[Winpcap-users] VOIP [RTP]
Camiel Vanderhoeven
iamcamiel at gmail.com
Thu Apr 3 19:05:20 GMT 2008
Hello Wajdi,
You should record each direction into a separate file, so you get two
files; have you done this? If you record every packet you get into a
single file, it will become a mess. Once you have the two files,
convert both files to wav, and then use another program to mix them
together.
Camiel.
On Mon, Mar 31, 2008 at 11:31 AM, TORKHANI Wajdi
<wajdi.torkhani at laposte.net> wrote:
>
>
>
> Hi,
> please help me :(
> i don't know where to go, or what to search, so any suggestions .
> Let's go step by step :
> If i record in one direction the voice run quickly !!
> But when it recorded in both directions; there is a noise on the packets!!
> (I used a linear list to sort the recived packet by the timestamp and then
> store it in a binary file)
>
> Thank you.
>
> ----- Original Message -----
> From: Maria de Fatima Requena
> To: winpcap-users at winpcap.org
> Sent: Tuesday, March 18, 2008 9:09 AM
> Subject: RE: [Winpcap-users] VOIP [RTP]
>
>
>
>
> Just like you use lame, there are other programs to mix two files (with a
> little help of google I'm sure you will find the best for you)
>
>
>
>
>
>
>
>
> María de Fátima Requena Cabot (2488)
> +34 91 787 23 00 alhambra-eidos.es
>
>
>
>
>
>
>
> De: winpcap-users-bounces at winpcap.org
> [mailto:winpcap-users-bounces at winpcap.org] En nombre de TORKHANI Wajdi
> Enviado el: lunes, 17 de marzo de 2008 23:52
> Para: winpcap-users at winpcap.org
> Asunto: Re: [Winpcap-users] VOIP [RTP]
>
>
>
>
>
> Thank you so much
>
> After 4 weeks I can finally to hear the voice,
> But now I have another problem!
> If i record only one direction the sound run very quickly and if record both
> direction (in one file) i have a very very very bad quality of voice !!!!
>
> 1-I record the payload in a binary file:
>
>
>
> Code:
>
>
>
>
>
> void rawfile(unsigned char * payload,FILE *f){
> fwrite(payload, 10,1,f); //10 :because audio data is packed into 80 bits
> (10 bytes)
> }
>
>
>
> 2- I decode the binary file by using voiceage G729, which gives me a file :
> "16-bit mono PCM speech data sampled at 8000 Hz"
>
> 3- convert PCM file into wav by using Lame with:
> lame --decode -x -r -s 8000 -m m -b 16 file.pcm file.wav
>
> Is it correct ?!
>
>
> If i create two file one for each direction how can i mix them later ?
>
>
> thank you so much
>
>
>
>
>
>
>
>
>
> ----- Original Message -----
>
>
> From: Maria de Fatima Requena
>
>
> To: winpcap-users at winpcap.org
>
>
> Sent: Monday, March 17, 2008 8:26 AM
>
>
> Subject: RE: [Winpcap-users] VOIP [RTP]
>
>
>
>
> RTP packets can be captured on two streams (one for each direction), and
> later you can mix them. I think raw files doesn't need a header, but you can
> use programs to open your streams specifying a certain format
>
>
>
>
>
>
>
>
> María de Fátima Requena Cabot (2488)
> +34 91 787 23 00 alhambra-eidos.es
>
>
>
>
>
>
>
> De: winpcap-users-bounces at winpcap.org
> [mailto:winpcap-users-bounces at winpcap.org] En nombre de TORKHANI Wajdi
> Enviado el: jueves, 13 de marzo de 2008 20:49
> Para: winpcap-users at winpcap.org
> Asunto: Re: [Winpcap-users] VOIP [RTP]
>
>
>
>
> Hello,
>
>
>
>
>
> Does any one know how can i create a bitstream seems the (.raw) file
> exported by ethreal (seems the output file of rtpdum.exe) ?
