diff options
Diffstat (limited to 'radio_output.c')
| -rw-r--r-- | radio_output.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/radio_output.c b/radio_output.c new file mode 100644 index 0000000..a49687b --- /dev/null +++ b/radio_output.c @@ -0,0 +1,294 @@ +/* + * Copyright (C) 2017 Konsulko Group + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <pulse/pulseaudio.h> + +#include "radio_output.h" +#include "rtl_fm.h" + +static pa_threaded_mainloop *mainloop; +static pa_context *context; +static pa_stream *stream; + +static unsigned int extra; +static int16_t extra_buf[1]; +static unsigned char *output_buf; + +static void pa_context_state_cb(pa_context *c, void *data) { + pa_operation *o; + + assert(c); + switch (pa_context_get_state(c)) { + case PA_CONTEXT_CONNECTING: + case PA_CONTEXT_AUTHORIZING: + case PA_CONTEXT_SETTING_NAME: + case PA_CONTEXT_READY: + break; + case PA_CONTEXT_TERMINATED: + pa_threaded_mainloop_stop(mainloop); + break; + case PA_CONTEXT_FAILED: + default: + fprintf(stderr, "PA connection failed: %s\n", + pa_strerror(pa_context_errno(c))); + pa_threaded_mainloop_stop(mainloop); + break; + } + pa_threaded_mainloop_signal(mainloop, 0); +} + +int radio_output_open(void) +{ + pa_context *c; + pa_mainloop_api *mapi; + char *client; + + if(context) + return 0; + + if (!(mainloop = pa_threaded_mainloop_new())) { + fprintf(stderr, "pa_mainloop_new() failed.\n"); + return -1; + } + + pa_threaded_mainloop_set_name(mainloop, "pa_mainloop"); + mapi = pa_threaded_mainloop_get_api(mainloop); + + client = pa_xstrdup("radio"); + if (!(c = pa_context_new(mapi, client))) { + fprintf(stderr, "pa_context_new() failed.\n"); + goto exit; + } + + pa_context_set_state_callback(c, pa_context_state_cb, NULL); + if (pa_context_connect(c, NULL, 0, NULL) < 0) { + fprintf(stderr, "pa_context_connect(): %s", pa_strerror(pa_context_errno(c))); + goto exit; + } + + if (pa_threaded_mainloop_start(mainloop) < 0) { + fprintf(stderr, "pa_mainloop_run() failed.\n"); + goto exit; + } + + context = c; + + extra = 0; + output_buf = malloc(sizeof(unsigned char) * RTL_FM_MAXIMUM_BUF_LENGTH); + + return 0; + +exit: + if (c) + pa_context_unref(c); + + if (mainloop) + pa_threaded_mainloop_free(mainloop); + + pa_xfree(client); + return -1; +} + +int radio_output_start(void) +{ + int error = 0; + pa_sample_spec *spec; + + if(stream) + return 0; + + if(!context) { + error = radio_output_open(); + if(error != 0) + return error; + } + + while(pa_context_get_state(context) != PA_CONTEXT_READY) + pa_threaded_mainloop_wait(mainloop); + + spec = (pa_sample_spec*) calloc(1, sizeof(pa_sample_spec)); + spec->format = PA_SAMPLE_S16LE; + spec->rate = 24000; + spec->channels = 2; + if (!pa_sample_spec_valid(spec)) { + fprintf(stderr, "%s\n", + pa_strerror(pa_context_errno(context))); + return -1; + } + + pa_threaded_mainloop_lock(mainloop); + pa_proplist *props = pa_proplist_new(); + pa_proplist_sets(props, PA_PROP_MEDIA_ROLE, "radio"); + stream = pa_stream_new_with_proplist(context, "radio-output", spec, 0, props); + if(!stream) { + fprintf(stderr, "Error creating stream %s\n", + pa_strerror(pa_context_errno(context))); + pa_proplist_free(props); + free(spec); + pa_threaded_mainloop_unlock(mainloop); + return -1; + } + pa_proplist_free(props); + free(spec); + + if(pa_stream_connect_playback(stream, + NULL, + NULL, + (pa_stream_flags_t) 