What causes "%s: sorry, entropy optimization was not compiled in " in DrKLO/Telegram?

Drop -optimize (default tables will be used).

%s: sorry, entropy optimization was not compiled in

Error message

%s: sorry, entropy optimization was not compiled in

What it means

cjpeg was built without entropy-optimization support (ENTROPY_OPT_SUPPORTED undefined). The -optimize/-optimise switch (which enables optimal Huffman table generation) is therefore unavailable; cjpeg prints this message and exits with EXIT_FAILURE. Most standard libjpeg/mozjpeg builds DO define ENTROPY_OPT_SUPPORTED, so hitting this means a deliberately stripped build.

Source

Thrown at TMessagesProj/jni/mozjpeg/cjpeg.c:414

      if (sscanf(argv[argn], "%ld%c", &lval, &ch) < 1)
        usage();
      if (ch == 'm' || ch == 'M')
        lval *= 1000L;
      cinfo->mem->max_memory_to_use = lval * 1000L;

    } else if (keymatch(arg, "dc-scan-opt", 3)) {
      if (++argn >= argc) {      /* advance to next argument */
        fprintf(stderr, "%s: missing argument for dc-scan-opt\n", progname);
        usage();
      }
      jpeg_c_set_int_param(cinfo, JINT_DC_SCAN_OPT_MODE, atoi(argv[argn]));

    } else if (keymatch(arg, "optimize", 1) || keymatch(arg, "optimise", 1)) {
      /* Enable entropy parm optimization. */
#ifdef ENTROPY_OPT_SUPPORTED
      cinfo->optimize_coding = TRUE;
#else
      fprintf(stderr, "%s: sorry, entropy optimization was not compiled in\n",
              progname);
      exit(EXIT_FAILURE);
#endif

    } else if (keymatch(arg, "outfile", 4)) {
      /* Set output file name. */
      if (++argn >= argc) {      /* advance to next argument */
        fprintf(stderr, "%s: missing argument for outfile\n", progname);
        usage();
      }
      outfilename = argv[argn]; /* save it away for later use */

    } else if (keymatch(arg, "progressive", 1)) {
      /* Select simple progressive mode. */
#ifdef C_PROGRESSIVE_SUPPORTED
      simple_progressive = TRUE;
      /* We must postpone execution until num_components is known. */
#else

View on GitHub (pinned to 45ab8f4308)

Solutions

Drop -optimize (default tables will be used).
Rebuild libjpeg/mozjpeg with ENTROPY_OPT_SUPPORTED defined if optimized coding is required.

Example fix

# before
cjpeg -optimize -quality 80 in.ppm > out.jpg

# after
cjpeg -quality 80 in.ppm > out.jpg

Defensive patterns

Strategy: fallback

Validate before calling

# Probe entropy-optimization support before relying on -optimize.
if cjpeg -h 2>&1 | grep -q optimize; then
  OPT=-optimize
else
  OPT=   # fall back to default tables
fi
cjpeg $OPT -quality 80 in.ppm > out.jpg

Prevention

Do not assume -optimize is always compiled in.
Rebuild with ENTROPY_OPT_SUPPORTED if optimized Huffman tables are required.

When it happens

Trigger: Invoking `cjpeg -optimize ...` against a mozjpeg/libjpeg build compiled without ENTROPY_OPT_SUPPORTED.

Common situations: A minimal/embedded libjpeg build that disabled entropy optimization to reduce code size; a stripped vendor build.

Related errors

AI-assisted analysis of DrKLO/Telegram@45ab8f4308 (2026-08-14). Data as JSON: /api/errors/434ec3f61dc2899b. Report an issue: GitHub.