>
>
>
>
>
> Thank you,
>
>
>
> ----- Original Message -----
>
>
> From: TORKHANI Wajdi
>
>
> To: winpcap-users at winpcap.org
>
>
> Sent: Wednesday, March 12, 2008 12:09 AM
>
>
> Subject: Re: [Winpcap-users] VOIP [RTP]
>
>
>
>
>
> thank you so so much :)
>
>
>
>
>
> I took your advice and I solved the problem number 3 :
>
>
> _______________________________________
>
>
> I- change Structure RTP header :
>
>
> struct rtphdr{
>
>
> unsigned short CSRC_count:4; // CSRC count
> unsigned short extension:1; // header extension flag
> unsigned short padding:1; // padding flag
> unsigned short ver:2; // protocol version
> unsigned short Payload:7; // payload type
> unsigned short Marker:1; // marker bit
> unsigned short Sequence; // sequence number
> unsigned int Timestamp; // timestamp
> unsigned int SSRC; // synchronization source
> //unsigned int csrc[1]; // optional CSRC list
>
>
> };
>
>
> _________________________
>
>
> II- replace : sizeof(struct iphdr) by (ip->ihl * 4)
>
>
> rtp=(struct rtphdr *)(pkt_data+(sizeof(struct ethhdr)+(ip->ihl *
> 4)+sizeof(struct udphdr)));
>
>
> ________________________
>
>
> III- htons and htonl :
>
>
> fprintf(stdout,"------------------------------------------------------\n");
> fprintf(stdout,"Version : %d |\r\n",rtp->ver);
> fprintf(stdout,"Padding : %.5d |\r\n",htons(rtp->padding));
> fprintf(stdout,"Extension : %.5d |\r\n",htons(rtp->extension));
> fprintf(stdout,"CSRC_count : %.5d |\r\n",htons(rtp->CSRC_count));
> fprintf(stdout,"Marker : %.5d |\r\n",htons(rtp->Marker));
> fprintf(stdout,"Payload : %d |\r\n",rtp->Payload);
> fprintf(stdout,"Sequence Number : %u |\r\n",htons(rtp->Sequence));
> fprintf(stdout,"Timestamp : %u |\r\n",htonl(rtp->Timestamp));
> fprintf(stdout,"Synchronization source : %u |\r\n",htonl(rtp->SSRC));
>
>
> _____________________________
>
>
>
>
>
> For the first and second question i will give you more details maybe they
> can help you to help me :P
> 1-I must create a voip sniffer (to capture communication VOIP on the LAN)
> and then to convert them into audio format.
> 2-regroup the paquet of a communication together to store it the bitstream
> format required by the decoder (voiceage G729).
> I succeeded in :
> preparing a sniffer in C++ (by using the library winpcap) (capture network
> traffic,filtre UDP trafic,Read ethernet,ip,udp and RTP header)
> and now i'm working on the bulding of the bitstream file.
>
>
>
>
>
>
>
>
> Thank you,
>
>
> Wajdi TORKHANI
>
>
>
> ----- Original Message -----
>
>
> From: Maria de Fatima Requena
>
>
> To: winpcap-users at winpcap.org
>
>
> Sent: Tuesday, March 11, 2008 8:23 AM
>
>
> Subject: RE: [Winpcap-users] VOIP [RTP]
>
>
>
>
> Maybe the problem is byte order. If you take a look at wireshark examples,
> you will see instructions like ntohs, or some ones that apply bit masks,
> that do this change.
>
>
>
> On the other hand, once you have stopped reading packets, you can use tools
> to give the streams format. For example goldwave lets you determine the type
> of coding you need before opening the file. Anyway, you can manually add
> header format to your files.
>
>
>
> I hope this helps
>
>
>
>
>
>
>
>
> María de Fátima Requena Cabot (2488)
> +34 91 787 23 00 alhambra-eidos.es
>
>
>
>
>
>
>
> De: winpcap-users-bounces at winpcap.org
> [mailto:winpcap-users-bounces at winpcap.org] En nombre de Gianluca Varenni
> Enviado el: viernes, 07 de marzo de 2008 18:12
> Para: winpcap-users at winpcap.org
> Asunto: Re: [Winpcap-users] VOIP [RTP]
>
>
>
>
> I'm not an expert about RTP, so I cannot answer questions 1 and 2. Regarding
> 3, for sure there's something that "smells" in your code
>
>
> - you are assuming that you are always receiving UDP packets encapsulated
> over IPv4. Unless you are filtering the captured packets to make sure they
> are IPv4 and UDP, you should check the ethertype and the L3 protocol type.
