For information, it looks like not all of libjpeg8 is actually implemented in libjpeg-turbo, ref: http://libjpeg-turbo.svn.sourceforge.net/viewvc/libjpeg-turbo/trunk/README-turbo.txt
In particular: libjpeg v7 and v8 Features: --------------------------- Fully supported: -- cjpeg: Separate quality settings for luminance and chrominance Note that the libpjeg v7+ API was extended to accommodate this feature only for convenience purposes. It has always been possible to implement this feature with libjpeg v6b (see rdswitch.c for an example.) -- libjpeg: IDCT scaling extensions in decompressor libjpeg-turbo supports IDCT scaling with scaling factors of 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, 9/8, 5/4, 11/8, 3/2, 13/8, 7/4, 15/8, and 2/1 (only 1/4 and 1/2 are SIMD-accelerated.) -- cjpeg: 32-bit BMP support -- jpegtran: lossless cropping -- jpegtran: -perfect option -- rdjpgcom: -raw option -- rdjpgcom: locale awareness Fully supported when using libjpeg v7/v8 emulation: -- libjpeg: In-memory source and destination managers Not supported: -- libjpeg: DCT scaling in compressor cinfo.scale_num and cinfo.scale_denom are silently ignored. There is no technical reason why DCT scaling cannot be supported, but without the SmartScale extension (see below), it would only be able to down-scale using ratios of 1/2, 8/15, 4/7, 8/13, 2/3, 8/11, 4/5, and 8/9, which is of limited usefulness. -- libjpeg: SmartScale cinfo.block_size is silently ignored. SmartScale is an extension to the JPEG format that allows for DCT block sizes other than 8x8. It would be difficult to support this feature while retaining backward compatibility with libjpeg v6b. -- libjpeg: Fancy downsampling in compressor cinfo.do_fancy_downsampling is silently ignored. This requires the DCT scaling feature, which is not supported. -- jpegtran: Scaling This requires both the DCT scaling and SmartScale features, which are not supported. -- Lossless RGB JPEG files This requires the SmartScale feature, which is not supported. -- To UNSUBSCRIBE, email to debian-wnpp-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/ca+7wusxopw_ak5cfd-pn2uy4rqx5fsqx5sqnzbifskroznb...@mail.gmail.com
