/* used to track pcm position without actually performing decode. Useful for sequential 'fast forward' */
static public int vorbis_synthesis_trackonly(ref vorbis_block vb, ref Ogg.ogg_packet op)
{
vorbis_dsp_state vd = vb.vd;
private_state b = vd.backend_state as private_state;
vorbis_info vi = vd.vi;
codec_setup_info ci = vi.codec_setup as codec_setup_info;
Ogg.oggpack_buffer opb = vb.opb;
int mode;
/* first things first. Make sure decode is ready */
_vorbis_block_ripcord(ref vb);
Ogg.oggpack_readinit(ref opb, op.packet, op.bytes);
/* Check the packet type */
if (Ogg.oggpack_read(ref opb, 1) != 0)
{
/* Oops. This is not an audio data packet */
return(OV_ENOTAUDIO);
}
/* read our mode and pre/post windowsize */
mode = Ogg.oggpack_read(ref opb, b.modebits);
if (mode == -1)
{
return(OV_EBADPACKET);
}
vb.mode = mode;
vb.W = ci.mode_param[mode].blockflag;
if (vb.W > 0)
{
vb.lW = Ogg.oggpack_read(ref opb, 1);
vb.nW = Ogg.oggpack_read(ref opb, 1);
if (vb.nW == -1)
{
return(OV_EBADPACKET);
}
}
else
{
vb.lW = 0;
vb.nW = 0;
}
/* more setup */
vb.granulepos = op.granulepos;
vb.sequence = op.packetno;
vb.eofflag = op.e_o_s;
/* no pcm */
vb.pcmend = 0;
vb.pcm = null;
return(0);
}
static public int vorbis_analysis(ref vorbis_block vb, ref Ogg.ogg_packet op)
{
int ret, i;
vorbis_block_internal vbi = vb._internal as vorbis_block_internal;
vb.glue_bits = 0;
vb.time_bits = 0;
vb.floor_bits = 0;
vb.res_bits = 0;
/* first things first. Make sure encode is ready */
for (i = 0; i < PACKETBLOBS; i++)
{
Ogg.oggpack_reset(ref vbi.packetblob[i]);
}
/* we only have one mapping type (0), and we let the mapping code itself figure out what soft mode to use.
* This allows easier bitrate management */
if ((ret = _mapping_P[0].forward(ref vb)) != 0)
{
return(ret);
}
if (vorbis_bitrate_managed(ref vb) != 0)
{
/* The app is using a bitmanaged mode... but not using the
* bitrate management interface. */
return(OV_EINVAL);
}
op.packet = Ogg.oggpack_get_buffer(ref vb.opb);
op.bytes = Ogg.oggpack_bytes(ref vb.opb);
op.b_o_s = 0;
op.granulepos = vb.granulepos;
op.packetno = vb.sequence; /* for sake of completeness */
return(0);
}
/* Is this packet a vorbis ID header? */
static public int vorbis_synthesis_idheader(ref Ogg.ogg_packet op)
{
Ogg.oggpack_buffer opb = new Ogg.oggpack_buffer();
char[] buffer = new char[6];
if (op == null)
{
return(0);
}
Ogg.oggpack_readinit(ref opb, op.packet, op.bytes);
if (op.b_o_s == 0)
{
return(0); /* Not the initial packet */
}
if (Ogg.oggpack_read(ref opb, 8) != 1)
{
return(0); /* Not an ID header */
}
_v_readstring(ref opb, ref buffer, 6);
if
(
buffer[0] != 'v' ||
buffer[1] != 'o' ||
buffer[2] != 'r' ||
buffer[3] != 'b' ||
buffer[4] != 'i' ||
buffer[5] != 's'
)
{
return(0); /* not vorbis */
}
return(1);
}
static public int vorbis_packet_blocksize(ref vorbis_info vi, ref Ogg.ogg_packet op)
{
codec_setup_info ci = vi.codec_setup as codec_setup_info;
Ogg.oggpack_buffer opb = new Ogg.oggpack_buffer();
int mode;
Ogg.oggpack_readinit(ref opb, op.packet, op.bytes);
/* Check the packet type */
if (Ogg.oggpack_read(ref opb, 1) != 0)
{
/* Oops. This is not an audio data packet */
return(OV_ENOTAUDIO);
}
{
int modebits = 0;
int v = ci.modes;
while (v > 1)
{
modebits++;
v >>= 1;
}
/* read our mode and pre/post windowsize */
mode = Ogg.oggpack_read(ref opb, modebits);
}
if (mode == -1)
{
return(OV_EBADPACKET);
}
return(ci.blocksizes[ci.mode_param[mode].blockflag]);
}
