void VP8PutSignedValue(VP8BitWriter* const bw, int value, int nb_bits) {
if (!VP8PutBitUniform(bw, value != 0))
return;
if (value < 0) {
VP8PutValue(bw, ((-value) << 1) | 1, nb_bits + 1);
} else {
VP8PutValue(bw, value << 1, nb_bits + 1);
}
}
void VP8WriteProbas(VP8BitWriter* const bw, const VP8Proba* const probas) {
int t, b, c, p;
for (t = 0; t < NUM_TYPES; ++t) {
for (b = 0; b < NUM_BANDS; ++b) {
for (c = 0; c < NUM_CTX; ++c) {
for (p = 0; p < NUM_PROBAS; ++p) {
const uint8_t p0 = probas->coeffs_[t][b][c][p];
const int update = (p0 != VP8CoeffsProba0[t][b][c][p]);
if (VP8PutBit(bw, update, VP8CoeffsUpdateProba[t][b][c][p])) {
VP8PutBits(bw, p0, 8);
}
}
}
}
}
if (VP8PutBitUniform(bw, probas->use_skip_proba_)) {
VP8PutBits(bw, probas->skip_proba_, 8);
}
}
static int PutCoeffs(VP8BitWriter* const bw, int ctx, const VP8Residual* res) {
int n = res->first;
// should be prob[VP8EncBands[n]], but it's equivalent for n=0 or 1
const uint8_t* p = res->prob[n][ctx];
if (!VP8PutBit(bw, res->last >= 0, p[0])) {
return 0;
}
while (n < 16) {
const int c = res->coeffs[n++];
const int sign = c < 0;
int v = sign ? -c : c;
if (!VP8PutBit(bw, v != 0, p[1])) {
p = res->prob[VP8EncBands[n]][0];
continue;
}
if (!VP8PutBit(bw, v > 1, p[2])) {
p = res->prob[VP8EncBands[n]][1];
} else {
if (!VP8PutBit(bw, v > 4, p[3])) {
if (VP8PutBit(bw, v != 2, p[4]))
VP8PutBit(bw, v == 4, p[5]);
} else if (!VP8PutBit(bw, v > 10, p[6])) {
if (!VP8PutBit(bw, v > 6, p[7])) {
VP8PutBit(bw, v == 6, 159);
} else {
VP8PutBit(bw, v >= 9, 165);
VP8PutBit(bw, !(v & 1), 145);
}
} else {
int mask;
const uint8_t* tab;
if (v < 3 + (8 << 1)) { // VP8Cat3 (3b)
VP8PutBit(bw, 0, p[8]);
VP8PutBit(bw, 0, p[9]);
v -= 3 + (8 << 0);
mask = 1 << 2;
tab = VP8Cat3;
} else if (v < 3 + (8 << 2)) { // VP8Cat4 (4b)
VP8PutBit(bw, 0, p[8]);
VP8PutBit(bw, 1, p[9]);
v -= 3 + (8 << 1);
mask = 1 << 3;
tab = VP8Cat4;
} else if (v < 3 + (8 << 3)) { // VP8Cat5 (5b)
VP8PutBit(bw, 1, p[8]);
VP8PutBit(bw, 0, p[10]);
v -= 3 + (8 << 2);
mask = 1 << 4;
tab = VP8Cat5;
} else { // VP8Cat6 (11b)
VP8PutBit(bw, 1, p[8]);
VP8PutBit(bw, 1, p[10]);
v -= 3 + (8 << 3);
mask = 1 << 10;
tab = VP8Cat6;
}
while (mask) {
VP8PutBit(bw, !!(v & mask), *tab++);
mask >>= 1;
}
}
p = res->prob[VP8EncBands[n]][2];
}
VP8PutBitUniform(bw, sign);
if (n == 16 || !VP8PutBit(bw, n <= res->last, p[0])) {
return 1; // EOB
}
}
return 1;
}
void VP8PutValue(VP8BitWriter* const bw, int value, int nb_bits) {
int mask;
for (mask = 1 << (nb_bits - 1); mask; mask >>= 1)
VP8PutBitUniform(bw, value & mask);
}
