initial_setup (j_compress_ptr cinfo, boolean transcode_only)
/* Do computations that are needed before master selection phase */
{
int ci;
jpeg_component_info *compptr;
long samplesperrow;
JDIMENSION jd_samplesperrow;
#if JPEG_LIB_VERSION >= 70
#if JPEG_LIB_VERSION >= 80
if (!transcode_only)
#endif
jpeg_calc_jpeg_dimensions(cinfo);
#endif
/* Sanity check on image dimensions */
if (cinfo->_jpeg_height <= 0 || cinfo->_jpeg_width <= 0
|| cinfo->num_components <= 0 || cinfo->input_components <= 0)
ERREXIT(cinfo, JERR_EMPTY_IMAGE);
/* Make sure image isn't bigger than I can handle */
if ((long) cinfo->_jpeg_height > (long) JPEG_MAX_DIMENSION ||
(long) cinfo->_jpeg_width > (long) JPEG_MAX_DIMENSION)
ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
/* Width of an input scanline must be representable as JDIMENSION. */
samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
jd_samplesperrow = (JDIMENSION) samplesperrow;
if ((long) jd_samplesperrow != samplesperrow)
ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
/* For now, precision must match compiled-in value... */
if (cinfo->data_precision != BITS_IN_JSAMPLE)
ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
/* Check that number of components won't exceed internal array sizes */
if (cinfo->num_components > MAX_COMPONENTS)
ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
MAX_COMPONENTS);
/* Compute maximum sampling factors; check factor validity */
cinfo->max_h_samp_factor = 1;
cinfo->max_v_samp_factor = 1;
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
ci++, compptr++) {
if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
ERREXIT(cinfo, JERR_BAD_SAMPLING);
cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
compptr->h_samp_factor);
cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
compptr->v_samp_factor);
}
/* Compute dimensions of components */
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
ci++, compptr++) {
/* Fill in the correct component_index value; don't rely on application */
compptr->component_index = ci;
/* For compression, we never do DCT scaling. */
#if JPEG_LIB_VERSION >= 70
compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = DCTSIZE;
#else
compptr->DCT_scaled_size = DCTSIZE;
#endif
/* Size in DCT blocks */
compptr->width_in_blocks = (JDIMENSION)
jdiv_round_up((long) cinfo->_jpeg_width * (long) compptr->h_samp_factor,
(long) (cinfo->max_h_samp_factor * DCTSIZE));
compptr->height_in_blocks = (JDIMENSION)
jdiv_round_up((long) cinfo->_jpeg_height * (long) compptr->v_samp_factor,
(long) (cinfo->max_v_samp_factor * DCTSIZE));
/* Size in samples */
compptr->downsampled_width = (JDIMENSION)
jdiv_round_up((long) cinfo->_jpeg_width * (long) compptr->h_samp_factor,
(long) cinfo->max_h_samp_factor);
compptr->downsampled_height = (JDIMENSION)
jdiv_round_up((long) cinfo->_jpeg_height * (long) compptr->v_samp_factor,
(long) cinfo->max_v_samp_factor);
/* Mark component needed (this flag isn't actually used for compression) */
compptr->component_needed = TRUE;
}
/* Compute number of fully interleaved MCU rows (number of times that
* main controller will call coefficient controller).
*/
cinfo->total_iMCU_rows = (JDIMENSION)
jdiv_round_up((long) cinfo->_jpeg_height,
(long) (cinfo->max_v_samp_factor*DCTSIZE));
}
initial_setup (j_compress_ptr cinfo, boolean transcode_only)
/* Do computations that are needed before master selection phase */
{
int ci, ssize;
jpeg_component_info *compptr;
long samplesperrow;
JDIMENSION jd_samplesperrow;
if (transcode_only)
jpeg_calc_trans_dimensions(cinfo);
else
jpeg_calc_jpeg_dimensions(cinfo);
/* Sanity check on image dimensions */
if (cinfo->jpeg_height <= 0 || cinfo->jpeg_width <= 0 ||
cinfo->num_components <= 0 || cinfo->input_components <= 0)
ERREXIT(cinfo, JERR_EMPTY_IMAGE);
/* Make sure image isn't bigger than I can handle */
if ((long) cinfo->jpeg_height > (long) JPEG_MAX_DIMENSION ||
(long) cinfo->jpeg_width > (long) JPEG_MAX_DIMENSION)
ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
/* Width of an input scanline must be representable as JDIMENSION. */
samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
jd_samplesperrow = (JDIMENSION) samplesperrow;
if ((long) jd_samplesperrow != samplesperrow)
ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
/* For now, precision must match compiled-in value... */
if (cinfo->data_precision != BITS_IN_JSAMPLE)
ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
/* Check that number of components won't exceed internal array sizes */
if (cinfo->num_components > MAX_COMPONENTS)
ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
MAX_COMPONENTS);
/* Compute maximum sampling factors; check factor validity */
cinfo->max_h_samp_factor = 1;
cinfo->max_v_samp_factor = 1;
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
ci++, compptr++) {
if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
ERREXIT(cinfo, JERR_BAD_SAMPLING);
cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
compptr->h_samp_factor);
cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
compptr->v_samp_factor);
}
/* Compute dimensions of components */
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
ci++, compptr++) {
/* Fill in the correct component_index value; don't rely on application */
compptr->component_index = ci;
/* In selecting the actual DCT scaling for each component, we try to
* scale down the chroma components via DCT scaling rather than downsampling.
* This saves time if the downsampler gets to use 1:1 scaling.
* Note this code adapts subsampling ratios which are powers of 2.
*/
ssize = 1;
#ifdef DCT_SCALING_SUPPORTED
while (cinfo->min_DCT_h_scaled_size * ssize <=
(cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
(cinfo->max_h_samp_factor % (compptr->h_samp_factor * ssize * 2)) == 0) {
ssize = ssize * 2;
}
#endif
compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size * ssize;
ssize = 1;
#ifdef DCT_SCALING_SUPPORTED
while (cinfo->min_DCT_v_scaled_size * ssize <=
(cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
(cinfo->max_v_samp_factor % (compptr->v_samp_factor * ssize * 2)) == 0) {
ssize = ssize * 2;
}
#endif
compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size * ssize;
/* We don't support DCT ratios larger than 2. */
if (compptr->DCT_h_scaled_size > compptr->DCT_v_scaled_size * 2)
compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size * 2;
else if (compptr->DCT_v_scaled_size > compptr->DCT_h_scaled_size * 2)
compptr->DCT_v_scaled_size = compptr->DCT_h_scaled_size * 2;
/* Size in DCT blocks */
compptr->width_in_blocks = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_width * (long) compptr->h_samp_factor,
(long) (cinfo->max_h_samp_factor * cinfo->block_size));
compptr->height_in_blocks = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_height * (long) compptr->v_samp_factor,
(long) (cinfo->max_v_samp_factor * cinfo->block_size));
/* Size in samples */
compptr->downsampled_width = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_width *
(long) (compptr->h_samp_factor * compptr->DCT_h_scaled_size),
(long) (cinfo->max_h_samp_factor * cinfo->block_size));
compptr->downsampled_height = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_height *
(long) (compptr->v_samp_factor * compptr->DCT_v_scaled_size),
(long) (cinfo->max_v_samp_factor * cinfo->block_size));
/* Mark component needed (this flag isn't actually used for compression) */
compptr->component_needed = TRUE;
}
/* Compute number of fully interleaved MCU rows (number of times that
* main controller will call coefficient controller).
*/
cinfo->total_iMCU_rows = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_height,
(long) (cinfo->max_v_samp_factor * cinfo->block_size));
}
