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• Capturing video over USB/HDMI/Thunderbolt

  12 novembre 2016, par Yatko

  Looking for a solution for capturing video over USB/HDMI/Thunderbolt from a digital output (e.g. digital camera) to a computer, Mac and/or Windows.

  The goal is to have an URL to a real-time video stream (e.g. IP/PATH/ ?.mp4) that we can further process/transcode/send to a media server.

  I’m looking for tips and ideas -similar to the method below-, maybe someone met a new project that’s focusing on capture-cards and devices, that does’n need a custom FFmpeg build. Something different.

  • we can capture the HDMI stream form a GoPro, using a Blackmagic Intensity Shuttle and DeckLink SDK with custom FFmpeg build using --extra-cflags and --extra-ldflags and the rest is straightforward

  Is there any tool, open-source project, something that’s made for this purpose ? Maybe something that also supports the Elgato Game Capture HD60 as well ? Any experimental projects for capturing and processing the incoming video over USB/HDMI/Thunderbolt ?

  The ultimate goal is live streaming to Wowza, using Cameleon live and a Sony Alpha a7S.

• Java - Stream OpenGL Display to Android

  24 octobre 2016, par Intektor

  I tried to solve this problem for days now, but I couldn’t find a working solution. I am trying to stream my game screen (lwjgl) to my android smartphone(I have a frame buffer with the texture), and I already built a fully working packet system and all that stuff. But there are several problem I have no idea how to solve them, first of all, I don’t know in which format I should send the frame buffer, e.g I can’t send it as a Buffered Image, because it doesn’t exist on android. I tried using the jcodec library, but there is no documentation for it, and I didn’t find any examples that fit my case. I think I have to encode and decode it with h264 to make it a realtime live stream(that’s very important). I also heard about ffmpeg (and I found a java library for it : https://github.com/bramp/ffmpeg-cli-wrapper) but there is again no documentation for how to use it to stream it to my mobile. Also I have the problem, that when would get the frames to my smartphone, how can I make them load by the graphics card

  Here is what I have done so far :
  My packet :

  public class ImagePacketToClient implements Packet {
  
  
  
  public byte[] jpgInfo;
  
  public int width;
  
  public int height;
  
  
  
  BufferedImage image;
  
  
  
  public ImagePacketToClient() {
  
  }
  
  
  
  public ImagePacketToClient(BufferedImage image, int width, int height) {
  
      this.image = image;
  
      this.width = width;
  
      this.height = height;
  
  }
  
  
  
  @Override
  
  public void write(DataOutputStream out) throws IOException {
  
      ByteArrayOutputStream baos = new ByteArrayOutputStream();
  
      ImageIO.write(image, "jpg", baos);
  
      baos.flush();
  
      byte[] bytes = baos.toByteArray();
  
      baos.close();
  
      out.writeInt(bytes.length);
  
      for (byte aByte : bytes) {
  
          out.writeInt(aByte);
  
      }
  
  }
  
  
  
  @Override
  
  public void read(DataInputStream in) throws IOException {
  
      int length = in.readInt();
  
      jpgInfo = new byte[length];
  
      for (int i = 0; i < length; i++) {
  
          jpgInfo[i] = in.readByte();
  
      }
  
  }

  The code that gets called after the rendering has finished : mc.framebuffer is the frame buffer I can use :

  ScaledResolution resolution = new ScaledResolution(mc);
  
              BufferedImage screenshot = ScreenShotHelper.createScreenshot(resolution.getScaledWidth(), resolution.getScaledHeight(), mc.getFramebuffer());
  
              ImagePacketToClient packet = new ImagePacketToClient(screenshot, screenshot.getWidth(), screenshot.getHeight());
  
              PacketHelper.sendPacket(packet, CardboardMod.communicator.connectedSocket);
  
              screenshot.flush();
  
  
  
  public static BufferedImage createScreenshot(int width, int height, Framebuffer framebufferIn)
  
  {
  
      if (OpenGlHelper.isFramebufferEnabled())
  
