libao2/ao_v4l2.c

   1 /*
   2  * audio output for V4L2 hardware MPEG decoders
   3  *
   4  * WARNING: You need to force -ac hwmpa for audio output to work.
   5  *
   6  * Copyright (C) 2007 Benjamin Zores
   7  *
   8  * This file is part of MPlayer.
   9  *
  10  * MPlayer is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * MPlayer is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License along
  21  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  22  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23  */
  24
  25 #include <inttypes.h>
  26
  27 #include "config.h"
  28
  29 #include "mp_msg.h"
  30 #include "help_mp.h"
  31
  32 #include "audio_out.h"
  33 #include "audio_out_internal.h"
  34 #include "libaf/af_format.h"
  35 #include "libmpdemux/mpeg_packetizer.h"
  36 #include "libvo/vo_v4l2.h"
  37
  38 #define MPEG_AUDIO_ID 0x1C0
  39
  40 static int freq = 0;
  41
  42 static const ao_info_t info =
  43 {
  44   "V4L2 MPEG Audio Decoder output",
  45   "v4l2",
  46   "Benjamin Zores",
  47   ""
  48 };
  49
  50 LIBAO_EXTERN (v4l2)
  51
  52 /* to set/get/query special features/parameters */
  53 static int
  54 control (int cmd,void *arg)
  55 {
  56   return CONTROL_UNKNOWN;
  57 }
  58
  59 /* open & setup audio device */
  60 static int
  61 init (int rate, int channels, int format, int flags)
  62 {
  63   extern int v4l2_fd;
  64
  65   if (v4l2_fd < 0)
  66     return 0;
  67
  68   if (format != AF_FORMAT_MPEG2)
  69   {
  70     mp_msg (MSGT_AO, MSGL_FATAL,
  71             "AO: [v4l2] can only handle MPEG audio streams.\n");
  72     return 0;
  73   }
  74
  75   ao_data.outburst = 2048;
  76   ao_data.samplerate = rate;
  77   ao_data.channels = channels;
  78   ao_data.format = AF_FORMAT_MPEG2;
  79   ao_data.buffersize = 2048;
  80   ao_data.bps = rate * 2 * 2;
  81   ao_data.pts = 0;
  82   freq = rate;
  83
  84   /* check for supported audio rate */
  85   if (rate != 32000 || rate != 41000 || rate != 48000)
  86   {
  87     mp_msg (MSGT_AO, MSGL_ERR, MSGTR_AO_MPEGPES_UnsupSamplerate, rate);
  88     rate = 48000;
  89   }
  90
  91   return 1;
  92 }
  93
  94 /* close audio device */
  95 static void
  96 uninit (int immed)
  97 {
  98   /* nothing to do */
  99 }
 100
 101 /* stop playing and empty buffers (for seeking/pause) */
 102 static void
 103 reset (void)
 104 {
 105   /* nothing to do */
 106 }
 107
 108 /* stop playing, keep buffers (for pause) */
 109 static void
 110 audio_pause (void)
 111 {
 112   reset ();
 113 }
 114
 115 /* resume playing, after audio_pause() */
 116 static void
 117 audio_resume (void)
 118 {
 119   /* nothing to do */
 120 }
 121
 122 /* how many bytes can be played without blocking */
 123 static int
 124 get_space (void)
 125 {
 126   extern int vo_pts;
 127   float x;
 128   int y;
 129
 130   x = (float) (vo_pts - ao_data.pts) / 90000.0;
 131   if (x <= 0)
 132     return 0;
 133
 134   y  = freq * 4 * x;
 135   y /= ao_data.outburst;
 136   y *= ao_data.outburst;
 137
 138   if (y > 32000)
 139     y = 32000;
 140
 141   return y;
 142 }
 143
 144 /* number of bytes played */
 145 static int
 146 play (void *data, int len, int flags)
 147 {
 148   if (ao_data.format != AF_FORMAT_MPEG2)
 149     return 0;
 150
 151   send_mpeg_pes_packet (data, len, MPEG_AUDIO_ID, ao_data.pts, 2, v4l2_write);
 152
 153   return len;
 154 }
 155
 156 /* delay in seconds between first and last sample in buffer */
 157 static float
 158 get_delay (void)
 159 {
 160   return 0.0;
 161 }