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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.

• Qt browser plugin with Live555 and FFMPEG

  7 mars 2014, par user1047400

  I built a widget in Qt that play a rtsp audio/video stream with Live555 and FFMPEG.
  I works and now I want to include it inside a Qt BrowserPlugin.
  My plugin at the moment is able to start the RTSP session (i can see packets start to arrive from the camera) but an error occurs and plugin stops with an error.

  Could anyone say me anything about this kind of problem ?

  The only thing that Firefox says is "anomalous plugin crash". In practice it starts for some seconds and than crashs, even if with WireShark I can see that the RTSP session is started and packets are coming from the camera to my PC.

  My .pro file is :

  QT += core
  
  QT += gui
  
  QT += multimedia
  
  
  
  CONFIG   += console
  
  CONFIG   -= app_bundle
  
  TEMPLATE = app
  
  
  
  TARGET = pluginvs
  
  
  
  win32 {
  
  RC_FILE     = pluginvs.rc
  
  } else:mac {
  
  QMAKE_INFO_PLIST = Info.plist
  
  REZ_FILES += pluginvs.r
  
  rsrc_files.files = pluginvs.rsrc
  
  rsrc_files.path = Contents/Resources
  
  QMAKE_BUNDLE_DATA += rsrc_files
  
  }
  
  
  
  SOURCES += \
  
  virtualscreen.cpp \
  
  videosink.cpp \
  
  threadlistener.cpp \
  
  rtspmanager.cpp \
  
  livetaskscheduler.cpp \
  
  audiosink.cpp \
  
  audioplayer.cpp \
  
  pluginvs.cpp
  
  
  
  HEADERS += \
  
  virtualscreen.h \
  
  videosink.h \
  
  threadlistener.h \
  
  rtspmanager.h \
  
  livetaskscheduler.h \
  
  audiosink.h \
  
  audioplayer.h
  
  
  
  include(src/qtbrowserplugin.pri)
  
  
  
  
  
  # Requied for some C99 defines
  
  DEFINES += __STDC_CONSTANT_MACROS
  
  
  
  FFMPEG_ROOT = C:/dev/ffmpeg/ffmpeg-git-059707e-win32-dev
  
  FFMPEG_LIBRARY_PATH = $$FFMPEG_ROOT/lib
  
  FFMPEG_INCLUDE_PATH = $$FFMPEG_ROOT/include
  
  LIVE555_LIBRARY_PATH = C:/dev/live/
  
  
  
  LIBS += -L$$FFMPEG_LIBRARY_PATH \
  
  $$LIVE555_LIBRARY_PATH/BasicUsageEnvironment/libBasicUsageEnvironment.a \
  
  $$LIVE555_LIBRARY_PATH/groupsock/libgroupsock.a \
  
  $$LIVE555_LIBRARY_PATH/UsageEnvironment/libUsageEnvironment.a \
  
  $$LIVE555_LIBRARY_PATH/liveMedia/libliveMedia.a \
  
  C:/MinGW/lib/libws2_32.a \
  
  -lavutil \
  
  -lavcodec \
  
  -lavformat \
  
  -lswscale
  
  
  
  INCLUDEPATH += $$FFMPEG_INCLUDE_PATH \
  
  $$LIVE555_LIBRARY_PATH/liveMedia/include \
  
  $$LIVE555_LIBRARY_PATH/BasicUsageEnvironment/include \
  
  $$LIVE555_LIBRARY_PATH/groupsock/include \
  
  $$LIVE555_LIBRARY_PATH/UsageEnvironment/include

  Thank you
   Antonio

• TV channel Identification using Linux C Programming

  2 septembre 2013, par Aditya Suku Raghav

  I need to develop an application which will identify the channel name which is currently running in the Television. I am using Easy CaP Video capturing device to take the video in from the dth set top boxes. Currently i am used ffmpeg to cut it into frames . then i used Tesseract OCR to read the image contents. It does not seems to be perfect. So i need some other method to implement that. Can any one help me on implementing this application.