0, + NULL, + NULL) < 0) { + fprintf(stderr, "Error connecting to PulseAudio : %s\n", + pa_strerror(pa_context_errno(context))); + pa_stream_unref(stream); + stream = NULL; + pa_threaded_mainloop_unlock(mainloop); + return -1; + } + + pa_threaded_mainloop_unlock(mainloop); + + while(pa_stream_get_state(stream) != PA_STREAM_READY) + pa_threaded_mainloop_wait(mainloop); + + return error; +} + +void radio_output_stop(void) +{ + if(stream) { + pa_threaded_mainloop_lock(mainloop); + + pa_stream_set_state_callback(stream, 0, 0); + pa_stream_set_write_callback(stream, 0, 0); + pa_stream_set_underflow_callback(stream, 0, 0); + pa_stream_set_overflow_callback(stream, 0, 0); + pa_stream_set_latency_update_callback(stream, 0, 0); + + pa_operation *o = pa_stream_flush(stream, NULL, NULL); + if(o) + pa_operation_unref(o); + + pa_stream_disconnect(stream); + pa_stream_unref(stream); + stream = NULL; + + pa_threaded_mainloop_unlock(mainloop); + } +} + +void radio_output_suspend(int state) +{ + if(stream) { + pa_stream_cork(stream, state, NULL, NULL); + } +} + +void radio_output_close(void) +{ + radio_output_stop(); + + if(context) { + pa_context_disconnect(context); + pa_context_unref(context); + context = NULL; + } + + if(mainloop) { + pa_threaded_mainloop_stop(mainloop); + pa_threaded_mainloop_free(mainloop); + mainloop = NULL; + } + + free(output_buf); + output_buf = NULL; +} + +int radio_output_write(void *buf, int len) +{ + int rc = -EINVAL; + int error; + size_t n = len; + size_t avail; + int samples = len / 2; + void *p; + + if(!stream) { + return -1; + } + + if(!buf) { + fprintf(stderr, "Error: buf == null!\n"); + return rc; + } + + pa_threaded_mainloop_lock(mainloop); + + avail = pa_stream_writable_size(stream); + if(avail < n) { + /* + * NOTE: Definitely room for improvement here,but for now just + * check for the no space case that happens when the + * stream is corked. + */ + if(!avail) { + rc = 0; + goto exit; + } + } + + /* + * Handle the rtl_fm code giving us an odd number of samples, which + * PA does not like. This extra buffer copying approach is not + * particularly efficient, but works for now. It looks feasible to + * hack in something in the demod and output thread routines in + * rtl_fm.c to handle it there if more performance is required. + */ + p = output_buf; + if(extra) { + memcpy(output_buf, extra_buf, sizeof(int16_t)); + if((extra + samples) % 2) { + // We still have an extra sample, n remains the same, store the extra + memcpy(output_buf + sizeof(int16_t), buf, n - 2); + memcpy(extra_buf, ((unsigned char*) buf) + n - 2, sizeof(int16_t)); + } else { + // We have an even number of samples, no extra + memcpy(output_buf + sizeof(int16_t), buf, n); + n += 2; + extra = 0; + } + } else if(samples % 2) { + // We have an extra sample, store it, and decrease n + n -= 2; + memcpy(output_buf + sizeof(int16_t), buf, n); + memcpy(extra_buf, ((unsigned char*) buf) + n, sizeof(int16_t)); + extra = 1; + } else { + p = buf; + } + + if ((rc = pa_stream_write(stream, p, n, NULL, 0, PA_SEEK_RELATIVE)) < 0) { + fprintf(stderr, "Error writing %d bytes to PulseAudio : %s\n", + n, pa_strerror(pa_context_errno(context))); + } +exit: + pa_threaded_mainloop_unlock(mainloop); + + return rc; +} |