recieve them continuously in order to implement a real time video streaming application. The reason I am sending images instead of video is because I will later work on image processing. I realized that image size is too big for this which is 6404803 BYTES. But I also can't switch to TCP because I need the speed of UDP.

                    1 Reply Last reply
                    0
                    • CP71C Offline
                      CP71C Offline
                      CP71
                      wrote on last edited by CP71
                      #21

                      Ok,
                      I apologize to mother tongue people for my English, I know, it isn’t good
                      Anyway, If I have understood correctly there is a limit of 1Mb, but limit apart, to do this I always do:

                      The server application

                      • Send a header with a fixed size and with the following information: a security key (to recognise a my flow), data size, …. and then send data
                      • You can get and save a pointer of data from QbyteArray by “data” function
                      • With a loop I send few pieces of data ( < 1Mb) by writeDatagram, it is easy, all you need to do you have to use an index to move on the data pointer

                      The client application:

                      • When it will receive your header and recognise it, it will know data size too
                      • read all data that will receive and reassemble the all image

                      For me UDP is a good choice.

                      I hope to help you.

                      JonBJ 1 Reply Last reply
                      3
                      • CP71C CP71

                        Ok,
                        I apologize to mother tongue people for my English, I know, it isn’t good
                        Anyway, If I have understood correctly there is a limit of 1Mb, but limit apart, to do this I always do:

                        The server application

                        • Send a header with a fixed size and with the following information: a security key (to recognise a my flow), data size, …. and then send data
                        • You can get and save a pointer of data from QbyteArray by “data” function
                        • With a loop I send few pieces of data ( < 1Mb) by writeDatagram, it is easy, all you need to do you have to use an index to move on the data pointer

                        The client application:

                        • When it will receive your header and recognise it, it will know data size too
                        • read all data that will receive and reassemble the all image

                        For me UDP is a good choice.

                        I hope to help you.

                        JonBJ Offline
                        JonBJ Offline
                        JonB
                        wrote on last edited by
                        #22

                        @CP71 said in QUdpSocket does not trigger ReadyRead signal:

                        The client application:

                        • When it will receive your header and recognise it, it will know data size too
                        • read all data that will receive and reassemble the all image

                        For me UDP is a good choice.

                        How do you manage to "read all data" corresponding to "it will know data size" given that you're using UDP?

                        CP71C 1 Reply Last reply
                        0
                        • SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on last edited by
                          #23

                          If you want to stream videos then you should follow the standards currently used to minimise bandwidth usage while keeping image quality.

                          As for video processing, you should give more information about what you want to do.

                          Interested in AI ? www.idiap.ch
                          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                          1 Reply Last reply
                          1
                          • JonBJ JonB

                            @CP71 said in QUdpSocket does not trigger ReadyRead signal:

                            The client application:

                            • When it will receive your header and recognise it, it will know data size too
                            • read all data that will receive and reassemble the all image

                            For me UDP is a good choice.

                            How do you manage to "read all data" corresponding to "it will know data size" given that you're using UDP?

                            CP71C Offline
                            CP71C Offline
                            CP71
                            wrote on last edited by
                            #24

                            @JonB Ok,
                            you are right, I think to know what you want to say, all depend of kind of application you are doing.
                            You believe me, I done real-time application with UDP and they work well.
                            Ok, TCP is more safety but UDP is faster, I’m not game developer but as far as I know more games are based on UDP, because it is faster.
                            It's obvious, the client must check the integrity of data and discard the bad data, e.g by checksum.
                            I don’t know the goal of @onurcevik, but if a frame video is delayed or lost it will be discarded.
                            All depend if you want to prefer the speed or the quality of information therefore what the client application must do.

                            JonBJ 1 Reply Last reply
                            0
                            • CP71C CP71

                              @JonB Ok,
                              you are right, I think to know what you want to say, all depend of kind of application you are doing.
                              You believe me, I done real-time application with UDP and they work well.
                              Ok, TCP is more safety but UDP is faster, I’m not game developer but as far as I know more games are based on UDP, because it is faster.
                              It's obvious, the client must check the integrity of data and discard the bad data, e.g by checksum.
                              I don’t know the goal of @onurcevik, but if a frame video is delayed or lost it will be discarded.
                              All depend if you want to prefer the speed or the quality of information therefore what the client application must do.

                              JonBJ Offline
                              JonBJ Offline
                              JonB
                              wrote on last edited by JonB
                              #25

                              @CP71
                              You may well know more than I. But as I understand it UDP can happily lose any packets at the client, that's the point of it. By splitting your datagrams like you said if one does not arrive what happens at the client, it seems to me that protocol just won't work? Maybe in your "real-world" apps none get missed, I don't actually have experience, I am just interested/concerned. :)

                              CP71C 1 Reply Last reply
                              1
                              • JonBJ JonB

                                @CP71
                                You may well know more than I. But as I understand it UDP can happily lose any packets at the client, that's the point of it. By splitting your datagrams like you said if one does not arrive what happens at the client, it seems to me that protocol just won't work? Maybe in your "real-world" apps none get missed, I don't actually have experience, I am just interested/concerned. :)

                                CP71C Offline
                                CP71C Offline
                                CP71
                                wrote on last edited by
                                #26

                                @JonB Don’t worry, I happy to communicate with you, so I’m training in English that is useful for me ;).
                                I don’t know if I can post a link to other site or forum, so I avoid.
                                I don’t say UDP is better than of TCP, I say that depend of your goal of application, each protocol has its scope.
                                For me, I would use UDP for stream video, especially if the client must be only show the image.
                                But it is only my idea.

                                1 Reply Last reply
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