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• Ode to the Gravis Ultrasound

  1er août 2011, par Multimedia Mike — General

  WARNING : This post is a bunch of nostalgia. Feel free to follow along if you recall the DOS days of the early-mid 1990s.

  I finally let go of my Gravis Ultrasound MAX sound card a little while ago. It felt like the end of an era for me, even though I had scarcely used the card in recent memory.

  
  
  

  The Beginning
  What is the Gravis Ultrasound ? Only the finest PC sound card from the classic DOS days. Back in the day (very early 1990s), most consumer PC sound cards were Yamaha OPL FM synthesizers paired with a basic digital to analog converter (DAC). Gravis, a company known for game controllers, dared to break with the dominant paradigm of Sound Blaster clones and create a sound card that had 32 digital channels.
  
  I heard about the GUS sometime in 1992 through one of the dominant online services at the time, Prodigy. Through the message boards, I learned of a promotion with Electronic Arts in which customers could pre-order a GUS at a certain discount along with 2 EA games from a selected catalog (with progressive discounts when ordering more games from the list). I know I got the DOS version of PowerMonger ; I think the other was Night Shift, though that doesn’t seem to be an EA title.

  Anyway, 1992 saw many maddening delays of the GUS hardware. Finally, reports of GUS shipments began to trickle into the Prodigy message forums. Then one day in November, 1992, mine arrived. Into the 286 machine it went and a valiant attempt at software installation was made. A friend and I fought with the software late into the evening, trying to make this thing work reasonably. I remember grabbing a pair of old headphones sitting near the computer that were used for an ancient (even for the time) portable radio. That was the only means of sound reproduction we had available at that moment. And it still sounded incredible.

  After graduating to progressively superior headphones, I would later return to that original pair only to feel my ears were being physically assaulted. Strange, they sounded fine that first night I was trying to make the GUS work. I guess this was my first understanding that the degree to which one is a snobby audiophile is all a matter of hard-earned experience.

  Technology
  The GUS was powered by something called a GF1 which was supposed to use a technology called wavetable synthesis. In the early days, I thought (and I wasn’t alone in this) that this meant that the GF1 chip had a bunch of digitized instrument samples stored in the ASIC. That wasn’t it.

  However, it did feature 32 digital channels at a time when most PC audio cards had 2 (plus that Yamaha FM synthesizer). There was some hemming and hawing about how the original GUS couldn’t drive all 32 channels at a full 44.1 kHz ("CD quality") playback rate. It’s true— if 14 channels were enabled, all could be played at 44.1 kHz. Enabling more channels started progressive degradation and with all 32 channels, each was only playing at around 19 kHz. Still, from my emerging game programmer perspective, that allowed for 8-channel tracker music and 6 channels of sound effects, all at the vaunted CD level of quality.

  Games and Compatibility
  The primary reason to have a discrete sound card was for entertainment applications — ahem, games. GUS support was pretty sketchy out of the gate (ostensibly a major reason for the card’s delay). While many sound cards offered Sound Blaster emulation by basically having the same hardware as Sound Blaster cards, the GUS took a software route towards emulating the SB. To do this required a program called the Sound Blaster Operating System, or SBOS.

  Oh, how awesome it was to hear the program exclaim "SBOS installed !" And how harshly it grated on your nerves after the 200th time hearing it due to so many reboots and fiddling with options to make your games work. Also, I’ve always wondered if there’s something special about sampling an ’s’ sound — does it strain the sampling frequency range ? Perhaps the phrase was sampled at too low a bitrate because the ’s’ sounds didn’t come through very clearly, which is something you notice after hundreds of iterations when there are 3 ’s’ sounds in the phrase.

  Fortunately, SBOS became less relevant with the advent of Mega-Em, a separate emulator which intercepted calls to Roland MIDI systems and routed them to the very capable GUS. Roland-supporting games sounded beautiful.

  Eventually, more and more DOS games were released with native Gravis support, sometimes with the help of The Miles Sound System (from our friends at Rad Game Tools — you know, the people behind Smacker and Bink). The library changelog is quite the trip down PC memory lane.

  An important area where the GUS shined brightly was that of demos and music trackers. The emerging PC demo scene embraced the powerful GUS (aided, no doubt, by Gravis’ sponsorship of the community) and the coolest computer art and music of the time natively supported the card.

  Programming
  At this point in my life, I was a budding programmer in high school and was fairly intent on programming video games. So far, I had figured out how to make a few blips using a borrowed Sound Blaster card. I went to great lengths to learn how to program the Gravis Ultrasound.

