Recherche avancée

Sur d’autres sites (10849)

• Building static FFmpeg libs for Windows 64-bit application

  6 avril 2016, par Igor R.

  I build static FFmpeg libs for Windows 64 bit. Configuring as follows :

  ./configure --disable-everything --enable-static --disable-shared --enable-memalign-hack --disable-debug --enable-stripping --enable-protocol=file --enable-yasm --enable-decoder=mp3,mpeg4,h264 --enable-muxer=mp4,avi --enable-encoder=mjpeg .

  The application is built in Visual Studio 2012 with /MT option and linked with libavformat.a, libavcodec.a etc. I also link it with libmingwex.a, libgcc.a.

  The linker fails with the following errors :

  6>libavformat.a(file.o) : error LNK2001: unresolved external symbol __imp__wrmdir
  
  6>libavformat.a(file.o) : error LNK2001: unresolved external symbol __imp__rmdir
  
  6>libavformat.a(file.o) : error LNK2001: unresolved external symbol __imp__wunlink
  
  6>libavformat.a(file.o) : error LNK2001: unresolved external symbol __imp__unlink
  
  6>libavutil.a(time.o) : error LNK2001: unresolved external symbol clock_gettime
  
  6>libavutil.a(time.o) : error LNK2001: unresolved external symbol nanosleep

  As for the 2 latter errors, I can solve them by manually defining macros in config.h : #define HAVE_NANOSLEEP 1 and #define HAVE_CLOCK_GETTIME 1.

  The question is how to solve the former 4. These look like functions imported from a dll (__imp prefix), but my application is built with /MT, and I don’t want any dynamic dependencies in FFmpeg. How to get rid of them ?

  I tried to configure FFmpeg with --extra-cflags="-static", but it doesn’t help.

• Set RTSP/UDP buffer size in FFmpeg

  16 mars 2015, par chuckleplant

  Note : I’m aware ffmpeg and libav are different libraries. This is a problem common to both.

  Disclaimer : Duplicate of SO question marked as answered but actually didn’t give a proper solution.

  ---

  Insufficient UDP buffer size causes broken streams for several high resolution video streams. In LibAV/FFMPEG it’s possible to set the udp buffer size for udp urls (udp ://...) by appending some options to it.

  However, for RTSP urls this is not supported. These are the only solutions I’ve found :

  • Rebuilding ffmpeg/libav changing the UDP_MAX_PKT_SIZE in the udp.c source file.
  • Using a nasty hack to find the required value.
  • Using a different decoding library (proposed solution to aforementioned related SO question).

  None of these is actually a solution. From what I found it should be possible to use the API’s AVOptions to find and set this value. Or else, the AVDictionary.

  It’s very difficult to find how to set these throughout the documentation of either libav or ffmpeg.

• "How can we use Ffmpeg to apply blur, overlay a logo and waveform, and add a border around a video, step by step ? [closed]

  1er février 2024, par itsfaisalkhalid

  We're looking to enhance a video using Ffmpeg by implementing several effects sequentially. First, we aim to apply a blur effect to the entire video. Then, we want to overlay a logo and a waveform onto the blurred video. Finally, we need to add a border around the entire composition. This step-by-step process requires precise commands and careful consideration of parameters to achieve the desired result effectively.

  


  I utilized Ffmpeg commands to sequentially apply blur, overlay the logo and waveform, and add a border to the video. I expected each effect to be applied in the specified order, resulting in a visually enhanced video with all desired elements. However, I encountered challenges in properly configuring the parameters for each effect, leading to unexpected results such as misaligned overlays or improper blur intensity.

  


  @echo off
setlocal enabledelayedexpansion

rem Set paths and directories
set "ffmpeg_path=C:\ffmpeg\bin\ffmpeg.exe"
set "input_dir=_input"
set "output_dir=_output"

rem Ensure input and output directories exist
if not exist "%input_dir%" (
    echo Error: Input directory "%input_dir%" not found.
    exit /b 1
)

if not exist "%output_dir%" (
    mkdir "%output_dir%"
)

rem Loop through input directory
for %%t in ("%input_dir%\*.*") DO (

    rem Process each file with ffmpeg
"%ffmpeg_path%" -y -i "%%t" -i logo.png -filter_complex "\
    [0:v]eq=brightness=0.2:saturation=2.0:contrast=1.2, crop=iw/1.2:ih/1.2, \
    boxblur=1:2 [blurred_bg]; \
    [blurred_bg][1:v]overlay=(main_w-overlay_w)/2:(main_h-overlay_h-10)[bg_with_logo]; \
    [0:a]showwaves=s=1080x100:mode=line:colors=white [waveform]; \
    [bg_with_logo][waveform]overlay=10:H-h-10, \
    format=yuv420p[v]; \
    [v]pad=iw+20:ih+20:x=10:y=10:color=white[final_output]" \
    -map "[final_output]" -map 0:a -c:v h264 -c:a aac -b:a 128k -ar 44100 "%output_dir%\temp.mp4"

    rem Check if output file exists
    if exist "%output_dir%\temp.mp4" (
        rem Calculate new MD5 hash
        certutil -hashfile "%output_dir%\temp.mp4" MD5 > "%output_dir%\temp_md5.txt"

        rem Remove ID3 tag metadata
        "%ffmpeg_path%" -i "%output_dir%\temp.mp4" -map_metadata -1 -c:v copy -c:a copy "%output_dir%\%%~nt.mp4"

        rem Clean up temporary files
        del "%output_dir%\temp.mp4"
        del "%output_dir%\temp_md5.txt"
    ) else (
        echo Error: Failed to create output file for "%%~nt"
    )
)

pause