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• libavcodec : Implementation of 32 bit fixed point FFT

  3 juin 2013, par Nedeljko Babic

  libavcodec : Implementation of 32 bit fixed point FFT
  Iterative implementation of 32 bit fixed point split-radix FFT.
  
  Max FFT that can be calculated currently is 2^12.
  Signed-off-by : Nedeljko Babic <nbabic@mips.com>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] doc/mips.txt
  • [DH] libavcodec/Makefile
  • [DH] libavcodec/fft-fixed32-test.c
  • [DH] libavcodec/fft-internal.h
  • [DH] libavcodec/fft-test.c
  • [DH] libavcodec/fft.c
  • [DH] libavcodec/fft.h
  • [DH] libavcodec/fft_fixed.c
  • [DH] libavcodec/fft_fixed_32.c
  • [DH] libavcodec/fft_float.c
  • [DH] libavcodec/fft_init_table.c
  • [DH] libavcodec/fft_table.h
  • [DH] libavcodec/mdct.c
  • [DH] libavcodec/mdct_fixed.c
  • [DH] libavcodec/mdct_fixed_32.c
  • [DH] libavcodec/mdct_float.c
  • [DH] libavcodec/mips/Makefile
  • [DH] libavcodec/mips/fft_mips.c
  • [DH] tests/fate/fft.mak

• Revisiting the Belco Alpha-400

  26 août 2010, par Multimedia Mike — General

  Relieved of the primary FATE maintenance duties, I decided to dust off my MIPS-based Belco Alpha-400 and try to get it doing FATE cycles. And just as I was about to get FATE running, I saw that Mans already got his MIPS-based Popcorn Hour device to run FATE. But here are my notes anyway.

  
  
  

  Getting A Prompt
  For my own benefit, I made a PDF to remind me precisely how to get a root prompt on the Alpha-400. The ‘jailbreak’ expression seems a little juvenile to me, but it seems to be in vogue right now.

  alpha-400-jailbreak.pdf

  Toolchain
  When I last tinkered with the Alpha-400, I was trying to build a toolchain that could build binaries to run on the unit’s MIPS chip, to no avail. Sometime last year, MichaelK put together x86_32-hosted toolchains that are able to build mipsel 32-bit binaries for Linux 2.4 and 2.6. The Alpha-400 uses a 2.4 kernel and the corresponding toolchain works famously for building current FFmpeg (--disable-devices is necessary for building).

  FATE Samples
  Next problem : Making the FATE suite available to the Alpha-400. I copied all of the FATE suite samples onto a VFAT-formatted SD card. The filename case is not preserved for all files which confounds me since it is preserved in other cases. I tried formatting the card for ext3 but the Alpha-400 would not mount it, even though /proc/filesystems lists ext3 (supporting an older version of ext3 ?).

  Alternative : Copy all of the FATE samples to the device’s rootfs. Space will be a little tight, though. Then again, there is over 600 MB of space free ; I misread earlier and thought there were only 300 MB free.

  Remote Execution
  To perform FATE cycles on a remote device, it helps to be able to SSH into that remote device. I don’t even want to know how complicated it would be to build OpenSSH for the device. However, the last time I brought up this topic, I learned about a lighter weight SSH replacement called Dropbear. It turns out that Dropbear runs great on this MIPS computer.

  Running FATE Remotely
  I thought all the pieces would be in place to run FATE at this point. However, there is one more issue : Running FATE on a remote system requires that the host and the target are sharing a filesystem somehow. My personal favorite remote filesystem method is sshfs which is supposed to work wherever there is an SSH server. That’s not entirely true, though– sshfs also requires sftp-server to be installed on the server side, a program that Dropbear does not currently provide.

  I’m not even going to think about getting Samba or NFS server software installed on the Alpha-400. According to the unit’s /proc/filesystems file, nfs is a supported filesystem. I hate setting up NFS but may see if I can get that working anyway.

  Residual Weirdness
  The unit comes with the venerable Busybox program (BusyBox v1.4.1 (2007-06-01 20:37:18 CST) multi-call binary) for most of its standard command line utilities. I noticed a quirk where BusyBox’s md5sum gives weird hex characters. This might be a known/fixed issue.

  Another item is that the Alpha-400′s /dev/null file only has rwxr-xr-x per default. This caused trouble when I first tried to scp using Dropbear using a newly-created, unprivileged user.

• Revision 827e22c732 : unset executable bit on source code Change-Id : I0ddc849495c34f44c0b315cd7d58ad3

  13 juillet 2012, par John Koleszar

  Changed Paths : Modify /vp8/common/mips/dspr2/dequantize_dspr2.c Modify /vp8/common/mips/dspr2/filter_dspr2.c Modify /vp8/common/mips/dspr2/idct_blk_dspr2.c Modify /vp8/common/mips/dspr2/idctllm_dspr2.c Modify /vp8/common/mips/dspr2/loopfilter_filters_dspr2.c (...)