diff --git a/ChangeLog.txt b/ChangeLog.txt index 14d251ae..100eddd7 100644 --- a/ChangeLog.txt +++ b/ChangeLog.txt @@ -3,13 +3,17 @@ [1] The algorithm used by the SIMD quantization function cannot produce correct results when the JPEG quality is >= 98 and the fast integer forward DCT is -used. Thus, the non-SIMD quantization function is now used for those cases. +used. Thus, the non-SIMD quantization function is now used for those cases, +and libjpeg-turbo should now produce identical output to libjpeg v6b in all +cases. [2] Despite the above, the fast integer forward DCT still degrades somewhat for JPEG qualities greater than 95, so TurboJPEG/OSS will now automatically use the slow integer forward DCT when generating JPEG images of quality 96 or greater. This reduces compression performance by as much as 15% for these high-quality images but is necessary to ensure that the images are perceptually lossless. +It also ensures that the library can avoid the performance pitfall created by +[1]. [3] Ported jpgtest.cxx to pure C to avoid the need for a C++ compiler.