>
>
> - you are assuming that the IP header has a fixed size (...sizeof(struct
> iphdr)...). This is not true. You need to compute the length of the IPv4
> header by looking at the first byte in the IP header itself.
>
>
>
>
>
> Hope it helps
>
>
> GV
>
>
>
>
>
>
> ----- Original Message -----
>
>
> From: TORKHANI Wajdi
>
>
> To: winpcap-users at winpcap.org
>
>
> Sent: Tuesday, March 04, 2008 2:40 PM
>
>
> Subject: [Winpcap-users] VOIP [RTP]
>
>
>
>
>
> Hi,
>
> I get the rtp packet from winpcap but i have the following problem:
>
> 1-how to regroup the paquet of a communication together to store it and
> apply the CODEC(G.729A)?
> 2-how detect the end of call ?!
> 3-I have a problem with reading the RTP header, below a part of my source
> code :
> ------------------
>
>
>
> Code:
>
>
>
>
>
> struct rtphdr{
>
> unsigned short ver:2 ;
> unsigned short padding:1;
> unsigned short extension:1 ;
> unsigned short CSRC_count:4 ;
> unsigned short Marker:1 ;
> unsigned short Payload :7 ;
> unsigned short Sequence ;// 16 bits
> unsigned int Timestamp;//32 bits
> unsigned int SSRC ;//32 bits
> };
>
>
> --------------------
> Code:
>
>
> rtp=(struct rtphdr *)(pkt_data+(sizeof(struct ethhdr)+sizeof(struct
> iphdr)+sizeof(struct udphdr)));
>
>
> ---------------------------
>
>
> Code:
>
>
>
>
>
> fprintf(stdout,"------------------------------------------------------\n");
> fprintf(stdout,"Version : %d |\r\n",rtp->ver);
> fprintf(stdout,"Padding : %.5d |\r\n",htons(rtp->padding));
> fprintf(stdout,"Extension : %.5d |\r\n",htons(rtp->extension));
> fprintf(stdout,"CSRC_count : %.5d |\r\n",htons(rtp->CSRC_count));
> fprintf(stdout,"Marker : %.5d |\r\n",htons(rtp->Marker));
> fprintf(stdout,"Payload : %.5d |\r\n",htons(rtp->Payload));
> fprintf(stdout,"Sequence Number : %.5d |\r\n",htons(rtp->Sequence));
> fprintf(stdout,"Timestamp : %.5d |\r\n",htons(rtp->Timestamp));
> fprintf(stdout,"Synchronization source : %.5d
> |\r\n",htons(rtp->SSRC));
> ------------------------
> Ethernet,IP and UDP header are correct.
> When i compare the result whith ethreal result i fin that only SSRC is
> correct !
> thank you.
> I'm sorry for my bad english
>
>
>
>
>
> TORKHANI Wajdi
> ________________________________
>
>
> _______________________________________________
> Winpcap-users mailing list
> Winpcap-users at winpcap.org
> https://www.winpcap.org/mailman/listinfo/winpcap-users
> ________________________________
>
>
> _______________________________________________
> Winpcap-users mailing list
> Winpcap-users at winpcap.org
> https://www.winpcap.org/mailman/listinfo/winpcap-users
> ________________________________
>
>
> _______________________________________________
> Winpcap-users mailing list
> Winpcap-users at winpcap.org
> https://www.winpcap.org/mailman/listinfo/winpcap-users
> ________________________________
>
>
> _______________________________________________
> Winpcap-users mailing list
> Winpcap-users at winpcap.org
> https://www.winpcap.org/mailman/listinfo/winpcap-users
>
> ________________________________
>
>
> _______________________________________________
> Winpcap-users mailing list
> Winpcap-users at winpcap.org
> https://www.winpcap.org/mailman/listinfo/winpcap-users
>
> _______________________________________________
> Winpcap-users mailing list
> Winpcap-users at winpcap.org
> https://www.winpcap.org/mailman/listinfo/winpcap-users
>
>
More information about the Winpcap-users
mailing list