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02d5520c5f
The decoder gave the DSP samples with two fractional bits (sample depth 17), far fewer than any other codec. The DSP's filters are only as precise as the samples they are given: with an equalizer band at a low frequency the output was noise, or held at full scale. Scale the last stage of the synthesis filter up by 11 bits and set the sample depth to 28. On ARMv4 the bits are taken from the 64-bit sums of the dewindowing, which had them. Elsewhere the input of that stage is scaled, in its matrixing step; that is not done on ARMv4 because its multiplier takes longer for the larger operands (51.97 against 48.85 MHz below). The Coldfire path uses the C matrixing and has not been run. Seven files decoded under perfsim for the Sansa e200v1 and Clip+: shifted down again, the e200v1 output is within one step of the old output, and the Clip+ output no further from the e200v1's than before. Through a ten band equalizer with bands at 32 and 64 Hz (the filter fix of the DSP included), the noise of atrac3_lp2_132.oma falls from -64 dB to -101 dB relative to the signal. Estimated with perfsim (not measured on a device), atrac3_lp2_132.oma: e200v1 48.81 -> 48.85 MHz, Clip+ 26.91 -> 26.96 MHz. 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!