  Oh you kids today, with your easy access to information at the tips of your fingers thanks to Google and the broader internet. I had to track down whatever information I could find through a combination of Prodigy message boards and local dialup BBSes and FidoNet message bases. Gravis was initially tight-lipped about programming information for its powerful card, as was de rigueur of hardware companies (something that largely persists to this day). But Gravis eventually saw an opportunity to one-up encumbent Creative Labs and released a full SDK for the Ultrasound. I wanted the SDK badly.

  So it was early-mid 1993. Gravis released an SDK. I heard that it was available on their support BBS. Their BBS with a long distance phone number. If memory serves, the SDK was only in the neighborhood of 1.5 Mbytes. That takes a long time to transfer via a 2400 baud modem at a time when long distance phone charges were still a thing and not insubstantial.

  Luckily, they also put the SDK on something called an ’FTP site’. Fortunately, about this time, I had the opportunity to get some internet access via the local university.

  Indeed, my entire motivation for initially wanting to get on the internet was to obtain special programming information. Is that nerdy enough for you ?

  I see that the GUS SDK is still available via the Gravis FTP site. The file GUSDK222.ZIP is dated 1998 and is less than a megabyte.

  Next Generation : CD Support
  So I had my original GUS by the end of 1992. That was just the first iteration of the Gravis Ultrasound. The next generation was the GUS MAX. When I was ready to get into the CD-ROM era, this was what I wanted in my computer. This is because the GUS MAX had CD-ROM support. This is odd to think about now when all optical drives have SATA interfaces and (P)ATA interfaces before that— what did CD-ROM compatibility mean back then ? I wasn’t quite sure. But in early 1995, I headed over to Computer City (R.I.P.) and bought a new GUS MAX and Sony double-speed CD-ROM drive to install in the family’s PC.

  
  
  

  About the "CD-ROM compatibility" : It seems that there were numerous competing interfaces in the early days of CD-ROM technology. The GUS MAX simply integrated 3 different CD-ROM controllers onto the audio card. This was superfluous to me since the Sony drive came with an appropriate controller card anyway, though I didn’t figure out that the extra controller card was unnecessary until after I installed it. No matter ; computers of the day were rife with expansion ports.

  
  
  The 3 different CD-ROM controllers on the GUS MAX
  

  Explaining The Difference
  It was difficult to explain the difference in quality to those who didn’t really care. Sometime during 1995, I picked up a quasi-promotional CD-ROM called "The Gravis Ultrasound Experience" from Babbage’s computer store (remember when that was a thing ?). As most PC software had been distributed on floppy discs up until this point, this CD-ROM was an embarrassment of riches. Tons of game demos, scene demos, tracker music, and all the latest GUS drivers and support software.

  Further, the CD-ROM had a number of red book CD audio tracks that illustrated the difference between Sound Blaster cards and the GUS. I remember loaning this to a tech-savvy coworker who disbelieved how awesome the GUS was. The coworker took it home, listened to it, and wholly agreed that the GUS audio sounded better than the SB audio in the comparison — and was thoroughly confused because she was hearing this audio emanating from her Sound Blaster. It was the difference between real-time and pre-rendered audio, I suppose, but I failed to convey that message. I imagine the same issue comes up even today regarding real-time video rendering vs., e.g., a pre-rendered HD cinematic posted on YouTube.

  Regrettably, I can’t find that CD-ROM anymore which leads me to believe that the coworker never gave it back. Too bad, because it was quite the treasure trove.

  Aftermath
  According to folklore I’ve heard, Gravis couldn’t keep up as the world changed to Windows and failed to deliver decent drivers. Indeed, I remember trying to keep my GUS in service under Windows 95 well into 1998 but eventually relented and installed some kind of more appropriate sound card that was better supported under Windows.

  Of course, audio output capability has been standard issue for any PC for at least 10 years and many people aren’t even aware that discrete sound cards still exist. Real-time audio rendering has become less essential as full musical tracks can be composed and compressed into PCM format and delivered with the near limitless space afforded by optical storage.

  A few years ago, it was easy to pick up old GUS cards on eBay for cheap. As of this writing, there are only a few and they’re pricy (but perhaps not selling). Maybe I was just viewing during the trough of no value a few years ago.

  Nowadays, of course, anyone interested in studying the old GUS or getting a nostalgia fix need only boot up the always-excellent DOSBox emulator which provides remarkable GUS emulation support.

• SOX got nothing from SoundFlower

  12 septembre 2016, par xiaose

  For some reason on some comps SoundFlower does not catch audio.
  I.e. there are SoundFlower but when I switch input\output to the SoundFlower I cannot get any sound. I have got only not empty file without any sound.

  Okay, how I try to get the sound...

