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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.

• Samsung S3 : 'Cannot play Video' on stock Video player

  18 mars 2013, par d33pika

  I am unable to play a mp4 video(H.264 Baseline, AAC) on Samsung S3, Android Version : 4.1.1, stock video player but plays on VLC. The same video plays on Galaxy Beam, Android Version : 2.3.6, stock Video Player. I want to figure out why it does not play on S3. I ran ffprobe and mediainfo on the fie :

  ffprobe results :

  ffprobe version 0.11.1 Copyright (c) 2007-2012 the FFmpeg developers
  
    built on Jan 25 2013 15:16:27 with llvm_gcc 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/0.11.1 --enable-shared --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --cc=/usr/bin/llvm-gcc --host-cflags='-Os -w -pipe -march=core2 -msse4 -mmacosx-version-min=10.7' --host-ldflags=-L/usr/local/lib --enable-libx264 --enable-libfaac --enable-libmp3lame --enable-libxvid
  
    libavutil      51. 54.100 / 51. 54.100
  
    libavcodec     54. 23.100 / 54. 23.100
  
    libavformat    54.  6.100 / 54.  6.100
  
    libavdevice    54.  0.100 / 54.  0.100
  
    libavfilter     2. 77.100 /  2. 77.100
  
    libswscale      2.  1.100 /  2.  1.100
  
    libswresample   0. 15.100 /  0. 15.100
  
    libpostproc    52.  0.100 / 52.  0.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '86535_360p_1301310230.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 1
  
      compatible_brands: isomavc1
  
      creation_time   : 2013-01-31 02:36:22
  
    Duration: 00:03:49.53, start: 0.000000, bitrate: 799 kb/s
  
      Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 640x360 [SAR 1:1 DAR 16:9], 699 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc
  
      Metadata:
  
        creation_time   : 2013-01-31 02:34:00
  
        handler_name    : GPAC ISO Video Handler
  
      Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 96000 Hz, stereo, s16, 95 kb/s
  
      Metadata:
  
        creation_time   : 2013-01-31 02:36:22
  
        handler_name    : GPAC ISO Audio Handler

  Media info results :

  General
  
  Complete name                            : a.mp4
  
  Format                                   : MPEG-4
  
  Format profile                           : Base Media
  
  Codec ID                                 : isom
  
  File size                                : 21.9 MiB
  
  Duration                                 : 3mn 49s
  
  Overall bit rate mode                    : Variable
  
  Overall bit rate                         : 799 Kbps
  
  Encoded date                             : UTC 2013-01-31 02:36:22
  
  Tagged date                              : UTC 2013-01-31 02:36:22
  
  
  
  Video
  
  ID                                       : 1
  
  Format                                   : AVC
  
  Format/Info                              : Advanced Video Codec
  
  Format profile                           : Baseline@L3.0
  
  Format settings, CABAC                   : No
  
  Format settings, ReFrames                : 3 frames
  
  Format settings, GOP                     : M=1, N=30
  
  Codec ID                                 : avc1
  
  Codec ID/Info                            : Advanced Video Coding
  
  Duration                                 : 3mn 49s
  
  Bit rate                                 : 700 Kbps
  
  Maximum bit rate                         : 2 721 Kbps
  
  Width                                    : 640 pixels
  
  Height                                   : 360 pixels
  
  Display aspect ratio                     : 16:9
  
  Frame rate mode                          : Constant
  
  Frame rate                               : 23.976 fps
  
  Color space                              : YUV
  
  Chroma subsampling                       : 4:2:0
  
  Bit depth                                : 8 bits
  
  Scan type                                : Progressive
  
  Bits/(Pixel*Frame)                       : 0.127
  
  Stream size                              : 19.1 MiB (88%)
  
  Writing library                          : Zencoder Video Encoding System
  
  Encoded date                             : UTC 2013-01-31 02:34:00
  
  Tagged date                              : UTC 2013-01-31 02:36:22
  
  
  
  Audio
  
  ID                                       : 2
  
  Format                                   : AAC
  
  Format/Info                              : Advanced Audio Codec
  
  Format profile                           : LC
  
  Codec ID                                 : 40
  
  Duration                                 : 3mn 49s
  
  Bit rate mode                            : Variable
  
  Bit rate                                 : 96.0 Kbps
  
  Maximum bit rate                         : 121 Kbps
  
  Channel(s)                               : 2 channels
  
  Channel positions                        : Front: L R
  
  Sampling rate                            : 96.0 KHz
  
  Compression mode                         : Lossy
  
  Stream size                              : 2.62 MiB (12%)
  
  Encoded date                             : UTC 2013-01-31 02:36:22
  
  Tagged date                              : UTC 2013-01-31 02:36:22

  I suspect the video player is more stricter on some codec header values. The level is set to 3.0 and this should be correct. Any help in figuring this out is appreciated !

