Files
2011-02-07 12:59:02 +00:00

376 lines
12 KiB
C

/*
* SDL_sound -- An abstract sound format decoding API.
* Copyright (C) 2001 Ryan C. Gordon.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Ogg Vorbis decoder for SDL_sound.
*
* This driver handles .OGG audio files, and depends on libvorbisfile to
* do the actual decoding work. libvorbisfile is part of libvorbis, which
* is part of the Ogg Vorbis project.
*
* Ogg Vorbis: http://www.xiph.org/ogg/vorbis/
* vorbisfile documentation: http://www.xiph.org/ogg/vorbis/doc/vorbisfile/
*
* Please see the file COPYING in the source's root directory.
*
* This file written by Ryan C. Gordon. (icculus@icculus.org)
*/
#if HAVE_CONFIG_H
# include <config.h>
#endif
#ifdef SOUND_SUPPORTS_OGG
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "SDL_sound.h"
#define __SDL_SOUND_INTERNAL__
#include "SDL_sound_internal.h"
#include <vorbis/codec.h>
#include <vorbis/vorbisfile.h>
static int OGG_init(void);
static void OGG_quit(void);
static int OGG_open(Sound_Sample *sample, const char *ext);
static void OGG_close(Sound_Sample *sample);
static Uint32 OGG_read(Sound_Sample *sample);
static int OGG_rewind(Sound_Sample *sample);
static int OGG_seek(Sound_Sample *sample, Uint32 ms);
static const char *extensions_ogg[] = { "OGG", NULL };
const Sound_DecoderFunctions __Sound_DecoderFunctions_OGG =
{
{
extensions_ogg,
"Ogg Vorbis audio through VorbisFile",
"Ryan C. Gordon <icculus@icculus.org>",
"http://www.icculus.org/SDL_sound/"
},
OGG_init, /* init() method */
OGG_quit, /* quit() method */
OGG_open, /* open() method */
OGG_close, /* close() method */
OGG_read, /* read() method */
OGG_rewind, /* rewind() method */
OGG_seek /* seek() method */
};
static int OGG_init(void)
{
return(1); /* always succeeds. */
} /* OGG_init */
static void OGG_quit(void)
{
/* it's a no-op. */
} /* OGG_quit */
/*
* These are callbacks from vorbisfile that let them read data from
* a RWops...
*/
static size_t RWops_ogg_read(void *ptr, size_t size, size_t nmemb, void *datasource)
{
return((size_t) SDL_RWread((SDL_RWops *) datasource, ptr, size, nmemb));
} /* RWops_ogg_read */
static int RWops_ogg_seek(void *datasource, ogg_int64_t offset, int whence)
{
return(SDL_RWseek((SDL_RWops *) datasource, offset, whence));
} /* RWops_ogg_seek */
static int RWops_ogg_close(void *datasource)
{
/* do nothing; SDL_sound will delete the RWops at a higher level. */
return(0); /* this is success in fclose(), so I guess that's okay. */
} /* RWops_ogg_close */
static long RWops_ogg_tell(void *datasource)
{
return((long) SDL_RWtell((SDL_RWops *) datasource));
} /* RWops_ogg_tell */
static const ov_callbacks RWops_ogg_callbacks =
{
RWops_ogg_read,
RWops_ogg_seek,
RWops_ogg_close,
RWops_ogg_tell
};
/* Return a human readable version of an VorbisFile error code... */
#if (defined DEBUG_CHATTER)
static const char *ogg_error(int errnum)
{
switch(errnum)
{
case OV_EREAD:
return("i/o error");
case OV_ENOTVORBIS:
return("not a vorbis file");
case OV_EVERSION:
return("Vorbis version mismatch");
case OV_EBADHEADER:
return("invalid Vorbis bitstream header");
case OV_EFAULT:
return("internal logic fault in Vorbis library");
} /* switch */
return("unknown error");
} /* ogg_error */
#endif
static __inline__ void output_ogg_comments(OggVorbis_File *vf)
