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• Aspect ratio problems at transcoding with ffmpeg [closed]

  19 novembre 2023, par udippel

  I have a huge collection of videos from the last 20+ years, videos in all sorts of formats. I use gerbera as open source UPnP-AV media server. Our TV handles only very limited of these formats. Therefore I use the transcoding feature of gerbera (I don't want to convert the 2000+ files ; thereby avoiding loss of multiple audio tracks, (multiple) subtitles, and so forth).

  


  This is my current unified argument line for ffmpeg :
-c:v mpeg2video -maxrate 20000k -vf setdar=16/9 -r 24000/1001 -qscale:v 4 -top 1 -c:a mp2 -f mpeg -y
It works pretty okay, except of the aspect ratios. Well, I don't understand this fully, because ffprobe for File A states :
Stream #0:0: Video: mpeg4 (Simple Profile) (XVID / 0x44495658), yuv420p, 624x464 [SAR 1:1 DAR 39:29], 1500 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
This file displays very well.
File B comes as :
Stream #0:0(eng): Video: h264 (High), yuv420p(tv, bt709, progressive), 960x720, SAR 1:1 DAR 4:3, 23.98 fps, 23.98 tbr, 1k tbn, 180k tbc (default)
This file displays horribly squeezed vertically and doesn't fill the screen left and right neither, with the same settings of the TV. Also, playing this file (and others, naturally) the TV doesn't offer the 14:9 display option, which is available e.g. for the file further up.

  


  Both have same SAR, DAR, almost identical H:V ratios (1.345, 1.333) ; and almost identical DAR.

  


  My questions :

  


  

  1. Why, despite of almost identical pixel ratios, DAR and SAR are these files handled so differently in one and the same session on the same TV (SONY), please ?

  


  2. With which method could I instruct ffmpeg to display the second file properly, too, please ?
(I have already tried 'scale' ; but to no avail. Which could have been foreseen, since the ratios are already very close.)
My guess is, that the (tv, bt709, progressive) mess things up.
(I have already tried to add the yuv420p in the argument line, also to no avail.)

  


  


  Appreciate any help,

  


  Uwe

  


  I have already tried to add a 'scale' option ; but to no avail. Which could have been foreseen, since the ratios are already very close.
I have already tried to add the yuv420p in the argument line, also to no avail.
I have already tried force_original_aspect_ratio, but also here, nothing improving.
Also, I played with -aspect, but the aspects are okay, and would need individual corrections, which I can't and don't to do for 2000+ files. A simple 16:9 doesn't cut it.

  


• FFMPEG command for video based on ratio [duplicate]

  21 novembre 2017, par pocek

  This question already has an answer here :

  • FFMPEG : Add a fixed size image on a video, regardless of the video width & height (resolution)
    
    1 answer
    

  I am using ffmpeg (in linux server with php)

  and I want to watermark a png logo on the mp4 file, my problem is that

  I want to scale my logo and change it based on source video size(for example 1/4 of height),

  I have this code bellow :

  shell_exec('ffmpeg -i file.mp4 -i logo.png -filter_complex "overlay=10:10" file-watered.mp4");

  it works on every video.

  For Normal (medium) size image :

  

  For Small (medium) size image (which is bad !)

  

  Ideal output for this size would be :

  

  I’ve changed a little bit my first code like this :

  shell_exec('ffmpeg -i file.mp4 -i logo.png -filter_complex "[0:v]scale=500:-1[bg];[bg][1:v]overlay=(main_w-overlay_w):(main_h-overlay_h)" watered.mp4');

  The main problem is that, I want to change the logo size based on video size.

  How can I do it with ffmpeg ?

• Keep getting WIN32Exception when running FFMPEG in ASP.NET project

  23 octobre 2014, par Lance Bloom

  I have an ASP.NET project and I want to use FFMPEG to help create thumbails for my videos. I’ve loaded FFMPEG into the project, and whenever I run my code I get the same error :

  ’ffmpeg.MainModule’ threw an exception of type ’System.ComponentModel.Win32Exception’
  "A 32 bit processes cannot access modules of a 64 bit process."

  I’m using VS 2013, and I’ve set my target platform to x86, and made 100% sure I am using the 32bit version of ffmpeg. I’m using the static libraries from this site (http://ffmpeg.zeranoe.com/builds/) I also tried to change the target platform to All CPUs or x64, and tried with both 32 and 64 bit versions of FFMPEG. Always the same error. I am running IIS Express when I test in my local environment.

  Here is my code. Would appreciate any help !

  String vSource = "http://example.com/myvideo.mp4";
  
  String path1 = HttpContext.Current.Request.PhysicalApplicationPath;
  
  
  
  Process ffmpeg = new Process();
  
  ProcessStartInfo startinfo = new ProcessStartInfo(HostingEnvironment.MapPath("~/App_Data/exe/ffmpeg.exe"), "-i " + vSource + "-ss 00:00:05.000 -f image2 -vframes 1 " + path1 +"thumbnail1.jpg");
  
  
  
  startinfo.RedirectStandardError = true;
  
  startinfo.RedirectStandardOutput = true;
  
  startinfo.RedirectStandardInput = true;
  
  startinfo.UseShellExecute = false;
  
  startinfo.CreateNoWindow = true;
  
  ffmpeg.StartInfo = startinfo;
  
  
  
  ffmpeg.Start();