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Use TLM markers to optimize opj_decode() (on a subset of tiles)
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@rouault
rouault committed Jul 1, 2024
1 parent 206ede7 commit ed3a818
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Showing 2 changed files with 136 additions and 0 deletions.
126 changes: 126 additions & 0 deletions src/lib/openjp2/j2k.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9366,6 +9366,9 @@ void opj_j2k_destroy(opj_j2k_t *p_j2k)
opj_free(p_j2k->m_specific_param.m_decoder.m_tlm.m_tile_part_infos);
p_j2k->m_specific_param.m_decoder.m_tlm.m_tile_part_infos = NULL;

opj_free(p_j2k->m_specific_param.m_decoder.m_intersecting_tile_parts_offset);
p_j2k->m_specific_param.m_decoder.m_intersecting_tile_parts_offset = NULL;

} else {

if (p_j2k->m_specific_param.m_encoder.m_encoded_tile_data) {
Expand Down Expand Up @@ -9716,6 +9719,39 @@ OPJ_BOOL opj_j2k_read_tile_header(opj_j2k_t * p_j2k,
while ((!p_j2k->m_specific_param.m_decoder.m_can_decode) &&
(l_current_marker != J2K_MS_EOC)) {

if (p_j2k->m_specific_param.m_decoder.m_num_intersecting_tile_parts > 0 &&
p_j2k->m_specific_param.m_decoder.m_idx_intersecting_tile_parts <
p_j2k->m_specific_param.m_decoder.m_num_intersecting_tile_parts) {
OPJ_OFF_T next_tp_sot_pos;

next_tp_sot_pos =
p_j2k->m_specific_param.m_decoder.m_intersecting_tile_parts_offset[p_j2k->m_specific_param.m_decoder.m_idx_intersecting_tile_parts];
++p_j2k->m_specific_param.m_decoder.m_idx_intersecting_tile_parts;
if (!(opj_stream_read_seek(p_stream,
next_tp_sot_pos,
p_manager))) {
opj_event_msg(p_manager, EVT_ERROR, "Problem with seek function\n");
return OPJ_FALSE;
}

/* Try to read 2 bytes (the marker ID) from stream and copy them into the buffer */
if (opj_stream_read_data(p_stream,
p_j2k->m_specific_param.m_decoder.m_header_data, 2, p_manager) != 2) {
opj_event_msg(p_manager, EVT_ERROR, "Stream too short\n");
return OPJ_FALSE;
}

/* Read 2 bytes from the buffer as the marker ID */
opj_read_bytes(p_j2k->m_specific_param.m_decoder.m_header_data,
&l_current_marker,
2);

if (l_current_marker != J2K_MS_SOT) {
opj_event_msg(p_manager, EVT_ERROR, "Did not get expected SOT marker\n");
return OPJ_FALSE;
}
}

/* Try to read until the Start Of Data is detected */
while (l_current_marker != J2K_MS_SOD) {

Expand Down Expand Up @@ -11875,6 +11911,18 @@ static OPJ_BOOL opj_j2k_are_all_used_components_decoded(opj_j2k_t *p_j2k,
return OPJ_TRUE;
}

static int CompareOffT(const void* a, const void* b)
{
const OPJ_OFF_T offA = *(const OPJ_OFF_T*)a;
const OPJ_OFF_T offB = *(const OPJ_OFF_T*)b;
if (offA < offB) {
return -1;
}
if (offA == offB) {
return 0;
}
return 1;
}

static OPJ_BOOL opj_j2k_decode_tiles(opj_j2k_t *p_j2k,
opj_stream_private_t *p_stream,
Expand All @@ -11885,6 +11933,7 @@ static OPJ_BOOL opj_j2k_decode_tiles(opj_j2k_t *p_j2k,
OPJ_INT32 l_tile_x0, l_tile_y0, l_tile_x1, l_tile_y1;
OPJ_UINT32 l_nb_comps;
OPJ_UINT32 nr_tiles = 0;
OPJ_OFF_T end_pos = 0;

/* Particular case for whole single tile decoding */
/* We can avoid allocating intermediate tile buffers */
Expand Down Expand Up @@ -11927,6 +11976,77 @@ static OPJ_BOOL opj_j2k_decode_tiles(opj_j2k_t *p_j2k,
return OPJ_TRUE;
}

p_j2k->m_specific_param.m_decoder.m_num_intersecting_tile_parts = 0;
p_j2k->m_specific_param.m_decoder.m_idx_intersecting_tile_parts = 0;
opj_free(p_j2k->m_specific_param.m_decoder.m_intersecting_tile_parts_offset);
p_j2k->m_specific_param.m_decoder.m_intersecting_tile_parts_offset = NULL;

/* If the area to decode only intersects a subset of tiles, and we have
* valid TLM information, then use it to plan the tilepart offsets to
* seek to.
*/
if (!(p_j2k->m_specific_param.m_decoder.m_start_tile_x == 0 &&
p_j2k->m_specific_param.m_decoder.m_start_tile_y == 0 &&
p_j2k->m_specific_param.m_decoder.m_end_tile_x == p_j2k->m_cp.tw &&
p_j2k->m_specific_param.m_decoder.m_end_tile_y == p_j2k->m_cp.th) &&
!p_j2k->m_specific_param.m_decoder.m_tlm.m_is_invalid &&
opj_stream_has_seek(p_stream)) {
OPJ_UINT32 m_num_intersecting_tile_parts = 0;

