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• Elacarte Presto Tablets

  14 mars 2013, par Multimedia Mike — General

  I visited an Applebee’s restaurant this past weekend. The first thing I spied was a family at a table with what looked like a 7-inch tablet. It’s not an uncommon sight. However, as I moved through the restaurant, I noticed that every single table was equipped with such a tablet. It looked like this :

  
  
  

  For a computer nerd like me, you could probably guess that I was be far more interested in this gadget than the cuisine. The thing said “Presto” on the front and “Elacarte” on the back. Putting this together, we get the website of Elacarte, the purveyors of this restaurant tablet technology. Months after the iPad was released on 2010, I remember stories about high-end restaurants showing their wine list via iPads. This tablet goes well beyond that.

  How was it ? Well, confusing, mostly. The hostess told us we could order through the tablet or through her. Since we already knew what we wanted, she just manually took our order and presumably entered it into the system. So, right away, the question is : Do we order through a human or through a computer ? Or a combination ? Do we have to use the tablet if we don’t want to ?

  Hardware
  When picking up the tablet, it’s hard not to notice that it is very heavy. At first, I suspected that it was deliberately weighted down as some minor attempt at an anti-theft measure. But then I remembered what I know about power budgets of phones and tablets– powering the screen accounts for much of the battery usage. I realized that this device needs to drive the screen for about 14 continuous hours each day. I.e., the weight must come from a massive battery.

  The screen is good. It’s a capacitive touchscreen, so nice and responsive. When I first spied the device, I felt certain it would be a resistive touchscreen (which is more accurately called a touch-and-press-down screen). There is an AC adapter on the side of the tablet. This is the only interface to the device :

  
  
  

  That looks to me like an internal SATA connector (different from an eSATA connector). Foolishly, I didn’t have a SATA cable on me so I couldn’t verify.

  User Interface
  The interface options are : Order, Games, Neighborhood, and Pay. One big benefit of accessing the menu through the Order option is that each menu item can have a picture. For people who order more by picture than text description, this is useful. Rather, it would be, if more items had pictures. I’m not sure there were more pictures than seen in the print menu.
  
  For Games, there were a variety of party games. The interface clearly stated that we got to play 2 free games. This implied to me that further games cost money. We tried one game briefly and the food came.

  2 more options : Neighborhood– I know I dug into this option, but I forget what it was. Maybe it discussed local attractions. Finally, Pay. This thing has an integrated credit card reader. There is no integrated printer, though, so if you want one, you will have to request one from a human.

  Experience
  So we ordered through a human since we didn’t feel like being thrust into this new paradigm when we just wanted lunch. The staff was obviously amenable to that. However, I got a chance to ask them a lot of questions about the particulars. Apparently, they have had this system for about 5 months. It was confirmed that the tablets do, in fact, have gargantuan batteries that have to last through the restaurant’s entire business hours. Do they need to be charged every night ? Yes, they do. But how ? The staff described this several large charging blocks with many cables sprouting out. Reportedly, some units still don’t make it through the entire day.

  When it was time to pay, I pressed the Pay button on the interface. The bill I saw had nothing in common with what we ordered (actually, it was cheaper, so perhaps I should have just accepted it). But I pointed it out to a human and they said that this happens sometimes. So they manually printed my bill. There was a dollar charge for the game that was supposed to be free. I pointed this out and they removed it. It’s minor, I know, but it’s still worth trying to work out these bugs.

  One of the staff also described how a restaurant doesn’t need to employ as many people thanks to the tablet. She gave a nervous, awkward, self-conscious laugh when she said this. All I could think of was this Dilbert comic strip in which the boss realizes that his smartphone could perform certain key functions previously handled by his assistant.

  Not A New Idea
  Some people might think this is a totally new concept. It’s not. I was immediately reminded of my university days in Boulder, Colorado, USA, circa 1997. The local Taco Bell and Arby’s restaurants both had touchscreen ordering kiosks. Step up, interact with the (probably resistive) touchscreen, get a number, and step to the counter to change money, get your food, and probably clarify your order because there is only so much that can be handled through a touchscreen.

  What I also remember is when they tore out those ordering kiosks, also circa 1997. I don’t know the exact reason. Maybe people didn’t like them. Maybe there were maintenance costs that made them not worth the hassle.

  Then there are the widespread self-checkout lanes in grocery stores. Personally, I like those, though I know many don’t. However, this restaurant tablet thing hasn’t won me over yet. What’s the difference ? Perhaps that automated lanes at grocery stores require zero external assistance– at least, if you do everything correctly. Personally, I work well with these lanes because I can pretty much guess the constraints of the system and I am careful not to confuse the computer in any way. Until they deploy serving droids, or at least food conveyors, there still needs to be some human interaction and I think the division between the human and computer roles is unintuitive in the restaurant case.

  I don’t really care to return to the same restaurant. I’ll likely avoid any other restaurant that has these tablets. For some reason, I think I’m probably supposed to be the ideal consumer of this concept. But the idea will probably perform all right anyway. Elacarte’s website has plenty of graphs demonstrating that deploying these tablets is extremely profitable.

• Video processing to support different web players and qualities [closed]

  15 mai 2013, par Linas

  I am trying to accomplish something similar to youtube player.

  The biggest issues I'm facing now is how should I process user uploaded video file.

  For example since i want to switch between 240p, 360p, 480p and 720p I need to convert uploaded video file to 4 different files for each resolution, and because not all browsers can play mp4 i need ogg, mp4, webm, so that makes 12 video files, and say if it takes 10 minutes to process 1h video file it would take me about 2h just to process that file which is insane. I know that youtube is ussing cloud servers to process each video file and they have a lot of processing power but I think there some kind of trick to this.

