static size_t encode_tiles(VP9_COMP *cpi, uint8_t *data_ptr) {
VP9_COMMON *const cm = &cpi->common;
vpx_writer residual_bc;
int tile_row, tile_col;
TOKENEXTRA *tok_end;
size_t total_size = 0;
const int tile_cols = 1 << cm->log2_tile_cols;
const int tile_rows = 1 << cm->log2_tile_rows;
memset(cm->above_seg_context, 0,
sizeof(*cm->above_seg_context) * mi_cols_aligned_to_sb(cm->mi_cols));
for (tile_row = 0; tile_row < tile_rows; tile_row++) {
for (tile_col = 0; tile_col < tile_cols; tile_col++) {
int tile_idx = tile_row * tile_cols + tile_col;
TOKENEXTRA *tok = cpi->tile_tok[tile_row][tile_col];
tok_end = cpi->tile_tok[tile_row][tile_col] +
cpi->tok_count[tile_row][tile_col];
if (tile_col < tile_cols - 1 || tile_row < tile_rows - 1)
vpx_start_encode(&residual_bc, data_ptr + total_size + 4);
else
vpx_start_encode(&residual_bc, data_ptr + total_size);
write_modes(cpi, &cpi->tile_data[tile_idx].tile_info,
&residual_bc, &tok, tok_end);
assert(tok == tok_end);
vpx_stop_encode(&residual_bc);
if (tile_col < tile_cols - 1 || tile_row < tile_rows - 1) {
// size of this tile
mem_put_be32(data_ptr + total_size, residual_bc.pos);
total_size += 4;
}
total_size += residual_bc.pos;
}
}
return total_size;
}
void encode_with_adaptive_probability() {
memcpy(tmp, uncompressed, sizeof(uncompressed));
(*transform)(tmp); // this currently is a no-op but it may be helpful for the EXERCISE
DynProb encode;
vpx_writer wri ={0};
vpx_start_encode(&wri, tmp);
for (size_t i = 0; i < sizeof(uncompressed); ++i) {
for(int bit = 1; bit < 256; bit <<= 1) {
bool cur_bit = !!(tmp[i] & bit);
vpx_write(&wri, cur_bit, encode.prob);
encode.record_bit(cur_bit); // <-- this a new line for lesson1 that lets the encoder adapt to data
}
}
vpx_stop_encode(&wri);
printf("Buffer encoded with final prob(0) = %.2f results in %d size (%.2f%%)\n",
encode.prob / 255.,
wri.pos,
100 * wri.pos / float(sizeof(uncompressed)));
DynProb decode;
vpx_reader rea={0};
vpx_reader_init(&rea,
wri.buffer,
wri.pos);
memset(roundtrip, 0, sizeof(roundtrip));
for (size_t i = 0; i < sizeof(roundtrip); ++i) {
for(int bit = 1; bit < 256; bit <<= 1) {
if (vpx_read(&rea, decode.prob)) {
roundtrip[i] |= bit;
decode.record_bit(true); // <-- this a new line for lesson1
} else {
decode.record_bit(false); // <-- this a new line for lesson1
}
}
}
assert(vpx_reader_has_error(&rea) == 0);
(*untransform)(uncompressed); // this is, again a no-op, but may be helpful for the EXERCISE
assert(memcmp(uncompressed, roundtrip, sizeof(uncompressed)) == 0);
}
static size_t write_compressed_header(VP9_COMP *cpi, uint8_t *data) {
VP9_COMMON *const cm = &cpi->common;
MACROBLOCKD *const xd = &cpi->td.mb.e_mbd;
FRAME_CONTEXT *const fc = cm->fc;
FRAME_COUNTS *counts = cpi->td.counts;
vpx_writer header_bc;
vpx_start_encode(&header_bc, data);
if (xd->lossless)
cm->tx_mode = ONLY_4X4;
else
encode_txfm_probs(cm, &header_bc, counts);
update_coef_probs(cpi, &header_bc);
update_skip_probs(cm, &header_bc, counts);
if (!frame_is_intra_only(cm)) {
int i;
for (i = 0; i < INTER_MODE_CONTEXTS; ++i)
prob_diff_update(vp9_inter_mode_tree, cm->fc->inter_mode_probs[i],
counts->inter_mode[i], INTER_MODES, &header_bc);
if (cm->interp_filter == SWITCHABLE)
update_switchable_interp_probs(cm, &header_bc, counts);
for (i = 0; i < INTRA_INTER_CONTEXTS; i++)
vp9_cond_prob_diff_update(&header_bc, &fc->intra_inter_prob[i],
counts->intra_inter[i]);
if (cpi->allow_comp_inter_inter) {
const int use_compound_pred = cm->reference_mode != SINGLE_REFERENCE;
const int use_hybrid_pred = cm->reference_mode == REFERENCE_MODE_SELECT;
vpx_write_bit(&header_bc, use_compound_pred);
if (use_compound_pred) {
vpx_write_bit(&header_bc, use_hybrid_pred);
if (use_hybrid_pred)
for (i = 0; i < COMP_INTER_CONTEXTS; i++)
vp9_cond_prob_diff_update(&header_bc, &fc->comp_inter_prob[i],
counts->comp_inter[i]);
}
}
if (cm->reference_mode != COMPOUND_REFERENCE) {
for (i = 0; i < REF_CONTEXTS; i++) {
vp9_cond_prob_diff_update(&header_bc, &fc->single_ref_prob[i][0],
counts->single_ref[i][0]);
vp9_cond_prob_diff_update(&header_bc, &fc->single_ref_prob[i][1],
counts->single_ref[i][1]);
}
}
if (cm->reference_mode != SINGLE_REFERENCE)
for (i = 0; i < REF_CONTEXTS; i++)
vp9_cond_prob_diff_update(&header_bc, &fc->comp_ref_prob[i],
counts->comp_ref[i]);
for (i = 0; i < BLOCK_SIZE_GROUPS; ++i)
prob_diff_update(vp9_intra_mode_tree, cm->fc->y_mode_prob[i],
counts->y_mode[i], INTRA_MODES, &header_bc);
for (i = 0; i < PARTITION_CONTEXTS; ++i)
prob_diff_update(vp9_partition_tree, fc->partition_prob[i],
counts->partition[i], PARTITION_TYPES, &header_bc);
vp9_write_nmv_probs(cm, cm->allow_high_precision_mv, &header_bc,
&counts->mv);
}
vpx_stop_encode(&header_bc);
assert(header_bc.pos <= 0xffff);
return header_bc.pos;
}