  Just FYI :

  $ system_profiler SPSoftwareDataType

  Software:
  
  
  
      System Software Overview:
  
  
  
        System Version: OS X 10.10.5 (14F1912)
  
        Kernel Version: Darwin 14.5.0
  
        Boot Volume: Macintosh HD
  
        Boot Mode: Normal
  
        Computer Name: Craig Computer
  
        User Name: Craig (craigm)
  
        Secure Virtual Memory: Enabled
  
        Time since boot: 1 day22:12

  Gonna check is AVFoundation works :

  $ ./ffmpeg -h demuxer=avfoundation

  Demuxer avfoundation [AVFoundation input device]:
  
  AVFoundation input device AVOptions:
  
    -list_devices      <int>        .D...... list available devices (from 0 to 1) (default false)
  
       true                         .D...... 
  
       false                        .D...... 
  
    -video_device_index <int>        .D...... select video device by index for devices with same name (starts at 0) (from -1 to INT_MAX) (default -1)
  
    -audio_device_index <int>        .D...... select audio device by index for devices with same name (starts at 0) (from -1 to INT_MAX) (default -1)
  
    -pixel_format          .D...... set pixel format (default yuv420p)
  
    -framerate          .D...... set frame rate (default "ntsc")
  
    -video_size         .D...... set video size
  
    -capture_cursor    <int>        .D...... capture the screen cursor (from 0 to 1) (default 0)
  
    -capture_mouse_clicks <int>        .D...... capture the screen mouse clicks (from 0 to 1) (default 0)
  
  </int></int></int></int></int>

  Gonna get list of AVFoundation audio devices :

  $ ./ffmpeg -f avfoundation -list_devices true -i ’’

  ffmpeg version 3.1.1-tessus Copyright (c) 2000-2016 the FFmpeg developers
  
    built with Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn)
  
    configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg --as=yasm --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopus --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzmq --enable-version3 --disable-ffplay --disable-indev=qtkit --disable-indev=x11grab_xcb
  
    libavutil      55. 28.100 / 55. 28.100
  
    libavcodec     57. 48.101 / 57. 48.101
  
    libavformat    57. 41.100 / 57. 41.100
  
    libavdevice    57.  0.101 / 57.  0.101
  
    libavfilter     6. 47.100 /  6. 47.100
  
    libswscale      4.  1.100 /  4.  1.100
  
    libswresample   2.  1.100 /  2.  1.100
  
    libpostproc    54.  0.100 / 54.  0.100
  
  [AVFoundation input device @ 0x7fda40421000] AVFoundation video devices:
  
  [AVFoundation input device @ 0x7fda40421000] [0] Built-in iSight
  
  [AVFoundation input device @ 0x7fda40421000] [1] Capture screen 0
  
  [AVFoundation input device @ 0x7fda40421000] AVFoundation audio devices:
  
  [AVFoundation input device @ 0x7fda40421000] [0] Soundflower (64ch)
  
  [AVFoundation input device @ 0x7fda40421000] [1] Built-in Microphone
  
  [AVFoundation input device @ 0x7fda40421000] [2] Soundflower (2ch)
  
  [AVFoundation input device @ 0x7fda40421000] [3] Built-in Input
  
  : Input/output error

  Okay, we have SoundFlower in devices :

  [AVFoundation input device @ 0x7fda40421000] [2] Soundflower (2ch)

  Then I run AppleScript which gonna switch to the "SoundFlower (2ch)" :

  enableSF("input")

  enableSF("output")

  Where enableSF(stdname) is :

  on enableSF(stdname)    
  
      tell application "System Preferences"   
  
          -- activate 
  
          tell anchor stdname of pane "com.apple.preference.sound" to reveal  
  
          tell application "System Events"    
  
              tell application process "System Preferences"   
  
                  tell tab group 1 of window 1    
  
                      delay 2 
  
                      set rowslist to selected of row of table 1 of scroll area 1 
  
                      set counter to 0    
  
                      repeat with id in rowslist  
  
                          set counter to counter + 1  
  
                          set rowName to (value of text field 1 of row counter of table 1 of scroll area 1)   
  
  
  
                          set output to stdname & " " & rowName   
  
                          set scrpt to "echo \"" & output & "\" >> ~/Desktop/ds.log"  
  
                          do shell script scrpt   
  
  
  
                          if (rowName is equal to "Soundflower (2ch)") then   
  
                              set selected of row counter of table 1 of scroll area 1 to true 
  
  
  
                              set output to "
  
                              !!! FOUND SF for " & stdname & " " & rowName    
  
                              set scrpt to "echo \"" & output & "\" >> ~/Desktop/ds.log"  
  
                              log output  
  
                              do shell script scrpt
  
                              exit repeat 
  
                          end if  
  
                      end repeat  
  
                  end tell    
  
              end tell    
  
          end tell    
  
      end tell    
  
  end enableSF    

  In result I have got this :

  input Internal Microphone
  
  input Line In
  
  input Digi CoreAudio Device
  
  input Soundflower (2ch)
  
  
  
          !!! FOUND SF for input Soundflower (2ch)
  
  
  
  output Headphones
  
  output Digi CoreAudio Device
  
  output Soundflower (2ch)
  
  
  
          !!! FOUND SF for output Soundflower (2ch)

  It means that we switch to the SoundFlower. Actually the same can be done by hands, but the script is more reliable as for me.

