1 #ifndef _CUBEB_MEDIA_LIBRARY_H_
2 #define _CUBEB_MEDIA_LIBRARY_H_
3
4 struct media_lib {
5 void * libmedia;
6 int32_t (* get_output_latency)(uint32_t * latency, int stream_type);
7 };
8
9 typedef struct media_lib media_lib;
10
11 media_lib *
cubeb_load_media_library()12 cubeb_load_media_library()
13 {
14 media_lib ml = {0};
15 ml.libmedia = dlopen("libmedia.so", RTLD_LAZY);
16 if (!ml.libmedia) {
17 return NULL;
18 }
19
20 // Get the latency, in ms, from AudioFlinger. First, try the most recent signature.
21 // status_t AudioSystem::getOutputLatency(uint32_t* latency, audio_stream_type_t streamType)
22 ml.get_output_latency =
23 dlsym(ml.libmedia, "_ZN7android11AudioSystem16getOutputLatencyEPj19audio_stream_type_t");
24 if (!ml.get_output_latency) {
25 // In case of failure, try the signature from legacy version.
26 // status_t AudioSystem::getOutputLatency(uint32_t* latency, int streamType)
27 ml.get_output_latency =
28 dlsym(ml.libmedia, "_ZN7android11AudioSystem16getOutputLatencyEPji");
29 if (!ml.get_output_latency) {
30 return NULL;
31 }
32 }
33
34 media_lib * rv = NULL;
35 rv = calloc(1, sizeof(media_lib));
36 assert(rv);
37 *rv = ml;
38 return rv;
39 }
40
41 void
cubeb_close_media_library(media_lib * ml)42 cubeb_close_media_library(media_lib * ml)
43 {
44 dlclose(ml->libmedia);
45 ml->libmedia = NULL;
46 ml->get_output_latency = NULL;
47 free(ml);
48 }
49
50 uint32_t
cubeb_get_output_latency_from_media_library(media_lib * ml)51 cubeb_get_output_latency_from_media_library(media_lib * ml)
52 {
53 uint32_t latency = 0;
54 const int audio_stream_type_music = 3;
55 int32_t r = ml->get_output_latency(&latency, audio_stream_type_music);
56 if (r) {
57 return 0;
58 }
59 return latency;
60 }
61
62 #endif // _CUBEB_MEDIA_LIBRARY_H_
63