Recherche avancée

Sur d’autres sites (5560)

• Monster Battery Power Revisited

  28 mai 2010, par Multimedia Mike — Python, Science Projects

  So I have this new fat netbook battery and I performed an experiment to determine how long it really lasts. In my last post on the matter, it was suggested that I should rely on the information that gnome-power-manager is giving me. However, I have rarely seen GPM report more than about 2 hours of charge ; even on a full battery, it only reports 3h25m when I profiled it as lasting over 5 hours in my typical use. So I started digging to understand how GPM gets its numbers and determine if, perhaps, it’s not getting accurate data from the system.

  I started poking around /proc for the data I wanted. You can learn a lot in /proc as long as you know the right question to ask. I had to remember what the power subsystem is called — ACPI — and this led me to /proc/acpi/battery/BAT0/state which has data such as :

  present :                 yes
  capacity state :          ok
  charging state :          charged
  present rate :            unknown
  remaining capacity :      100 mAh
  present voltage :         8326 mV
  

  "Remaining capacity" rated in mAh is a little odd ; I would later determine that this should actually be expressed as a percentage (i.e., 100% charge at the time of this reading). Examining the GPM source code, it seems to determine as a function of the current CPU load (queried via /proc/stat) and the battery state queried via a facility called devicekit. I couldn’t immediately find any source code to the latter but I was able to install a utility called ’devkit-power’. Mostly, it appears to rehash data already found in the above /proc file.

  Curiously, the file /proc/acpi/battery/BAT0/info, which displays essential information about the battery, reports the design capacity of my battery as only 4400 mAh which is true for the original battery ; the new monster battery is supposed to be 10400 mAh. I can imagine that all of these data points could be conspiring to under-report my remaining battery life.

  Science project : Repeat the previous power-related science project but also parse and track the remaining capacity and present voltage fields from the battery state proc file.

  Let’s skip straight to the results (which are consistent with my last set of results in terms of longevity) :

  
  
  

  So there is definitely something strange going on with the reporting— the 4400 mAh battery reports discharge at a linear rate while the 10400 mAh battery reports precipitous dropoff after 60%.

  Another curious item is that my script broke at first when there was 20% power remaining which, as you can imagine, is a really annoying time to discover such a bug. At that point, the "time to empty" reported by devkit-power jumped from 0 seconds to 20 hours (the first state change observed for that field).

  Here’s my script, this time elevated from Bash script to Python. It requires xdotool and devkit-power to be installed (both should be available in the package manager for a distro).
  

  PLAIN TEXT

  PYTHON :

  1. # !/usr/bin/python
  2.  
  3. import commands
  4. import random
  5. import sys
  6. import time
  7.  
  8. XDOTOOL = "/usr/bin/xdotool"
  9. BATTERY_STATE = "/proc/acpi/battery/BAT0/state"
  10. DEVKIT_POWER = "/usr/bin/devkit-power -i /org/freedesktop/DeviceKit/Power/devices/battery_BAT0"
  11.  
  12. print "count, unixtime, proc_remaining_capacity, proc_present_voltage, devkit_percentage, devkit_voltage"
  13.  
  14. count = 0
  15. while 1 :
  16.   commands.getstatusoutput("%s mousemove %d %d" % (XDOTOOL, random.randrange(0,800), random.randrange(0, 480)))
  17.   battery_state = open(BATTERY_STATE).read().splitlines()
  18.   for line in battery_state :
  19.     if line.startswith("remaining capacity :") :
  20.       proc_remaining_capacity = int(line.lstrip("remaining capacity : ").rstrip("mAh"))
  21.     elif line.startswith("present voltage :") :
  22.       proc_present_voltage = int(line.lstrip("present voltage : ").rstrip("mV"))
  23.   devkit_state = commands.getoutput(DEVKIT_POWER).splitlines()
  24.   for line in devkit_state :
  25.     line = line.strip()
  26.     if line.startswith("percentage :") :
  27.       devkit_percentage = int(line.lstrip("percentage :").rstrip(’\%’))
  28.     elif line.startswith("voltage :") :
  29.       devkit_voltage = float(line.lstrip("voltage :").rstrip(’V’)) * 1000
  30.   print "%d, %d, %d, %d, %d, %d" % (count, time.time(), proc_remaining_capacity, proc_present_voltage, devkit_percentage, devkit_voltage)
  31.   sys.stdout.flush()
  32.   time.sleep(60)
  33.   count += 1

• FFMPGE:avio will ues more battery than use file on harddisk ?

  27 juillet 2012, par 7bigtrees

  I have tested that avio will ues more battery than using file on harddisk.
  In same time,avio spend twice as much than file on harddisk.
  Anybody know why ?
  amazing

  FFMPEG:0.8.10
  Platform：Android 2.2.3，Moto XT800+

• Safari on Mac and IOS 14 Won't Play HTML 5 MP4 Video

  10 mars 2021, par Glen Elkins

  So i have developed a chat application that uses node for the back-end. When a user selects a video on their iphone it usually is .mov format so when it's sent to the node server it's then converted to mp4 with ffmpeg. All that works fine, then if i load up my chat again in Chrome on my mac the video plays just fine as the mp4.

