/*
Encode a single frame of audio from 1152 samples
Audio samples are taken from glopts->buffer
Encoded bit stream is placed in to parameter bs
(not intended for use outside the library)
Returns the size of the frame
or -1 if there is an error
*/
static int encode_frame(twolame_options * glopts, bit_stream * bs)
{
int nch = glopts->num_channels_out;
int sb, ch, adb, i;
unsigned long frameBits, initial_bits;
short sam[2][1056];
if (!glopts->twolame_init) {
fprintf(stderr, "Please call twolame_init_params() before starting encoding.\n");
return -1;
}
// Scale and mix the input buffer
scale_and_mix_samples(glopts);
// Clear the saved audio buffer
memset((char *) sam, 0, sizeof(sam));
// Number of bits to calculate CRC on
glopts->num_crc_bits = 0;
// Store the number of bits initially in the bit buffer
initial_bits = twolame_buffer_sstell(bs);
adb = twolame_available_bits(glopts);
/* allow the user to reserve some space at the end of the frame This will however leave fewer
bits for the audio. Need to do a sanity check here to see that there are *some* bits left. */
if (glopts->num_ancillary_bits > 0.6 * adb) {
/* Trying to reserve more than 60% of the frame. 0.6 is arbitrary. but since most
applications probably only want to reserve a few bytes, this seems fine. Typical frame
size is about 800bytes */
fprintf(stderr,
"You're trying to reserve more than 60%% of the mpeg frame for ancillary data\n");
fprintf(stderr, "This is probably an error. But I'll keep going anyway...\n");
}
adb -= glopts->num_ancillary_bits;
/* The DAB scf-crc calc is done below. The frontend will have to keep the previous frame in
memory. As of 09May 2014 all that needs to be done is for the frontend to buffer one frame in
memory and call twolame_set_DAB_scf_crc */
{
int gr, bl, ch;
/* New polyphase filter Combines windowing and filtering. Ricardo Feb'03 */
for (gr = 0; gr < 3; gr++)
for (bl = 0; bl < 12; bl++)
for (ch = 0; ch < nch; ch++)
twolame_window_filter_subband(&glopts->smem,
&glopts->buffer[ch][gr * 12 * 32 + 32 * bl], ch,
&(*glopts->sb_sample)[ch][gr][bl][0]);
}
twolame_scalefactor_calc(*glopts->sb_sample, glopts->scalar, nch, glopts->sblimit);
twolame_find_sf_max(glopts, glopts->scalar, glopts->max_sc);
if (glopts->mode == TWOLAME_JOINT_STEREO) {
// this way we calculate more mono than we need but it is cheap
twolame_combine_lr(*glopts->sb_sample, *glopts->j_sample, glopts->sblimit);
twolame_scalefactor_calc(glopts->j_sample, &glopts->j_scale, 1, glopts->sblimit);
}
if ((glopts->quickmode == TRUE) && (++glopts->psycount % glopts->quickcount != 0)) {
/* We're using quick mode, so we're only calculating the model every 'quickcount' frames.
Otherwise, just copy the old ones across */
for (ch = 0; ch < nch; ch++) {
for (sb = 0; sb < SBLIMIT; sb++) {
glopts->smr[ch][sb] = glopts->smrdef[ch][sb];
}
}
} else {
// calculate the psymodel
switch (glopts->psymodel) {
case -1:
twolame_psycho_n1(glopts, glopts->smr, nch);
break;
case 0: // Psy Model A
twolame_psycho_0(glopts, glopts->smr, glopts->scalar);
break;
case 1:
twolame_psycho_1(glopts, glopts->buffer, glopts->max_sc, glopts->smr);
break;
case 2:
twolame_psycho_2(glopts, glopts->buffer, sam, glopts->smr);
break;
case 3:
// Modified psy model 1
twolame_psycho_3(glopts, glopts->buffer, glopts->max_sc, glopts->smr);
break;
case 4:
// Modified psy model 2
twolame_psycho_4(glopts, glopts->buffer, sam, glopts->smr);
break;
default:
fprintf(stderr, "Invalid psy model specification: %i\n", glopts->psymodel);
return -1;
break;
}
if (glopts->quickmode == TRUE) {
// copy the smr values and reuse them later
for (ch = 0; ch < nch; ch++) {
for (sb = 0; sb < SBLIMIT; sb++)
glopts->smrdef[ch][sb] = glopts->smr[ch][sb];
}
}
}
twolame_sf_transmission_pattern(glopts, glopts->scalar, glopts->scfsi);
twolame_main_bit_allocation(glopts, glopts->smr, glopts->scfsi, glopts->bit_alloc, &adb);
twolame_write_header(glopts, bs);
// Leave space for 2 bytes of CRC to be filled in later
if (glopts->error_protection)
buffer_putbits(bs, 0, 16);
twolame_write_bit_alloc(glopts, glopts->bit_alloc, bs);
twolame_write_scalefactors(glopts, glopts->bit_alloc, glopts->scfsi, glopts->scalar, bs);
twolame_subband_quantization(glopts, glopts->scalar, *glopts->sb_sample, glopts->j_scale,
*glopts->j_sample, glopts->bit_alloc, *glopts->subband);
twolame_write_samples(glopts, *glopts->subband, glopts->bit_alloc, bs);
// If not all the bits were used, write out a stack of zeros
for (i = 0; i < adb; i++)
buffer_put1bit(bs, 0);
/* pad the current frame when needed */
if (glopts->header.padding)
// input file
buffer_putbits(bs, 0, 8);
if (glopts->do_dab) {
// Do the CRC calc for DAB stuff if required.
