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 it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * 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 <assert.h>
  33 #include <vlc_common.h>
  34 #include <vlc_plugin.h>
  35 #include <vlc_demux.h>
  36
  37 /*****************************************************************************
  38  * Module descriptor
  39  *****************************************************************************/
  40 static int  Open ( vlc_object_t * );
  41 static void Close( vlc_object_t * );
  42
  43 vlc_module_begin ()
  44     set_description( N_("XA demuxer") )
  45     set_category( CAT_INPUT )
  46     set_subcategory( SUBCAT_INPUT_DEMUX )
  47     set_capability( "demux", 10 )
  48     set_callbacks( Open, Close )
  49 vlc_module_end ()
  50
  51 /*****************************************************************************
  52  * Local prototypes
  53  *****************************************************************************/
  54 static int Demux  ( demux_t * );
  55 static int Control( demux_t *, int i_query, va_list args );
  56
  57 struct demux_sys_t
  58 {
  59     es_out_id_t     *p_es;
  60
  61     unsigned int    i_data_size;
  62     unsigned int    i_block_frames;
  63     unsigned int    i_frame_size;
  64     unsigned int    i_bitrate;
  65
  66     date_t          pts;
  67 };
  68
  69 typedef struct xa_header_t
  70 {
  71     char     xa_id[4];
  72     uint32_t iSize;
  73
  74     uint16_t wFormatTag;
  75     uint16_t nChannels;
  76     uint32_t nSamplesPerSec;
  77     uint32_t nAvgBytesPerSec;
  78     uint16_t nBlockAlign;
  79     uint16_t wBitsPerSample;
  80 } xa_header_t;
  81
  82 #define HEADER_LENGTH 24
  83
  84 static_assert(offsetof(xa_header_t, wBitsPerSample) == 22, "Bad padding");
  85
  86 #define FRAME_LENGTH 28 /* samples per frame */
  87
  88 /*****************************************************************************
  89  * Open: check file and initializes structures
  90  *****************************************************************************/
  91 static int Open( vlc_object_t * p_this )
  92 {
  93     demux_t     *p_demux = (demux_t*)p_this;
  94     const uint8_t *peek;
  95
  96     /* XA file heuristic */
  97     if( vlc_stream_Peek( p_demux->s, &peek, 10 ) < 10 )
  98         return VLC_EGENERIC;
  99     if( memcmp( peek, "XAI", 4 ) && memcmp( peek, "XAJ", 4 ) &&
 100             memcmp( peek, "XA\0", 4 ) )
 101         return VLC_EGENERIC;
 102     if( GetWLE( peek + 8 ) != 1 ) /* format tag */
 103         return VLC_EGENERIC;
 104
 105     demux_sys_t *p_sys = malloc( sizeof( demux_sys_t ) );
 106     if( unlikely( p_sys == NULL ) )
 107         return VLC_ENOMEM;
 108
 109     /* read XA header*/
 110     xa_header_t xa;
 111
 112     if( vlc_stream_Read( p_demux->s, &xa, HEADER_LENGTH ) < HEADER_LENGTH )
 113     {
 114         free( p_sys );
 115         return VLC_EGENERIC;
 116     }
 117
 118     es_format_t fmt;
 119     es_format_Init( &fmt, AUDIO_ES, VLC_CODEC_ADPCM_XA_EA );
 120
 121     msg_Dbg( p_demux, "assuming EA ADPCM audio codec" );
 122     fmt.audio.i_rate = GetDWLE( &xa.nSamplesPerSec );
 123     fmt.audio.i_bytes_per_frame = 15 * GetWLE( &xa.nChannels );
 124     fmt.audio.i_frame_length = FRAME_LENGTH;
 125
 126     fmt.audio.i_channels = GetWLE ( &xa.nChannels );
 127     fmt.audio.i_blockalign = fmt.audio.i_bytes_per_frame;
 128     fmt.audio.i_bitspersample = GetWLE( &xa.wBitsPerSample );
 129     fmt.i_bitrate = (fmt.audio.i_rate * fmt.audio.i_bytes_per_frame * 8)
