npv/clk/public/code.frag.c

   1 static void clk_init_once(void)
   2 {
   3         int r;
   4
   5         r = snd_pcm_status_malloc(&clk_l.ref.status);
   6         if (r != 0)
   7                 FATALCLK("alsa:unable to allocate an alsa status structure\n");
   8         r = snd_pcm_status_malloc(&clk_l.now.status);
   9         if (r != 0)
  10                 FATALCLK("alsa:unable to allocate an alsa status structure\n");
  11         /* we pre-allocate alsa pcm hw_params container */
  12         r = snd_pcm_hw_params_malloc(&clk_pcm_hw_params_l);
  13         if (r < 0)
  14                 FATALCLK("alsa:unable to allocate hardware parameters context\n");
  15 }
  16 #define NO_REF_TIME_POINT 1
  17 static u8 clk_get_audio_st_ts(s64 *ts)
  18 {
  19         int r;
  20         snd_pcm_audio_tstamp_config_t ac;
  21         snd_htimestamp_t hts;
  22         f64 now_ns;
  23         f64 ref_ns;
  24         f64 ref_status_ns;
  25         f64 ref_delay_frs_n;
  26         f64 ref_audio_ts;
  27         f64 audio_tb_num;
  28         f64 audio_tb_den;
  29         f64 audio_rate_num;
  30         unsigned int audio_rate_num_ui;
  31         f64 audio_rate_den;
  32         unsigned int audio_rate_den_ui;
  33         f64 written_frs_n;
  34         f64 now_audio_ts;
  35         f64 now_video_ts;
  36
  37         if (!clk_l.ref_valid)
  38                 return NO_REF_TIME_POINT;
  39         memset(clk_l.now.status, 0, snd_pcm_status_sizeof());
  40         ac.report_delay = 0;
  41         ac.type_requested = (unsigned int)audio_selected_ts_type_p;
  42         snd_pcm_status_set_audio_htstamp_config(clk_l.now.status, &ac);
  43         r = snd_pcm_status(audio_pcm_p, clk_l.now.status);
  44         if (r < 0)
  45                 FATALCLK("alsa:unable to sample timing information for 'now' time point\n");
  46         snd_pcm_status_get_audio_htstamp(clk_l.now.status, &hts);
  47         now_ns = (f64)hts.tv_sec * 1e9 + (f64)hts.tv_nsec;
  48
  49         snd_pcm_status_get_audio_htstamp(clk_l.ref.status, &hts);
  50         ref_status_ns = (f64)hts.tv_sec * 1e9 + (f64)hts.tv_nsec;
  51
  52         ref_audio_ts = (f64)clk_l.ref.audio_st_ts;
  53         ref_delay_frs_n = (f64)snd_pcm_status_get_delay(clk_l.ref.status);
  54         audio_tb_num = (f64)audio_st_p.tb.num;
  55         audio_tb_den = (f64)audio_st_p.tb.den;
  56         /*--------------------------------------------------------------------*/
  57         r = snd_pcm_hw_params_current(audio_pcm_p, clk_pcm_hw_params_l);
  58         if (r != 0)
  59                 FATALCLK("alsa:unable to get current hardware parameters\n");
  60         r = snd_pcm_hw_params_get_rate_numden(clk_pcm_hw_params_l,
  61                                         &audio_rate_num_ui, &audio_rate_den_ui);
  62         if (r < 0)
  63                 FATALCLK("alsa:unable to get exact rate\n");
  64         audio_rate_num = (f64)audio_rate_num_ui;
  65         audio_rate_den = (f64)audio_rate_den_ui;
  66         /*--------------------------------------------------------------------*/
  67         written_frs_n = (f64)clk_l.ref.written_ufrs_n;
  68
  69         /* time translation */
  70         ref_ns = ref_status_ns + (ref_delay_frs_n - written_frs_n)
  71                                         * audio_rate_den * 1e9 / audio_rate_num;
  72         /* basic linear interpolation */
  73         now_audio_ts = audio_tb_den * 1e-9 * (now_ns - ref_ns) / audio_tb_num
  74                                                                 + ref_audio_ts;
  75         *ts = (s64)lrint(now_audio_ts);
  76         return TS_RETURNED;
  77 }
  78 #undef NO_REF_TIME_POINT
  79 static u8 clk_get_video_st_ts(s64 *ts)
  80 {
  81         f64 audio_tb_num;
  82         f64 audio_tb_den;
  83         f64 video_tb_num;
  84         f64 video_tb_den;
  85         f64 now_audio_ts;
  86         s64 now_audio_ts_s64;
  87         f64 now_video_ts;
  88         u8 r;
  89
  90         audio_tb_num = (f64)audio_st_p.tb.num;
  91         audio_tb_den = (f64)audio_st_p.tb.den;
  92         video_tb_num = (f64)video_st_p.tb.num;
  93         video_tb_den = (f64)video_st_p.tb.den;
  94
  95         r = clk_get_audio_st_ts(&now_audio_ts_s64);
  96         if (r != TS_RETURNED)
  97                 return r;
  98         now_audio_ts = (f64)now_audio_ts_s64;
  99         /* basic conversion */
 100         now_video_ts = audio_tb_num * video_tb_den * now_audio_ts
 101                                                 / (audio_tb_den * video_tb_num);
 102         *ts = (s64)lrint(now_video_ts);
 103         return TS_RETURNED;
 104 }
 105 static void clk_ref_time_point_update(s64 audio_ts,
 106                                                 snd_pcm_ufrs_t written_ufrs_n)
 107 {
 108         int r;
 109         snd_pcm_audio_tstamp_config_t ac;
 110
 111         memset(clk_l.ref.status, 0, snd_pcm_status_sizeof());
 112         ac.report_delay = 0;
 113         ac.type_requested = (unsigned int)audio_selected_ts_type_p;
 114         snd_pcm_status_set_audio_htstamp_config(clk_l.ref.status, &ac);
 115         r = snd_pcm_status(audio_pcm_p, clk_l.ref.status);
 116         if (r < 0)
 117                 FATALCLK("unable to sample timing information for reference time point\n");
 118         clk_l.ref.audio_st_ts = audio_ts;
 119         clk_l.ref.written_ufrs_n = written_ufrs_n;
 120         clk_l.ref_valid = true;
 121 }
 122 static void clk_invalidate(void)
 123 {
 124         clk_l.ref_valid = false;
 125 }