Add multithreading support in the T1 (entropy phase) encoder

- API wise, opj_codec_set_threads() can be used on the encoding side
- opj_compress has a -threads switch similar to opj_uncompress

src/bin/jp2/opj_compress.c

@@ -301,6 +301,10 @@ static void encode_help_display(void)
     fprintf(stdout, "    Currently supports only RPCL order.\n");
     fprintf(stdout, "-C <comment>\n");
     fprintf(stdout, "    Add <comment> in the comment marker segment.\n");
+    if (opj_has_thread_support()) {
+        fprintf(stdout, "  -threads <num_threads|ALL_CPUS>\n"
+                "    Number of threads to use for encoding or ALL_CPUS for all available cores.\n");
+    }
     /* UniPG>> */
 #ifdef USE_JPWL
     fprintf(stdout, "-W <params>\n");
@@ -579,7 +583,8 @@ static int parse_cmdline_encoder(int argc, char **argv,
                                  img_fol_t *img_fol, raw_cparameters_t *raw_cp, char *indexfilename,
                                  size_t indexfilename_size,
                                  int* pOutFramerate,
-                                 OPJ_BOOL* pOutPLT)
+                                 OPJ_BOOL* pOutPLT,
+                                 int* pOutNumThreads)
 {
     OPJ_UINT32 i, j;
     int totlen, c;
@@ -596,7 +601,8 @@ static int parse_cmdline_encoder(int argc, char **argv,
         {"jpip", NO_ARG, NULL, 'J'},
         {"mct", REQ_ARG, NULL, 'Y'},
         {"IMF", REQ_ARG, NULL, 'Z'},
-        {"PLT", NO_ARG, NULL, 'A'}
+        {"PLT", NO_ARG, NULL, 'A'},
+        {"threads",   REQ_ARG, NULL, 'B'}
     };
 
     /* parse the command line */
@@ -1679,6 +1685,19 @@ static int parse_cmdline_encoder(int argc, char **argv,
         }
         break;
 
+        /* ----------------------------------------------------- */
+        case 'B': { /* Number of threads */
+            if (strcmp(opj_optarg, "ALL_CPUS") == 0) {
+                *pOutNumThreads = opj_get_num_cpus();
+                if (*pOutNumThreads == 1) {
+                    *pOutNumThreads = 0;
+                }
+            } else {
+                sscanf(opj_optarg, "%d", pOutNumThreads);
+            }
+        }
+        break;
+
         /* ------------------------------------------------------ */
 
 
@@ -1860,6 +1879,7 @@ int main(int argc, char **argv)
     OPJ_FLOAT64 t = opj_clock();
 
     OPJ_BOOL PLT = OPJ_FALSE;
+    int num_threads = 0;
 
     /* set encoding parameters to default values */
     opj_set_default_encoder_parameters(&parameters);
@@ -1880,7 +1900,7 @@ int main(int argc, char **argv)
     parameters.tcp_mct = (char)
                          255; /* This will be set later according to the input image or the provided option */
     if (parse_cmdline_encoder(argc, argv, &parameters, &img_fol, &raw_cp,
-                              indexfilename, sizeof(indexfilename), &framerate, &PLT) == 1) {
+                              indexfilename, sizeof(indexfilename), &framerate, &PLT, &num_threads) == 1) {
         ret = 1;
         goto fin;
     }
@@ -2141,6 +2161,15 @@ int main(int argc, char **argv)
             }
         }
 
+        if (num_threads >= 1 &&
+                !opj_codec_set_threads(l_codec, num_threads)) {
+            fprintf(stderr, "failed to set number of threads\n");
+            opj_destroy_codec(l_codec);
+            opj_image_destroy(image);
+            ret = 1;
+            goto fin;
+        }
+
         /* open a byte stream for writing and allocate memory for all tiles */
         l_stream = opj_stream_create_default_file_stream(parameters.outfile, OPJ_FALSE);
         if (! l_stream) {

src/lib/openjp2/openjpeg.c

@@ -657,6 +657,9 @@ opj_codec_t* OPJ_CALLCONV opj_create_compress(OPJ_CODEC_FORMAT p_format)
                        const char* const*,
                        struct opj_event_mgr *)) opj_j2k_encoder_set_extra_options;
 
+        l_codec->opj_set_threads =
+            (OPJ_BOOL(*)(void * p_codec, OPJ_UINT32 num_threads)) opj_j2k_set_threads;
+
         l_codec->m_codec = opj_j2k_create_compress();
         if (! l_codec->m_codec) {
             opj_free(l_codec);
@@ -700,6 +703,9 @@ opj_codec_t* OPJ_CALLCONV opj_create_compress(OPJ_CODEC_FORMAT p_format)
                        const char* const*,
                        struct opj_event_mgr *)) opj_jp2_encoder_set_extra_options;
 
+        l_codec->opj_set_threads =
+            (OPJ_BOOL(*)(void * p_codec, OPJ_UINT32 num_threads)) opj_jp2_set_threads;
+
         l_codec->m_codec = opj_jp2_create(OPJ_FALSE);
         if (! l_codec->m_codec) {
             opj_free(l_codec);

src/lib/openjp2/openjpeg.h

@@ -1348,15 +1348,14 @@ OPJ_API OPJ_BOOL OPJ_CALLCONV opj_setup_decoder(opj_codec_t *p_codec,
  * number, or "ALL_CPUS". If OPJ_NUM_THREADS is set and this function is called,
  * this function will override the behaviour of the environment variable.
  *
- * Currently this function must be called after opj_setup_decoder() and
- * before opj_read_header().
+ * This function must be called after opj_setup_decoder() and
+ * before opj_read_header() for the decoding side, or after opj_setup_encoder()
+ * and before opj_start_compress() for the encoding side.
  *
- * Note: currently only has effect on the decompressor.
- *
- * @param p_codec       decompressor handler
+ * @param p_codec       decompressor or compressor handler
  * @param num_threads   number of threads.
  *
- * @return OPJ_TRUE     if the decoder is correctly set
+ * @return OPJ_TRUE     if the function is successful.
  */
 OPJ_API OPJ_BOOL OPJ_CALLCONV opj_codec_set_threads(opj_codec_t *p_codec,
         int num_threads);