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util/dtype/JFIFdt44.lha

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Short:fast JFIF (JPEG) picture datatype 44.15
Author:Henryk Richter, gni at gecko.de (Gunther Nikl)
Uploader:henryk richter gmx net (Henryk Richter)
Type:util/dtype
Version:44.15
Architecture:m68k-amigaos >= 3.0.0
Distribution:NoCD
Date:2021-08-02
Download:http://aminet.net/util/dtype/JFIFdt44.lha - View contents
Readme:http://aminet.net/util/dtype/JFIFdt44.readme
Downloads:2757

Release 44.14+ contains an overhauled Huffman decoder that is especially
tuned for high bitrate (or high quality) JPEG files. In addition, 
grayscale JPEGs are now handled with less CPU overhead. In short, the
fastest 68k Amiga JPEG datatype got faster again. The only change in
44.15 is a quick bugfix for OS3.9 picture.datatype compatibility.

A performance comparison is shown below. (on A4000 with MatzeTK060 at 50 MHz, 
3.2 ROM, PicassoIV in HiColor, picture.datatype 47.5 from OS3.2, all 
datatypes at default settings; times in seconds measured as median over 
5 iterations with "visage nojpeg time test")

Name                                |akjfif  |jfif    |warpjpeg|OS3.2   |
Version                             |45.95   |44.14   |45.15   |47.6    |
------------------------------------|--------|--------|--------|--------|
AnalogPac640x480_70_seq.jpg         |0.944   |0.624   |0.951   |0.736   |
BGA1024x1024_gray.jpg               |2.705   |2.331   |2.671   |2.607   |
CasaDeCampo_2592x1728_70_seq_420.jpg|9.334   |6.597   |9.053   |7.762   |
CasaDeCampo_2592x1728_90_seq_444.jpg|16.451  |11.322  |16.687  |13.562  |
Goose1024x768_12_baselineopt.jpg    |3.952   |2.875   |3.921   |3.632   |
Molli512x384_9_seq.jpg              |0.723   |0.493   |0.708   |0.600   |
Peacock800x600_10_baseline.jpg      |1.812   |1.240   |1.854   |1.508   |
Sail768x576_9_seq.jpg               |1.336   |0.864   |1.330   |1.040   |
Wnmde1152x768_70_422v_prog.jpg      |3.556   |2.963   |3.543   |3.309   |
Wnmde1536x1024_90_422h_seq.jpg      |3.670   |2.582   |3.727   |3.015   |
jordan199b.jpg                      |2.366   |1.627   |2.352   |1.848   |

The test images, benchmarking scripts and raw results are available
at http://bax.comlab.uni-rostock.de/fileadmin/downloads/jpegbench.zip


The datatype is an all-in-one binary for any 68020+ Amiga.
A 68000 version (without assembly optimizations) is provided as well. 


Changes in this release
 44.15:
 - fixed incompatibility with picture.datatype 45.17 (OS3.9BB2)
 44.14:
 - enabled arithmetic residual coding (not part of the JPEG standard
   last I checked, but there are some pictures on the internet using 
   this mode)
 - improvements to Huffman decoding functions
 - leverage V47 picture.datatype features for more performance
 - improvements to grayscale image handling


Feature overview

 - supports normal and progressive JFIFs with all its flavours
 - supports HAM output (HAM6 as well as HAM8)
 - switches to V43 mode if a picture.datatype V43 or newer is found
 - asynchronous file I/O to speedup image loading and decoding
 - utilizes WritePixelLine8() for chunky-to-planar in V42 mode
 - automatic colour quantizing of true-colour data for V42
 - can be configured to suit personal preferences
 - OS 3.5 and later support (minimum OS3.0)
 - FBlit support
 - based on libjpeg-turbo
 - ASM optimizations to Huffman decoding, iDCT and color 
   transform (68020+)
 - 30 bit internal resolution for color transform functions
 - Highly accurate and fast default inverse cosine transform
   function (stock libjpeg methods still available as options)
 - AMMX optimization for Apollo Core Gold 2.7 and later
 - FPU and AMMX availability is checked before use at runtime
 - support for XMP JFIF files
 - all-in-one binary for 68020+


Tuning (see also the guide file for additional options):

 Classic 68k based Amigas
 - The old fast iDCT is still about 5% faster than the new default.
   If you care more for speed than accuracy, just type 
    makedir envarc:classes
    makedir envarc:classes/datatypes
    echo "DCT=FAST" >envarc:classes/datatypes/jfif44.prefs
   in a shell window. Alternatively, a single commandline
   call is also possible:
    setenv envarc:classes/datatypes/jfif44.prefs DCT=FAST
   
 Vampire Amigas
 - On Vampire, the default iDCT is the AMMX fast, less accurate iDCT. 
   If you'd like to have the better accuracy of the new iDCT, type 
   the following lines in a shell window:
    makedir envarc:classes
    makedir envarc:classes/datatypes
    echo "DCT=FASTGOOD" >envarc:classes/datatypes/jfif44.prefs
  alternative:
    setenv envarc:classes/datatypes/jfif44.prefs DCT=FASTGOOD


Contents of util/dtype/JFIFdt44.lha
PERMISSION  UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP     NAME
---------- ----------- ------- ------- ------ ---------- ------------ ----------
[unknown]                43238   79112  54.7% -lh5- a2c6 Aug  2 09:54 jfifdt44.15/Classes/Datatypes-68000/jfif.datatype
[unknown]                45532   82968  54.9% -lh5- 6d51 Aug  2 09:54 jfifdt44.15/Classes/Datatypes/jfif.datatype
[unknown]                  286     342  83.6% -lh5- 540a Aug  2 09:54 jfifdt44.15/Devs/Datatypes/JFIF
[unknown]                 1978    2279  86.8% -lh5- aa94 Aug  2 09:54 jfifdt44.15/Devs/Datatypes/JFIF.info
[unknown]                 7270   17528  41.5% -lh5- b78f Aug  2 09:56 jfifdt44.15/JFIFdt.guide
[unknown]                 1887    2299  82.1% -lh5- 8ebf Aug  2 09:54 jfifdt44.15/JFIFdt.guide.info
[unknown]                 2119    4440  47.7% -lh5- 883f Aug  2 09:55 jfifdt44.15/JFIFdt44.readme
[unknown]               795084  795084 100.0% -lh0- eaee Aug  2 09:57 jfifdt44.15/Source.zip
---------- ----------- ------- ------- ------ ---------- ------------ ----------
 Total         8 files  897394  984052  91.2%            Aug  2 11:35

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