JackAudio September 2016

jackaudio@lists.linuxaudio.org

22 participants
27 discussions

by Miroslav Urbanek

Hi, JACK1 prints negative values in xrun errors. The problem started with Linux kernel 4.0, and I believe it is caused by the following commit: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=… A patch is attached. MU

7 years, 7 months

[Jack-Devel] Fwd: [PATCH] Explicitly enable timestamps in the ALSA backend

by Josh de Kock

Forwarding to Jack-devel (it was a direct reply to me, but I can't do anything with it at this stage). -------- Forwarded Message -------- Subject: Re: [Jack-Devel] Negative xruns Date: Fri, 9 Sep 2016 12:11:01 +0200 From: Miroslav Urbanek <mu(a)miroslavurbanek.com> To: Josh de Kock <josh(a)itanimul.li> Here you go. MU

7 years, 7 months

[Jack-Devel] How to handle freewheeling failure

by Kjetil Matheussen

Hi, I wonder how you normally handle the situation when the program exits abnormally (for instance if the user kills a client) while freewheeling. I'm not so interested in detecting this when it happens, but I want to handle it somewhat gracefully when my program is started again. I.e. I don't want the program not producing any sound and not informing that something is wrong. As far as I can see, there is no function to check whether jack is currently freewheeling (or is there?). So are there any potential problems just calling "jack_set_freewheel(g_jack_client, 1)" during program startup? (i.e. whether we are freewheeling or not)

7 years, 7 months

[Jack-Devel] jack_transport_query(client, NULL) always returns JackTransportStopped

by Kjetil Matheussen

Maybe I have misunderstood how things work, or I'm using too old version of jack, but here's what happens: 1. Start jack 2 (jack-audio-connection-kit-devel-1.9.9.5-1.fc17.x86_64) 2. Press the "Start transport rolling" button in qjackctl. 3. Qjackctl reports "Rolling" in the display. 4. Create jack client 5. Call jack_transport_query(client, NULL). 6. jack_transport_query(client, NULL) always returns JackTransportStopped Shouldn't jack_transport_query(client, NULL) return JackTransportRolling? (It doesn't matter whether I activate the client or not before calling jack_transport_query(client, NULL)).