  So my question is what can i do about this, and how does youtube deal with this ?

  My second question is ffmpeg suited for this kind of work, and if so why does this command takes pretty much for ever to finish, I ran this command on a 720p 3minutes long video file and after 15minutes of processing I just canceled the process.

  ffmpeg -i hd.webm a.mp4

  This one on the other hand took about 7 minutes to finish but it generated 200mb video file out of 25mb file

  ffmpeg -i hd.webm -c:v libx264 -preset ultrafast a.mp4

• ffmpeg : stream copy from .mxf into NLE-compatible format

  9 juin 2013, par David

  Because my NLE software does not support the .mxf-files from Canon XF100 I need to convert them into a supported format.

  As far as I know, mxf-files are just another container format for mpeg2 streams, so it would be really nice to extract the streams and place them into another container (without reencoding).

  I think ffmpeg can do this – correct me if I'm wrong – by running the following command :

  ffmpeg -i in.mxf -vcodec copy out.m2ts (or .ts, .mts, ...)

  ffmpeg finishes without errors after about 2 seconds (in.mxf is abut 170mb) :

  c:\video>c:\ffmpeg\bin\ffmpeg -i in.MXF -vcodec copy out.m2ts
  
  ffmpeg version N-53680-g0ab9362 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on May 30 2013 12:14:03 with gcc 4.7.3 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
  
  isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
  
  le-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetyp
  
  e --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --ena
  
  ble-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-l
  
  ibopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libsp
  
  eex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-
  
  amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --
  
  enable-libxvid --enable-zlib
  
    libavutil      52. 34.100 / 52. 34.100
  
    libavcodec     55. 12.102 / 55. 12.102
  
    libavformat    55.  8.100 / 55.  8.100
  
    libavdevice    55.  2.100 / 55.  2.100
  
    libavfilter     3. 73.100 /  3. 73.100
  
    libswscale      2.  3.100 /  2.  3.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  3.100 / 52.  3.100
  
  Guessed Channel Layout for  Input Stream #0.1 : mono
  
  Guessed Channel Layout for  Input Stream #0.2 : mono
  
  Input #0, mxf, from 'in.MXF':
  
    Metadata:
  
      uid             : 1bb23c97-6205-4800-80a2-e00002244ba7
  
      generation_uid  : 1bb23c97-6205-4800-8122-e00002244ba7
  
      company_name    : CANON
  
      product_name    : XF100
  
      product_version : 1.00
  
      product_uid     : 060e2b34-0401-010d-0e15-005658460100
  
      modification_date: 2013-01-06 11:05:02
  
      timecode        : 01:42:14:22
  
    Duration: 00:00:28.32, start: 0.000000, bitrate: 51811 kb/s
  
      Stream #0:0: Video: mpeg2video (4:2:2), yuv422p, 1920x1080 [SAR 1:1 DAR 16:9
  
  ], 25 fps, 25 tbr, 25 tbn, 50 tbc
  
      Stream #0:1: Audio: pcm_s16le, 48000 Hz, mono, s16, 768 kb/s
  
      Stream #0:2: Audio: pcm_s16le, 48000 Hz, mono, s16, 768 kb/s
  
  Output #0, mpegts, to 'out.m2ts':
  
    Metadata:
  
      uid             : 1bb23c97-6205-4800-80a2-e00002244ba7
  
      generation_uid  : 1bb23c97-6205-4800-8122-e00002244ba7
  
      company_name    : CANON
  
      product_name    : XF100
  
      product_version : 1.00
  
      product_uid     : 060e2b34-0401-010d-0e15-005658460100
  
      modification_date: 2013-01-06 11:05:02
  
      timecode        : 01:42:14:22
  
      encoder         : Lavf55.8.100
  
      Stream #0:0: Video: mpeg2video, yuv422p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-3
  
  1, 25 fps, 90k tbn, 25 tbc
  
      Stream #0:1: Audio: mp2, 48000 Hz, mono, s16, 128 kb/s
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
    Stream #0:1 -> #0:1 (pcm_s16le -> mp2)
  
  Press [q] to stop, [?] for help
  
  frame=  532 fps=0.0 q=-1.0 size=  143511kB time=00:00:21.25 bitrate=55314.1kbits
  
  frame=  561 fps=435 q=-1.0 size=  151254kB time=00:00:22.42 bitrate=55242.0kbits
  
  frame=  586 fps=314 q=-1.0 size=  158021kB time=00:00:23.41 bitrate=55288.0kbits
  
  frame=  609 fps=255 q=-1.0 size=  164182kB time=00:00:24.34 bitrate=55235.4kbits
  
  frame=  636 fps=217 q=-1.0 size=  171463kB time=00:00:25.42 bitrate=55235.1kbits
  
  frame=  669 fps=194 q=-1.0 size=  180133kB time=00:00:26.72 bitrate=55226.3kbits
  
  frame=  699 fps=173 q=-1.0 size=  188326kB time=00:00:27.92 bitrate=55256.6kbits
  
  frame=  708 fps=169 q=-1.0 Lsize=  190877kB time=00:00:28.30 bitrate=55233.6kbit
  
  s/s
  
  video:172852kB audio:442kB subtitle:0 global headers:0kB muxing overhead 10.1461
  
  18%

  Unfortunately the output file turns out to be displayed correctly only by vlc player.
  My NLE-software (Cyberlink Power Director) is able to open the file but most of the picture is green. Only a few pixels on the left edge show the original video :

  output file

  Any ideas how to solve that problem ? Is there a better way to use .mxf-files in NLE-software without native support ?

  thanks in advance