Commit 51d021bf0168ee2d6ad79f70248a88b7f57156d0
2024-06-24T12:17:22
TurboJPEG: Fix 12-bit-per-sample arith-coded compr (Regression introduced by 7bb958b732e6b4f261595e2d1527d46964fe3aed) Because of 7bb958b732e6b4f261595e2d1527d46964fe3aed, the TurboJPEG compression and encoding functions no longer transfer the value of TJPARAM_OPTIMIZE into cinfo->data_precision unless the data precision is 8. The intent of that was to prevent using_std_huff_tables() from being called more than once when reusing the same compressor object to generate multiple 12-bit-per-sample JPEG images. However, because cinfo->optimize_coding is always set to TRUE by jpeg_set_defaults() if the data precision is 12, calling applications that use 12-bit data precision had to unset cinfo->optimize_coding if they set cinfo->arith_code after calling jpeg_set_defaults(). Because of 7bb958b732e6b4f261595e2d1527d46964fe3aed, the TurboJPEG API stopped doing that except with 8-bit data precision. Thus, attempting to generate a 12-bit-per-sample arithmetic-coded lossy JPEG image using the TurboJPEG API failed with "Requested features are incompatible." Since the compressor will always fail if cinfo->arith_code and cinfo->optimize_coding are both set, and since cinfo->optimize_coding has no relevance for arithmetic coding, the most robust and user-proof solution is for jinit_c_master_control() to set cinfo->optimize_coding to FALSE if cinfo->arith_code is TRUE. This commit also: - modifies TJBench so that it no longer reports that it is using optimized baseline entropy coding in modes where that setting is irrelevant, - amends the cjpeg documentation to clarify that -optimize is implied when specifying -progressive or '-precision 12' without -arithmetic, and - prevents jpeg_set_defaults() from uselessly checking the value of cinfo->arith_code immediately after it has been set to FALSE.