OPJ_UINT32 j;
for (j = 0; j < p_j2k->m_cp.tw * p_j2k->m_cp.th; ++j) {
if (p_j2k->cstr_index->tile_index[j].nb_tps > 0 &&
p_j2k->cstr_index->tile_index[j].tp_index[
p_j2k->cstr_index->tile_index[j].nb_tps - 1].end_pos > end_pos) {
end_pos = p_j2k->cstr_index->tile_index[j].tp_index[
p_j2k->cstr_index->tile_index[j].nb_tps - 1].end_pos;
}
}

for (j = p_j2k->m_specific_param.m_decoder.m_start_tile_y;
j < p_j2k->m_specific_param.m_decoder.m_end_tile_y; ++j) {
OPJ_UINT32 i;
for (i = p_j2k->m_specific_param.m_decoder.m_start_tile_x;
i < p_j2k->m_specific_param.m_decoder.m_end_tile_x; ++i) {
const OPJ_UINT32 tile_number = j * p_j2k->m_cp.tw + i;
m_num_intersecting_tile_parts +=
p_j2k->cstr_index->tile_index[tile_number].nb_tps;
}
}

p_j2k->m_specific_param.m_decoder.m_intersecting_tile_parts_offset =
(OPJ_OFF_T*)
opj_malloc(m_num_intersecting_tile_parts * sizeof(OPJ_OFF_T));
if (m_num_intersecting_tile_parts > 0 &&
p_j2k->m_specific_param.m_decoder.m_intersecting_tile_parts_offset) {
OPJ_UINT32 idx = 0;
for (j = p_j2k->m_specific_param.m_decoder.m_start_tile_y;
j < p_j2k->m_specific_param.m_decoder.m_end_tile_y; ++j) {
OPJ_UINT32 i;
for (i = p_j2k->m_specific_param.m_decoder.m_start_tile_x;
i < p_j2k->m_specific_param.m_decoder.m_end_tile_x; ++i) {
const OPJ_UINT32 tile_number = j * p_j2k->m_cp.tw + i;
OPJ_UINT32 k;
for (k = 0; k < p_j2k->cstr_index->tile_index[tile_number].nb_tps; ++k) {
const OPJ_OFF_T next_tp_sot_pos =
p_j2k->cstr_index->tile_index[tile_number].tp_index[k].start_pos;
p_j2k->m_specific_param.m_decoder.m_intersecting_tile_parts_offset[idx] =
next_tp_sot_pos;
++idx;
}
}
}

p_j2k->m_specific_param.m_decoder.m_num_intersecting_tile_parts = idx;

/* Sort by increasing offset */
qsort(p_j2k->m_specific_param.m_decoder.m_intersecting_tile_parts_offset,
p_j2k->m_specific_param.m_decoder.m_num_intersecting_tile_parts,
sizeof(OPJ_OFF_T),
CompareOffT);
}
}

for (;;) {
if (p_j2k->m_cp.tw == 1 && p_j2k->m_cp.th == 1 &&
p_j2k->m_cp.tcps[0].m_data != NULL) {
Expand Down Expand Up @@ -11986,6 +12106,12 @@ static OPJ_BOOL opj_j2k_decode_tiles(opj_j2k_t *p_j2k,
if (++nr_tiles == p_j2k->m_cp.th * p_j2k->m_cp.tw) {
break;
}
if (p_j2k->m_specific_param.m_decoder.m_num_intersecting_tile_parts > 0 &&
p_j2k->m_specific_param.m_decoder.m_idx_intersecting_tile_parts ==
p_j2k->m_specific_param.m_decoder.m_num_intersecting_tile_parts) {
opj_stream_seek(p_stream, end_pos + 2, p_manager);
break;
}
}

if (! opj_j2k_are_all_used_components_decoded(p_j2k, p_manager)) {
Expand Down
10 changes: 10 additions & 0 deletions src/lib/openjp2/j2k.h
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Original file line number Diff line number Diff line change
Expand Up @@ -519,6 +519,16 @@ typedef struct opj_j2k_dec {

opj_j2k_tlm_info_t m_tlm;

/** Below if used when there's TLM information available and we use
* opj_set_decoded_area() to a subset of all tiles.
*/
/* Current index in m_intersecting_tile_parts_offset[] to seek to */
OPJ_UINT32 m_idx_intersecting_tile_parts;
/* Number of elements of m_intersecting_tile_parts_offset[] */
OPJ_UINT32 m_num_intersecting_tile_parts;
/* Start offset of contributing tile parts */
OPJ_OFF_T* m_intersecting_tile_parts_offset;

/** to tell that a tile can be decoded. */
OPJ_BITFIELD m_can_decode : 1;
OPJ_BITFIELD m_discard_tiles : 1;
Expand Down

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