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• avformat/dhav : fix backward scanning for get_duration and optimize seeking

  21 mars, par Justin Ruggles

  avformat/dhav : fix backward scanning for get_duration and optimize seeking
  The backwards scanning done for incomplete final packets should not
  
  assume a specific alignment at the end of the file. Truncated files
  
  result in hundreds of thousands of seeks if the final packet does not
  
  fall on a specific byte boundary, which can be extremely slow.
  
  For example, with HTTP, each backwards seek results in a separate
  
  HTTP request.
  This changes the scanning to check for the end tag 1 byte at a time
  
  and buffers the last 1 MiB to avoid additional seek operations.
  Co-authored-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  
  Signed-off-by : Justin Ruggles <justinr@vimeo.com>
  
  Signed-off-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  

  • [DH] libavformat/dhav.c

• ProcessBuilder is not called when trying to start a process

  15 juin 2022, par xnok

  I am trying to understand more about the ffmpeg usage in JavaCV for android studio and for said task I am trying to use ProcessBuilder. I tried writting a simple program to debug the pb.start(); Although, I am not getting a response. What I did was to start a default/empty activity and pasted the following program :

  


  package com.example.myapplication;

import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;

import org.bytedeco.javacpp.Loader;

import android.os.Build;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {
    static final int cols = 192;
    static final int rows = 108;
    static final String ffmpeg = Loader.load(org.bytedeco.ffmpeg.ffmpeg.class);
    static final String rtmp_url = "test.flv";
    static final String[] command = {ffmpeg,
            "-y",
            "-f", "rawvideo",
            "-vcodec", "rawvideo",
            "-pix_fmt", "bgr24",
            "-s", (Integer.toString(cols) + "x" + Integer.toString(rows)),
            "-r", "10",
            "-i", "pipe:",
            "-c:v", "libx264",
            "-pix_fmt", "yuv420p",
            "-preset", "ultrafast",
            "-f", "flv",
            rtmp_url};
    @RequiresApi(api = Build.VERSION_CODES.O)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        new Thread(t1).start();

    }
    private static Runnable t1 = () -> {
        Log.e("TAG", "void OnCreate called successfully!");
        ProcessBuilder pb = new ProcessBuilder(command).redirectErrorStream(true);
        pb.redirectErrorStream(true);
        try {
            Process process = pb.start();
            BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            OutputStream writer = process.getOutputStream();
            Log.e("TAG", "Something good happened here");
        } catch (IOException e) {
            e.printStackTrace();
            Log.e("TAG", "Nothing good happened here");
        }
    };


}


  


  My current problem is that I can't seem to start properly the processBuilder process via pb.start() ;

  


  I get the following logs from the logcat panel :

  


  2022-06-14 17:24:46.328 13371-13371/com.example.myapplication E/TAG: void OnCreate called successfully!
2022-06-14 17:24:46.333 13371-13371/com.example.myapplication E/TAG: Nothing good happened here


  


  I'd like to understand why is it skipping the try/catch block and not starting the process ?

  


  EDIT : I made some changes as per @g00se's suggestions and I got the following stack trace from the code above :

  


  2022-06-15 00:32:26.700 29787-29787/? E/USNET: USNET: appName: com.example.myapplication
2022-06-15 00:32:29.328 29787-29828/com.example.myapplication E/TAG: void OnCreate called successfully!
2022-06-15 00:32:29.330 29787-29828/com.example.myapplication E/AndroidRuntime: FATAL EXCEPTION: Thread-4
    Process: com.example.myapplication, PID: 29787
    java.lang.NullPointerException
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1012)
        at com.example.myapplication.MainActivity.lambda$static$0(MainActivity.java:48)
        at com.example.myapplication.MainActivity$$ExternalSyntheticLambda0.run(Unknown Source:0)
        at java.lang.Thread.run(Thread.java:920)


  


• How to expose new API methods in the HTTP Reporting API – Introducing the Piwik Platform

  26 février 2015, par Thomas Steur — Development

  This is the next post of our blog series where we introduce the capabilities of the Piwik platform (our previous post was How to write UI tests for your plugin). This time you’ll learn how to extend our Reporting API. For this tutorial you will need to have basic knowledge of PHP.

  What is Piwik’s Reporting API ?

  It allows third party applications to access analytics data and manipulate miscellaneous data (such as users or websites) through HTTP requests.

  What is it good for ?

