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• FFMPEG MP3 file size much larger than expected on Windows 10

  8 avril 2018, par The Gora

  I’ve been using FFMPEG on Windows to :

  1. Convert iTunes M4A files to MP3s (with a bit rate of 128k) ; and
  2. Create 30 sec sample MP3s of the above MP3s (same bit rate).

  When I run FFMEG on a Windows 7 64 bit machine, the size of the MP3s (both for 1. & 2.) is in line with the rough calculation of :

  (Audio length in seconds) X (Bit rate)

  For example, a 4 minute audio yields an approx. 3.7MB MP3 file ; a 30 second sample MP3 is approx. 470KB.

  However when I run the same FFMPEG binary (copied from the Windows 7 machine) on a Windows 10 64 bit machine, all of the MP3s (both for 1. and for 2.) are inflated by approx 5MB. I’m using the same batch file on both machines to execute FFMEG with the required parameters, so pretty confident the difference is not down to user error.

  My questions are :

  1. Why is there this apparent 5MB overhead on Windows 10 ? and more importantly ;
  2. What can I do to remove this ?

  The large file size is a problem as the sample MP3s are to be put on a website for people to listen to a snippet of the song, and the webpage with multiple tags takes a long time to load completely (several minutes).

  Here is the version and lib info :

  ffmpeg version 3.4.1 Copyright (c) 2000-2017 the FFmpeg developers
 built with gcc 7.2.0 (GCC)
 configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth --enable-libmfx
 libavutil      55. 78.100 / 55. 78.100
 libavcodec     57.107.100 / 57.107.100
 libavformat    57. 83.100 / 57. 83.100
 libavdevice    57. 10.100 / 57. 10.100
 libavfilter     6.107.100 /  6.107.100
 libswscale      4.  8.100 /  4.  8.100
 libswresample   2.  9.100 /  2.  9.100
 libpostproc    54.  7.100 / 54.  7.100

  And here are the command lines I’m using :

  1. ffmpeg -i input.m4a -id3v2_version 3 -b:a 128k -output.mp3
  2. ffmpeg -i input.m4a -ss 30 -t 30 -af "afade=in:st=30:d=5,afade=out:st=55:d=5" -id3v2_version 3 -b:a 128k -output.mp3

• Converting mp4 to multiple resolutions using FFMPEG

  2 avril 2018, par Edwin Flataunet

  I am developing a E-Learning website where people can upload videos.

  When someone uploads a video, they usually upload it in 1080p full HD which is good.
  Now the issue is that when people watch the videos, they are only in 1080p and some people have bad internet (including myself) so watching a video in 1080p is not optimal.

  So I assume that converting the video to different formats (720p, 360 etc..) is the best way to go here.
  So I tried using FFMpeg, and it works, but its really slow, especially since some videos are over 10 minutes long and over 1gb in size.

  I use this command in FFMPEG :

  ffmpeg -i video.mp4 -vf scale:1280:720 -strict -2 output.mp4

  This works, but its really slow.

  Is there any better way to do this ? Since some people upload 5-10 videos and every video has to be in 3 different formats (1080p(original) 720p, 360p).

  Can someone give me some guidelines how to tackle this issue, as this kind of stops the website from progressing atm.

  Thanks

• Image sequence to video stream ?

  15 novembre 2020, par Hauns TM

  Like many people already seem to have (there are several threads on this subject here) I am looking for ways to create video from a sequence of images.

  



  I want to implement my functionality in C# !

  



  Here is what I wan't to do :

  



  /*Pseudo code*/&#xA;void CreateVideo(List<image> imageSequence, long durationOfEachImageMs, string outputVideoFileName, string outputFormat)&#xA;{&#xA;    // Info: imageSequence.Count will be > 30 000 images&#xA;    // Info: durationOfEachImageMs will be &lt; 300 ms&#xA;&#xA;    if (outputFormat = "mpeg")&#xA;    {&#xA;    }&#xA;    else if (outputFormat = "avi")&#xA;    {      &#xA;    }&#xA;    else&#xA;    {&#xA;    }&#xA;&#xA;    //Save video file do disk&#xA;}&#xA;</image>

  



  I know there's a project called Splicer (http://splicer.codeplex.com/) but I can't find suitable documentation or clear examples that I can follow (these are the examples that I found).

  



  The closest I want to do, which I find here on CodePlex is this :
How can I create a video from a directory of images in C# ?

  



  I have also read a few threads about ffmpeg (for example this : C# and FFmpeg preferably without shell commands ? and this : convert image sequence using ffmpeg) but I find no one to help me with my problem and I don't think ffmpeg-command-line-style is the best solution for me (because of the amount of images).

  



  I believe that I can use the Splicer-project in some way (?).

  



  In my case, it is about about > 30 000 images where each image should be displayed for about 200 ms (in the videostream that I want to create).

  



  (What the video is about ? Plants growing ...)

  



  Can anyone help me complete my function ?