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• Creating a reflection

  9 juin 2010, par Mikko Koppanen — Imagick, PHP stuff

  Here is a simple example of creating a reflection of an image. The reflection is created by flipping the image and overlaying a gradient on it. Then both, the original image and the reflection is overlayed on a canvas.

  This example is created for Imagick 2.1.x but with a little tuning it should work with earlier versions.

  php

  < view plain text >

  1. < ?php
  2.  
  3. /* Read the image */
  4. $im = new Imagick( "strawberry.png" ) ;
  5.  
  6. /* Thumbnail the image */
  7. $im->thumbnailImage( 200, null ) ;
  8.  
  9. /* Create a border for the image */
  10. $im->borderImage( "white", 5, 5 ) ;
  11.  
  12. /* Clone the image and flip it */
  13. $reflection = $im->clone() ;
  14. $reflection->flipImage() ;
  15.  
  16. /* Create gradient. It will be overlayd on the reflection */
  17. $gradient = new Imagick() ;
  18.  
  19. /* Gradient needs to be large enough for the image
  20. and the borders */
  21. $gradient->newPseudoImage( $reflection->getImageWidth() + 10,
  22.               $reflection->getImageHeight() + 10,
  23.               "gradient:transparent-black"
  24.             ) ;
  25.  
  26. /* Composite the gradient on the reflection */
  27. $reflection->compositeImage( $gradient, imagick: :COMPOSITE_OVER, 0, 0 ) ;
  28.  
  29. /* Add some opacity */
  30. $reflection->setImageOpacity( 0.3 ) ;
  31.  
  32. /* Create empty canvas */
  33. $canvas = new Imagick() ;
  34.  
  35. /* Canvas needs to be large enough to hold the both images */
  36. $width = $im->getImageWidth() + 40 ;
  37. $height = ( $im->getImageHeight() * 2 ) + 30 ;
  38. $canvas->newImage( $width, $height, "black", "png" ) ;
  39.  
  40. /* Composite the original image and the reflection on the canvas */
  41. $canvas->compositeImage( $im, imagick: :COMPOSITE_OVER, 20, 10 ) ;
  42. $canvas->compositeImage( $reflection, imagick: :COMPOSITE_OVER,
  43.             20, $im->getImageHeight() + 10 ) ;
  44.  
  45. /* Output the image*/
  46. header( "Content-Type : image/png" ) ;
  47. echo $canvas ;
  48.  
  49.  ?>

  The source image :

  

  And the result :

  

  P.S. Please send me some new images which I can use in these examples

• Dreamcast Operating Systems

  16 septembre 2010, par Multimedia Mike — Sega Dreamcast

  The Sega Dreamcast was famously emblazoned with a logo proudly announcing that it was compatible with Windows CE :

  
  
  

  It’s quite confusing. The console certainly doesn’t boot into some version of Windows to launch games. Apparently, there was a special version of CE developed for the DC and game companies had the option to leverage it. I do recall that some game startup screens would similarly advertise Windows CE.

  Once the homebrew community got ahold of the device, the sky was the limit. I think NetBSD was the first alternative OS to support the Dreamcast. Meanwhile, I have recollections of DC Linux and LinuxDC projects along with more generic Linux-SH and SH-Linux projects.

  
  
  

  DC Evolution hosts a disc image available for download with an unofficial version of DC Linux, assembled by one Adrian O’Grady. I figured out how to burn the disc (burning DC discs is a blog post of its own) and got it working in the console.

  It’s possible to log in directly via the physical keyboard or through a serial terminal provided that you have a coder’s cable. That reminds me– my local Fry’s had a selection of USB-to-serial cables. I think this is another area that is sufficiently commoditized that just about any cable ought to work with Linux out of the box. Or maybe I’m just extrapolating from the experience of having the cheapest cable in the selection (made by io connect) plug and play with Linux.

  
  
  

  Look ! No messy converter box in the middle as in the Belkin case. The reason I went with this cable is that the packaging claimed it was capable of up to 500 Kbits/sec. Most of the cables advertised a max of 115200 bps. I distinctly recall being able to use the DC coder’s cable at 230400 bps a long time ago. Alas, 115200 seems to be the speed limit, even with this new USB cable.

