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
  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, NULL )
  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 typedef struct
  57 {
  58     es_out_id_t     *p_es;
  59
  60     unsigned int    i_data_size;
  61     unsigned int    i_block_frames;
  62     unsigned int    i_frame_size;
  63     unsigned int    i_bitrate;
  64
  65     date_t          pts;
  66 } demux_sys_t;
  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 #define HEADER_LENGTH 24
  82
  83 static_assert(offsetof(xa_header_t, wBitsPerSample) == 22, "Bad padding");
  84
  85 #define FRAME_LENGTH 28 /* samples per frame */
  86
  87 /*****************************************************************************
  88  * Open: check file and initializes structures
  89  *****************************************************************************/
  90 static int Open( vlc_object_t * p_this )
  91 {
  92     demux_t     *p_demux = (demux_t*)p_this;
  93     const uint8_t *peek;
  94
  95     /* XA file heuristic */
  96     if( vlc_stream_Peek( p_demux->s, &peek, 10 ) < 10 )
  97         return VLC_EGENERIC;
  98     if( memcmp( peek, "XAI", 4 ) && memcmp( peek, "XAJ", 4 ) &&
  99             memcmp( peek, "XA\0", 4 ) )
 100         return VLC_EGENERIC;
 101     if( GetWLE( peek + 8 ) != 1 ) /* format tag */
 102         return VLC_EGENERIC;
 103
 104     demux_sys_t *p_sys = vlc_obj_malloc( p_this, sizeof (*p_sys) );
 105     if( unlikely( p_sys == NULL ) )
 106         return VLC_ENOMEM;
 107
 108     /* read XA header*/
 109     xa_header_t xa;
 110
 111     if( vlc_stream_Read( p_demux->s, &xa, HEADER_LENGTH ) < HEADER_LENGTH )
 112         return VLC_EGENERIC;
 113
 114     es_format_t fmt;
 115     es_format_Init( &fmt, AUDIO_ES, VLC_CODEC_ADPCM_XA_EA );
 116
 117     msg_Dbg( p_demux, "assuming EA ADPCM audio codec" );
 118     fmt.audio.i_rate = GetDWLE( &xa.nSamplesPerSec );
 119     fmt.audio.i_bytes_per_frame = 15 * GetWLE( &xa.nChannels );
 120     fmt.audio.i_frame_length = FRAME_LENGTH;
 121
 122     fmt.audio.i_channels = GetWLE ( &xa.nChannels );
 123     fmt.audio.i_blockalign = fmt.audio.i_bytes_per_frame;
 124     fmt.audio.i_bitspersample = GetWLE( &xa.wBitsPerSample );
 125     fmt.i_bitrate = (fmt.audio.i_rate * fmt.audio.i_bytes_per_frame * 8)
 126                     / fmt.audio.i_frame_length;
 127
 128     /* FIXME: better computation */
 129     p_sys->i_data_size = xa.iSize * 15 / 56;
 130     /* How many frames per block (1:1 is too CPU intensive) */
 131     p_sys->i_block_frames = fmt.audio.i_rate / (FRAME_LENGTH * 20) + 1;
 132     p_sys->i_frame_size = fmt.audio.i_bytes_per_frame;
 133     p_sys->i_bitrate = fmt.i_bitrate;
 134
 135     msg_Dbg( p_demux, "fourcc: %4.4s, channels: %d, "
 136              "freq: %d Hz, bitrate: %dKo/s, blockalign: %d",
 137              (char *)&fmt.i_codec, fmt.audio.i_channels, fmt.audio.i_rate,
 138              fmt.i_bitrate / 8192, fmt.audio.i_blockalign );
 139
 140     if( fmt.audio.i_rate == 0 || fmt.audio.i_channels == 0
 141      || fmt.audio.i_bitspersample != 16 )
 142         return VLC_EGENERIC;
 143
 144     p_sys->p_es = es_out_Add( p_demux->out, &fmt );
 145     if( unlikely(p_sys->p_es == NULL) )
 146         return VLC_ENOMEM;
 147
 148     date_Init( &p_sys->pts, fmt.audio.i_rate, 1 );
 149     date_Set( &p_sys->pts, VLC_TICK_0 );
 150
 151     p_demux->pf_demux   = Demux;
 152     p_demux->pf_control = Control;
 153     p_demux->p_sys      = p_sys;
 154     return VLC_SUCCESS;
 155 }
 156
 157 /*****************************************************************************
 158  * Demux: read packet and send them to decoders
 159  *****************************************************************************
 160  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 161  *****************************************************************************/
 162 static int Demux( demux_t *p_demux )
 163 {
 164     demux_sys_t *p_sys = p_demux->p_sys;
 165     block_t     *p_block;
 166     int64_t     i_offset = vlc_stream_Tell( p_demux->s );
 167     unsigned    i_frames = p_sys->i_block_frames;
 168
 169     if( p_sys->i_data_size > 0 &&
 170         (i_offset - HEADER_LENGTH) >= p_sys->i_data_size )
 171     {
 172         return VLC_DEMUXER_EOF;
 173     }
 174
 175     p_block = vlc_stream_Block( p_demux->s, p_sys->i_frame_size * i_frames );
 176     if( p_block == NULL )
 177     {
 178         msg_Warn( p_demux, "cannot read data" );
 179         return VLC_DEMUXER_EOF;
 180     }
 181
 182     i_frames = p_block->i_buffer / p_sys->i_frame_size;
 183     p_block->i_dts = p_block->i_pts = date_Get( &p_sys->pts );
 184     es_out_SetPCR( p_demux->out, p_block->i_pts );
 185     es_out_Send( p_demux->out, p_sys->p_es, p_block );
 186
 187     date_Increment( &p_sys->pts, i_frames * FRAME_LENGTH );
 188
 189     return VLC_DEMUXER_SUCCESS;
 190 }
 191
 192 /*****************************************************************************
 193  * Control:
 194  *****************************************************************************/
 195 static int Control( demux_t *p_demux, int i_query, va_list args )
 196 {
 197     demux_sys_t *p_sys  = p_demux->p_sys;
 198
 199     return demux_vaControlHelper( p_demux->s, HEADER_LENGTH,
 200         p_sys->i_data_size ? (int64_t)HEADER_LENGTH + p_sys->i_data_size : -1,
 201                                   p_sys->i_bitrate, p_sys->i_frame_size,
 202                                   i_query, args );
 203 }