Newest 'ffmpeg' Questions - Stack Overflow

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• Create 30s audio clip from middle of file using ffmpeg [on hold]

  15 octobre 2016, par Draven

  I want to create a sample audio file that is 30 seconds long from the middle of the audio file.

  Is it possible to do something like that in a one line command?

  I know I can use -ss to jump ahead, but I am not sure how to jump ahead 50% of the file length (minus 15s).

  And I know I can use -t for the length.

  Here's what I am currently using in my command line PHP script:

  (I am making sure it's a 128k bit mp3 file)

  ffmpeg -y -i file.ogg -acodec libmp3lame -ac 2 -ab 128k file.mp3

• How to access windows enviroment variables on MSYS ?

  15 octobre 2016, par Mostafa Sataki

  I want to build ffmpeg by vs2015 from msys2.

  In the first add vs2015\vc\bin\amd64 in to path enviroment in windows.

  Run "vs2015 x64 command prompt" as administrator then run vcvarsall.bat amd64.

  In the final go to "msys" path and then run "msys2_shell.cmd".

  I use "which cl" command for localize cl.exe.

  Output:

  which: no cl in (/usr/local/bin:/usr/bin:/bin:/opt/bin:/c/Windows/System32:/c/Windows:/c/Windows/System32/Wbem:/c/Windows/System32/WindowsPowerShell/v1.0/)

  How to access to windows enviroments in the msys ?

• Precise sample auto-alignment of two identical audio files, shifted by few milliseconds

  15 octobre 2016, par Vasyl Shumskyi

  I'm trying to achieve precise sample auto-alignment of two identical audio files, which are shifted by few milliseconds.

  Offset of the two files is unknown and the difference of the files duration is not the same as the samples shift.

  The solution should be automatic and reusable.

  Can this be done with CLI audio tools SoX/FFmpeg or the likes?

• Decoding of 4k video causing overflow of buffer in a multi process application

  15 octobre 2016, par mkreddy

  I am quite new in working with FFMPEG. Please excuse me if I made any mistake while explaining my problem.

  I am working on an application where PCAP captures 1316 bytes of data split that into 188 bytes and writes it into it to corresponding shared memory. The other process reads the data and decode using ffmpeg and process it.

  This whole process is working fine with H264 and HEVC video. The problem comes with 4k video. While decodig the 4k video I am encountering buffer overflow. I have observed that on a machine with high CPU frequence the overflow rate was less. Hence If I can reduce the time taken to decode and process the video data at ffmpeg might solve my problem. I am not able to find a good solution for my problem.

  Is there any way to speed up the process at ffmpeg decoder?, is thre any other way to supress the overflows?

• NReco video to sequence of bitmaps

  15 octobre 2016, par Christine

  How can I convert video to a sequence of bitmaps? I need every frame one by one and process them in memory (no disc output).

  I chose NReco.VideoConverter but not sure which method can do this. I understand that FFMpegConverter.GetVideoThumbnail() is useless, since you can extract image only based on time input.

  Can I use FFMpegConverter.ConvertMedia() ? Please, how? I've been searching for hours.