  


  

  


  This screenshot shows the video embed is there, set to mp4 yet it won't play in Safari on my mac or my phone, in fact it just shows the video as 0 seconds long yet i can play it in chrome and also download the mp4 file by accessing the embed url directly.

  


  Any ideas ? I had it convert to mp4 to prevent things like this, but safari doesn't seem to even like mp4 files.

  


  The back-end part that serves the private file is in Symfony 4 (PHP) :

  


  /**
     * @Route("/private/files/download/{base64Path}", name="downloadFile")
     * @param string $base64Path
     * @param Request $request
     * @return Response
     */
    public function downloadFile(string $base64Path, Request $request) : Response
    {


        // get token
        if(!$token = $request->query->get('token')){
            return new Response('Access Denied',403);
        }



        /** @var UserRepository $userRepo */
        $userRepo = $this->getDoctrine()->getRepository(User::class);

        /** @var User $user */
        if(!$user = $userRepo->findOneBy(['deleted'=>false,'active'=>true,'systemUser'=>false,'apiKey'=>$token])){
            return new Response('Access Denied',403);
        }



        // get path
        if($path = base64_decode($base64Path)){

            // make sure the folder we need exists
            $fullPath = $this->getParameter('private_upload_folder') . '/' . $path;



            if(!file_exists($fullPath)){
                return new Response('File Not Found',404);
            }

        

            $response = new Response();
            $response->headers->set('Content-Type', mime_content_type($fullPath));
            $response->headers->set('Content-Disposition', 'inline; filename="' . basename($fullPath) . '"');
            $response->headers->set('Content-Length', filesize($fullPath));
            $response->headers->set('Pragma', "no-cache");
            $response->headers->set('Expires', "0");
            $response->headers->set('Content-Transfer-Encoding', "binary");

            $response->sendHeaders();

            $response->setContent(readfile($fullPath));

            return $response;
        }

        return new Response('Invalid Path',404);
    }


  


  This works fine everywhere except safari when trying to embed the video. It's done like this because the videos are not public and need an access token.

  


  UPDATE : Here is a test link of an mp4, you'll have to allow the insecure certificate as it's on a quick test sub domain. If you open it in chrome, you'll see a 3 second video of my 3d printer curing station, if you load the same link in safari, you'll see it doesn't work

  


  https://tester.nibbrstaging.com/private/files/download/Y2hhdC83Nzk1Y2U2MC04MDFmLTExZWItYjkzYy1lZjI4ZGYwMDhkOTMubXA0?token=6ab1720bfe922d44208c25f655d61032

  


  The server runs on cPanel with Apache and i think it might be something to do with the video needs streaming ?

  


  UPDATED CODE THAT WORKS IN SAFARI BUT NOW BROKEN IN CHROME :

  


  Chrome is now giving Content-Length : 0 but it's working fine in safari.

  


  public function downloadFile(string $base64Path, Request $request) : ?Response
    {

        ob_clean();

        // get token
        if(!$token = $request->query->get('token')){
            return new Response('Access Denied',403);
        }


        

        /** @var UserRepository $userRepo */
        $userRepo = $this->getDoctrine()->getRepository(User::class);

        /** @var User $user */
        if(!$user = $userRepo->findOneBy(['deleted'=>false,'active'=>true,'systemUser'=>false,'apiKey'=>$token])){
            return new Response('Access Denied',403);
        }



        // get path
        if($path = base64_decode($base64Path)){

            // make sure the folder we need exists
            $fullPath = $this->getParameter('private_upload_folder') . '/' . $path;



            if(!file_exists($fullPath)){
                return new Response('File Not Found',404);
            }


            $filesize = filesize($fullPath);
            $mime = mime_content_type($fullPath);

            header('Content-Type: ' . $mime);

            if(isset($_SERVER['HTTP_RANGE'])){

                // Parse the range header to get the byte offset
                $ranges = array_map(
                    'intval', // Parse the parts into integer
                    explode(
                        '-', // The range separator
                        substr($_SERVER['HTTP_RANGE'], 6) // Skip the `bytes=` part of the header
                    )
                );



                // If the last range param is empty, it means the EOF (End of File)
                if(!$ranges[1]){
                    $ranges[1] = $filesize - 1;
                }

                header('HTTP/1.1 206 Partial Content');
                header('Accept-Ranges: bytes');
                header('Content-Length: ' . ($ranges[1] - $ranges[0])); // The size of the range

                // Send the ranges we offered
                header(
                    sprintf(
                        'Content-Range: bytes %d-%d/%d', // The header format
                        $ranges[0], // The start range
                        $ranges[1], // The end range
                        $filesize // Total size of the file
                    )
                );

                // It's time to output the file
                $f = fopen($fullPath, 'rb'); // Open the file in binary mode
                $chunkSize = 8192; // The size of each chunk to output