// It will be up to the frontend to insert it into the end of the
// previous frame.
for (i = glopts->dab_crc_len - 1; i >= 0; i--) {
twolame_dab_crc_calc(glopts, glopts->bit_alloc, glopts->scfsi, glopts->scalar,
&glopts->dab_crc[i], i);
}
}
// Allocate space for the reserved ancillary bits
for (i = 0; i < glopts->num_ancillary_bits; i++)
buffer_put1bit(bs, 0);
// Calulate the number of bits in this frame
frameBits = twolame_buffer_sstell(bs) - initial_bits;
if (frameBits % 8) { /* a program failure */
fprintf(stderr, "Sent %ld bits = %ld slots plus %ld\n", frameBits, frameBits / 8,
frameBits % 8);
fprintf(stderr, "If you are reading this, the program is broken\n");
fprintf(stderr, "email %s with the command line arguments and other info\n",
PACKAGE_BUGREPORT);
return -1;
}
// Store the energy levels at the end of the frame
if (glopts->do_energy_levels)
twolame_do_energy_levels(glopts, bs);
// MEANX: Recompute checksum from bitstream
if (glopts->error_protection) {
unsigned char *frame_ptr = bs->buf + (initial_bits >> 3);
twolame_crc_writeheader(frame_ptr, glopts->num_crc_bits);
}
/*
Encode a single frame of audio from 1152 samples
Audio samples are taken from glopts->buffer
Encoded bit stream is placed in to parameter bs
(not intended for use outside the library)
Returns the size of the frame
or -1 if there is an error
*/
static int encode_frame(twolame_options *glopts, bit_stream *bs)
{
int nch = glopts->frame.nch;
int sb, ch, adb, i;
unsigned long frameBits, initial_bits;
short sam[2][1056];
// MEANX
int head1,head2;
// /MEANX
if (!glopts->twolame_init) {
fprintf (stderr, "Please call twolame_init_params() before starting encoding.\n");
return -1;
}
// Scale and mix the input buffer
scale_and_mix_samples( glopts );
// Clear the saved audio buffer
memset ((char *) sam, 0, sizeof (sam));
/* Store the number of bits initially in the bit buffer */
initial_bits = buffer_sstell(bs);
adb = available_bits ( glopts );
/* allow the user to reserve some space at the end of the frame
This will however leave fewer bits for the audio.
Need to do a sanity check here to see that there are *some*
bits left. */
if (glopts->num_ancillary_bits > 0.6*adb) {
/* Trying to reserve more than 60% of the frame.
0.6 is arbitrary. but since most applications
probably only want to reserve a few bytes, this seems fine.
Typical frame size is about 800bytes */
fprintf(stderr,"You're trying to reserve more than 60%% of the mpeg frame for ancillary data\n");
fprintf(stderr,"This is probably an error. But I'll keep going anyway...\n");
}
adb -= glopts->num_ancillary_bits;
/* MFC 26 July 2003
Doing DAB became a bit harder in the reorganisation of the code.
Now there is no guarantee that there is more than one frame in the bitbuffer.
But DAB requires that the CRC for the *current* frame be written at the end
of the *previous* frame.
Workaround: Users (Nicholas?) wanting to implement DAB will have to do some work
in the frontend.
First: Reserve some bits for yourself (options->num_ancillary_bits)
Second: Put the encoder into "single frame mode" i.e. only read 1152 samples
per channel. (frontendoptions->singleFrameMode)
Third: When you receive each mp2 frame back from the library, you'll have to insert
the options->dabCrc[i] values into the end of the frame yourself. (DAB crc calc is
done below)
The frontend will have to keep the previous frame in memory.
As of 26July all that needs to be done is for the frontend to buffer one frame in memory, such that
the CRC for the next frame can be written in at the end of it.
