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util/dtype/JFIFdt44.lha

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Showing:m68k-amigaosgeneric
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Short:fast JFIF (JPEG) picture datatype 44.13
Author:Henryk Richter, gni at gecko.de (Gunther Nikl)
Uploader:henryk richter gmx net (Henryk Richter)
Type:util/dtype
Version:44.13
Architecture:m68k-amigaos >= 3.0.0
Distribution:NoCD
Date:2020-05-18
Download:http://aminet.net/util/dtype/JFIFdt44.lha - View contents
Readme:http://aminet.net/util/dtype/JFIFdt44.readme
Downloads:1673
In this release, both the inverse discrete cosine transform
and the color transform got major improvements, both in terms
of picture quality and speed. The new iDCT utilizes the whole
32 bit integer dynamic range with careful rounding for improved 
quality and is fully aware of the DCT block sparsity to avoid 
redundant computations whenever possible. The new color transform 
operates on a 30 bit intermediate color depth. 

The quality improvements were implemented with runtime performance
in mind. Thus, jfifdt became the fastest 68k Amiga JPEG decoder in 
datatype form to date.


A performance comparison (on A4000/60 with 3.1.4 ROM, PicassoIV in
HiColor, picture.datatype 45.17 from 3.9BB2, all datatypes with
default settings; times in seconds measured as median over 5
iterations with "visage nojpeg time test") is shown below:

Name                                |akjfif  |jfif    |warpjpeg|
Version                             |45.95   |44.13   |45.14   |
------------------------------------|--------|--------|--------|
AnalogPac640x480_70_seq.jpg         |1.060   |0.802   |1.059   |
BGA1024x1024_gray.jpg               |2.926   |3.549   |2.882   |
CasaDeCampo_2592x1728_70_seq_420.jpg|10.954  |8.985   |10.365  |
CasaDeCampo_2592x1728_90_seq_444.jpg|18.324  |14.259  |18.133  |
Goose1024x768_12_baselineopt.jpg    |4.342   |3.564   |4.198   |
Molli512x384_9_seq.jpg              |0.808   |0.630   |0.779   |
Peacock800x600_10_baseline.jpg      |2.020   |1.561   |2.033   |
Sail768x576_9_seq.jpg               |1.508   |1.131   |1.476   |
Wnmde1152x768_70_422v_prog.jpg      |4.005   |3.565   |3.980   |
Wnmde1536x1024_90_422h_seq.jpg      |4.177   |3.429   |4.215   |
jordan199b.jpg                      |2.809   |2.253   |2.736   |

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

 - improved color transform accuracy and speed
 - new default iDCT algorithm with considerably more accuracy
   (actually better than the classic "slow" integer iDCT algorithm)
 - again some percent faster than the previous release 


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+ support (minimum OS3.0)
 - FBlit support
 - based on libjpeg-turbo
 - ASM optimizations to Huffman decoding, iDCT and color 
   transform (68020+)
 - 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.
   
 Vampire Amigas
 - On Vampire, the default iDCT is the AMMX fast 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



Contents of util/dtype/JFIFdt44.lha
PERMISSION  UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP     NAME
---------- ----------- ------- ------- ------ ---------- ------------ ----------
[unknown]                 1860    3781  49.2% -lh5- 57e0 May 18 20:33 jfifdt44.13/Changes.readme
[unknown]                44132   81656  54.0% -lh5- 1de8 May 18 20:45 jfifdt44.13/Classes/Datatypes-68000/jfif.datatype
[unknown]                46149   83952  55.0% -lh5- 0682 May 18 20:45 jfifdt44.13/Classes/Datatypes/jfif.datatype
[unknown]                  286     342  83.6% -lh5- 540a May 18 20:33 jfifdt44.13/Devs/Datatypes/JFIF
[unknown]                 1978    2279  86.8% -lh5- aa94 May 18 20:33 jfifdt44.13/Devs/Datatypes/JFIF.info
[unknown]                 7171   17223  41.6% -lh5- 49c0 May 18 20:38 jfifdt44.13/JFIFdt.guide
[unknown]                 1887    2299  82.1% -lh5- 8ebf May 18 20:33 jfifdt44.13/JFIFdt.guide.info
[unknown]                 1950    3984  48.9% -lh5- cf51 May 18 20:34 jfifdt44.13/JFIFdt44.readme
[unknown]               734794  734794 100.0% -lh0- c572 May 18 20:39 jfifdt44.13/Source.zip
---------- ----------- ------- ------- ------ ---------- ------------ ----------
 Total         9 files  840207  930310  90.3%            May 18 23:31

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