modules/demux/xa.c

   1 /*****************************************************************************
   2  * xa.c : xa file demux module for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2005 Rémi Denis-Courmont
   5  * $Id$
   6  *
   7  * Authors: Rémi Denis-Courmont <rem # videolan.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <vlc_common.h>
  33 #include <vlc_plugin.h>
  34 #include <vlc_demux.h>
  35
  36 /*****************************************************************************
  37  * Module descriptor
  38  *****************************************************************************/
  39 static int  Open ( vlc_object_t * );
  40 static void Close( vlc_object_t * );
  41
  42 vlc_module_begin ()
  43     set_description( N_("XA demuxer") )
  44     set_category( CAT_INPUT )
  45     set_subcategory( SUBCAT_INPUT_DEMUX )
  46     set_capability( "demux", 10 )
  47     set_callbacks( Open, Close )
  48 vlc_module_end ()
  49
  50 /*****************************************************************************
  51  * Local prototypes
  52  *****************************************************************************/
  53 static int Demux  ( demux_t * );
  54 static int Control( demux_t *, int i_query, va_list args );
  55
  56 struct demux_sys_t
  57 {
  58     es_format_t     fmt;
  59     es_out_id_t     *p_es;
  60
  61     int64_t         i_data_offset;
  62     unsigned int    i_data_size;
  63     unsigned int    i_block_frames;
  64
  65     date_t          pts;
  66 };
  67
  68 typedef struct xa_header_t
  69 {
  70     char     xa_id[4];
  71     uint32_t iSize;
  72
  73     uint16_t wFormatTag;
  74     uint16_t nChannels;
  75     uint32_t nSamplesPerSec;
  76     uint32_t nAvgBytesPerSec;
  77     uint16_t nBlockAlign;
  78     uint16_t wBitsPerSample;
  79 } xa_header_t;
  80
  81 /*****************************************************************************
  82  * Open: check file and initializes structures
  83  *****************************************************************************/
  84 static int Open( vlc_object_t * p_this )
  85 {
  86     demux_t     *p_demux = (demux_t*)p_this;
  87     demux_sys_t *p_sys;
  88     xa_header_t p_xa;
  89     const uint8_t *p_buf;
  90
  91     /* XA file heuristic */
  92     if( stream_Peek( p_demux->s, &p_buf, sizeof( p_xa ) )
  93             < (signed)sizeof( p_xa ) )
  94         return VLC_EGENERIC;
  95
  96     memcpy( &p_xa, p_buf, sizeof( p_xa ) );
  97     if( ( strncmp( p_xa.xa_id, "XAI", 4 )
  98        && strncmp( p_xa.xa_id, "XAJ", 4 ) )
  99      || ( GetWLE( &p_xa.wFormatTag  ) != 0x0001)
 100      || ( GetWLE( &p_xa.wBitsPerSample ) != 16) )
 101         return VLC_EGENERIC;
 102
 103     p_demux->pf_demux   = Demux;
 104     p_demux->pf_control = Control;
 105     p_demux->p_sys      = p_sys = malloc( sizeof( demux_sys_t ) );
 106     p_sys->p_es         = NULL;
 107
 108     /* skip XA header -- cannot fail */
 109     stream_Read( p_demux->s, NULL, sizeof( p_xa ) );
 110
 111     es_format_Init( &p_sys->fmt, AUDIO_ES, VLC_FOURCC('X','A','J',0) );
 112
 113     msg_Dbg( p_demux, "assuming EA ADPCM audio codec" );
 114     p_sys->fmt.audio.i_rate = GetDWLE( &p_xa.nSamplesPerSec );
 115     p_sys->fmt.audio.i_bytes_per_frame = 15 * GetWLE( &p_xa.nChannels );
 116     p_sys->fmt.audio.i_frame_length = 28; /* 28 samples of 4 bits each */
 117
 118     p_sys->fmt.audio.i_channels = GetWLE ( &p_xa.nChannels );
 119     p_sys->fmt.audio.i_blockalign = p_sys->fmt.audio.i_bytes_per_frame;
 120     p_sys->fmt.audio.i_bitspersample = 16;
 121     p_sys->fmt.i_bitrate = (p_sys->fmt.audio.i_rate
