wav_filter.c

   1 /*
   2  * Copyright (C) 2005-2009 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 #include "error.h"
  11
  12 #include "list.h"
  13 #include "sched.h"
  14 #include "ggo.h"
  15 #include "filter.h"
  16 #include "string.h"
  17 #include "portable_io.h"
  18
  19 /** size of the output buffer */
  20 #define WAV_OUTBUF_SIZE 81920
  21 /** a wav header is always 44 bytes */
  22 #define WAV_HEADER_LEN 44
  23 /** always write 16 bit header */
  24 #define BITS 16
  25
  26 static void make_wav_header(unsigned int channels, unsigned int samplerate,
  27                 struct filter_node *fn)
  28 {
  29
  30         char *headbuf = fn->buf;
  31         unsigned int size = 0x7fffffff;
  32         int bytespersec = channels * samplerate * BITS / 8;
  33         int align = channels * BITS / 8;
  34
  35         PARA_DEBUG_LOG("writing wave header: %d channels, %d KHz\n", channels, samplerate);
  36         memset(headbuf, 0, WAV_HEADER_LEN);
  37         memcpy(headbuf, "RIFF", 4);
  38         write_u32(headbuf + 4, size - 8);
  39         memcpy(headbuf + 8, "WAVE", 4);
  40         memcpy(headbuf + 12, "fmt ", 4);
  41         write_u32(headbuf + 16, 16); /* 16 + extra format bytes (zero) */
  42         write_u16(headbuf + 20, 1);     /* format (1 == PCM/uncompressed) */
  43         write_u16(headbuf + 22, channels);
  44         write_u32(headbuf + 24, samplerate);
  45         write_u32(headbuf + 28, bytespersec);
  46         write_u16(headbuf + 32, align); /* number of bytes per sample slice */
  47         write_u16(headbuf + 34, BITS); /* significant bits per sample */
  48         memcpy(headbuf + 36, "data", 4); /* chunk ID */
  49         write_u32(headbuf + 40, size - 44); /* chunk size */
  50 }
  51
  52 static ssize_t wav_convert(char *inbuf, size_t len, struct filter_node *fn)
  53 {
  54         size_t copy;
  55         int *bof = fn->private_data;
  56
  57         if (*bof) {
  58                 if (!len)
  59                         return 0;
  60                 if (!fn->fc->channels || !fn->fc->samplerate) {
  61                         PARA_ERROR_LOG("%s\n", para_strerror(E_WAV_BAD_FC));
  62                         return -E_WAV_BAD_FC;
  63                 }
  64                 make_wav_header(fn->fc->channels, fn->fc->samplerate, fn);
  65                 fn->loaded = WAV_HEADER_LEN;
  66                 *bof = 0;
  67 //              return 0;
  68         }
  69         copy = PARA_MIN(len, fn->bufsize - fn->loaded);
  70         memmove(fn->buf + fn->loaded, inbuf, copy);
  71         fn->loaded += copy;
  72 //      PARA_DEBUG_LOG("len = %d, copy = %d\n", len, copy);
  73         return copy;
  74 }
  75
  76 static void wav_close(struct filter_node *fn)
  77 {
  78         free(fn->buf);
  79         fn->buf = NULL;
  80         free(fn->private_data);
  81         fn->private_data = NULL;
  82 }
  83
  84 static void wav_open(struct filter_node *fn)
  85 {
  86         int *bof;
  87
  88         fn->bufsize = WAV_OUTBUF_SIZE;
  89         fn->buf = para_malloc(fn->bufsize);
  90         fn->private_data = para_malloc(sizeof(int));
  91         bof = fn->private_data;
  92         fn->loaded = 0;
  93         *bof = 1;
  94         PARA_INFO_LOG("wav filter node: %p, output buffer: %p, loaded: %zd\n",
  95                 fn, fn->buf, fn->loaded);
  96 }
  97
  98 /**
  99  * the init function of the wav filter
 100  *
 101  * \param f struct to initialize
 102  */
 103 void wav_filter_init(struct filter *f)
 104 {
 105         f->convert = wav_convert;
 106         f->close = wav_close;
 107         f->open = wav_open;
 108 }