Reflect encoder behaviour (creation of JPH files) to documentation an…

…d drop .jphc extension from encoder and decoder

README.md

@@ -93,7 +93,8 @@ To see a help, use `-h` option.
 ## Supported file types
 ### Encoder
 - input image formats: .pgm, .ppm, .pgx, .tif (libtiff required)
-- output codestreams: .j2k, .j2c, .jphc (Part 15 codestream), .jph (Part 15 file format)
+- output codestreams: .jhc (Part 15 codestream, .j2k and .j2c can be used as aliases), .jph (Part 15 file format)
+  - Note: Specifying .jph as the output triggers a JPH file creation, otherwise just a codestream will be generated.
 ### Decoder
-- input codestreams : .j2k, .j2c, .jphc
+- input codestreams : .j2k, .j2c, .jhc
 - output image formats: .raw, .ppm, .pgm, .pgx

source/apps/decoder/main_dec.cpp

@@ -47,7 +47,7 @@ void print_help(char *cmd) {
   printf("JPEG 2000 Part 1 and Part 15 decoder\n");
   printf("USAGE: %s [options]\n\n", cmd);
   printf("OPTIONS:\n");
-  printf("-i: Input file. .j2k, .j2c, .jhc, and .jphc are supported.\n");
+  printf("-i: Input file. .j2k, .j2c, and .jhc are supported.\n");
   printf("    .jp2 and .jph (box based file-format) are not supported.\n");
   printf("-o: Output file. Supported formats are PPM, PGM, PGX and RAW.\n");
   printf("-reduce n: Number of DWT resolution reduction.\n");
@@ -67,8 +67,8 @@ int main(int argc, char *argv[]) {
   }
   infile_ext_name = strrchr(infile_name, '.');
   if (strcmp(infile_ext_name, ".j2k") != 0 && strcmp(infile_ext_name, ".j2c") != 0
-      && strcmp(infile_ext_name, ".jhc") != 0 && strcmp(infile_ext_name, ".jphc") != 0) {
-    printf("ERROR: Supported extensions are .j2k, .j2c, .jhc, and .jphc\n");
+      && strcmp(infile_ext_name, ".jhc") != 0) {
+    printf("ERROR: Supported extensions are .j2k, .j2c, .jhc\n");
     exit(EXIT_FAILURE);
   }
   if (nullptr == (outfile_name = get_command_option(argc, argv, "-o"))) {

source/apps/encoder/enc_utils.hpp

@@ -37,7 +37,10 @@ void print_help(char *cmd) {
   printf("%s: JPEG 2000 Part 15 encoder\n", cmd);
   printf("USAGE: %s -i input-image(s) -o output-codestream [options...]\n\n", cmd);
   printf("-i: Input-image(s)\n  PGM, PPM, and TIFF (optional, 8 or 16 bpp only) are supported.\n");
-  printf("-o: Output codestream\n  `.jhc` or `.j2c` are recommended as the extension.\n");
+  printf(
+      "-o: Output codestream/file\n  To create a codestream, `.jhc` or `.j2c` are recommended as the "
+      "extension.\n");
+  printf("  Specifying `.jph` triggers a JPH file creation.\n");
   printf("  Note: If this option is unspecified, encoding result is placed on a memory buffer.\n\n");
   printf("OPTIONS:\n");
   printf(