7 years, 7 months

[Jack-Devel] Suggestion for an example program

by Peter Hoppe

Hi! In reference to https://github.com/jackaudio/example-clients: I saw the code as part of a question on Stackoverflow (http://stackoverflow.com/q/29748082/6544953). Would it be possible to include the source code below as an example? * There's already a midi controlled synth application in that repo (midisine.c). But I feel the example demonstrates in a clearer way how to send audio to the sound card's stereo output, because it just uses audio data, not audio data plus midi handling. * There's also the simple client example (simple_client.c), but that one (effectively) handles bi-directional audio data streaming. This client just sends audio data which makes it clearer how to use data output (and, by implication, data input). Long story in short - this example is clearer to n00bs (like me). Thank you for your consideration! > |/** @file simple_client.c * * @brief This simple client demonstrates > the basic features of JACK * as they would be used by many > applications. > */#include<stdio.h>#include<errno.h>#include<stdlib.h>#include<string.h>#include<math.h>#include<signal.h>#ifndefWIN32 > #include<unistd.h>#endif#include<jack/jack.h>jack_port_t*output_port1,*output_port2;jack_client_t*client;#ifndefM_PI > #defineM_PI (3.14159265)#endif#defineTABLE_SIZE > (200)typedefstruct{floatsine[TABLE_SIZE];intleft_phase;intright_phase;}paTestData;staticvoidsignal_handler(intsig){jack_client_close(client);fprintf(stderr,"signal > received, exiting ...\n");exit(0);}/** * The process callback for this > JACK application is called in a * special realtime thread once for > each audio cycle. * * This client follows a simple rule: when the JACK > transport is * running, copy the input port to the output. When it > stops, exit. > */intprocess(jack_nframes_tnframes,void*arg){jack_default_audio_sample_t*out1,*out2;paTestData > *data =(paTestData*)arg;inti;out1 > =(jack_default_audio_sample_t*)jack_port_get_buffer(output_port1,nframes);out2 > =(jack_default_audio_sample_t*)jack_port_get_buffer(output_port2,nframes);for(i > =0;i<nframes;i++){out1[i]=data->sine[data->left_phase];// left > out2[i]=data->sine[data->right_phase];// right data->left_phase > +=1;if(data->left_phase >=TABLE_SIZE)data->left_phase > -=TABLE_SIZE;data->right_phase +=10;// higher pitch so we can > distinguish left and right. if(data->right_phase > >=TABLE_SIZE)data->right_phase -=TABLE_SIZE;}return0;}/** * JACK calls > this shutdown_callback if the server ever shuts down or * decides to > disconnect the client. > */voidjack_shutdown(void*arg){exit(1);}intmain(intargc,char*argv[]){constchar**ports;constchar*client_name;constchar*server_name > =NULL;jack_options_toptions > =JackNullOption;jack_status_tstatus;paTestData data;inti;/*if (argc >= > 2) { // client name specified? client_name = argv[1]; if (argc >= 3) { > // server name specified? server_name = argv[2]; int my_option = > JackNullOption | JackServerName; options = (jack_options_t)my_option; > } } else { // use basename of argv[0] client_name = strrchr(argv[0], > '/'); if (client_name == 0) { client_name = argv[0]; } else { > client_name++; } }*/client_name ="mytest";for(i > =0;i<TABLE_SIZE;i++){data.sine[i]=0.2*(float)sin(((double)i > /(double)TABLE_SIZE)*M_PI *2.);}data.left_phase =data.right_phase > =0;// open a client connection to the JACK server client > =jack_client_open(client_name,options,&status,server_name);if(client > ==NULL){fprintf(stderr,"jack_client_open() failed, ""status = > 0x%2.0x\n",status);if(status &JackServerFailed){fprintf(stderr,"Unable > to connect to JACK server\n");}exit(1);}if(status > &JackServerStarted){fprintf(stderr,"JACK server started\n");}if(status > &JackNameNotUnique){client_name > =jack_get_client_name(client);fprintf(stderr,"unique name `%s' > assigned\n",client_name);}// tell the JACK server to call `process()' > whenever//there is work to be > done.jack_set_process_callback(client,process,&data);// tell the JACK > server to call `jack_shutdown()' if//it ever shuts down, either > entirely, or if it//just decides to stop calling > us.jack_on_shutdown(client,jack_shutdown,0);// create two ports > output_port1 > =jack_port_register(client,"output1",JACK_DEFAULT_AUDIO_TYPE,JackPortIsOutput,0);output_port2 > =jack_port_register(client,"output2",JACK_DEFAULT_AUDIO_TYPE,JackPortIsOutput,0);if((output_port1 > ==NULL)||(output_port2 ==NULL)){fprintf(stderr,"no more JACK ports > available\n");exit(1);}//Tell the JACK server that we are ready to > roll. Our// process() callback will start running now. > if(jack_activate(client)){fprintf(stderr,"cannot activate > client");exit(1);}// Connect the ports. You can't do this before the > client is// activated, because we can't make connections to clients// > that aren't running. Note the confusing (but necessary)// orientation > of the driver backend ports: playback ports are// "input" to the > backend, and capture ports are "output" from// it.ports > =jack_get_ports(client,NULL,NULL,JackPortIsPhysical|JackPortIsInput);if(ports > ==NULL){fprintf(stderr,"no physical playback > ports\n");exit(1);}if(jack_connect(client,jack_port_name(output_port1),ports[0])){fprintf(stderr,"cannot > connect output > ports\n");}if(jack_connect(client,jack_port_name(output_port2),ports[1])){fprintf(stderr,"cannot > connect output ports\n");}jack_free(ports);// install a signal handler > to properly quits jack client #ifdefWIN32 > signal(SIGINT,signal_handler);signal(SIGABRT,signal_handler);signal(SIGTERM,signal_handler);#elsesignal(SIGQUIT,signal_handler);signal(SIGTERM,signal_handler);signal(SIGHUP,signal_handler);signal(SIGINT,signal_handler);#endif// > keep running until the Ctrl+C while(1){#ifdefWIN32 > Sleep(1000);#elsesleep(1);#endif}jack_client_close(client);exit(0);}|

7 years, 7 months

Re: [Jack-Devel] helpful stuff

by Daniele Torelli

Hi! I know you're interested in stuff like that, so I think that information is gonna be helpful to you, read it here please <http://nophustupu.nicholasyost.com/e4sxf> Faithfully, Daniele Torelli

7 years, 7 months

Re: [Jack-Devel] many thanks

by Daniele Torelli

Hello friend, I wanted to thank you a lot for all you've done, it was a real help. Please read my whole message here <http://jisethyzo.juliaburnessjewellery.com/e4taq> Yours faithfully, Daniele Torelli

7 years, 7 months

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JackAudio September 2016