libao2/ao_ivtv.c

   1 /*
   2  * audio output for WinTV PVR-150/250/350 (a.k.a IVTV) cards
   3  * through Connexant hardware MPEG decoder
   4  * See http://ivtvdriver.org/index.php/Main_Page for more details on the
   5  * cards supported by the ivtv driver.
   6  *
   7  * WARNING: You need to force -ac hwmpa for audio output to work.
   8  *
   9  * Copyright (C) 2006 Benjamin Zores
  10  *
  11  * This file is part of MPlayer.
  12  *
  13  * MPlayer is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * MPlayer is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License along
  24  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  25  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  26  */
  27
  28 #include <inttypes.h>
  29
  30 #include "config.h"
  31
  32 #include "mp_msg.h"
  33 #include "help_mp.h"
  34
  35 #include "audio_out.h"
  36 #include "audio_out_internal.h"
  37 #include "libaf/af_format.h"
  38 #include "libmpdemux/mpeg_packetizer.h"
  39
  40 #define MPEG_AUDIO_ID 0x1C0
  41
  42 static int freq = 0;
  43
  44 static const ao_info_t info =
  45 {
  46   "IVTV MPEG Audio Decoder output",
  47   "ivtv",
  48   "Benjamin Zores",
  49   ""
  50 };
  51
  52 LIBAO_EXTERN(ivtv)
  53
  54 /* to set/get/query special features/parameters */
  55 static int
  56 control (int cmd,void *arg)
  57 {
  58   return CONTROL_UNKNOWN;
  59 }
  60
  61 /* open & setup audio device */
  62 static int
  63 init (int rate, int channels, int format, int flags)
  64 {
  65   extern int ivtv_fd;
  66
  67   if (ivtv_fd < 0)
  68     return 0;
  69
  70   if (format != AF_FORMAT_MPEG2)
  71   {
  72     mp_msg (MSGT_AO, MSGL_FATAL,
  73             "AO: [ivtv] can only handle MPEG audio streams.\n");
  74     return 0;
  75   }
  76
  77   ao_data.outburst = 2048;
  78   ao_data.samplerate = rate;
  79   ao_data.channels = channels;
  80   ao_data.format = AF_FORMAT_MPEG2;
  81   ao_data.buffersize = 2048;
  82   ao_data.bps = rate * 2 * 2;
  83   ao_data.pts = 0;
  84   freq = rate;
  85
  86   /* check for supported audio rate */
  87   if (rate != 32000 || rate != 41000 || rate != 48000)
  88   {
  89     mp_msg (MSGT_AO, MSGL_ERR, MSGTR_AO_MPEGPES_UnsupSamplerate, rate);
  90     rate = 48000;
  91   }
  92
  93   return 1;
  94 }
  95
  96 /* close audio device */
  97 static void
  98 uninit (int immed)
  99 {
 100   /* nothing to do */
 101 }
 102
 103 /* stop playing and empty buffers (for seeking/pause) */
 104 static void
 105 reset (void)
 106 {
 107   /* nothing to do */
 108 }
 109
 110 /* stop playing, keep buffers (for pause) */
 111 static void
 112 audio_pause (void)
 113 {
 114   reset ();
 115 }
 116
 117 /* resume playing, after audio_pause() */
 118 static void
 119 audio_resume (void)
 120 {
 121   /* nothing to do */
 122 }
 123
 124 /* how many bytes can be played without blocking */
 125 static int
 126 get_space (void)
 127 {
 128   extern int vo_pts;
 129   float x;
 130   int y;
 131
 132   x = (float) (vo_pts - ao_data.pts) / 90000.0;
 133   if (x <= 0)
 134     return 0;
 135
 136   y  = freq * 4 * x;
 137   y /= ao_data.outburst;
 138   y *= ao_data.outburst;
 139
 140   if (y > 32000)
 141     y = 32000;
 142
 143   return y;
 144 }
 145
 146 /* number of bytes played */
 147 static int
 148 play (void *data, int len, int flags)
 149 {
 150   int ivtv_write (unsigned char *data, int len);
 151
 152   if (ao_data.format != AF_FORMAT_MPEG2)
 153     return 0;
 154
 155   send_mpeg_pes_packet (data, len, MPEG_AUDIO_ID, ao_data.pts, 2, ivtv_write);
 156
 157   return len;
 158 }
 159
 160 /* delay in seconds between first and last sample in buffer */
 161 static float
 162 get_delay (void)
 163 {
 164   return 0.0;
 165 }