• avcodec_find_encoder(AV_CODEC_ID_H264) returns null

  28 février 2017, par Monjura Rumi

  I am building an android application which will encode image captured from camera preview and later decode it. I am using ffmpeg library to encode and decode. To build static library with x264 I have used this tutorial. http://dl.dropbox.com/u/22605641/ffmpeg_android/main.html. As a source code of ffmpeg if I use the one downloaded from the link given in tutorial I can built it but can’t build library if i use source code downloaded from here git clone git ://source.ffmpeg.org/ffmpeg.git ffmpeg. I have built library in ubuntu and using it in windows 7 in Eclipse. As I need only h264 encoder and decoder I have used following code for ffmpeg, slightly modified from tutorial.

  #!/bin/bash
  
  
  
  NDK=~/Documents/android-ndk-r8e
  
  PLATFORM=$NDK/platforms/android-8/arch-arm
  
  PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86
  
  PREFIX=/home/android-ffmpeg
  
  
  
  function build_one
  
  {
  
      ./configure --target-os=linux --prefix=$PREFIX \
  
      --enable-cross-compile \
  
      --enable-runtime-cpudetect \
  
      --disable-asm \
  
      --arch=arm \
  
      --cc=$PREBUILT/bin/arm-linux-androideabi-gcc \
  
      --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \
  
      --disable-stripping \
  
      --nm=$PREBUILT/bin/arm-linux-androideabi-nm \
  
      --sysroot=$PLATFORM \
  
      --enable-nonfree \
  
      --enable-version3 \
  
      --disable-everything \
  
      --enable-gpl \
  
      --disable-doc \
  
      --enable-avresample \
  
      --disable-ffplay \
  
      --disable-ffserver \
  
      --enable-ffmpeg \
  
      --disable-ffprobe \
  
      --enable-avcodec \
  
      --enable-libx264 \
  
      --enable-encoder=libx264 \
  
      --enable-encoder=libx264rgb \
  
      --enable-decoder=h263 \
  
      --enable-decoder=h264 \
  
      --enable-decoder=svq3 \   
  
      --enable-zlib \
  
      --enable-gpl \
  
      --enable-pic \
  
      --disable-devices \
  
      --disable-avdevice \
  
      --extra-cflags="-I/home/android-ffmpeg/include -fPIC -DANDROID -D__thumb__ -mthumb -Wfatal-errors -Wno-deprecated -mfloat-abi=softfp -mfpu=vfpv3-d16 -marm -march=armv7-a" \
  
      --extra-ldflags="-L/home/android-ffmpeg/lib"
  
  make -j4 install
  
  $PREBUILT/bin/arm-linux-androideabi-ar d libavcodec/libavcodec.a inverse.o
  
  $PREBUILT/bin/arm-linux-androideabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -L$PREFIX/lib  -soname libffmpeg.so -shared -nostdlib  -z,noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg.so libavcodec/libavcodec.a libavfilter/libavfilter.a libavresample/libavresample.a libavformat/libavformat.a libavutil/libavutil.a libswscale/libswscale.a -lc -lm -lz -ldl -llog -lx264 --warn-once --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/arm-linux-androideabi/4.4.3/libgcc.a
  
  }
  
  
  
  build_one

  After building library I have been able to build android ndk. A little part of my JNI code is here.

  JNIEXPORT jint JNICALL Java_com_example_testjava_TestjniActivity_initencoder(JNIEnv* env,jobject obj){
  
  
  
      av_register_all();
  
      avcodec_register_all();
  
      codec = avcodec_find_encoder(AV_CODEC_ID_H264);
  
      if (!codec) {
  
        __android_log_write(ANDROID_LOG_INFO, "debug", "not found");                
  
         return -1;
  
      }
  
  .
  
  .
  
  .
  
  }

  When I run my java source code that calls initencoder() I get -1 as return value and logcat prints "not found". That means avcodec_find_encoder() returns null and if condition is being ok. I don’t know what’s wrong. Why this function is returning null ? I have searched a lot but did not find any solution that could guide me to right direction. some says to use avcodec_init(). But ndk-build command fails and shows error saying undefined reference to ’avcodec_init()’. I have started with library build because I thought may be I am doing wrong from the first stage. Did I make any mistake in library building like not enabling things that I should ? Please help me here. This is kind of urgent for me.