/* internal globals */
typedef struct {
- unsigned int old_energy;
+ unsigned int old_energy; ///< previous frame energy
/* the swapped buffers */
unsigned int lpc_tables[4][10];
- unsigned int *lpc_refl; //< LPC reflection coefficients
- unsigned int *lpc_coef; //< LPC coefficients
- unsigned int *lpc_refl_old; //< previous frame LPC reflection coefs
- unsigned int *lpc_coef_old; //< previous frame LPC coefficients
+ unsigned int *lpc_refl; ///< LPC reflection coefficients
+ unsigned int *lpc_coef; ///< LPC coefficients
+ unsigned int *lpc_refl_old; ///< previous frame LPC reflection coefs
+ unsigned int *lpc_coef_old; ///< previous frame LPC coefficients
unsigned int buffer[5];
- uint16_t adapt_cb[148]; //< Adaptative codebook
+ uint16_t adapt_cb[148]; ///< adaptive codebook
} RA144Context;
static int ra144_decode_init(AVCodecContext * avctx)
return (ff_sqrt(x << 20) << s) << 2;
}
-/* do 'voice' */
-static void do_voice(const int *a1, int *a2)
+/**
+ * Evaluate the LPC filter coefficients from the reflection coefficients.
+ * Does the inverse of the eval_refl() function.
+ */
+static void eval_coefs(const int *refl, int *coefs)
{
int buffer[10];
int *b1 = buffer;
- int *b2 = a2;
+ int *b2 = coefs;
int x, y;
for (x=0; x < 10; x++) {
- b1[x] = a1[x] << 4;
+ b1[x] = refl[x] << 4;
for (y=0; y < x; y++)
- b1[y] = ((a1[x] * b2[x-y-1]) >> 12) + b2[y];
+ b1[y] = ((refl[x] * b2[x-y-1]) >> 12) + b2[y];
FFSWAP(int *, b1, b2);
}
for (x=0; x < 10; x++)
- a2[x] >>= 4;
+ coefs[x] >>= 4;
}
/* rotate block */
/* do quarter-block output */
static void do_output_subblock(RA144Context *ractx,
- const uint16_t *gsp, unsigned int gval,
+ const uint16_t *lpc_coefs, unsigned int gval,
int16_t *output_buffer, GetBitContext *gb)
{
uint16_t buffer_a[40];
uint16_t *block;
- int cba_idx = get_bits(gb, 7); // Index of the adaptative CB. 0 if none.
+ int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none
int gain = get_bits(gb, 8);
int cb1_idx = get_bits(gb, 7);
int cb2_idx = get_bits(gb, 7);
add_wav(gain, cba_idx, m, buffer_a, etable1[cb1_idx], etable2[cb2_idx],
block);
- final(gsp, block, output_buffer, ractx->buffer, BLOCKSIZE);
+ final(lpc_coefs, block, output_buffer, ractx->buffer, BLOCKSIZE);
}
-static int dec1(int16_t *decsp, const int *data, const int *inp, int f)
+static void int_to_int16(int16_t *decsp, const int *inp)
{
int i;
for (i=0; i<30; i++)
*(decsp++) = *(inp++);
-
- return rms(data, f);
}
-static int eq(const int16_t *in, int *target)
+/**
+ * Evaluate the reflection coefficients from the filter coefficients.
+ * Does the inverse of the eval_coefs() function.
+ *
+ * @return 1 if one of the reflection coefficients is of magnitude greater than
+ * 4095, 0 if not.
