wav_filter.c

   1 /*
   2  * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file wav_filter.c A filter that inserts a wave header. */
   8
   9 #include "para.h"
  10
  11 #include "list.h"
  12 #include "sched.h"
  13 #include "filter.h"
  14 #include "string.h"
  15 #include "portable_io.h"
  16
  17 /** size of the output buffer */
  18 #define WAV_OUTBUF_SIZE 81920
  19 /** a wav header is always 44 bytes */
  20 #define WAV_HEADER_LEN 44
  21 /** always write 16 bit header */
  22 #define BITS 16
  23
  24 static void make_wav_header(unsigned int channels, unsigned int samplerate,
  25                 struct filter_node *fn)
  26 {
  27
  28         char *headbuf = fn->buf;
  29         unsigned int size = 0x7fffffff;
  30         int bytespersec = channels * samplerate * BITS / 8;
  31         int align = channels * BITS / 8;
  32
  33         assert(channels);
  34         PARA_DEBUG_LOG("writing wave header: %d channels, %d KHz\n", channels, samplerate);
  35         memset(headbuf, 0, WAV_HEADER_LEN);
  36         memcpy(headbuf, "RIFF", 4);
  37         write_u32(headbuf + 4, size - 8);
  38         memcpy(headbuf + 8, "WAVE", 4);
  39         memcpy(headbuf + 12, "fmt ", 4);
  40         write_u32(headbuf + 16, 16);
  41         write_u16(headbuf + 20, 1);     /* format */
  42         write_u16(headbuf + 22, channels);
  43         write_u32(headbuf + 24, samplerate);
  44         write_u32(headbuf + 28, bytespersec);
  45         write_u16(headbuf + 32, align);
  46         write_u16(headbuf + 34, BITS);
  47         memcpy(headbuf + 36, "data", 4);
  48         write_u32(headbuf + 40, size - 44);
  49 }
  50
  51 static ssize_t wav_convert(char *inbuf, size_t len, struct filter_node *fn)
  52 {
  53         size_t copy;
  54         int *bof = fn->private_data;
  55
  56         if (*bof) {
  57                 if (!len)
  58                         return 0;
  59                 make_wav_header(fn->fc->channels, fn->fc->samplerate, fn);
  60                 fn->loaded = WAV_HEADER_LEN;
  61                 *bof = 0;
  62 //              return 0;
  63         }
  64         copy = PARA_MIN(len, fn->bufsize - fn->loaded);
  65         memmove(fn->buf + fn->loaded, inbuf, copy);
  66         fn->loaded += copy;
  67 //      PARA_DEBUG_LOG("len = %d, copy = %d\n", len, copy);
  68         return copy;
  69 }
  70
  71 static void wav_close(struct filter_node *fn)
  72 {
  73         free(fn->buf);
  74         fn->buf = NULL;
  75         free(fn->private_data);
  76         fn->private_data = NULL;
  77 }
  78
  79 static void wav_open(struct filter_node *fn)
  80 {
  81         int *bof;
  82
  83         fn->bufsize = WAV_OUTBUF_SIZE;
  84         fn->buf = para_malloc(fn->bufsize);
  85         fn->private_data = para_malloc(sizeof(int));
  86         bof = fn->private_data;
  87         fn->loaded = 0;
  88         *bof = 1;
  89         PARA_INFO_LOG("wav filter node: %p, output buffer: %p, loaded: %zd\n",
  90                 fn, fn->buf, fn->loaded);
  91 }
  92
  93 /**
  94  * the init function of the wav filter
  95  *
  96  * \param f struct to initialize
  97  */
  98 void wav_filter_init(struct filter *f)
  99 {
 100         f->convert = wav_convert;
 101         f->close = wav_close;
 102         f->open = wav_open;
 103 }