#define BUFFERSIZE 146 /* for do_output */
-/* internal globals */
typedef struct {
- unsigned int oldval;
+ unsigned int old_energy; ///< previous frame energy
/* the swapped buffers */
- unsigned int swapbuffers[4][10];
- unsigned int *swapbuf1;
- unsigned int *swapbuf2;
- unsigned int *swapbuf1alt;
- unsigned int *swapbuf2alt;
-
- unsigned int buffer[5];
- uint16_t adapt_cb[148]; //< Adaptative codebook
+ unsigned int lpc_tables[2][10];
+ unsigned int *lpc_coef; ///< LPC coefficients
+ unsigned int *lpc_coef_old; ///< previous frame LPC coefficients
+ unsigned int lpc_refl_rms;
+ unsigned int lpc_refl_rms_old;
+
+ /** the current subblock padded by the last 10 values of the previous one*/
+ int16_t curr_sblock[50];
+
+ uint16_t adapt_cb[148]; ///< adaptive codebook
} RA144Context;
static int ra144_decode_init(AVCodecContext * avctx)
{
RA144Context *ractx = avctx->priv_data;
- ractx->swapbuf1 = ractx->swapbuffers[0];
- ractx->swapbuf2 = ractx->swapbuffers[1];
- ractx->swapbuf1alt = ractx->swapbuffers[2];
- ractx->swapbuf2alt = ractx->swapbuffers[3];
+ ractx->lpc_coef = ractx->lpc_tables[0];
+ ractx->lpc_coef_old = ractx->lpc_tables[1];
return 0;
}
-/* lookup square roots in table */
+/**
+ * Evaluate sqrt(x << 24). x must fit in 20 bits. This value is evaluated in an
+ * odd way to make the output identical to the binary decoder.
+ */
static int t_sqrt(unsigned int x)
{
- int s = 0;
+ int s = 2;
while (x > 0xfff) {
s++;
x = x >> 2;
}
- return (ff_sqrt(x << 20) << s) << 2;
+ return ff_sqrt(x << 20) << s;
}
-/* 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 */
-static void rotate_block(const int16_t *source, int16_t *target, int offset)
+/**
+ * Copy the last offset values of *source to *target. If those values are not
+ * enough to fill the target buffer, fill it with another copy of those values.
+ */
+static void copy_and_dup(const int16_t *source, int16_t *target, int offset)
{
- int i=0, k=0;
source += BUFFERSIZE - offset;
- while (i<BLOCKSIZE) {
- target[i++] = source[k++];
-
- if (k == offset)
- k = 0;
+ if (offset > BLOCKSIZE) {
+ memcpy(target, source, BLOCKSIZE*sizeof(*target));
+ } else {
+ memcpy(target, source, offset*sizeof(*target));
+ memcpy(target + offset, source, (BLOCKSIZE - offset)*sizeof(*target));
}
}
v[0] = 0;
for (i=!skip_first; i<3; i++)
- v[i] = (wavtable1[n][i] * m[i]) >> (wavtable2[n][i] + 1);
+ v[i] = (gain_val_tab[n][i] * m[i]) >> (gain_exp_tab[n][i] + 1);
for (i=0; i < BLOCKSIZE; i++)
dest[i] = ((*(s1++))*v[0] + (*(s2++))*v[1] + (*(s3++))*v[2]) >> 12;
}
-
-static void final(const int16_t *i1, const int16_t *i2,
- void *out, int *statbuf, int len)
+/**
+ * LPC Filter. Each output value is predicted from the 10 previous computed
+ * ones. It overwrites the input with the output.
+ *
+ * @param in the input of the filter. It should be an array of size len + 10.
+ * The 10 first input values are used to evaluate the first filtered one.
