Merging G.711 files

Started by Andrew Chalk in comp.dsp11 years ago 17 replies

I have two G.711 files/streams and I want to merge them. They represent each side of a telephone conversation. I know I can create a 'stereo'...

I have two G.711 files/streams and I want to merge them. They represent each side of a telephone conversation. I know I can create a 'stereo' .wav file but I would rather create a single channel (mono) file. Can I just add together each contemporaneous data point? If not, how should I do this. Many thanks.


G.711 implementation

Started by kostbill in comp.dsp11 years ago 9 replies

Hello. I have read the G.711 spec from ITU and I have seen some implementations written in C. There is something I don't understand because...

Hello. I have read the G.711 spec from ITU and I have seen some implementations written in C. There is something I don't understand because I cannot understand it from the spec and the different implementations I have seen produce different results! So, my question is in the bit ordering and in the bit inversing. Example: 520 (dec) = 1000001000 -> 0 0 0 1 0 0 0 0 0 1 0 0 0 (sign bi


Coding distortion for a G.711 codec.

Started by Anonymous in comp.dsp12 years ago 1 reply

I have implemented a G.711 encoder and decoder over the StarCore 1400. I need to determine the distortion produced by the conversion of...

I have implemented a G.711 encoder and decoder over the StarCore 1400. I need to determine the distortion produced by the conversion of linear 16 bit samples to 8 bit non linear PCM (encoding) and back to 16 bit linear samples (decoding). I was looking for a standard look-up table or something of that sort which tells me what 8 bit PCM value maps onto a 16 bit linear sample and conversely ...


vocoder transcoding question

Started by radiohead in comp.dsp14 years ago 5 replies

hello, i am endeavoring to transcode G.729 r8 to G.711 as my first serious DSP project for a production environment. I am seeking any relevant...

hello, i am endeavoring to transcode G.729 r8 to G.711 as my first serious DSP project for a production environment. I am seeking any relevant resources including how-tos, reference docs, tutorials, working code, ..annnything I am fairly new to DSP and don't really have much of an idea of how to get started. Any advice is GREATLY appreciated regards chris


Do I really need a DSP? If yes, how to choose one?

Started by alpb in comp.dsp6 years ago 16 replies

Hi everybody, For our next project, we need to develop & engineer a VOIP gateway which must support 8 radio channels. The codec is G.711 . The...

Hi everybody, For our next project, we need to develop & engineer a VOIP gateway which must support 8 radio channels. The codec is G.711 . The requirement for the latency of voice on the gateway is 1/4 seconds. My gut feeling says that we can accomplish this with by using a 8 channel professional sound card (~$200) and PJSIP library without using a DSP, with the help of a Intel i7 processor and...


audio transcoding

Started by DragosD in comp.dsp12 years ago 1 reply

Hi all, I was wondering if anyone can give me some information (links, forums, possible books) on audio transcoding topic. I've been assigned...

Hi all, I was wondering if anyone can give me some information (links, forums, possible books) on audio transcoding topic. I've been assigned this task and I need a starting point. I'm generally interested in audio transcoding but more specific in G.729.A or G.729.AB to G.723.1A transcoding. Now the trick is the transcoding path should be direct without going through G.711 Many thank...


Comfort Noise Generator

Started by kanhaiya in comp.dsp13 years ago 3 replies

Dear Experts Well I've read a few previous posts on this aspect. The documents or references I used were: RTP Payload for Comfort Noise...

Dear Experts Well I've read a few previous posts on this aspect. The documents or references I used were: RTP Payload for Comfort Noise RFC3389. Appendix II of G.711 Annex B of G.729 Well my query is regarding implementation of a codec independent CNG: 1) Which excitation is best for this CN (white or pink)? 2) I tried with only noise energy level transmission, and generating pink...


Need info on speech CODECS

Started by Anonymous in comp.dsp12 years ago 2 replies

Hi, I work for a Multimedia startup company. we are luking for speech codecs implemented on ARM9 platform for our end system.Can any one...

Hi, I work for a Multimedia startup company. we are luking for speech codecs implemented on ARM9 platform for our end system.Can any one give some info abt good companies who does Porting of speech codecs. we need ITU G.723.1 or 3gpp AMR-NB and G.726, G.711. Also cud any tell me how much each codec will cost(in USD$)so that we can choose the one which fits our budget. TIA.


Wimax Baseband Algorithms

Started by walter2k in comp.dsp10 years ago 3 replies

Hi, How complicated are Wimax baseband algorithms as compared to voice algorithms (eg G.711). I am new to wimax and need to have an...

Hi, How complicated are Wimax baseband algorithms as compared to voice algorithms (eg G.711). I am new to wimax and need to have an estimate of the time required to code and optimize wimax baseband algorithms. Walter


Need help improve the Freeswitch open-source telephony switch.

Started by mstate in comp.dsp2 years ago

We would like to sponsor someone to contribute a small bit of C-programming to the Freeswitch open-source telephony project. Specifically, we...

We would like to sponsor someone to contribute a small bit of C-programming to the Freeswitch open-source telephony project. Specifically, we need help to update beep-detection algorithm used in mod_avmd module. Mod_avmd attempts to identify a beep of unknown frequency at the end of a voicemail message. The stream being analyzed is an SIP G.711 with an 8K sample rate and encoded as mu-law. W...