{
#if (defined DEBUG_CHATTER)
int i;
vorbis_comment *vc = ov_comment(vf, -1);
if (vc == NULL)
return;
SNDDBG(("OGG: vendor == [%s].\n", vc->vendor));
for (i = 0; i < vc->comments; i++)
{
SNDDBG(("OGG: user comment [%s].\n", vc->user_comments[i]));
} /* for */
#endif
} /* output_ogg_comments */
static int OGG_open(Sound_Sample *sample, const char *ext)
{
int rc;
OggVorbis_File *vf;
vorbis_info *info;
Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
vf = (OggVorbis_File *) malloc(sizeof (OggVorbis_File));
BAIL_IF_MACRO(vf == NULL, ERR_OUT_OF_MEMORY, 0);
rc = ov_open_callbacks(internal->rw, vf, NULL, 0, RWops_ogg_callbacks);
if (rc != 0)
{
SNDDBG(("OGG: can't grok data. reason: [%s].\n", ogg_error(rc)));
free(vf);
BAIL_MACRO("OGG: Not valid Ogg Vorbis data.", 0);
} /* if */
info = ov_info(vf, -1);
if (info == NULL)
{
ov_clear(vf);
free(vf);
BAIL_MACRO("OGG: failed to retrieve bitstream info", 0);
} /* if */
SNDDBG(("OGG: Accepting data stream.\n"));
output_ogg_comments(vf);
SNDDBG(("OGG: bitstream version == (%d).\n", info->version));
SNDDBG(("OGG: bitstream channels == (%d).\n", info->channels));
SNDDBG(("OGG: bitstream sampling rate == (%ld).\n", info->rate));
SNDDBG(("OGG: seekable == {%s}.\n", ov_seekable(vf) ? "TRUE" : "FALSE"));
SNDDBG(("OGG: number of logical bitstreams == (%ld).\n", ov_streams(vf)));
SNDDBG(("OGG: serial number == (%ld).\n", ov_serialnumber(vf, -1)));
SNDDBG(("OGG: total seconds of sample == (%f).\n", ov_time_total(vf, -1)));
internal->decoder_private = vf;
sample->flags = SOUND_SAMPLEFLAG_CANSEEK;
sample->actual.rate = (Uint32) info->rate;
sample->actual.channels = (Uint8) info->channels;
/*
* Since we might have more than one logical bitstream in the OGG file,
* and these bitstreams may be in different formats, we might be
* converting two or three times: once in vorbisfile, once again in
* SDL_sound, and perhaps a third time to get it to the sound device's
* format. That's wickedly inefficient.
*
* To combat this a little, if the user specified a desired format, we
* claim that to be the "actual" format of the collection of logical
* bitstreams. This means that VorbisFile will do a conversion as
* necessary, and SDL_sound will not. If the user didn't specify a
* desired format, then we pretend the "actual" format is something that
* OGG files are apparently commonly encoded in.
*/
sample->actual.format = (sample->desired.format == 0) ?
AUDIO_S16LSB : sample->desired.format;
return(1);
} /* OGG_open */
static void OGG_close(Sound_Sample *sample)
{
Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
OggVorbis_File *vf = (OggVorbis_File *) internal->decoder_private;
ov_clear(vf);
free(vf);
} /* OGG_close */
/* Note: According to the Vorbis documentation:
* "ov_read() will decode at most one vorbis packet per invocation,
* so the value returned will generally be less than length."
* Due to this, for buffer sizes like 16384, SDL_Sound was always getting
* an underfilled buffer and always setting the EAGAIN flag.
* Since the SDL_Sound API implies that the entire buffer
* should be filled unless EOF, additional code has been added
* to this function to call ov_read() until the buffer is filled.
* However, there may still be some corner cases where the buffer
* cannot be entirely filled. So be aware.
