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• Encoding video settings with Transloadit and FFMPEG

  2 octobre 2015, par David Soler

  I’m using Transloadit to convert and compress videos from .mov to .ts format. I’m using the json templates but unfortunately the docs are not too extensive. The thing is the quality I’m getting rigth now is very poor and pixeled. If I do it through console with ffmpeg command and including some parameters as crf (Constant Rate Factor) the quality gets a lot better but I dont know how edit it in transloadit template to get the same result.

  This is the ffmpeg command I’m using to convert the video in console

  ./ffmpeg -i ../canales.mov -c:v libx264 -crf 23 -bsf:a aac_adtstoasc output.ts

  And this is the json template I’m using right now. I guess I should add parameters to ffmpeg hash but I don’t know which settings are allowed

  {
  
    "steps": {
  
      "file": {
  
        "robot": "/file/filter",
  
        "accepts": [
  
          [
  
            "${file.mime}",
  
            "regex",
  
            "video"
  
          ]
  
        ],
  
        "declines": [
  
          [
  
            "${file.size}",
  
            ">",
  
            "10485760"
  
          ],
  
          [
  
            "${file.meta.duration}",
  
            ">",
  
            "16"
  
          ]
  
        ],
  
        "error_on_decline": true
  
      },
  
      "segments": {
  
        "robot": "/video/encode",
  
        "preset": "iphone-high",
  
        "width": 1242,
  
        "height": 2208,
  
        "use": "file",
  
        "segment": true,
  
        "segment_duration": 10,
  
        "ffmpeg_stack": "v2.2.3",
  
        "ffmpeg": {
  
          "b": "1200K",
  
          "crf": 23
  
        }
  
      },
  
      "thumb": {
  
        "robot": "/video/thumbs",
  
        "use": "file",
  
        "count": 1
  
      },
  
      "store": {
  
        "robot": "/s3/store",
  
        "use": [
  
          "segments",
  
          "thumb"
  
        ],
  
        "key": "key",
  
        "secret": "Secret",
  
        "bucket": "bucket"
  
      }
  
    }
  
  }

• php exec() for ffmpeg not working

  15 mars 2015, par user3196597

  hai i am using ffmpeg command in php exec() for converting any type of video to flv format the command i’m using i sworking fine in the command prompt but when i run the same commend it returns nothing..actully the output is Array( ) and the the third parameter $result is "1"

  i’ve read similar questions like this on stackoverflow but it’s not helping

  most of the time i noticed that the issue is in path and the safe mode of php

  and i have disabled safe mode using .htaccess the syntax is given below and i am using windows 7 os

  the directory to the ffmpeg application is c :\ffmpeg\bin\ffmpeg

  the full script and output is given below :

  the ffmpeg command :

     ffmpeg -i c:\xampp\htdocs\video\original\robot.mp4 -c:v libx264 -ar 44100 -crf 17 c:\xampp\htdocs\video\vids\robot.flv

  the php script :

   echo "starting ffmpeg...<br />";
  
  
  
   echo exec("ffmpeg -i c:\xampp\htdocs\video\original\robot.mp4 -c:v libx264 -ar 44100 -crf 17 c:\xampp\htdocs\video\vids\robot.flv",$out,$r);
  
   var_dump($out);
  
   echo $r."<br />";
  
   echo "done...<br />";
  
   ?>

  the htaccess for switching off the safe mode :

   php_value safe_mode "0" 

  the output :

   starting ffmpeg...
  
   array(0) { } 1 
  
   done...

• FFmpeg latency is over 3 seconds (must be subsecond)

  20 mai 2022, par Georges Casassovici

  I'm working on a robot (raspberry pi 4 based) that is accessible from anywhere. My robot is currently at a 3-second latency. I also use OvenMediaEngine (RTMP to WebRTC) to transmit my stream to the client (on a website).Here is my command :

  


  raspivid -n -t 0 -w 1280 -h 720 -fps 25 -b 3500000 -g 50 -fl -o - | ffmpeg -thread_queue_size 1024 -i - -itsoffset 6 -f alsa -channels 1 -thread_queue_size 1024 -i hw:2 -preset ultrafast -tune zerolatency -vcodec libx264 -r 25 -b:v 512k -s 1280x720 -acodec aac -ac 2 -ab 32k -ar 44100 -f flv rtmp ://xxxxxxxx:1935/app/stream

  


  Does anyone know why it won't stream at subsecond latency ?

  


  Thanks in advance !