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• Fun With Tablets And Amazon’s App Store

  24 décembre 2011, par Multimedia Mike — General, amazon, android, app store, cyanogenmod, ios, smurfs, tablet

  I bought an Android tablet a few months ago. It is less expensive than the best tablets but no where near the bottom end of the market. I think it’s pretty good. However, one downside is that it’s not “certified” to use Google’s official marketplace. That would seem to be somewhat limiting, however…

  Enter Amazon’s Android App Store
  Amazon got into the business of selling Android Apps some time ago. I started experimenting with this on a Nexus One phone that Google gave me. When I installed the App Store on the Android tablet and logged in, I was pleasantly surprised to see all of my Amazon apps ready for downloading onto the tablet.

  So I have an App Store for use with this Android tablet.

  Anyway, the reason I bring this up is because I managed to screw up this tablet in an unusual and humorous manner. You might be wondering if an app downloaded from the Amazon App Store requires the App Store to be present in order to run. The answer is : Oh yeah ! It works like this :

  
  
  

  This means that if — perhaps out of curiosity, for example — you login to the Amazon App Store, download an app, install it, and then subsequently log out of the App Store or uninstall it altogether, the downloaded app will decline to run until you log back into the store.

  Here’s the thing– I wanted to provide a minimal level of security for my Android tablet. At the very least, I wished to lock the Amazon App Store itself since Amazon is famously (and, let’s face it, understandably) reluctant to deliberately add any friction to their shopping processes. I.e., without any external protection app, the App Store app would allow anyone to purchase any app using my tablet.

  So I purchased App Protector Pro from the Amazon App Store and it worked quite well. By default, it also password protects against modifying any system settings as well as installing new apps.

  So, here’s where I screwed up : App Protector Pro was doing its faithful duty and I uninstalled the Amazon App Store as an experiment. Suddenly, no apps obtained from the App Store would work unless I reinstalled the App Store. Okay, fair enough, except for one thing– App Protector Pro wouldn’t run without the App Store. Well, it did, it started to, tried to, but then exited. So I couldn’t re-install the App Store :

  
  
  Oops
  

  I eventually learned how to perform a factory reset of the unit which solved the problem. And, as indicated earlier, all of my apps were available for me to re-download.

  Modding, Cyanogen-style
  Open source aficionados will likely point out that there are alternate firmware options which allow me to take control of my Android tablet in a free and open manner. Among these options is CyanogenMod. After I got stuck in the situation described above, I thought I would have to resort to such an option.

  On the plus side, researching alternative firmware options is what taught me to boot the device into a recovery mode and ultimately restore to a factory default setting. But if you’ll allow me to indulge in a mini-rant regarding accessibility of open source software : I was more than a little frustrated in trying to understand what CyanogenMod could possibly offer me. Their homepage says it’s “an aftermarket firmware”. I’m not entirely sure what that means or how it can benefit me. Fortunately, they have a full feature list linked from the front page. They are, in order : Lockscreen gestures, phone goggles, OpenVPN, incognito mode, themes support, and DSP equalizer. I can’t say that any of those really add any value for me. I’d love to know if CyanogenMod supports Google Android Market and various other Google apps (such as maps and GMail). That’s a question that I can’t seem to find the answer to.

  The themes feature opens another old wound for me. Back around 1999 when I was first getting into Linux in a serious way, I remember that themes were a big theme at the Linux User Groups I would attend. I also remember lots are online articles at the time that emphasized how highly customizable the Linux desktop was in comparison to Windows 9x. I was bothered for 2 reasons : First, I thought there were more pressing problems that needed to be addressed in Linux ; and second, none of these customization options seemed particularly straightforward ; many apparently required hours of compiling and tinkering.

  Small digression. Anyway, back to CyanogenMod, I was glad to see that they prominently display a button in order to “View Video Tour”. Ah, internet video has us so spoiled these days. I was eager to see this aftermarket firmware in action to see what it could do for me. However, the link leads to… a forum post ? The thread seems to discuss how it would be a cool idea if the community could put together a video tour. At this point, the investigation just seems bizarre. It feels like a bunch of kids doing their best to do things the grown-up way.

  Okay, sorry, rant over. I try to stay positive these days. I’m sure the CyanogenMod folks are doing great, fun, and interesting work on their project. The problems they choose to solve might lack mainstream appeal, however.

  Free iPad
  Ultimately, I recently unloaded the little Android tablet because, well… when a free iPad comes your way, lower spec tablets feel a little silly to keep around. Yeah, it’s great to play around with. Though here’s one unsettling thing I noticed about Apple’s App Store. While browsing for worthwhile games to indulge in, I noticed that they had a section for “Top Grossing Games”. This was a separate list from the “Top Apps” charts. I found the list weird for 2 reasons : 1) Why do I care which games are raking in the most cash ? How does this communicate value to me, personally ? Seriously, why would I base a purchasing decision around which vendor has earned the most money ?

  Anyway, let’s move on to reason #2 this was scary : Most of the games in this list had a price of FREE. One of them was that Capcom Smurfs game that stirred up controversy some months ago because of kids making unsupervised in-app purchases of virtual smurfberries. I tend to think that a top-grossing, free to play game is probably one that heavily encourages in-app purchases. Strange how this emerging trend actually encourages me to seek out games from the “top paid” list vs. “top free”.

