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• 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 666fd1300c : Added high precision transforms The high precision are only used if configured

  3 juin 2014, par Peter de Rivaz

  Changed Paths :
   Modify /configure

  
   Modify /test/dct16x16_test.cc

  
   Modify /test/dct32x32_test.cc

  
   Modify /test/fdct4x4_test.cc

  
   Modify /test/fdct8x8_test.cc

  
   Modify /test/idct8x8_test.cc

  
   Modify /test/partial_idct_test.cc

  
   Modify /vp9/common/vp9_blockd.h

  
   Modify /vp9/common/vp9_idct.c

  
   Modify /vp9/common/vp9_idct.h

  
   Modify /vp9/common/vp9_quant_common.c

  
   Modify /vp9/common/vp9_quant_common.h

  
   Modify /vp9/common/vp9_rtcd_defs.pl

  
   Modify /vp9/decoder/vp9_decodeframe.c

  
   Modify /vp9/decoder/vp9_detokenize.c

  
   Modify /vp9/encoder/vp9_block.h

  
   Modify /vp9/encoder/vp9_context_tree.c

  
   Modify /vp9/encoder/vp9_context_tree.h

  
   Modify /vp9/encoder/vp9_dct.c

  
   Modify /vp9/encoder/vp9_encodemb.c

  
   Modify /vp9/encoder/vp9_firstpass.c

  
   Modify /vp9/encoder/vp9_picklpf.c

  
   Modify /vp9/encoder/vp9_pickmode.c

  
   Modify /vp9/encoder/vp9_quantize.c

  
   Modify /vp9/encoder/vp9_ratectrl.c

  
   Modify /vp9/encoder/vp9_rdopt.c

  
   Modify /vp9/encoder/vp9_tokenize.c

  
  
  Added high precision transforms

  The high precision are only used if
  configured with —enable-high-transforms

  It gives greater precision in the transform.
  This gives PSNR improvements when encoding
  true 10 and 12 bit streams.

  At the moment, the quantizer used is shifted
  up by 2/4 for 10/12 bits so that the quantized
  coefficients fit in the current token range.

  Change-Id : Ia9c19a417cf030b8a7a889fcb3f5788bfca8215f

• Revision 91d01b8f9b4c96cfc1fb8f1139507bd608b41768 : Si le premier argument de {{{spip_connect}}} n’est pas une chaîne ...

  4 juin 2010, par Committo,Ergo:sum — Log

  Si le premier argument de spip_connect n’est pas une chaîne (normalement c’est le nom d’un fichier de connexion) assimiler systématiquement cette situation à "". Non seulement ça évite des erreurs PHP, mais ça permet à calculer_url d’être appelée avec True comme dernier argument pour forcer un calcul (...)