+ */
+static void lpc_filter(const int16_t *lpc_coefs, uint16_t *in, int len)
{
int x, i;
- uint16_t work[50];
- int16_t *ptr = work;
-
- memcpy(work, statbuf,20);
- memcpy(work + 10, i2, len * 2);
+ int16_t *ptr = in;
for (i=0; i<len; i++) {
int sum = 0;
int new_val;
for(x=0; x<10; x++)
- sum += i1[9-x] * ptr[x];
+ sum += lpc_coefs[9-x] * ptr[x];
sum >>= 12;
new_val = ptr[10] - sum;
if (new_val < -32768 || new_val > 32767) {
- memset(out, 0, len * 2);
- memset(statbuf, 0, 20);
+ memset(in, 0, 100);
return;
}
ptr[10] = new_val;
ptr++;
}
+}
- memcpy(out, work+10, len * 2);
- memcpy(statbuf, work + 40, 20);
+static unsigned int rescale_rms(int rms, int energy)
+{
+ return (rms * energy) >> 10;
}
-static unsigned int rms(const int *data, int f)
+static unsigned int rms(const int *data)
{
int x;
unsigned int res = 0x10000;
if (res == 0)
return 0;
- if (res > 0x10000)
- return 0; /* We're screwed, might as well go out with a bang. :P */
-
while (res <= 0x3fff) {
b++;
res <<= 2;
res = t_sqrt(res);
res >>= (b + 10);
- res = (res * f) >> 10;
return res;
}
/* do quarter-block output */
static void do_output_subblock(RA144Context *ractx,
- const uint16_t *gsp, unsigned int gval,
- int16_t *output_buffer, GetBitContext *gb)
+ const uint16_t *lpc_coefs, unsigned int gval,
+ GetBitContext *gb)
{
uint16_t buffer_a[40];
uint16_t *block;
- int a = get_bits(gb, 7);
- int d = get_bits(gb, 8);
- int b = get_bits(gb, 7);
- int c = get_bits(gb, 7);
+ 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);
int m[3];
- if (a) {
- a += HALFBLOCK - 1;
- rotate_block(ractx->adapt_cb, buffer_a, a);
+ if (cba_idx) {
+ cba_idx += HALFBLOCK - 1;
+ copy_and_dup(ractx->adapt_cb, buffer_a, cba_idx);
m[0] = irms(buffer_a, gval) >> 12;
} else {
m[0] = 0;
}
- m[1] = ((ftable1[b] >> 4) * gval) >> 8;
- m[2] = ((ftable2[c] >> 4) * gval) >> 8;
+ m[1] = ((cb1_base[cb1_idx] >> 4) * gval) >> 8;
+ m[2] = ((cb2_base[cb2_idx] >> 4) * gval) >> 8;
memmove(ractx->adapt_cb, ractx->adapt_cb + BLOCKSIZE,
(BUFFERSIZE - BLOCKSIZE) * 2);
block = ractx->adapt_cb + BUFFERSIZE - BLOCKSIZE;
- add_wav(d, a, m, buffer_a, etable1[b], etable2[c], block);
+ add_wav(gain, cba_idx, m, buffer_a, cb1_vects[cb1_idx], cb2_vects[cb2_idx],
+ block);
+
+ memcpy(ractx->curr_sblock, ractx->curr_sblock + 40,
+ 10*sizeof(*ractx->curr_sblock));
+ memcpy(ractx->curr_sblock + 10, block,
+ BLOCKSIZE*sizeof(*ractx->curr_sblock));
- final(gsp, block, output_buffer, ractx->buffer, BLOCKSIZE);
+ lpc_filter(lpc_coefs, ractx->curr_sblock, BLOCKSIZE);
}
-static int dec1(int16_t *decsp, const int *data, const int *inp, int f)
+static void int_to_int16(int16_t *out, const int *inp)
{
int i;
for (i=0; i<30; i++)
- *(decsp++) = *(inp++);
-
- return rms(data, f);
+ *(out++) = *(inp++);
}
-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, RA144Context *ractx)
{
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 */
+ if (u + 0x1000 > 0x1fff) {
+ av_log(ractx, AV_LOG_ERROR, "Overflow. Broken sample?\n");
+ return 0;
+ }
for (c=8; c >= 0; c--) {
if (u == 0x1000)
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 interp(RA144Context *ractx, int16_t *out, 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);
+ out[x] = (a * ractx->lpc_coef[x] + b * ractx->lpc_coef_old[x])>> 2;
+
+ if (eval_refl(out, work, ractx)) {
+ // The interpolated coefficients are unstable, copy either new or old
+ // coefficients
+ if (copynew) {
+ int_to_int16(out, ractx->lpc_coef);
+ return rescale_rms(ractx->lpc_refl_rms, energy);
+ } else {
+ int_to_int16(out, ractx->lpc_coef_old);
+ return rescale_rms(ractx->lpc_refl_rms_old, energy);
+ }
+ } else {
+ return rescale_rms(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
+ unsigned int lpc_refl[10]; // LPC reflection coefficients of the frame
+ int i, c;
int16_t *data = vdata;
- unsigned int val;
+ unsigned int energy;
RA144Context *ractx = avctx->priv_data;
GetBitContext gb;
if(buf_size < 20) {
av_log(avctx, AV_LOG_ERROR,
"Frame too small (%d bytes). Truncated file?\n", buf_size);
+ *data_size = 0;
return buf_size;
}
init_get_bits(&gb, buf, 20 * 8);
for (i=0; i<10; i++)
// "<< 1"? Doesn't this make one value out of two of the table useless?