 122                             * p_sys->fmt.audio.i_bytes_per_frame * 8)
 123                             / p_sys->fmt.audio.i_frame_length;
 124     p_sys->fmt.i_extra = 0;
 125     p_sys->fmt.p_extra = NULL;
 126
 127     p_sys->i_data_offset = stream_Tell( p_demux->s );
 128     /* FIXME: better computation */
 129     p_sys->i_data_size = p_xa.iSize * 15 / 56;
 130     /* How many frames per block (1:1 is too CPU intensive) */
 131     p_sys->i_block_frames = p_sys->fmt.audio.i_rate / (28 * 20) + 1;
 132
 133     msg_Dbg( p_demux, "fourcc: %4.4s, channels: %d, "
 134              "freq: %d Hz, bitrate: %dKo/s, blockalign: %d",
 135              (char *)&p_sys->fmt.i_codec, p_sys->fmt.audio.i_channels,
 136              p_sys->fmt.audio.i_rate, p_sys->fmt.i_bitrate / 8192,
 137              p_sys->fmt.audio.i_blockalign );
 138
 139     p_sys->p_es = es_out_Add( p_demux->out, &p_sys->fmt );
 140
 141     date_Init( &p_sys->pts, p_sys->fmt.audio.i_rate, 1 );
 142     date_Set( &p_sys->pts, 1 );
 143
 144     return VLC_SUCCESS;
 145 }
 146
 147 /*****************************************************************************
 148  * Demux: read packet and send them to decoders
 149  *****************************************************************************
 150  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 151  *****************************************************************************/
 152 static int Demux( demux_t *p_demux )
 153 {
 154     demux_sys_t *p_sys = p_demux->p_sys;
 155     block_t     *p_block;
 156     int64_t     i_offset;
 157     unsigned    i_frames = p_sys->i_block_frames;
 158
 159     i_offset = stream_Tell( p_demux->s );
 160
 161     if( p_sys->i_data_size > 0 &&
 162         i_offset >= p_sys->i_data_offset + p_sys->i_data_size )
 163     {
 164         /* EOF */
 165         return 0;
 166     }
 167
 168     p_block = stream_Block( p_demux->s, p_sys->fmt.audio.i_bytes_per_frame *
 169                             i_frames );
 170     if( p_block == NULL )
 171     {
 172         msg_Warn( p_demux, "cannot read data" );
 173         return 0;
 174     }
 175
 176     i_frames = p_block->i_buffer / p_sys->fmt.audio.i_bytes_per_frame;
 177     p_block->i_dts = p_block->i_pts = VLC_TS_0 + date_Get( &p_sys->pts );
 178     es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block->i_pts );
 179     es_out_Send( p_demux->out, p_sys->p_es, p_block );
 180
 181     date_Increment( &p_sys->pts, i_frames * p_sys->fmt.audio.i_frame_length );
 182
 183     return 1;
 184 }
 185
 186 /*****************************************************************************
 187  * Close: frees unused data
 188  *****************************************************************************/
 189 static void Close ( vlc_object_t * p_this )
 190 {
 191     demux_sys_t *p_sys  = ((demux_t *)p_this)->p_sys;
 192
 193     free( p_sys );
 194 }
 195
 196 /*****************************************************************************
 197  * Control:
 198  *****************************************************************************/
 199 static int Control( demux_t *p_demux, int i_query, va_list args )
 200 {
 201     demux_sys_t *p_sys  = p_demux->p_sys;
 202
 203     return demux_vaControlHelper( p_demux->s, p_sys->i_data_offset,
 204                                    p_sys->i_data_size ? p_sys->i_data_offset
 205                                    + p_sys->i_data_size : -1,
 206                                    p_sys->fmt.i_bitrate,
 207                                    p_sys->fmt.audio.i_blockalign,
 208                                    i_query, args );
 209 }