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• Avconv / FFmpeg - VOB to mp4

  26 septembre 2017, par 0ne_Up

  I am using avconv/ffmpeg to convert VOB files copied from a DVD to mp4. The command I’m using is

  avconv -i "concat:1.VOB|2.VOB|3.VOB|4.VOB|5.VOB" -c:v libx264 -crf 28 -c:a libvo_aacenc -b:a 128k output.mp4

  This is working, but I’ve seen many different commands using different kinds of arguments, and I’m wondering if this is the "right" way to do it, and if someone has suggestions about which arguments I should (not) use and why (not). The file should be compatible with mobile devices and smart TV’s. I’ve also seen "libmp3lame" being used as audio codec, is it better to use AAC or MP3 ?

  The file size is 732.6MB for a video lasting 00:58:37, is this reasonable ?
  Maybe I can use something to reduce the filesize further without too much quality loss ?

  I’m also confused about the difference between Avconv and FFmpeg. I thought that FFmpeg is deprecated and Avconv is "newer and better", I have two installations of Linux Mint, when I run "avconv —help" on a 17.1 installations I see

  avconv version 9.20-6:9.20-0ubuntu0.14.04.1, Copyright (c) 2000-2014 the Libav developers

  And when I run the same command on a 18.1 installation I see

  ffmpeg version 2.8.11-0ubuntu0.16.04.1 Copyright (c) 2000-2017 the FFmpeg developers

  Is avconv newer than ffmpeg or is it just a different name for the same thing ?

• Slient crash when calls to ffmpeg's libav exist

  9 juin 2021, par William Lohan

  I have a fairly simple example.

  


  #include <iostream>&#xA;&#xA;extern "C"&#xA;{&#xA;#include <libavutil></libavutil>opt.h>&#xA;#include <libavutil></libavutil>avutil.h>&#xA;#include <libavcodec></libavcodec>avcodec.h>&#xA;#include <libavformat></libavformat>avformat.h>&#xA;}&#xA;&#xA;int main(int, char **)&#xA;{&#xA;  AVFormatContext *format = 0; // avformat_alloc_context();&#xA;&#xA;  // avformat_open_input(&amp;format, "http://s5radio.ponyvillelive.com:8026/stream.mp3", NULL, NULL);&#xA;  // avformat_find_stream_info(format, NULL);&#xA;&#xA;  std::cout &lt;&lt; "Hello, world!" &lt;&lt; std::endl;&#xA;&#xA;  return 0;&#xA;}&#xA;</iostream>

  


  I this outputs "Hello, world !" and I can set break points but the moment I uncomment anything calling avformat code the program silently closes with no error and no break points are hit making it impossible to debug.

  


  An example would be changing AVFormatContext *format = 0; to AVFormatContext *format = avformat_alloc_context(); or uncommenting avformat_open_input(&format, "http://s5radio.ponyvillelive.com:8026/stream.mp3", NULL, NULL);. Without breakpoints or errors how do I solve ?

  


  Update :
This is what I get from the debugger :

  


  


  ERROR : Unable to start debugging. Unexpected GDB output from command "-exec-run". During startup program exited with code 0xc0000139.
The program 'path\to\my\project\LibavPlayground.exe' has exited with code 0 (0x00000000).

  


  


  Update2 :

  


  this is my cmake :

  


  cmake_minimum_required(VERSION 3.0.0)
project(LibavPlayground VERSION 0.1.0 LANGUAGES CXX C)

find_package(PkgConfig REQUIRED) 
pkg_check_modules(LIBAV REQUIRED libavutil libavcodec libavformat)
include_directories(${LIBAV_INCLUDE_DIRS})
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D__STDC_CONSTANT_MACROS -Wno-deprecated-declarations")

include_directories(include PUBLIC)
include_directories(src PRIVATE)

file(GLOB SRC_FILES ${PROJECT_SOURCE_DIR}/src/*.cpp)

add_executable(LibavPlayground ${SRC_FILES})
target_link_libraries(LibavPlayground ${LIBAV_LIBRARIES})


  


  and all the libav* libraries were installed with a single pacman -S mingw-w64-x86_64-ffmpeg command

  


• Splitting audio by vocal / voice

  1er octobre 2020, par ML85

  I am working with audio file using webrtcvad and pydub. The split of any fragment is by silence of the sentence.
Is there any way by which the split can be done at each vocal (after each spoken word) ?
If librosa/ffmpeg/pydub has any feature like this, can split is possible at each vocal ? but after split, I need start and end time of the vocal exactly what that vocal part has positioned in the original file.
One simple solution or way to split by ffmpeg is also defined by :

  


  https://gist.github.com/vadimkantorov/00bf4fbe4323360722e3d2220cc2915e

  


  but this is also splitting by silence, and with each padding number or the frame size, the split is different. I am trying split by vocal.