- ractx->swapbuf1[i] = decodetable[i][get_bits(&gb, sizes[i]) << 1];
+ lpc_refl[i] = lpc_refl_cb[i][get_bits(&gb, sizes[i]) << 1];
- do_voice(ractx->swapbuf1, ractx->swapbuf2);
+ eval_coefs(lpc_refl, ractx->lpc_coef);
+ ractx->lpc_refl_rms = rms(lpc_refl);
- val = decodeval[get_bits(&gb, 5) << 1]; // Useless table entries?
- a = t_sqrt(val*ractx->oldval) >> 12;
+ energy = energy_tab[get_bits(&gb, 5) << 1]; // Useless table entries?
- gbuf1[0] = dec2(gbuf2[0], ractx->swapbuf1alt, ractx->swapbuf2alt, ractx->oldval, ractx->swapbuf2, 3);
- if (ractx->oldval < val) {
- gbuf1[1] = dec2(gbuf2[1], ractx->swapbuf1, ractx->swapbuf2, a, ractx->swapbuf2alt, 2);
- } else {
- gbuf1[1] = dec2(gbuf2[1], ractx->swapbuf1alt, ractx->swapbuf2alt, a, ractx->swapbuf2, 2);
- }
- gbuf1[2] = dec2(gbuf2[2], ractx->swapbuf1, ractx->swapbuf2, val, ractx->swapbuf2alt, 3);
- gbuf1[3] = dec1(gbuf2[3], ractx->swapbuf1, ractx->swapbuf2, val);
+ refl_rms[0] = interp(ractx, block_coefs[0], 0, 0, ractx->old_energy);
+ refl_rms[1] = interp(ractx, block_coefs[1], 1, energy > ractx->old_energy,
+ t_sqrt(energy*ractx->old_energy) >> 12);
+ refl_rms[2] = interp(ractx, block_coefs[2], 2, 1, energy);
+ refl_rms[3] = rescale_rms(ractx->lpc_refl_rms, 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], &gb);
- for (i=0; i<BLOCKSIZE; i++) {
- *data = av_clip_int16(*data << 2);
- data++;
- }
+ for (i=0; i<BLOCKSIZE; i++)
+ *data++ = av_clip_int16(ractx->curr_sblock[i + 10] << 2);
}
- ractx->oldval = val;
+ ractx->old_energy = energy;
+ ractx->lpc_refl_rms_old = ractx->lpc_refl_rms;
- FFSWAP(unsigned int *, ractx->swapbuf1alt, ractx->swapbuf1);
- FFSWAP(unsigned int *, ractx->swapbuf2alt, ractx->swapbuf2);
+ FFSWAP(unsigned int *, ractx->lpc_coef_old, ractx->lpc_coef);
*data_size = 2*160;
return 20;
}
-
AVCodec ra_144_decoder =
{
"real_144",
NULL,
NULL,
ra144_decode_frame,
- .long_name = "RealAudio 1.0 (14.4K)",
+ .long_name = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"),
};