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• Dreamcast Archival

  24 mai 2011, par Multimedia Mike — Sega Dreamcast

  Console homebrew communities have always had a precarious relationship with console pirates. The same knowledge and skills useful for creating homebrew programs can usually be parlayed into ripping games and cajoling a console into honoring ripped copies. For this reason, the Dreamcast homebrew community tried hard to distance itself from pirates, rippers, and other unsavory characters.

  
  
  

  Funny how times change. While I toed the same line while I was marginally a part of the community back in the day, now I think I’m performing a service for video game archivists and historians by openly publishing the same information. I know of at least one solution already. But I think it’s possible to do much better.

  Pre-existing Art
  Famed Japanese game hacker BERO (FFmpeg contributors should recognize his name from a number of Dreamcast-related multimedia contributions including CRI ADX and SH-4 optimizations) crafted a program called dreamrip based on KOS’s precursor called libdream. This is the program I used to extract 4XM multimedia files from Alone in the Dark : The New Nightmare.

  Fun facts : The Sega Dreamcast used special optical discs called GD-ROMs. The GD stands for ‘GigaDisc’ which implied that they could hold roughly a gigabyte of data. How long do you think it takes to transfer that much data over a serial cable operating at 115,200 bits/second (on the order of 11 Kbytes/sec) ? I seem to recall entire discs requiring on the order of 27-28 hours to archive.

  If only I possessed some expertise in data compression which might expedite this process.

  KallistiOS’ Unwitting Help
  The KallistiOS (KOS) console-oriented RTOS provides all the software infrastructure necessary for archiving (that’s what we’ll call it in this post) Dreamcast games. KOS exposes the optical disc’s filesystem via the /cd mount point on the VFS. From there, KOS provides functions for communicating with a host computer via ethernet (broadband adapter) or serial line (DC coder’s cable). To this end, KOS exposes another mount point on the VFS named /pc which allows direct access to the host PC’s filesystem.

  Thus, it’s pretty straightforward to use KOS to access the files (or raw sectors) of the Dreamcast disc and then send them over the communication line to the host PC. Simple.

  Compressing Before Transfer
  Right away, I wonder about compiling 3 different compression libraries : libz, libbz2, and liblzma. The latter 2 are exceptionally CPU-intensive to compress. Then again, it doesn’t really matter how long the compressor takes to do its job as long as it can average better than 11 Kbytes/sec on a 200MHz Hitachi SH-4 CPU. KOS can be set up in a preemptive threading mode which means it should be possible to read sectors and compress them while keeping the UART operating at full tilt.

  A 4th compression algorithm should be in play here as well : FLAC. Since some of these discs contain red book CD audio tracks that need archival, lossless audio compression should be useful.

  This post serves as a rough overview for possible future experiments. Readers might have further brainstorms.

• x264 CLI crash while encoding [migrated]

  28 août 2011, par Ithilion

  i'm having hard time with x264 CLI encoding.
  I'm trying to encode a blu-ray source (8gb .m2ts file) into a mp4 video, but x264.exe keeps always crashing at approximately 20% progress.

  This is the Avisynth script i'm using :

  Source="C:\Ithilion\Temp\Editing\Anime\input.m2ts"
  
  V=FFVideoSource(Source,fpsnum=24000,fpsden=1001)
  
  A=FFAudioSource(Source)
  
  AudioDub(V,A)
  
  
  
  GradFun2DBmod(str=1.2)
  
  
  
  aWarpSharp2(depth=20)
  
  LimitedSharpenFaster(strength=255)
  
  
  
  TextSub("C:\Ithilion\Temp\Editing\Anime\subs1.ass")
  
  TextSub("C:\Ithilion\Temp\Editing\Anime\subs2.ass")

  These are the commands i'm using for the encode :

  x264 --profile high10 --level 5.1 --crf 23 --bframes 10 --b-adapt 2 --direct auto
  
  --me umh --merange 24 --partitions all --rc-lookahead 60 --ref 16 --subme 10 
  
  --trellis 2 --deblock -2:-2 --psy-rd 0.6:0.0 --aq-strength 1 --acodec aac 
  
  --abitrate 256 --output "output.mp4" "input.avs"

  This is the error i get :

  Name of the application that generated the error: x264.exe, Version: 0.0.0.0, time stamp: 0x4e427829
  
  Module name that generated the error: KERNELBASE.dll, Version: 6.1.7601.17651, time stamp: 0x4e211319
  
  Exception Code: 0xc00000fd
  
  Fault offset 0x0000b9bc
  
  Process ID that generated the error: 0xaac
  
  Start time of the application that generated the error: 0x01cc64e7f962548a
  
  Path to the application that generated the error: C:\Ithilion\Temp\Editing\x264\x264.exe
  
  Path of the module that generated the error: C:\Windows\syswow64\KERNELBASE.dll
  
  ID alert: a702ec4e-d0e7-11e0-b4d3-0023547ccfc5

  I'm running Win7 64 on a Q9400 @3200mHz with 4 GB RAM

  Thanks in advance for your support
  Best regards

• Mediaspip init - préfigurer GIS

  16 août 2011

  Préconfigurer le plugin Gis dans Mediaspip init à l’initialisation de MediaSPIP :

  • L’api est googlev3 ;
  • Activer le geocoder ;
  • Activer les champs d’adresse ;
  • Mettre un zoom à 2 ;
  • Mettre le point par défaut au centre de l’Europe ;