*/
{
int gr, bl, ch;
/* New polyphase filter
Combines windowing and filtering. Ricardo Feb'03 */
for( gr = 0; gr < 3; gr++ )
for ( bl = 0; bl < 12; bl++ )
for ( ch = 0; ch < nch; ch++ )
window_filter_subband( &glopts->smem, &glopts->buffer[ch][gr * 12 * 32 + 32 * bl], ch,
&(*glopts->sb_sample)[ch][gr][bl][0] );
}
scalefactor_calc(*glopts->sb_sample, glopts->scalar, nch, glopts->frame.sblimit);
find_sf_max (glopts, glopts->scalar, glopts->max_sc);
if (glopts->frame.actual_mode == TWOLAME_JOINT_STEREO) {
/* this way we calculate more mono than we need */
/* but it is cheap */
combine_lr (*glopts->sb_sample, *glopts->j_sample, glopts->frame.sblimit);
scalefactor_calc (glopts->j_sample, &glopts->j_scale, 1, glopts->frame.sblimit);
}
if ((glopts->quickmode == TRUE) && (++glopts->psycount % glopts->quickcount != 0)) {
/* We're using quick mode, so we're only calculating the model every
'quickcount' frames. Otherwise, just copy the old ones across */
for (ch = 0; ch < nch; ch++) {
for (sb = 0; sb < SBLIMIT; sb++) {
glopts->smr[ch][sb] = glopts->smrdef[ch][sb];
}
}
} else {
/* calculate the psymodel */
switch (glopts->psymodel) {
case -1:
psycho_n1 (glopts, glopts->smr, nch);
break;
case 0: /* Psy Model A */
psycho_0 (glopts, glopts->smr, glopts->scalar);
break;
case 1:
psycho_1 (glopts, glopts->buffer, glopts->max_sc, glopts->smr);
break;
case 2:
psycho_2 (glopts, glopts->buffer, sam, glopts->smr );
break;
case 3:
/* Modified psy model 1 */
psycho_3 (glopts, glopts->buffer, glopts->max_sc, glopts->smr);
break;
case 4:
psycho_4 (glopts, glopts->buffer, sam, glopts->smr );
break;
default:
fprintf (stderr, "Invalid psy model specification: %i\n", glopts->psymodel);
return -1;
break;
}
if (glopts->quickmode == TRUE) {
/* copy the smr values and reuse them later */
for (ch = 0; ch < nch; ch++) {
for (sb = 0; sb < SBLIMIT; sb++) glopts->smrdef[ch][sb] = glopts->smr[ch][sb];
}
}
}
sf_transmission_pattern (glopts, glopts->scalar, glopts->scfsi);
main_bit_allocation (glopts, glopts->smr, glopts->scfsi, glopts->bit_alloc, &adb);
#if 0 //MEANX
if (glopts->error_protection)
crc_calc (glopts, glopts->bit_alloc, glopts->scfsi, &glopts->crc);
#endif
write_header (glopts, bs);
if (glopts->error_protection)
buffer_putbits (bs, glopts->crc, 16);
head1=write_bit_alloc (glopts, glopts->bit_alloc, bs);
head2=write_scalefactors(glopts, glopts->bit_alloc, glopts->scfsi, glopts->scalar, bs);
//MEANX printf("Bits: %d + %d = %d\n",head1,head2,head1+head2);
subband_quantization (glopts, glopts->scalar, *glopts->sb_sample, glopts->j_scale, *glopts->j_sample, glopts->bit_alloc,
*glopts->subband);
write_samples(glopts, *glopts->subband, glopts->bit_alloc, bs);
/* If not all the bits were used, write out a stack of zeros */
for (i = 0; i < adb; i++) buffer_put1bit (bs, 0);
/* MFC July 03
Write an extra byte for 16/24/32/48 input when padding is on.
Something must be going astray with the frame size calcs.
This fudge works fine for the moment */
if ((glopts->header.samplerate_idx != 0) && (glopts->padding)) // i.e. not a 44.1 or 22kHz input file
buffer_putbits (bs, 0, 8);
if (glopts->do_dab) {
// Do the CRC calc for DAB stuff if required.
// It will be up to the frontend to insert it into the end of the
// previous frame.
for (i=glopts->dab_crc_len-1; i>=0; i--) {
dab_crc_calc (glopts, glopts->bit_alloc, glopts->scfsi, glopts->scalar, &glopts->dab_crc[i], i);
}
}
// Allocate space for the reserved ancillary bits
for (i=0; i<glopts->num_ancillary_bits;i++)
buffer_put1bit(bs, 0);
// Calulate the number of bits in this frame
frameBits = buffer_sstell(bs) - initial_bits;
if (frameBits % 8) { /* a program failure */
fprintf (stderr, "Sent %ld bits = %ld slots plus %ld\n", frameBits, frameBits/8, frameBits%8);
fprintf (stderr, "If you are reading this, the program is broken\n");
fprintf (stderr, "email %s with the command line arguments and other info\n", PACKAGE_BUGREPORT);
return -1;
}
//fprintf(stdout,"Frame size: %li\n\n",frameBits/8);
// *** FIXME currently broken njh Sept 04
if (glopts->do_energy_levels)
do_energy_levels(glopts, bs);
// MEANX: Recompute checksum
if (glopts->error_protection)
{
unsigned char *begin=(initial_bits>>3)+bs->buf;
int protectedBits=head1+head2;
CRC_writeheader(protectedBits, begin);
}