/* simplistic, wasteful way of doing this (unique lookup for each mode/submapping); there should be a central repository for
* identical lookups. That will require minor work, so I'm putting it off as low priority.
*
* Why a lookup for each backend in a given mode? Because the blocksize is set by the mode, and low backend lookups may require
* parameters from other areas of the mode/mapping */
static void mapping0_free_info(ref vorbis_info_mapping i)
{
vorbis_info_mapping0 info = i as vorbis_info_mapping0;
if (info != null)
{
info = null;
}
}
static void mapping0_pack(ref vorbis_info vi, vorbis_info_mapping vm, ref Ogg.oggpack_buffer opb)
{
int i;
vorbis_info_mapping0 info = vm as vorbis_info_mapping0;
/* another 'we meant to do it this way' hack... up to beta 4, we packed 4 binary zeros here to signify one submapping in use. We
* now redefine that to mean four bitflags that indicate use of deeper features; bit0:submappings, bit1:coupling,
* bit2,3: reserved. This is backward compatable with all actual uses of the beta code. */
if (info.submaps > 1)
{
Ogg.oggpack_write(ref opb, 1, 1);
Ogg.oggpack_write(ref opb, (uint)(info.submaps - 1), 4);
}
else
{
Ogg.oggpack_write(ref opb, 0, 1);
}
if (info.coupling_steps > 0)
{
Ogg.oggpack_write(ref opb, 1, 1);
Ogg.oggpack_write(ref opb, (uint)(info.coupling_steps - 1), 8);
for (i = 0; i < info.coupling_steps; i++)
{
Ogg.oggpack_write(ref opb, (uint)info.coupling_mag[i], ilog((uint)vi.channels));
Ogg.oggpack_write(ref opb, (uint)info.coupling_ang[i], ilog((uint)vi.channels));
}
}
else
{
Ogg.oggpack_write(ref opb, 0, 1);
}
Ogg.oggpack_write(ref opb, 0, 2); /* 2,3:reserved */
/* we don't write the channel submappings if we only have one... */
if (info.submaps > 1)
{
for (i = 0; i < vi.channels; i++)
{
Ogg.oggpack_write(ref opb, (uint)info.chmuxlist[i], 4);
}
}
for (i = 0; i < info.submaps; i++)
{
Ogg.oggpack_write(ref opb, 0, 8); /* time submap unused */
Ogg.oggpack_write(ref opb, (uint)info.floorsubmap[i], 8);
Ogg.oggpack_write(ref opb, (uint)info.residuesubmap[i], 8);
}
}
static int mapping0_inverse(ref vorbis_block vb, vorbis_info_mapping l)
{
vorbis_dsp_state vd = vb.vd;
vorbis_info vi = vd.vi;
codec_setup_info ci = vi.codec_setup as codec_setup_info;
private_state b = vd.backend_state as private_state;
vorbis_info_mapping0 info = l as vorbis_info_mapping0;
int i, j;
int n = vb.pcmend = ci.blocksizes[vb.W];
float **pcmbundle = stackalloc float *[vi.channels];
int * zerobundle = stackalloc int[vi.channels];
int * nonzero = stackalloc int[vi.channels];
void **floormemo = stackalloc void *[vi.channels];
/* recover the spectral envelope; store it in the PCM vector for now */
for (i = 0; i < vi.channels; i++)
{
int submap = info.chmuxlist[i];
floormemo[i] = _floor_P[ci.floor_type[info.floorsubmap[submap]]].inverse1(ref vb, b.flr[info.floorsubmap[submap]]);
if (floormemo[i] != null)
{
nonzero[i] = 1;
}
else
{
nonzero[i] = 0;
}
ZeroMemory(vb.pcm[i], sizeof(float) * n / 2);
}
/* channel coupling can 'dirty' the nonzero listing */
for (i = 0; i < info.coupling_steps; i++)
{
if (nonzero[info.coupling_mag[i]] != 0 || nonzero[info.coupling_ang[i]] != 0)
{
nonzero[info.coupling_mag[i]] = 1;
nonzero[info.coupling_ang[i]] = 1;
}
}
/* recover the residue into our working vectors */
for (i = 0; i < info.submaps; i++)
{
int ch_in_bundle = 0;
for (j = 0; j < vi.channels; j++)
{
if (info.chmuxlist[j] == i)
{
if (nonzero[j] != 0)
{
zerobundle[ch_in_bundle] = 1;
}
else
{
zerobundle[ch_in_bundle] = 0;
}
pcmbundle[ch_in_bundle++] = vb.pcm[j];
}
}
_residue_P[ci.residue_type[info.residuesubmap[i]]].inverse(ref vb, b.residue[info.residuesubmap[i]], pcmbundle, zerobundle, ch_in_bundle);
}
/* channel coupling */
for (i = info.coupling_steps - 1; i >= 0; i--)
{
float *pcmM = vb.pcm[info.coupling_mag[i]];
float *pcmA = vb.pcm[info.coupling_ang[i]];
for (j = 0; j < n / 2; j++)
{
float mag = pcmM[j];
float ang = pcmA[j];
if (mag > 0)
{
if (ang > 0)
{
pcmM[j] = mag;
pcmA[j] = mag - ang;
}
else
{
pcmA[j] = mag;
pcmM[j] = mag + ang;
}
}
else
{
if (ang > 0)
{
pcmM[j] = mag;
pcmA[j] = mag + ang;
}
else
{
pcmA[j] = mag;
pcmM[j] = mag - ang;
}
}
}
}
/* compute and apply spectral envelope */
for (i = 0; i < vi.channels; i++)
{
float *pcm = vb.pcm[i];
int submap = info.chmuxlist[i];
_floor_P[ci.floor_type[info.floorsubmap[submap]]].inverse2(ref vb, b.flr[info.floorsubmap[submap]], floormemo[i], pcm);
}
/* transform the PCM data; takes PCM vector, vb; modifies PCM vector */
/* only MDCT right now.... */
for (i = 0; i < vi.channels; i++)
{
float *pcm = vb.pcm[i];
mdct_backward(b.transform[vb.W][0] as mdct_lookup, pcm, pcm);
}
/* all done! */
return(0);
}