• ‘undefined reference to xxxxx’ , 'check the directory for the files' it does not work

  26 décembre 2011, par sirupa

  Merry Christmas, everybody,

  I’m coding ffmpeg with gcc.

  But, on the build process, I met the errors of ‘undefined reference to xxxxx’ for all functions that I coded in my program, and I recognized that it was due to the libxxx.a file.

  And the every adviser on internet suggested that check the directory for the files.

  So, I searched the files in which include the function names in my computer, and I found the .a files are correctly set in the directory which I coded.

  And there are the other files which are named ‘libxxx.dll.a’, so I tried to build with the files ‘libxxx.dll.a’, but I got the same result.

  On this point, I have got some questions.

  1) If the gcc could not find the libxxx.a files, it would say that ‘cannot find the –lxxx’. But it just said ‘undefined reference to xxxx’. It means that those libxxx.a files are in the correct directories.

  2) And if the files do not define the functions, it is strange. Because those files include the function names and are the same files/directories I had searched in my computer, and I think it should have the definitions of the functions. But I am not sure that the files define the functions or not, because I cannot read the file myself.

  If I am wrong, what was my mistake ?

  3) Can libxxxlib.a files be replaced with the libxxx.a ? And if it can, what is the difference between libxxxlib.a and libxxx.a ? And the same for the libz and libzlib ?a

  Here is my line commend, the directory which include the libxxx.a files.

  g++ -o C :\ffmpeg\ffmpegTest C :\ffmpeg\ffmpegTest.cc -IC :\ffmpeg -LC :\ffmpeg\3rdparty\lib -lavutil -lavformat -lavcodec -lz -lavutil -lm -D__STDC_CONSTANT_MACROS

  C :\ffmpeg\3rdparty\lib

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0xec> : undefined reference to 'av_register_all()'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x11c> : undefined reference to 'av_open_input_file(AVFormatContext*, char const, AVInputFormat*, int, AVFormatParameters*)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x13b> : undefined reference to 'av_find_stream_info(AVFormatContext*)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x174> : undefined reference to 'dump_format(AVFormatContext, int, char const*, int)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x224> : undefined reference to 'avcodec_find_decoder(CodecID)'

  and all the errors are

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x281> : undefined reference to 'avcodec_open(AVCodecContext*, AVCodec)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x297> : undefined reference to 'avcodec_alloc_frame()'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x2a3> : undefined reference to 'avcodec_alloc_frame()'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x2e6> : undefined reference to 'avpicture_get_size(PixelFormat,int,int)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x2fc> : undefined reference to 'av_malloc(unsigned int)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x341> : undefined reference to 'avpicture_fill(AVPicture*, unsigned char*, PixelFormat, int, int)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x38c> : undefined reference to 'avcodec_decode_video2(AVCodecContext, AVFrame*, int, AVPacket*)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x409> : undefined reference to 'sws_getContext(int, int, PixelFormat, int, int, PixelFormat, int, SwsFilter*, swsFilter*, double const*)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x463> : undefined reference to 'sws_scale(SwsContext*, unsigned char const* const*, int const*, int, int, unsigned char* const*, int const*)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x4bb> : undefined reference to 'av_free_packet(AVPacket*)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x4cf> : undefined reference to 'av_read_frame(AVFormatContext, AVPacket*)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x36c> : undefined reference to 'av_free(void*)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x36c> : undefined reference to ' avcodec_close(AVCodecContext*)'

  C :\Users\AppData\Local\Temp\ccVHLzjK.o:ffmpegTest.cc :<.text+0x36c> : undefined reference to 'av_close_input_file(AVFormatContext)'

• executing ffmpeg command with getRuntime().exec() command

  12 mai 2015, par Iori

  i want to run ffmepg command directly on android.
  a simple command

  ffmpeg -i vid.mp4 out.mp4

  now the issue is that i have searched the internet and found the best android ffmpeg can be found here

  http://bambuser.com/opensource

  I have downloaded it and read the readme file and compiled it. the folder is ffmpeg. I have kept it in <--projectfolder-->/ffmpeg/

  there is a ffmpeg executeable file in ffmpeg folder called ffmpeg folder

  i have copied it in files folder and run this command

    try {    
  
  
  
      Toast.makeText(this, "Working", Toast.LENGTH_SHORT).show();
  
  
  
      Process p = Runtime.getRuntime().exec("/data/data/com.koder.testffmpeg/files/ffmpeg -i /sdcard/vid.mp4 /sdcard/out.mp4");
  
  
  
  
  
      } catch (IOException e) {
  
  
  
      txt.setText(e.toString());
  
  
  
      Toast.makeText(this, e.toString(), Toast.LENGTH_LONG).show();
  
  
  
      e.printStackTrace();
  
  
  
      }

  according to this link
  How do I reduce the video size captured by the default camera using FFMPEG in Android ?

  but still it does not work always exception i dont know what is going wrong
  can someone plz help me with this

  java.io.IOException: Error running exec(). Command:[/data/data/com.koder.testffmpeg/files/ffmpeg -i /sdcard/vid.mp4 /sdcard/out.mp4] Working Directory: null Environment:null