                // Seek to the requested start range
                fseek($f, $ranges[0]);

                // Start outputting the data
                while(true){
                    // Check if we have outputted all the data requested
                    if(ftell($f) >= $ranges[1]){
                        break;
                    }

                    // Output the data
                    echo fread($f, $chunkSize);

                    // Flush the buffer immediately
                    @ob_flush();
                    flush();
                }
            }else{

                // It's not a range request, output the file anyway
                header('Content-Length: ' . $filesize);

                // Read the file
                @readfile($filesize);

                // and flush the buffer
                @ob_flush();
                flush();



            }

        }else {

            return new Response('Invalid Path', 404);
        }
    }


  


  I have notice in chrome that it's sending the range header like this :

  


  Range : bytes=611609-

  


  Where safari sends

  


  Range : bytes=611609-61160

  


  So for some reason chrome is missing the second range amount, that obviously means my code can't find a range number for the second one.

  


  Doesn’t matter what I do I can’t get it working in both chrome and safari. Safari wants the byte range part , chrome seems to request it then sends a new request for the full file but even the full file part of the code gives a 500 error. If I take out the byte range bit then it works fine in chrome but not safari.

  


  UPDATE :

  


  Here is some strange things going on in chrome :

  


  For the video i am testing with it makes 3 range requests :

  


  REQUEST 1 HEADERS - asking for bytes 0- (to the end of the file)

  


  GET /private/files/download/Y2hhdC83Nzk1Y2U2MC04MDFmLTExZWItYjkzYy1lZjI4ZGYwMDhkOTMubXA0?token=6ab1720bfe922d44208c25f655d61032 HTTP/1.1

Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.192 Safari/537.36
Accept-Encoding: identity;q=1, *;q=0
Accept: */*
Sec-Fetch-Site: same-site
Sec-Fetch-Mode: no-cors
Sec-Fetch-Dest: video
Referer: https://gofollow.vip/
Accept-Language: en-US,en;q=0.9
Range: bytes=0-


  


  RESPONSE GIVES IT BACK ALL THE BYTES IN THE FILE AS THAT'S WHAT WAS ASKED FOR BY CHROME :

  


  HTTP/1.1 206 Partial Content
Date: Wed, 10 Mar 2021 12:35:54 GMT
Server: Apache
Accept-Ranges: bytes
Content-Length: 611609
Content-Range: bytes 0-611609/611610
Vary: User-Agent
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: video/mp4


  


  SECOND REQUEST HEADERS : NOW IT'S ASKING FOR 589824 to the end of the file :

  


  Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.192 Safari/537.36
Accept-Encoding: identity;q=1, *;q=0
Accept: */*
Sec-Fetch-Site: same-site
Sec-Fetch-Mode: no-cors
Sec-Fetch-Dest: video
Referer: https://gofollow.vip/
Accept-Language: en-US,en;q=0.9
Range: bytes=589824-


  


  RESPONSE OBLIGES :

  


  HTTP/1.1 206 Partial Content
Date: Wed, 10 Mar 2021 12:35:55 GMT
Server: Apache
Accept-Ranges: bytes
Content-Length: 21785
Content-Range: bytes 589824-611609/611610
Vary: User-Agent
Keep-Alive: timeout=5, max=99
Connection: Keep-Alive
Content-Type: video/mp4


  


  THEN IT'S MAKING THIS 3rd REQUEST THAT GIVES AN INTERNAL SERVER ERORR, THIS TIME IT'S LITERALLY ASKING FOR THE LAST BYTE :

  


  GET /private/files/download/Y2hhdC83Nzk1Y2U2MC04MDFmLTExZWItYjkzYy1lZjI4ZGYwMDhkOTMubXA0?token=6ab1720bfe922d44208c25f655d61032 HTTP/1.1

Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.192 Safari/537.36
Accept-Encoding: identity;q=1, *;q=0
Accept: */*
Sec-Fetch-Site: same-site
Sec-Fetch-Mode: no-cors
Sec-Fetch-Dest: video
Referer: https://gofollow.vip/
Accept-Language: en-US,en;q=0.9
Range: bytes=611609-


  


  RESPONSE - THE CONTENT LENGTH IS 0 BECAUSE THERE IS NO DIFFERENCE BETWEEN THE REQUESTED BYTES AND THE BYTES RETURNED :

  


  HTTP/1.1 500 Internal Server Error
Date: Wed, 10 Mar 2021 12:35:56 GMT
Server: Apache
Accept-Ranges: bytes
Cache-Control: max-age=0, must-revalidate, private
X-Frame-Options: DENY
X-XSS-Protection: 1
X-Content-Type-Options: nosniff
Referrer-Policy: origin
Strict-Transport-Security: max-age=31536000; includeSubDomains
Expires: Wed, 10 Mar 2021 12:35:56 GMT
Content-Length: 0
Content-Range: bytes 611609-611609/611610
Vary: User-Agent
Connection: close
Content-Type: text/html; charset=UTF-8