      {
  
          width = framebufferIn.framebufferTextureWidth;
  
          height = framebufferIn.framebufferTextureHeight;
  
      }
  
  
  
      int i = width * height;
  
  
  
      if (pixelBuffer == null || pixelBuffer.capacity() < i)
  
      {
  
          pixelBuffer = BufferUtils.createIntBuffer(i);
  
          pixelValues = new int[i];
  
      }
  
  
  
      GlStateManager.glPixelStorei(3333, 1);
  
      GlStateManager.glPixelStorei(3317, 1);
  
      pixelBuffer.clear();
  
  
  
      if (OpenGlHelper.isFramebufferEnabled())
  
      {
  
          GlStateManager.bindTexture(framebufferIn.framebufferTexture);
  
          GlStateManager.glGetTexImage(3553, 0, 32993, 33639, pixelBuffer);
  
      }
  
      else
  
      {
  
          GlStateManager.glReadPixels(0, 0, width, height, 32993, 33639, pixelBuffer);
  
      }
  
  
  
      pixelBuffer.get(pixelValues);
  
      TextureUtil.processPixelValues(pixelValues, width, height);
  
      BufferedImage bufferedimage;
  
  
  
      if (OpenGlHelper.isFramebufferEnabled())
  
      {
  
          bufferedimage = new BufferedImage(framebufferIn.framebufferWidth, framebufferIn.framebufferHeight, 1);
  
          int j = framebufferIn.framebufferTextureHeight - framebufferIn.framebufferHeight;
  
  
  
          for (int k = j; k < framebufferIn.framebufferTextureHeight; ++k)
  
          {
  
              for (int l = 0; l < framebufferIn.framebufferWidth; ++l)
  
              {
  
                  bufferedimage.setRGB(l, k - j, pixelValues[k * framebufferIn.framebufferTextureWidth + l]);
  
              }
  
          }
  
      }
  
      else
  
      {
  
          bufferedimage = new BufferedImage(width, height, 1);
  
          bufferedimage.setRGB(0, 0, width, height, pixelValues, 0, width);
  
      }
  
  
  
      return bufferedimage;
  
  }

  Honestly I don’t want to use this Buffered Image Stuff, because it halfs my framerate, and that’s not good.
  And I don’t have any code for my android application yet, because I couldn’t figure out how I could get this image recreated on Android, and how to load it after that.
  I hope you understand my problem and I am happy about every tip you can give to me :)

• Dreamcast Track Sizes

  1er mars 2015, par Multimedia Mike — Sega Dreamcast

  I’ve been playing around with Sega Dreamcast discs lately. Not playing the games on the DC discs, of course, just studying their structure. To review, the Sega Dreamcast game console used special optical discs named GD-ROMs, where the GD stands for “gigadisc”. They are capable of holding about 1 gigabyte of data.

  You know what’s weird about these discs ? Each one manages to actually store a gigabyte of data. Each disc has a CD portion and a GD portion. The CD portion occupies the first 45000 sectors and can be read in any standard CD drive. This area is divided between a brief data track and a brief (usually) audio track.

  The GD region starts at sector 45000. Sometimes, it’s just one humongous data track that consumes the entire GD region. More often, however, the data track is split between the first track and the last track in the region and there are 1 or more audio tracks in between. But the weird thing is, the GD region is always full. I made a study of it (click for a larger, interactive graph) :

  
  
  

  Some discs put special data or audio bonuses in the CD region for players to discover. But every disc manages to fill out the GD region. I checked up on a lot of those audio tracks that divide the GD data and they’re legitimate music tracks. So what’s the motivation ? Why would the data track be split in 2 pieces like that ?

  I eventually realized that I probably answered this question in this blog post from 4 years ago. The read speed from the outside of an optical disc is higher than the inside of the same disc. When I inspect the outer data tracks of some of these discs, sure enough, there seem to be timing-sensitive multimedia FMV files living on the outer stretches.

  One day, I’ll write a utility to take apart the split ISO-9660 filesystem offset from a weird sector.