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List:       rockbox-sf
Subject:    P#10177 Task opened by Unhelpful: core jpeg decoder (Attachment added)
From:       Rockbox <bugs () rockbox ! org>
Date:       2009-04-30 2:14:34
Message-ID: 20090430021434.7732.684147524.swift () www ! rockbox ! org
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A new Flyspray task has been opened.  Details are below. 

User who did this - Andrew Mahone (Unhelpful) 

Attached to Project - Rockbox
Summary - core jpeg decoder
Task Type - Patches
Category - WPS
Status - New
Assigned To - 
Player Type - All players
Severity - Low
Priority - Normal
Reported Version - Version 3.2
Due in Version - Undecided
Due Date - Undecided
Details - Core JPEG decoder for all targets with >1bit LCD. This is a port of the \
plugin jpeg decoder to work in core, along with some other changes. Data is read from \
disk as needed, IDCT have been split into separate horizontal and vertical passes, \
allowing different IDCT scaling on each axis, and 16-wide IDCT output is added, \
allowing for upscaling by 2x during decode (or upscaling chroma channels during IDCT \
when decoding at 1x). Output is fed to the scaler, and read_jpeg_file and \
read_jpeg_fd functions are added with call signatures identical to the similar \
functions for BMP files. Callers for these functions must pass a buffer in the struct \
bmp that is large enough for decoded image data, the struct jpeg used by the decoder, \
decode buffers (variable based on scaling and output width) and scaler buffers \
(variable based on output width). read_jpeg_file is exported in the plugin API, and a \
test_core_jpeg plugin is provided which will act as a viewer to decode and display \
one image (use the select button to exit). I have tested on images with 1x2-, 2x1-, \
2x2-, and non-subsampled chroma, as well as Y-only images and ones with varying sizes \
above or below display size and various reset marker intervals.

One or more files have been attached.

More information can be found at the following URL:
http://www.rockbox.org/tracker/task/10177


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