- for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
- ci++, compptr++) {
- prec += emit_dqt(cinfo, compptr->quant_tbl_no);
+ if (cinfo->process != JPROC_LOSSLESS) {
+ /* Emit DQT for each quantization table.
+ * Note that emit_dqt() suppresses any duplicate tables.
+ */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ prec += emit_dqt(cinfo, compptr->quant_tbl_no);
+ }
+ /* now prec is nonzero iff there are any 16-bit quant tables. */