mixer.c

   1 #include "modules.h"
   2 #include "graph.h"
   3 #include "errors.h"
   4 #include "assert.h"
   5
   6 ///// Simple additive mixer /////
   7 ///// TODO: handle different input formats /////
   8
   9 struct mixer {
  10     bool format_is_set;
  11     struct aformat af;
  12     struct graphpin *out_pin;
  13     int n_inputs;
  14 };
  15
  16 static bool is_acceptable_input_format(struct graphnode *node, struct graphpin *pin, const struct aformat *af)
  17 {
  18     struct mixer *m = node->extra;
  19     assert(pin != m->out_pin);
  20     if (m->format_is_set){
  21         return af->media == m->af.media
  22             && af->srate == m->af.srate
  23             && af->channels == m->af.channels;
  24     } else {
  25         return true;
  26     }
  27 }
  28
  29 static err_t get_output_format(struct graphnode *node, struct graphpin *pin, struct aformat *af)
  30 {
  31     struct mixer *m = node->extra;
  32     assert(pin == m->out_pin);
  33
  34     if (m->format_is_set){
  35         *af = m->af;
  36         return EOK;
  37     } else {
  38         return make_error(ECANNOT_GUESS_FORMAT, node, "mixer module is not yet bound to a format");
  39     }
  40 }
  41
  42 static err_t set_buffer(struct graphnode *node, struct graphpin *pin, struct buffer *buf)
  43 {
  44     struct mixer *m = node->extra;
  45     if (m->format_is_set){
  46         if (buf->format.media == m->af.media
  47           && buf->format.srate == m->af.srate
  48           && buf->format.channels == m->af.channels){
  49             return EOK;
  50         } else {
  51             return make_error(EBAD_FORMAT, node, "mixer module is being connected to a bad media format");
  52         }
  53     } else {
  54         m->af = buf->format;
  55         m->format_is_set = true;
  56         return EOK;
  57     }
  58 }
  59
  60 static size_t longest_in_buf_len(struct graphnode *restrict node)
  61 {
  62     struct graphpin *in_pin;
  63     size_t sz = 0;
  64
  65     for (in_pin=node->pins; in_pin; in_pin=in_pin->next){
  66         if (in_pin->dir != DIR_IN){
  67             continue;
  68         }
  69         if (in_pin->edge->buf.n_samples > sz){
  70             sz = in_pin->edge->buf.n_samples;
  71         }
  72     }
  73     return sz;
  74 }
  75
  76 static err_t run(struct graphnode *node)
  77 {
  78 #define DO_MIX(T) { \
  79     T *restrict s_ptr, *restrict d_ptr; \
  80     register int i; \
  81     /* clear the output buffer */ \
  82     d_ptr = d_buf->data; \
  83     for (i=sz; i; --i){ \
  84         *d_ptr++ = 0; \
  85     } \
  86     \
  87     for (in_pin=node->pins; in_pin; in_pin=in_pin->next){ \
  88         s_ptr = in_pin->edge->buf.data; \
  89         d_ptr = d_buf->data; \
  90         for (i=sz; i; --i){ \
  91             /* Mix! */ \
  92             *d_ptr++ += *s_ptr++ / m->n_inputs; /* *boggle* */ \
  93         } \
  94     } \
  95     return EOK; }
  96
  97     struct mixer *restrict m = node->extra;
  98     struct graphpin *in_pin;
  99     struct buffer *restrict d_buf = &m->out_pin->edge->buf;
 100     size_t sz;
 101     err_t err;
 102
 103     sz = longest_in_buf_len(node);
 104     err = buffer_alloc(d_buf, sz);
 105     if (err != EOK){
 106         return err;
 107     }
 108
 109     sz *= m->out_pin->edge->buf.format.channels;
 110
 111     switch (m->out_pin->edge->buf.format.media){
 112         case MT_AUDIO_32F:
 113             DO_MIX(float)
 114         case MT_AUDIO_16I:
 115             DO_MIX(short)
 116         case MT_AUDIO_32I:
 117             DO_MIX(int)
 118     }
 119     return make_error(ENOTIMPL, NULL, "mixing these media types is not implemented");
 120 }
 121
 122 static const struct graphnode_functab functab = {
 123     is_acceptable_input_format,
 124     NULL,   // get_ideal_input_format
 125     get_output_format,
 126     set_buffer,
 127     run,
 128 };
 129
 130 err_t mixer_create(struct graphnode **node_out, int n_inputs)
 131 {
 132     struct graphnode *node;
 133     struct mixer *m;
 134     struct graphpin *in_pin;
 135     err_t err;
 136     int i;
 137
 138     err = graphnode_create(&node, &functab, sizeof *m);
 139     if (err != EOK){
 140         return err;
 141     }
 142     m = node->extra;
 143
 144     m->n_inputs = n_inputs;
 145     m->format_is_set = false;
 146
 147     // create output pin
 148     err = graphnode_add_pin(node, &m->out_pin);
 149     if (err != EOK){
 150         return err;
 151     }
 152     m->out_pin->dir = DIR_OUT;
 153     m->out_pin->name = "out";
 154
 155     // create input pins
 156     for (i=0; i<n_inputs; ++i){
 157         err = graphnode_add_pin(node, &in_pin);
 158         if (err != EOK){
 159             return err;
 160         }
 161         in_pin->dir = DIR_IN;
 162         in_pin->name = "in"; // how original
 163     }
 164
 165     *node_out = node;
 166     return EOK;
 167 }