  Okay, next we can try to save some audio via SOX :

  $ /Applications/sox-14.3.2/sox -d /Desktop/out.wav

  Input File     : 'default' (coreaudio)
  
  Channels       : 2
  
  Sample Rate    : 44100
  
  Precision      : 32-bit
  
  Sample Encoding: 32-bit Signed Integer PCM
  
  
  
  
  
  In:0.00% 00:00:00.00 [00:00:00.00] Out:0     [      |      ]        Clip:0    
  
  ...
  
  ...
  
  ... 
  
  In:0.00% 00:00:02.51 [00:00:00.00] Out:106k  [      |      ]        Clip:0    
  
  ...
  
  ...
  
  ...
  
  In:0.00% 00:00:11.80 [00:00:00.00] Out:516k  [      |      ]        Clip:0    /Applications/sox-14.3.2/sox WARN coreaudio: coreaudio: unhandled buffer overrun.  Data discarded.
  
  ...
  
  ...
  
  ...    
  
  In:0.00% 00:00:12.35 [00:00:00.00] Out:545k  [      |      ]        Clip:0    /Applications/sox-14.3.2/sox WARN coreaudio: coreaudio: unhandled buffer overrun.  Data discarded.
  
  ...
  
  ...
  
  ...
  
  In:0.00% 00:00:13.28 [00:00:00.00] Out:582k  [      |      ]        Clip:0    
  
  Aborted.

  And, as you can see, the SOX gives me an empty file. Rather, it gives the data, but there is no sound.

  This happens on all OS from 10.10 to 10.11.6. Normal output should be this type :

  In:0.00% 00:00:00.28 [00:00:00.00] Out:8.19k [======|======]        Clip:0      
  
  ...
  
  ...
  
  ...
  
  In:0.00% 00:00:04.37 [00:00:00.00] Out:188k  [ -====|===== ] Hd:1.1 Clip:0 
  
  ...
  
  ...
  
  ...     
  
  In:0.00% 00:00:08.82 [00:00:00.00] Out:385k  [======|=====-] Hd:1.1 Clip:0      
  
  In:0.00% 00:00:09.01 [00:00:00.00] Out:393k  [-=====|=====-] Hd:1.1 Clip:0      
  
  In:0.00% 00:00:09.20 [00:00:00.00] Out:401k  [======|======] Hd:1.1 Clip:0 

• lavu,lavfi,ffmpeg : Remove experimental OpenCL API

  14 novembre 2017, par Mark Thompson

  lavu,lavfi,ffmpeg : Remove experimental OpenCL API
  This was added in early 2013 and abandoned several months later ; as far as
  
  I can tell, there are no external users.  Future OpenCL use will be via
  
  hwcontext, which requires neither special OpenCL-only API nor global state
  
  in libavutil.
  All internal users are also deleted - this is just the unsharp filter
  
  (replaced by unsharp_opencl, which is more flexible) and the deshake filter
  
  (no replacement).
  

  • [DH] configure
  • [DH] doc/APIchanges
  • [DH] doc/filters.texi
  • [DH] doc/utils.texi
  • [DH] fftools/Makefile
  • [DH] fftools/cmdutils.h
  • [DH] fftools/cmdutils_opencl.c
  • [DH] libavfilter/Makefile
  • [DH] libavfilter/allfilters.c
  • [DH] libavfilter/deshake.h
  • [DH] libavfilter/deshake_opencl.c
  • [DH] libavfilter/deshake_opencl.h
  • [DH] libavfilter/deshake_opencl_kernel.h
  • [DH] libavfilter/opencl_allkernels.c
  • [DH] libavfilter/opencl_allkernels.h
  • [DH] libavfilter/unsharp.h
  • [DH] libavfilter/unsharp_opencl.c
  • [DH] libavfilter/unsharp_opencl.h
  • [DH] libavfilter/unsharp_opencl_kernel.h
  • [DH] libavfilter/vf_deshake.c
  • [DH] libavfilter/vf_unsharp.c
  • [DH] libavutil/Makefile
  • [DH] libavutil/opencl.c
  • [DH] libavutil/opencl.h
  • [DH] libavutil/opencl_internal.c
  • [DH] libavutil/opencl_internal.h