*/
static Uint32 OGG_read(Sound_Sample *sample)
{
int rc;
int bitstream;
Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
OggVorbis_File *vf = (OggVorbis_File *) internal->decoder_private;
rc = ov_read(vf, internal->buffer, internal->buffer_size,
((sample->actual.format & 0x1000) ? 1 : 0), /* bigendian? */
((sample->actual.format & 0xFF) / 8), /* bytes per sample point */
((sample->actual.format & 0x8000) ? 1 : 0), /* signed data? */
&bitstream);
/* Make sure the read went smoothly... */
if (rc == 0)
sample->flags |= SOUND_SAMPLEFLAG_EOF;
else if (rc < 0)
sample->flags |= SOUND_SAMPLEFLAG_ERROR;
/* If the buffer isn't filled, keep trying to fill it
* until no more data can be grabbed */
else if ((Uint32) rc < internal->buffer_size)
{
/* Creating a pointer to the buffer that denotes where to start
* writing new data. */
Uint8* buffer_start_point = NULL;
int total_bytes_read = rc;
int bytes_remaining = internal->buffer_size - rc;
/* Keep grabbing data until something prevents
* us from getting more. (Could be EOF,
* packets are too large to fit in remaining
* space, or an error.)
*/
while( (rc > 0) && (bytes_remaining > 0) )
{
/* Set buffer pointer to end of last write */
/* All the messiness is to get rid of the warning for
* dereferencing a void*
*/
buffer_start_point = &(((Uint8*)internal->buffer)[total_bytes_read]);
rc = ov_read(vf, buffer_start_point, bytes_remaining,
((sample->actual.format & 0x1000) ? 1 : 0), /* bigendian? */
((sample->actual.format & 0xFF) / 8), /* bytes per sample point */
((sample->actual.format & 0x8000) ? 1 : 0), /* signed data? */
&bitstream);
/* Make sure rc > 0 because we don't accidently want
* to change the counters if there was an error
*/
if(rc > 0)
{
total_bytes_read += rc;
bytes_remaining = bytes_remaining - rc;
}
}
/* I think the minimum read size is 2, though I'm
* not sure about this. (I've hit cases where I
* couldn't read less than 4.) What I don't want to do is
* accidently claim we hit EOF when the reason rc == 0
* is because the requested amount of data was smaller
* than the minimum packet size.
* For now, I will be conservative
* and not set the EOF flag, and let the next call to
* this function figure it out.
* I think the ERROR flag is safe to set because
* it looks like OGG simply returns 0 if the
* read size is too small.
* And in most cases for sensible buffer sizes,
* this fix will fill the buffer,
* so we can set the EAGAIN flag without worrying
* that it will always be set.
*/
if(rc < 0)
{
sample->flags |= SOUND_SAMPLEFLAG_ERROR;
}
else if(rc == 0)
{
/* Do nothing for now until there is a better solution */
/* sample->flags |= SOUND_SAMPLEFLAG_EOF; */
}
/* Test for a buffer underrun. It should occur less frequently
* now, but it still may happen and not necessarily mean
* anything useful. */
if ((Uint32) total_bytes_read < internal->buffer_size)
{
sample->flags |= SOUND_SAMPLEFLAG_EAGAIN;
}
/* change rc to the total bytes read so function
* can return the correct value.
*/
rc = total_bytes_read;
}
return((Uint32) rc);
} /* OGG_read */
static int OGG_rewind(Sound_Sample *sample)
{
Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
OggVorbis_File *vf = (OggVorbis_File *) internal->decoder_private;
BAIL_IF_MACRO(ov_raw_seek(vf, 0) < 0, ERR_IO_ERROR, 0);
return(1);
} /* OGG_rewind */
static int OGG_seek(Sound_Sample *sample, Uint32 ms)
{
Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
OggVorbis_File *vf = (OggVorbis_File *) internal->decoder_private;
double timepos = (((double) ms) / 1000.0);
BAIL_IF_MACRO(ov_time_seek(vf, timepos) < 0, ERR_IO_ERROR, 0);
return(1);
} /* OGG_seek */
#endif /* SOUND_SUPPORTS_OGG */
/* end of ogg.c ... */