FAQ

Technical FAQ [Streaming] HTTP Live Streaming (HLS) Troubleshooting 30-Oct-2014

webOS TV supports HTTP Live Streaming (HLS) which is the adaptive streaming method that Apple has documented as an Internet-Draft (Reference URL of HLS: http://tools.ietf.org/html/draft-pantos-http-live-streaming-06). Here are some checklists you should verify when you meet a problem with playing HLS in webOS TV. 

 

  • Check if both video and audio-only streams are used in a playlist. In webOS TV, video and audio-only streams cannot be used at the same time in a playlist. If an audio-only stream is included in a playlist while others are video streams, “CODECS” attribute must be added in #EXT-X-STREAM-INF tag so that webOS TV can ignore the audio-only stream. Otherwise, HLS content will not be played normally. 

    When listing audio codec in the audio-only stream, only one audio codec should be specified. If two or more codecs exist in the "CODECS" attribute, HLS does not recognize it as the audio content and the HLS content will not be played normally. 

     

    Correct example

    #EXTM3U
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=96000
    96000/output_96000.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=256000
    256000/output_256000.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=800000
    800000/output_800000.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=64000, CODECS=”mp4a.40.5”
    audio_only.m3u8

     

    Incorrect example1
    In this HLS content, the  lowest bandwidth is audio-only stream. Therefore, CODECS="mp4a.40.5" must be added in its stream. (The codec type depends on your content)

    #EXTM3U
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=96000
    96000/output_96000.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=256000
    256000/output_256000.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=800000
    800000/output_800000.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=64000
    0/output_0.m3u8

     

    Incorrect example2

    Two audio-only codecs are listed in CODECS attribute. When specifying codec in CODECS attribute, only one codec should exist.

    #EXTM3U
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=241000,RESOLUTION=240x132
    241000/output1.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=64000,CODECS="mp4a.40.2,mp4a.40.5"
    output2.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=448000,RESOLUTION=320x176
    448000/output3.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=750000,RESOLUTION=640x352
    750000/output4.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1056000,RESOLUTION=640x352
    1056000/output5.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1682000,RESOLUTION=1280x704
    1682000/output6.m3u8
    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=2353000,RESOLUTION=1280x704
    2353000/output7.m3u8
  • If the 502 error occurs when playing HLS, you should check your server to resolve the problem.

     

  • If the buffering occurs when playing HLS, check in which bandwidth the buffering occurs and then check the stream file of that bandwidth.

Technical FAQ [SDK Installation] “Emulator Script Failed” occurs during webOS TV SDK v2.0.0 installation. 02-Mar-2015

If "Emulator Script Failed" error occurs during webOS TV SDK v2.0.0 installation on Windows 7, it may be a problem of system path environment variables.

Follow the next steps.

  1. Run Cmd.exe as administrator.
  2. Check the location and confirm execution of wmic: C:\Windows\System32\wbem\WMIC.exe
  3. Execute wmic sysaccount where sid='S-1-5-11' get name in the command line.
  4. If it works, check whether C:\Windows\System32\Wbem; is in the path environment variables.
  5. If C:\Windows\System32\Wbem; is not in the path environment variables, add on to it.
  6. Run the SDK installer as administrator.

 

To refer to wmic, see https://msdn.microsoft.com/en-us/library/aa394531(v=vs.85).aspx.

Technical FAQ [UX] Does LG provides the webOS TV UX Checklist? 17-Feb-2015

Yes. With the provided checklist, you can know about what is mandatory and what is recommended regarding to webOS TV UX.

 

Please read the webvOS TV UX Checklist article and follow the guidance.

 

Technical FAQ [SDK Installation] After I reinstall the patched webOS TV SDK v2.0.0, the Emulator v1.2.0 is not executed normally. Only remote control emulator is launched and emulator screen is not launched. 09-Feb-2015

If this case, please follow next steps.

  1. Uninstall the webOS TV SDK first.
  2. Start Oracle VM VirtualBox Manager. 
  3. Select virtual machines for webOS TV Emulator 2.0.0 and webOS TV Emulator in the left pane and click Remove menu.
  4. Open Virtual Media Manager and remove LG_webOS_TV_Emulator.vmdk files.
  5. Reinstall the SDK.
Technical FAQ [SDK Uninstallation] When uninstalling SDK, "java.lang.NumberFormatException: For input string: """ error occurs 04-Feb-2015

This error is caused by some problem in config file data. To figure out the problem, we should check the log file generated in the webOSLogs folder which is placed under the webOS_TV_SDK\Uninstall folder.

 

To proceed the uninstallation anyway, you should manually uninstall the SDK by following next steps.

  1. Remove the config file.
    [Windows] C:\Users\Public\lgsdkTvregistery\.webosTVregistery.xml
    [Mac OS] /var/.lgsdkTvregistry/.webosTVregistry.xml
    [Linux] /.lgsdkTvregistery/.webosTVregistery.xml
  2. Remove the webOS_TV_SDK folder which is located in the installation path.
  3. Remove SDK program file links and icons.
Technical FAQ [App Packaging] How can I set the deploy.json? 29-Jan-2015

If you want to make an Enyo app for webOS TV and also want to add your own library (except the original Enyo libraries) which is developed by you, you can add the special library in the “lib” folder in the root directory of the webOS template. Also in some cases you may need to add your own asset files such as image or video. To add your own resource like libraries and asset files, you should create a deploy.json file for your app deployment. Because the deploy.json file is not generated automatically when you download webOS Bootplate, you should create the file as below template.

{
    "enyo": "./enyo",
    "packagejs": "./package.js",
    "assets": ["./app_bg_1920x1080.png", "./app_bg2_1920x1080.png",
                "./appinfo.json", "./icon.png", "./largeIcon.png",
                "./index.html", "./assets"],
    "libs": ["./lib/moonstone", "./lib/layout", "./lib/spotlight"]
}

If the deployment files and directories are right, a “resources” folder should be added under “root\lib\moonstone” directory as below image though there is no file inside the resources folder.

folder_structure.png

 

You can also notice that the deploy.json file can be replaced with the asset property of appinfo.json file. For your deep understanding about the folder structure and app deployment, you also refer to Code Samples.

Technical FAQ [SDK Installation] “Exception in thread "Thread-3"” occurs during webOS TV SDK installation on Mac OS X Mountain Lion 09-Jan-2015

If then, you can solve this issue by downloading and installing Java for OS X 2014-001. For more information, please visit here.

Technical FAQ [SDK Installation] I've installed Windows 64-bit SDK but it does not work. What's the problem? 04-Dec-2014

In Windows 64, you must install JDK before installing the SDK because the SDK installer installs 32-bit Java by default if Java is not installed on your computer. We recommend you to use java -version command in command prompt before SDK installation to check whether the 64-bit Java has been installed.

Technical FAQ [Streaming] Can I develop an app using Smooth Streaming? 04-Aug-2014

LGE does not recommend you to use Smooth Streaming in your application. (Both on webOS TV and NetCast)

Technical FAQ [Audio] How to play multi-sound in my app? 14-Oct-2014

See Playing multi-sound for detailed guidance and sample code.