  Anyway, the distribution is based on a 2.4.5 kernel circa 2001. I tried to make PPP work over the serial cable but the kernel doesn’t have support. If you’re interested, here is some basic information about the machine from Linux’s perspective, gleaned from some simple commands. This helps remind us of a simpler time when Linux was able to run comfortably on a computer with 16 MB of RAM.

  Debian GNU/Linux testing/unstable dreamcast ttsc/1
  dreamcast login : root
  
  Linux dreamcast 2.4.5 #27 Thu May 31 07:06:51 JST 2001 sh4 unknown
  Most of the programs included with the Debian GNU/Linux system are
  
  freely redistributable ; the exact distribution terms for each program
  
  are described in the individual files in /usr/share/doc/*/copyright
  Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
  
  permitted by applicable law.
  dreamcast : # uname -a
  
  Linux dreamcast 2.4.5 #27 Thu May 31 07:06:51 JST 2001 sh4 unknown
  dreamcast : # cat /proc/cpuinfo 
  
  cpu family : SH-4
  
  cache size : 8K-byte/16K-byte
  
  bogomips : 199.47
  Machine : dreamcast
  
  CPU clock : 200.00MHz
  
  Bus clock : 100.00MHz
  
  Peripheral module clock : 50.00MHz
  dreamcast : # top -b
   09:14:54 up 14 min,  1 user,  load average : 0.04, 0.03, 0.03
  
  15 processes : 14 sleeping, 1 running, 0 zombie, 0 stopped
  
  CPU states :   1.1% user,   5.8% system,   0.0% nice,  93.1% idle
  
  Mem :     14616K total,    11316K used,     3300K free,     2296K buffers
  
  Swap :        0K total,        0K used,        0K free,     5556K cached
    PID USER     PRI  NI  SIZE  RSS SHARE STAT %CPU %MEM   TIME COMMAND
  
    219 root      18   0  1072 1068   868 R     5.6  7.3   0:00 top
  
      1 root       9   0   596  596   512 S     0.0  4.0   0:01 init
  
      2 root       9   0     0    0     0 SW    0.0  0.0   0:00 keventd
  
      3 root       9   0     0    0     0 SW    0.0  0.0   0:00 kswapd
  
      4 root       9   0     0    0     0 SW    0.0  0.0   0:00 kreclaimd
  
      5 root       9   0     0    0     0 SW    0.0  0.0   0:00 bdflush
  
      6 root       9   0     0    0     0 SW    0.0  0.0   0:00 kupdated
  
      7 root       9   0     0    0     0 SW    0.0  0.0   0:00 kmapled
  
     39 root       9   0   900  900   668 S     0.0  6.1   0:00 devfsd
  
     91 root       8   0   652  652   556 S     0.0  4.4   0:00 pump
  
     96 daemon     9   0   524  524   420 S     0.0  3.5   0:00 portmap
  
    149 root       9   0   944  944   796 S     0.0  6.4   0:00 syslogd
  
    152 root       9   0   604  604   456 S     0.0  4.1   0:00 klogd
  
    187 root       9   0   540  540   456 S     0.0  3.6   0:00 getty
  
    201 root       9   0  1380 1376  1112 S     0.0  9.4   0:01 bash
  

  Note that at this point I had shutdown both gpm and inetd. The rest of the processes, save for bash, are default. The above stats only report about 14 MB of RAM ; where are the other 2 MB ?

  dreamcast : # df -h
  Filesystem            Size  Used Avail Use% Mounted on
  /dev/rd/1             2.0M  560k  1.4M  28% /
  

• Ffmpeg video output is 0 seconds with correct filesize when uploading to google cloud bucket

  22 août 2022, par Turgut

  I've made a C++ program that lives in gke and takes some videos as input using ffmpeg, then does something with that input using opengl(not relevant), then finally encodes those edited videos as a single output. Normally the program works perfectly fine on my local machine, it encodes just as I want it to with no warnings or valgrind errors whatsoever. Then, after encoding the said video, I want my program to upload that video to the google cloud storage. This is where the problem comes, I have tried 2 methods for this : First, I tried using curl to upload to the cloud using a signed url. Second, I tried mounting the google storage using gcsfuse(I was already mounting the bucket to access the inputs in question). Both of those methods yielded undefined, weird behaviour's ranging from : Outputing a 0byte or 44byte file, (This is the most common one :) encoding in the correct file size 500mb but the video is 0 seconds long, outputing a 0.4 second video or just encoding the desired output normally (really rare).

