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b8861e3f09
The ARMv5E dewindowing routine takes 16 of each product's bits, rounded down, so each sum of 24 products came out about 12 units low. Through the filter bank that put a dc offset of about 12 LSB (of 16 bits) on the output and, from the high band, a tone at half the sample rate; together they were four fifths of the decoder's error on these targets. Start the sums 12 up. Also correct a comment in both ARM files. Checked with perfsim (Sansa Clip+ build) against ffmpeg's decode of seven files: the dc offset goes from 11 to 12 LSB down to under 1 LSB, and the error from about -66 dBFS to -69 to -72 dBFS, the same as the ARMv4 routine gives. Decoding is 0.7% slower (26.73 to 26.91 MHz for atrac3_lp2_132.oma). The ARMv4 output is unchanged. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> |
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| android | ||
| apps | ||
| backdrops | ||
| bootloader | ||
| docs | ||
| firmware | ||
| fonts | ||
| icons | ||
| lib | ||
| manual | ||
| packaging | ||
| tools | ||
| uisimulator | ||
| utils | ||
| wps | ||
| .gitattributes | ||
| .gitignore | ||
| .gitreview | ||
__________ __ ___.
Open \______ \ ____ ____ | | _\_ |__ _______ ___
Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
\/ \/ \/ \/ \/
Build Your Own Rockbox
1. Clone 'rockbox' from git (or extract a downloaded archive).
$ git clone git://git.rockbox.org/rockbox
or
$ tar xJf rockbox.tar.xz
2. Create a build directory, preferably in the same directory as the firmware/
and apps/ directories. This is where all generated files will be written.
$ cd rockbox
$ mkdir build
$ cd build
3. Make sure you have mips/m68k/arm-elf-gcc and siblings in the PATH. Make sure
that you have 'perl' in your PATH too. Your gcc cross compiler needs to be
a particular version depending on what player you are compiling for. These
can be generated using the rockboxdev.sh script in the /tools/ folder of the
source.
$ which arm-elf-eabi-gcc
$ which perl
4. In your build directory, run the 'tools/configure' script and enter what
target you want to build for and if you want a debug version or not (and a
few more questions). It'll prompt you. The debug version is for making a
gdb version out of it. It is only useful if you run gdb towards your target
Archos.
$ ../tools/configure
5. *ploink*. Now you have got a Makefile generated for you.
6. Run 'make' and soon the necessary pieces from the firmware and the apps
directories have been compiled, linked and scrambled for you.
$ make
$ make zip
7. unzip the rockbox.zip on your music player, reboot it and
*smile*.
If you want to build for more than one target, just create several build
directories and create a setup for each target:
$ mkdir build-fuzeplus
$ cd build-fuzeplus
$ ../tools/configure
$ mkdir build-xduoox3
$ cd build-xduoox3
$ ../tools/configure
Questions anyone? Ask on the mailing list or on IRC. We'll be happy to help you!