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• How can i crop part of a video while recording from desktop in real time using ffmpeg ? [on hold]

  28 juillet 2017, par daniel llee

  I’m using this line to record from the desktop to a video file :

  ffmpeg -f gdigrab -framerate 24 -i desktop -preset ultrafast -pix_fmt yuv420p out.mp4

  But this will record the whole desktop. Is there any way to record in real time only specific area/part of the desktop ?

  And this is how i’m using the ffmpeg with winforms :

  using System;  
  
  using System.Collections.Generic;  
  
  using System.Linq;  
  
  using System.Text;  
  
  using System.Threading.Tasks;  
  
  using System.IO;  
  
  using System.Diagnostics;  
  
  
  
  namespace Ffmpeg_App  
  
  {  
  
      class Ffmpeg  
  
      {  
  
          Process process;  
  
  
  
          public void Start(string FileName, int Framerate)  
  
          {  
  
              process = new System.Diagnostics.Process();  
  
              process.StartInfo.FileName = @"D:\ffmpegx86\ffmpeg.exe"; // Change the directory where ffmpeg.exe is.  
  
              process.EnableRaisingEvents = false;  
  
              process.StartInfo.WorkingDirectory = @"D:\ffmpegx86"; // The output directory  
  
              process.StartInfo.Arguments = @"-f gdigrab -framerate " + Framerate + " -i desktop -preset ultrafast -                                                                     pix_fmt yuv420p " + FileName;  
  
              process.Start();  
  
              process.StartInfo.UseShellExecute = false;  
  
              process.StartInfo.CreateNoWindow = false;  
  
              Close();  
  
          }  
  
  
  
          public void Close()  
  
          {  
  
              process.Close();  
  
          }  
  
      }  
  
  }  

• ffmpeg segments only the first part of my audio file

  30 juin 2012, par hammat

  I'm implementing a http live streaming server to send audio file to iOS devices.
  No problem with Apple's tools, mediafilesegmenter, my files are valid and it works fine.

  I'm trying now to segment the same file using ffmpeg. I've downloaded the last stable version which is the 0.10.2 for now.

  Here is how I try to segment my mp3 file :

  ./ffmpeg -re -i input.mp3 -f segment -segment_time 10 -segment_list outputList.m3u8 -acodec libmp3lame -map 0 output%03d.mp3

  It starts the mapping like expected but finish with only one .mp3 file.

  Did I miss something in the process ?
  Thanks in advance.

  edit

  Ok here is my latest command line :

  ffmpeg -i input.mp3 -c:a libmp3lame -b:a 128k -map 0:0 -f segment -segment_time 10 -segment_list outputlist.m3u8 -segment_format mp3 'output%03d.mp3'

  It still gives me only one file but the file is the hole song, not only one part.
  Here is the output of ffmpeg :

  ffmpeg version 0.10.2 Copyright (c) 2000-2012 the FFmpeg developers 
  
  built on Apr 20 2012 07:08:29 with gcc 4.5.2   
  
  configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libmp3lame   
  
      libavutil      51. 35.100 / 51. 35.100   
  
      libavcodec     53. 61.100 / 53. 61.100   
  
      libavformat    53. 32.100 /
  
          53. 32.100   
  
      libavdevice    53.  4.100 / 53.  4.100   
  
      libavfilter     2. 61.100 /  2. 61.100   
  
      libswscale      2.  1.100 /  2.  1.100   
  
      libswresample   0.  6.100 /  0.  6.100   
  
      libpostproc    52.  0.100 /  52.  0.100 
  
      [mp3 @ 0x8e4f120] max_analyze_duration 5000000 reached at 5015510
  
  Input #0, mp3, from 'BeachHouse-Myth.mp3':   
  
      Metadata:
  
              title           : Myth
  
              artist          : Beach House
  
              track           : /
  
              album           : Bloom
  
              disc            : /
  
              genre           : Alternative
  
              TSRC            : USSUB1296501   
  
      Duration: 00:04:18.69, start: 0.000000, bitrate: 320 kb/s
  
              Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16, 320 kb/s Output #0, segment, to 'stream%03d.mp3':   Metadata:
  
              title           : Myth
  
              artist          : Beach House
  
              track           : /
  
              album           : Bloom
  
              disc            : /
  
              genre           : Alternative
  
              TSRC            : USSUB1296501
  
              encoder         : Lavf53.32.100
  
              Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16, 128 kb/s
  
  Stream mapping:   
  
      Stream #0:0 -> #0:0 (mp3 -> libmp3lame) 
  
      Press [q] to stop, [?] for help 
  
      Truncating packet of size 1024 to 105ate=   0.0kbits/s    
  
      Truncating packet of size 1024 to 1 
  
      size=       0kB time=00:04:18.71 bitrate=   0.0kbits/s     video:0kB audio:4042kB global headers:0kB muxing overhead -100.000000%

• FFmpeg : how to burn subtitles into only part of the video ?

  30 octobre 2018, par xiatian

  I have a video which lasts for an hour but the ass subtitle only has the first 30 seconds. I want to burn this 30 seconds subtitle file into this video. Here are two options I have tried :

  • ffmpeg -i a.mp4 -vf "ass=a.ass" -ss 00:00:00 -t 30 b.mp4
    Then I only get a 30-second long video.

  • ffmpeg -i a.mp4 -vf "ass=a.ass"  b.mp4 I can get the whole one-hour long video but it takes a long time !

  How can I only encode only the first 30 seconds of this video and keep the rest of it unchanged (like the copy option) so that it takes less time to finish this burning process ?