+ */
+static int eval_refl(const int16_t *coefs, int *refl)
{
int retval = 0;
int b, c, i;
int *bp2 = buffer2;
for (i=0; i < 10; i++)
- buffer2[i] = in[i];
+ buffer2[i] = coefs[i];
- u = target[9] = bp2[9];
+ u = refl[9] = bp2[9];
if (u + 0x1000 > 0x1fff)
return 0; /* We're screwed, might as well go out with a bang. :P */
b++;
for (u=0; u<=c; u++)
- bp1[u] = ((bp2[u] - ((target[c+1] * bp2[c-u]) >> 12)) * (0x1000000 / b)) >> 12;
+ bp1[u] = ((bp2[u] - ((refl[c+1] * bp2[c-u]) >> 12)) * (0x1000000 / b)) >> 12;
- target[c] = u = bp1[c];
+ refl[c] = u = bp1[c];
if ((u + 0x1000) > 0x1fff)
retval = 1;
return retval;
}
-static int dec2(int16_t *decsp, const int *data, const int *inp,
- int f, const int *inp2, int a)
+static int dec2(RA144Context *ractx, int16_t *decsp, int block_num,
+ int copynew, int energy)
{
int work[10];
+ int a = block_num + 1;
int b = NBLOCKS - a;
int x;
+ // Interpolate block coefficients from the this frame forth block and
+ // last frame forth block
for (x=0; x<30; x++)
- decsp[x] = (a * inp[x] + b * inp2[x]) >> 2;
-
- if (eq(decsp, work))
- return dec1(decsp, data, inp, f);
- else
- return rms(work, f);
+ decsp[x] = (a * ractx->lpc_coef[x] + b * ractx->lpc_coef_old[x])>> 2;
+
+ if (eval_refl(decsp, work)) {
+ // The interpolated coefficients are unstable, copy either new or old
+ // coefficients
+ if (copynew) {
+ int_to_int16(decsp, ractx->lpc_coef);
+ return rms(ractx->lpc_refl, energy);
+ } else {
+ int_to_int16(decsp, ractx->lpc_coef_old);
+ return rms(ractx->lpc_refl_old, energy);
+ }
+ } else {
+ return rms(work, energy);
+ }
}
/* Uncompress one block (20 bytes -> 160*2 bytes) */
const uint8_t * buf, int buf_size)
{
static const uint8_t sizes[10] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2};
- unsigned int gbuf1[4];
- uint16_t gbuf2[4][30];
- unsigned int a, c;
- int i;
+ unsigned int refl_rms[4]; // RMS of the reflection coefficients
+ uint16_t block_coefs[4][30]; // LPC coefficients of each sub-block
+ int i, c;
int16_t *data = vdata;
unsigned int energy;
// "<< 1"? Doesn't this make one value out of two of the table useless?
ractx->lpc_refl[i] = decodetable[i][get_bits(&gb, sizes[i]) << 1];
- do_voice(ractx->lpc_refl, ractx->lpc_coef);
+ eval_coefs(ractx->lpc_refl, ractx->lpc_coef);
energy = decodeval[get_bits(&gb, 5) << 1]; // Useless table entries?
- a = t_sqrt(energy*ractx->old_energy) >> 12;
- gbuf1[0] = dec2(gbuf2[0], ractx->lpc_refl_old, ractx->lpc_coef_old, ractx->old_energy, ractx->lpc_coef, 3);
- if (ractx->old_energy < energy) {
- gbuf1[1] = dec2(gbuf2[1], ractx->lpc_refl, ractx->lpc_coef, a, ractx->lpc_coef_old, 2);
- } else {
- gbuf1[1] = dec2(gbuf2[1], ractx->lpc_refl_old, ractx->lpc_coef_old, a, ractx->lpc_coef, 2);
- }
- gbuf1[2] = dec2(gbuf2[2], ractx->lpc_refl, ractx->lpc_coef, energy, ractx->lpc_coef_old, 3);
- gbuf1[3] = dec1(gbuf2[3], ractx->lpc_refl, ractx->lpc_coef, energy);
+ refl_rms[0] = dec2(ractx, block_coefs[0], 0, 0, ractx->old_energy);
+ refl_rms[1] = dec2(ractx, block_coefs[1], 1, energy > ractx->old_energy,
+ t_sqrt(energy*ractx->old_energy) >> 12);
+ refl_rms[2] = dec2(ractx, block_coefs[2], 2, 1, energy);
+ refl_rms[3] = rms(ractx->lpc_refl, energy);
+
+ int_to_int16(block_coefs[3], ractx->lpc_coef);
/* do output */
for (c=0; c<4; c++) {
- do_output_subblock(ractx, gbuf2[c], gbuf1[c], data, &gb);
+ do_output_subblock(ractx, block_coefs[c], refl_rms[c], data, &gb);
for (i=0; i<BLOCKSIZE; i++) {
*data = av_clip_int16(*data << 2);
projects / ffmpeg / blobdiff