npv/clk/public/code.frag.c

   1 STATIC void npv_clk_init_once(void)
   2 {
   3         int r;
   4
   5         r = snd_pcm_status_malloc(&npv_clk_l.ref.status);
   6         if (r != 0)
   7                 npv_clk_fatal("alsa:unable to allocate an alsa status structure\n");
   8         r = snd_pcm_status_malloc(&npv_clk_l.now.status);
   9         if (r != 0)
  10                 npv_clk_fatal("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(&npv_clk_pcm_hw_params_l);
  13         if (r < 0)
  14                 npv_clk_fatal("alsa:unable to allocate hardware parameters context\n");
  15         npv_clk_l.paused = false;
  16 }
  17 #define NO_REF_TIME_POINT 1
  18 STATIC u8 npv_clk_get_audio_st_ts(s64 *ts)
  19 {
  20         int r;
  21         snd_pcm_audio_tstamp_config_t ac;
  22         snd_htimestamp_t hts;
  23         f64 now_ns;
  24         f64 ref_ns;
  25         f64 ref_status_ns;
  26         f64 ref_delay_frs_n;
  27         f64 ref_audio_ts;
  28         f64 audio_tb_num;
  29         f64 audio_tb_den;
  30         f64 audio_rate_num;
  31         unsigned int audio_rate_num_ui;
  32         f64 audio_rate_den;
  33         unsigned int audio_rate_den_ui;
  34         f64 written_frs_n;
  35         f64 now_audio_ts;
  36         f64 now_video_ts;
  37
  38         if (!npv_clk_l.ref_valid)
  39                 return NO_REF_TIME_POINT;
  40         if (!npv_clk_l.paused) {
  41                 memset(npv_clk_l.now.status, 0, snd_pcm_status_sizeof());
  42                 ac.report_delay = 0;
  43                 ac.type_requested = (unsigned int)npv_audio_selected_ts_type_p;
  44                 snd_pcm_status_set_audio_htstamp_config(npv_clk_l.now.status,
  45                                                                         &ac);
  46                 r = snd_pcm_status(npv_audio_pcm_p, npv_clk_l.now.status);
  47                 if (r < 0)
  48                         npv_clk_fatal("alsa:unable to sample timing information for 'now' time point\n");
  49         }
  50         snd_pcm_status_get_audio_htstamp(npv_clk_l.now.status, &hts);
  51         now_ns = (f64)hts.tv_sec * 1e9 + (f64)hts.tv_nsec;
  52
  53         snd_pcm_status_get_audio_htstamp(npv_clk_l.ref.status, &hts);
  54         ref_status_ns = (f64)hts.tv_sec * 1e9 + (f64)hts.tv_nsec;
  55
  56         ref_audio_ts = (f64)npv_clk_l.ref.audio_st_ts;
  57         ref_delay_frs_n = (f64)snd_pcm_status_get_delay(npv_clk_l.ref.status);
  58         audio_tb_num = (f64)npv_audio_st_p.tb.num;
  59         audio_tb_den = (f64)npv_audio_st_p.tb.den;
  60         /*--------------------------------------------------------------------*/
  61         r = snd_pcm_hw_params_current(npv_audio_pcm_p, npv_clk_pcm_hw_params_l);
  62         if (r != 0)
  63                 npv_clk_fatal("alsa:unable to get current hardware parameters\n");
  64         r = snd_pcm_hw_params_get_rate_numden(npv_clk_pcm_hw_params_l,
  65                                         &audio_rate_num_ui, &audio_rate_den_ui);
  66         if (r < 0)
  67                 npv_clk_fatal("alsa:unable to get exact rate\n");
  68         audio_rate_num = (f64)audio_rate_num_ui;
  69         audio_rate_den = (f64)audio_rate_den_ui;
  70         /*--------------------------------------------------------------------*/
  71         written_frs_n = (f64)npv_clk_l.ref.written_ufrs_n;
  72
  73         /* time translation */
  74         ref_ns = ref_status_ns + (ref_delay_frs_n - written_frs_n)
  75                                         * audio_rate_den * 1e9 / audio_rate_num;
  76         /* basic linear interpolation */
  77         now_audio_ts = audio_tb_den * 1e-9 * (now_ns - ref_ns) / audio_tb_num
  78                                                                 + ref_audio_ts;
  79         *ts = (s64)lrint(now_audio_ts);
  80         return TS_RETURNED;
  81 }
  82 #undef NO_REF_TIME_POINT
  83 STATIC u8 npv_clk_get_video_st_ts(s64 *ts)
  84 {
  85         f64 audio_tb_num;
  86         f64 audio_tb_den;
  87         f64 video_tb_num;
  88         f64 video_tb_den;
  89         f64 now_audio_ts;
  90         s64 now_audio_ts_s64;
  91         f64 now_video_ts;
  92         u8 r;
  93
  94         audio_tb_num = (f64)npv_audio_st_p.tb.num;
  95         audio_tb_den = (f64)npv_audio_st_p.tb.den;
  96         video_tb_num = (f64)npv_video_st_p.tb.num;
  97         video_tb_den = (f64)npv_video_st_p.tb.den;
  98
  99         r = npv_clk_get_audio_st_ts(&now_audio_ts_s64);
 100         if (r != TS_RETURNED)
 101                 return r;
 102         now_audio_ts = (f64)now_audio_ts_s64;
 103         /* basic conversion */
 104         now_video_ts = audio_tb_num * video_tb_den * now_audio_ts
 105                                                 / (audio_tb_den * video_tb_num);
 106         *ts = (s64)lrint(now_video_ts);
 107         return TS_RETURNED;
 108 }
 109 STATIC void npv_clk_ref_time_point_update(s64 audio_ts,
 110                                                 snd_pcm_ufrs_t written_ufrs_n)
 111 {
 112         int r;
 113         snd_pcm_audio_tstamp_config_t ac;
 114
 115         memset(npv_clk_l.ref.status, 0, snd_pcm_status_sizeof());
 116         ac.report_delay = 0;
 117         ac.type_requested = (unsigned int)npv_audio_selected_ts_type_p;
 118         snd_pcm_status_set_audio_htstamp_config(npv_clk_l.ref.status, &ac);
 119         r = snd_pcm_status(npv_audio_pcm_p, npv_clk_l.ref.status);
 120         if (r < 0)
 121                 npv_clk_fatal("unable to sample timing information for reference time point\n");
 122         npv_clk_l.ref.audio_st_ts = audio_ts;
 123         npv_clk_l.ref.written_ufrs_n = written_ufrs_n;
 124         npv_clk_l.ref_valid = true;
 125 }
 126 STATIC void npv_clk_invalidate(void)
 127 {
 128         npv_clk_l.ref_valid = false;
 129 }
 130 STATIC void npv_clk_pause(void)
 131 {
 132         int r;
 133         snd_pcm_audio_tstamp_config_t ac;
 134
 135         npv_clk_l.paused = true;
 136         memset(npv_clk_l.now.status, 0, snd_pcm_status_sizeof());
 137         ac.report_delay = 0;
 138         ac.type_requested = (unsigned int)npv_audio_selected_ts_type_p;
 139         snd_pcm_status_set_audio_htstamp_config(npv_clk_l.now.status, &ac);
 140         r = snd_pcm_status(npv_audio_pcm_p, npv_clk_l.now.status);
 141         if (r < 0)
 142                 npv_clk_fatal("alsa:unable to sample timing information for 'paused' time point\n");
 143 }
 144 STATIC void npv_clk_unpause(void)
 145 {
 146         npv_clk_l.paused = false;
 147         npv_clk_invalidate();
 148 }