 130                     / fmt.audio.i_frame_length;
 131
 132     /* FIXME: better computation */
 133     p_sys->i_data_size = xa.iSize * 15 / 56;
 134     /* How many frames per block (1:1 is too CPU intensive) */
 135     p_sys->i_block_frames = fmt.audio.i_rate / (FRAME_LENGTH * 20) + 1;
 136     p_sys->i_frame_size = fmt.audio.i_bytes_per_frame;
 137     p_sys->i_bitrate = fmt.i_bitrate;
 138
 139     msg_Dbg( p_demux, "fourcc: %4.4s, channels: %d, "
 140              "freq: %d Hz, bitrate: %dKo/s, blockalign: %d",
 141              (char *)&fmt.i_codec, fmt.audio.i_channels, fmt.audio.i_rate,
 142              fmt.i_bitrate / 8192, fmt.audio.i_blockalign );
 143
 144     if( fmt.audio.i_rate == 0 || fmt.audio.i_channels == 0
 145      || fmt.audio.i_bitspersample != 16 )
 146     {
 147         free( p_sys );
 148         return VLC_EGENERIC;
 149     }
 150
 151     p_sys->p_es = es_out_Add( p_demux->out, &fmt );
 152
 153     date_Init( &p_sys->pts, fmt.audio.i_rate, 1 );
 154     date_Set( &p_sys->pts, VLC_TS_0 );
 155
 156     p_demux->pf_demux   = Demux;
 157     p_demux->pf_control = Control;
 158     p_demux->p_sys      = p_sys;
 159     return VLC_SUCCESS;
 160 }
 161
 162 /*****************************************************************************
 163  * Demux: read packet and send them to decoders
 164  *****************************************************************************
 165  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 166  *****************************************************************************/
 167 static int Demux( demux_t *p_demux )
 168 {
 169     demux_sys_t *p_sys = p_demux->p_sys;
 170     block_t     *p_block;
 171     int64_t     i_offset = vlc_stream_Tell( p_demux->s );
 172     unsigned    i_frames = p_sys->i_block_frames;
 173
 174     if( p_sys->i_data_size > 0 &&
 175         (i_offset - HEADER_LENGTH) >= p_sys->i_data_size )
 176     {
 177         /* EOF */
 178         return 0;
 179     }
 180
 181     p_block = vlc_stream_Block( p_demux->s, p_sys->i_frame_size * i_frames );
 182     if( p_block == NULL )
 183     {
 184         msg_Warn( p_demux, "cannot read data" );
 185         return 0;
 186     }
 187
 188     i_frames = p_block->i_buffer / p_sys->i_frame_size;
 189     p_block->i_dts = p_block->i_pts = date_Get( &p_sys->pts );
 190     es_out_SetPCR( p_demux->out, p_block->i_pts );
 191     es_out_Send( p_demux->out, p_sys->p_es, p_block );
 192
 193     date_Increment( &p_sys->pts, i_frames * FRAME_LENGTH );
 194
 195     return 1;
 196 }
 197
 198 /*****************************************************************************
 199  * Close: frees unused data
 200  *****************************************************************************/
 201 static void Close ( vlc_object_t * p_this )
 202 {
 203     demux_sys_t *p_sys  = ((demux_t *)p_this)->p_sys;
 204
 205     free( p_sys );
 206 }
 207
 208 /*****************************************************************************
 209  * Control:
 210  *****************************************************************************/
 211 static int Control( demux_t *p_demux, int i_query, va_list args )
 212 {
 213     demux_sys_t *p_sys  = p_demux->p_sys;
 214
 215     return demux_vaControlHelper( p_demux->s, HEADER_LENGTH,
 216         p_sys->i_data_size ? (int64_t)HEADER_LENGTH + p_sys->i_data_size : -1,
 217                                   p_sys->i_bitrate, p_sys->i_frame_size,
 218                                   i_query, args );
 219 }