static public int vorbis_synthesis(ref vorbis_block vb, ref Ogg.ogg_packet op)
{
vorbis_dsp_state vd = (vb != null) ? vb.vd : null;
private_state b = (vd != null) ? (vd.backend_state as private_state) : null;
vorbis_info vi = (vd != null) ? vd.vi : null;
codec_setup_info ci = (vi != null) ? (vi.codec_setup as codec_setup_info) : null;
Ogg.oggpack_buffer opb = (vb != null) ? vb.opb : null;
int type, mode, i;
if (vd == null || b == null || vi == null || ci == null || opb == null)
{
return(OV_EBADHEADER);
}
/* first things first. Make sure decode is ready */
_vorbis_block_ripcord(ref vb);
Ogg.oggpack_readinit(ref opb, op.packet, op.bytes);
/* Check the packet type */
if (Ogg.oggpack_read(ref opb, 1) != 0)
{
/* Oops. This is not an audio data packet */
return(OV_ENOTAUDIO);
}
/* read our mode and pre/post windowsize */
mode = Ogg.oggpack_read(ref opb, b.modebits);
if (mode == -1)
{
return(OV_EBADPACKET);
}
vb.mode = mode;
if (ci.mode_param[mode] == null)
{
return(OV_EBADPACKET);
}
vb.W = ci.mode_param[mode].blockflag;
if (vb.W > 0)
{
/* this doesn't get mapped through mode selection as it's used only for window selection */
vb.lW = Ogg.oggpack_read(ref opb, 1);
vb.nW = Ogg.oggpack_read(ref opb, 1);
if (vb.nW == -1)
{
return(OV_EBADPACKET);
}
}
else
{
vb.lW = 0;
vb.nW = 0;
}
/* more setup */
vb.granulepos = op.granulepos;
vb.sequence = op.packetno;
vb.eofflag = op.e_o_s;
/* alloc pcm passback storage */
vb.pcmend = ci.blocksizes[vb.W];
vb.pcm = (float **)_vorbis_block_alloc(ref vb, sizeof(float *) * vi.channels);
for (i = 0; i < vi.channels; i++)
{
vb.pcm[i] = (float *)_vorbis_block_alloc(ref vb, sizeof(float) * vb.pcmend);
}
/* unpack_header enforces range checking */
type = ci.map_type[ci.mode_param[mode].mapping];
return(_mapping_P[type].inverse(ref vb, ci.map_param[ci.mode_param[mode].mapping]));
}
/* The Vorbis header is in three packets; the initial small packet in the first page that identifies basic parameters, a second packet
* with bitstream comments and a third packet that holds the codebook. */
static public int vorbis_synthesis_headerin(ref vorbis_info vi, ref vorbis_comment vc, ref Ogg.ogg_packet op)
{
Ogg.oggpack_buffer opb = new Ogg.oggpack_buffer();
Ogg.oggpack_readinit(ref opb, op.packet, op.bytes);
/* Which of the three types of header is this? */
/* Also verify header-ness, vorbis */
{
char[] buffer = new char[6];
int packtype = Ogg.oggpack_read(ref opb, 8);
_v_readstring(ref opb, ref buffer, 6);
if
(
buffer[0] != 'v' ||
buffer[1] != 'o' ||
buffer[2] != 'r' ||
buffer[3] != 'b' ||
buffer[4] != 'i' ||
buffer[5] != 's'
)
{
/* not a vorbis header */
return(OV_ENOTVORBIS);
}
switch (packtype)
{
case 0x01: /* least significant *bit* is read first */
{
if (op.b_o_s == 0)
{
/* Not the initial packet */
return(OV_EBADHEADER);
}
if (vi.rate != 0)
{
/* previously initialized info header */
return(OV_EBADHEADER);
}
}
return(_vorbis_unpack_info(ref vi, ref opb));
case 0x03: /* least significant *bit* is read first */
{
if (vi.rate == 0)
{
/* um... we didn't get the initial header */
return(OV_EBADHEADER);
}
}
return(_vorbis_unpack_comment(ref vc, ref opb));
case 0x05: /* least significant *bit* is read first */
{
if (vi.rate == 0 || vc.vendor == null)
{
/* um... we didn;t get the initial header or comments yet */
return(OV_EBADHEADER);
}
}
return(_vorbis_unpack_books(ref vi, ref opb));
default:
{
/* Not a valid vorbis header type */
return(OV_EBADHEADER);
}
}
}
}