static int
opensl_get_min_latency(cubeb * ctx, cubeb_stream_params params, uint32_t * latency_ms)
{
/* https://android.googlesource.com/platform/ndk.git/+/master/docs/opensles/index.html
* We don't want to deal with JNI here (and we don't have Java on b2g anyways),
* so we just dlopen the library and get the two symbols we need. */
int rv;
void * libmedia;
size_t (*get_primary_output_frame_count)(void);
int (*get_output_frame_count)(size_t * frameCount, int streamType);
uint32_t primary_sampling_rate;
size_t primary_buffer_size;
rv = opensl_get_preferred_sample_rate(ctx, &primary_sampling_rate);
if (rv) {
return CUBEB_ERROR;
}
libmedia = dlopen("libmedia.so", RTLD_LAZY);
if (!libmedia) {
return CUBEB_ERROR;
}
/* JB variant */
/* size_t AudioSystem::getPrimaryOutputFrameCount(void) */
get_primary_output_frame_count =
dlsym(libmedia, "_ZN7android11AudioSystem26getPrimaryOutputFrameCountEv");
if (!get_primary_output_frame_count) {
/* ICS variant */
/* status_t AudioSystem::getOutputFrameCount(int* frameCount, int streamType) */
get_output_frame_count =
dlsym(libmedia, "_ZN7android11AudioSystem19getOutputFrameCountEPii");
if (!get_output_frame_count) {
dlclose(libmedia);
return CUBEB_ERROR;
}
}
if (get_primary_output_frame_count) {
primary_buffer_size = get_primary_output_frame_count();
} else {
if (get_output_frame_count(&primary_buffer_size, params.stream_type) != 0) {
return CUBEB_ERROR;
}
}
/* To get a fast track in Android's mixer, we need to be at the native
* samplerate, which is device dependant. Some devices might be able to
* resample when playing a fast track, but it's pretty rare. */
*latency_ms = NBUFS * primary_buffer_size / (primary_sampling_rate / 1000);
dlclose(libmedia);
return CUBEB_OK;
}
static int
opensl_get_min_latency(cubeb * ctx, cubeb_stream_params params, uint32_t * latency_ms)
{
/* https://android.googlesource.com/platform/ndk.git/+/master/docs/opensles/index.html
* We don't want to deal with JNI here (and we don't have Java on b2g anyways),
* so we just dlopen the library and get the two symbols we need. */
int rv;
void * libmedia;
uint32_t (*get_primary_output_samplingrate)(void);
size_t (*get_primary_output_frame_count)(void);
uint32_t primary_sampling_rate;
size_t primary_buffer_size;
libmedia = dlopen("libmedia.so", RTLD_LAZY);
if (!libmedia) {
return CUBEB_ERROR;
}
/* uint32_t AudioSystem::getPrimaryOutputSamplingRate(void) */
get_primary_output_samplingrate =
dlsym(libmedia, "_ZN7android11AudioSystem28getPrimaryOutputSamplingRateEv");
if (!get_primary_output_samplingrate) {
dlclose(libmedia);
return CUBEB_ERROR;
}
/* size_t AudioSystem::getPrimaryOutputFrameCount(void) */
get_primary_output_frame_count =
dlsym(libmedia, "_ZN7android11AudioSystem26getPrimaryOutputFrameCountEv");
if (!get_primary_output_frame_count) {
dlclose(libmedia);
return CUBEB_ERROR;
}
primary_sampling_rate = get_primary_output_samplingrate();
primary_buffer_size = get_primary_output_frame_count();
/* To get a fast track in Android's mixer, we need to be at the native
* samplerate, which is device dependant. Some devices might be able to
* resample when playing a fast track, but it's pretty rare. */
if (primary_sampling_rate != params.rate) {
/* If we don't know what to use, let's say 4 * 20ms buffers will do. */
*latency_ms = NBUFS * 20;
} else {
*latency_ms = NBUFS * primary_buffer_size / (primary_sampling_rate / 1000);
}
dlclose(libmedia);
return CUBEB_OK;
}