  The Reporting API is used by the Piwik UI to render reports, to manage users, and more. If you want to add a feature to the Piwik UI, you might have to expose a method in the API to access this data. As the API is called via HTTP it allows you to fetch or manipulate any Piwik related data from anywhere. In these exposed API methods you can do pretty much anything you want, for example :

  • Enhance existing reports with additional data
  • Filter existing reports based on custom rules
  • Access the database and generate custom reports
  • Persist and read any data
  • Request server information

  Getting started

  In this series of posts, we assume that you have already set up your development environment. If not, visit the Piwik Developer Zone where you’ll find the tutorial Setting up Piwik.

  To summarize the things you have to do to get setup :

  • Install Piwik (for instance via git).
  • Activate the developer mode : ./console development:enable.
  • Generate a plugin : ./console generate:plugin --name="MyApiPlugin". There should now be a folder plugins/MyApiPlugin.
  • And activate the created plugin : ./console plugin:activate "MyApiPlugin"

  Let’s start creating an API

  We start by using the Piwik Console to create a new API :

  ./console generate:api

  The command will ask you to enter the name of the plugin the created API should belong to. I will simply use the above chosen plugin name “MyApiPlugin”. There should now be a file plugins/MyApiPlugin/API.php which contains already an example to get you started easily :

  class API extends \Piwik\Plugin\API
  {
      public function getAnswerToLife($truth = true)
      {
          if ($truth) {
              return 42;
          }
   
          return 24;
      }
   
      public function getExampleReport($idSite, $period, $date, $wonderful = false)
      {
          $table = DataTable::makeFromSimpleArray(array(
              array('label' => 'My Label 1', 'nb_visits' => '1'),
              array('label' => 'My Label 2', 'nb_visits' => '5'),
          ));
   
          return $table;
      }
  }
  Télécharger

  Any public method in that file will be available via the Reporting API. For example the method getAnswerToLife can be called via this URL : index.php?module=API&method=MyApiPlugin.getAnswerToLife. The URL parameter method is a combination of your plugin name and the method name within this class.

  Passing parameters to your method

  Both example methods define some parameters. To pass any value to a parameter of your method simply specify them by name in the URL. For example ...&method=MyApiPlugin.getExampleReport&idSite=1&period=week&date=today&wonderful=1 to pass values to the parameters of the method getExampleReport.

  Returning a value

  In an API method you can return any boolean, number, string or array value. A resource or an object cannot be returned unless it implements the DataTableInterface such as DataTable (the primary data structure used to store analytics data in Piwik), DataTable\Map (stores a set of DataTables) and DataTable\Simple (a DataTable where every row has two columns : label and value).

  Did you know ? You can choose the response format of your API request by appending a parameter &format=JSON|XML|CSV|... to the URL. Check out the Reporting API Reference for more information.

  Best practices

  Check user permissions

  Do not forget to check whether a user actually has permissions to access data or to perform an action. If you’re not familiar with Piwik’s permissions and how to check them read our User Permission guide.

  Keep API methods small

  At Piwik we aim to write clean code. Therefore, we recommend to keep API methods small (separation of concerns). An API pretty much acts like a Controller :

  public function createLdapUser($idSite, $login, $password)
  {
      Piwik::checkUserHasAdminAccess($idSite);
      $this->checkLogin($login);
      $this->checkPassword($password);
      
      $myModel = new LdapModel();
      $success = $myModel->createUser($idSite, $login, $password);
      
      return $success;
  }
  Télécharger

  This is not only easy to read, it will also allow you to create simple tests for LdapModel (without having to bootstrap the whole Piwik layer) and you will be able to reuse it in other places if needed.

  Calling APIs of other plugins

  For example if you want to fetch an existing report from another plugin, say a list of all Page URLs, do not request this report by calling that method directly :

  \Piwik\Plugins\Actions\API::getInstance()->getPageUrls($idSite, $period, $date);

  . Instead, issue a new API request :

  $report = \Piwik\API\Request::processRequest('Actions.getPageUrls', array(
  
      'idSite' => $idSite,
  
      'period' => $period,
  
      'date'   => $date,
  
  ));

  This has several advantages :

  • It avoids a fatal error if the requested plugin is not available on a Piwik installation
  • Other plugins can extend the called API method via events (adding additional report data to a report, doing additional permission checks) but those events will be only triggered when requesting the report as suggested
  • If the method parameters change, your request will most likely still work

  Publishing your Plugin on the Marketplace

  In case you want to share your API with other Piwik users you can do this by pushing your plugin to a public GitHub repository and creating a tag. Easy as that. Read more about how to distribute a plugin and best practices when publishing a plugin.

  Isn’t it easy to create a API ? We never even created a file ! If you have any feedback regarding our APIs or our guides in the Developer Zone feel free to send it to us.