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
  37 #define MPEG_AUDIO_ID 0x1C0
  38
  39 static int freq = 0;
  40
  41 static ao_info_t info =
  42 {
  43   "V4L2 MPEG Audio Decoder output",
  44   "v4l2",
  45   "Benjamin Zores",
  46   ""
  47 };
  48
  49 LIBAO_EXTERN (v4l2)
  50
  51 /* to set/get/query special features/parameters */
  52 static int
  53 control (int cmd,void *arg)
  54 {
  55   return CONTROL_UNKNOWN;
  56 }
  57
  58 /* open & setup audio device */
  59 static int
  60 init (int rate, int channels, int format, int flags)
  61 {
  62   extern int v4l2_fd;
  63
  64   if (v4l2_fd < 0)
  65     return 0;
  66
  67   if (format != AF_FORMAT_MPEG2)
  68   {
  69     mp_msg (MSGT_AO, MSGL_FATAL,
  70             "AO: [v4l2] can only handle MPEG audio streams.\n");
  71     return 0;
  72   }
  73
  74   ao_data.outburst = 2048;
  75   ao_data.samplerate = rate;
  76   ao_data.channels = channels;
  77   ao_data.format = AF_FORMAT_MPEG2;
  78   ao_data.buffersize = 2048;
  79   ao_data.bps = rate * 2 * 2;
  80   ao_data.pts = 0;
  81   freq = rate;
  82
  83   /* check for supported audio rate */
  84   if (rate != 32000 || rate != 41000 || rate != 48000)
  85   {
  86     mp_msg (MSGT_AO, MSGL_ERR, MSGTR_AO_MPEGPES_UnsupSamplerate, rate);
  87     rate = 48000;
  88   }
  89
  90   return 1;
  91 }
  92
  93 /* close audio device */
  94 static void
  95 uninit (int immed)
  96 {
  97   /* nothing to do */
  98 }
  99
 100 /* stop playing and empty buffers (for seeking/pause) */
 101 static void
 102 reset (void)
 103 {
 104   /* nothing to do */
 105 }
 106
 107 /* stop playing, keep buffers (for pause) */
 108 static void
 109 audio_pause (void)
 110 {
 111   reset ();
 112 }
 113
 114 /* resume playing, after audio_pause() */
 115 static void
 116 audio_resume (void)
 117 {
 118   /* nothing to do */
 119 }
 120
 121 /* how many bytes can be played without blocking */
 122 static int
 123 get_space (void)
 124 {
 125   extern int vo_pts;
 126   float x;
 127   int y;
 128
 129   x = (float) (vo_pts - ao_data.pts) / 90000.0;
 130   if (x <= 0)
 131     return 0;
 132
 133   y  = freq * 4 * x;
 134   y /= ao_data.outburst;
 135   y *= ao_data.outburst;
 136
 137   if (y > 32000)
 138     y = 32000;
 139
 140   return y;
 141 }
 142
 143 /* number of bytes played */
 144 static int
 145 play (void *data, int len, int flags)
 146 {
 147   int v4l2_write (unsigned char *data, int len);
 148
 149   if (ao_data.format != AF_FORMAT_MPEG2)
 150     return 0;
 151
 152   send_mpeg_pes_packet (data, len, MPEG_AUDIO_ID, ao_data.pts, 2, v4l2_write);
 153
 154   return len;
 155 }
 156
 157 /* delay in seconds between first and last sample in buffer */
 158 static float
 159 get_delay (void)
 160 {
 161   return 0.0;
 162 }