  &#xA;

  From the logs I can't see anything unusual, everything seems to work fine and ffmpeg does not give any errors or warnings, so does valgrind. Everything seems to work normally, even when I use curl to upload the video to the cloud the output is perfectly fine when it first encodes it (before sending it with curl) but the video gets messed up when curl uploads it to the cloud.

  &#xA;

  I'm using the muxing.c example of ffmpeg to encode my video with the only difference being :

  &#xA;

  void video_encoder::fill_yuv_image(AVFrame *frame, struct SwsContext *sws_context) {
    const int in_linesize[1] = { 4 * width };
    //uint8_t* dest[4] = { rgb_data, NULL, NULL, NULL };
    sws_context = sws_getContext(
            width, height, AV_PIX_FMT_RGBA,
            width, height, AV_PIX_FMT_YUV420P,
            SWS_BICUBIC, 0, 0, 0);

    sws_scale(sws_context, (const uint8_t * const *)&rgb_data, in_linesize, 0,
            height, frame->data, frame->linesize);
}


  &#xA;

  rgb_data is the data I got after editing the inputs. Again, this works fine and I don't think there are any errors here.

  &#xA;

  I'm not sure where the error is and since the code is huge I can't provide a replicable example. I'm just looking for someone to point me to the right direction.

  &#xA;

  Running the cloud's output in mplayer wields this result (This is when the video is the right size but is 0 seconds long, the most common one.) :

  &#xA;

  MPlayer 1.4 (Debian), built with gcc-11 (C) 2000-2019 MPlayer Team
do_connect: could not connect to socket
connect: No such file or directory
Failed to open LIRC support. You will not be able to use your remote control.

Playing /media/c36c2633-d4ee-4d37-825f-88ae54b86100.
libavformat version 58.76.100 (external)
libavformat file format detected.
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f2cba1168e0]moov atom not found
LAVF_header: av_open_input_stream() failed
libavformat file format detected.
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f2cba1168e0]moov atom not found
LAVF_header: av_open_input_stream() failed
RAWDV file format detected.
VIDEO:  [DVSD]  720x480  24bpp  29.970 fps    0.0 kbps ( 0.0 kbyte/s)
X11 error: BadMatch (invalid parameter attributes)
Failed to open VDPAU backend libvdpau_nvidia.so: cannot open shared object file: No such file or directory
[vdpau] Error when calling vdp_device_create_x11: 1
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
libavcodec version 58.134.100 (external)
[dvvideo @ 0x7f2cb987a380]Requested frame threading with a custom get_buffer2() implementation which is not marked as thread safe. This is not supported anymore, make your callback thread-safe.
Selected video codec: [ffdv] vfm: ffmpeg (FFmpeg DV)
==========================================================================
Load subtitles in /media/
==========================================================================
Opening audio decoder: [libdv] Raw DV Audio Decoder
Unknown/missing audio format -> no sound
ADecoder init failed :(
Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
[dvaudio @ 0x7f2cb987a380]Decoder requires channel count but channels not set
Could not open codec.
ADecoder init failed :(
ADecoder init failed :(
Cannot find codec for audio format 0x56444152.
Audio: no sound
Starting playback...
[dvvideo @ 0x7f2cb987a380]could not find dv frame profile
Error while decoding frame!
[dvvideo @ 0x7f2cb987a380]could not find dv frame profile
Error while decoding frame!
V:   0.0   2/  2 ??% ??% ??,?% 0 0 


Exiting... (End of file)




  &#xA;

  Edit : Since the code runs on a VM, I'm using xvfb-run ro start my application, but again even when using xvfb-run it works completely fine on when not encoding to the cloud.

  &#xA;