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• ffmpeg adelay audio out of sync

  30 juillet 2022, par benyamin

  im using ffmpeg to merge/mix some audio files and put each audio stream at a specific time using adelay and im using amix to get a single stream at the end.

  


  here is exactly what im doing :

  


  


  ffmpeg -i ./recFiles/1659162768910.webm -i ./recFiles/1659162867370.webm -i ./recFiles/1659162981321.webm -i ./recFiles/1659163143645.webm -i ./recFiles/1659163404833.webm -i ./recFiles/1659162778530.webm -i ./recFiles/1659162827630.webm -i ./recFiles/1659162879510.webm -i ./recFiles/1659162895790.webm -i ./recFiles/1659162985833.webm -i ./recFiles/1659163160042.webm -i ./recFiles/1659163247185.webm -i ./recFiles/1659162821149.webm -i ./recFiles/1659162875630.webm -i ./recFiles/1659162995533.webm -i ./recFiles/1659163150526.webm -i ./recFiles/1659163159313.webm -i ./recFiles/1659163258913.webm -i ./recFiles/1659163279414.webm -i ./recFiles/1659163328226.webm -i ./recFiles/1659163381885.webm -i ./recFiles/1659163412389.webm -i ./recFiles/1659163454570.webm -filter_complex "[0]adelay=150:all=1[a0] ;[1]adelay=98642:all=1[a1] ;[2]adelay=212549:all=1[a2] ;[3]adelay=374873[a3] ;[4]adelay=636061:all=1[a4] ;[5]adelay=9801:all=1[a5] ;[6]adelay=58862:all=1[a6] ;[7]adelay=110738:all=1[a7] ;[8]adelay=127022:all=1[a8] ;[9]adelay=217061:all=1[a9] ;[10]adelay=391269:all=1[a10] ;[11]adelay=478413:all=1[a11] ;[12]adelay=52423:all=1[a12] ;[13]adelay=106861:all=1[a13] ;[14]adelay=226765[a14] ;[15]adelay=381758:all=1[a15] ;[16]adelay=390542:all=1[a16] ;[17]adelay=490141:all=1[a17] ;[18]adelay=510642:all=1[a18] ;[19]adelay=559458:all=1[a19] ;[20]adelay=613118:all=1[a20] ;[21]adelay=643621[a21] ;[22]adelay=685797[a22] ;[a0][a1][a2][a3][a4][a5][a6][a7][a8][a9][a10][a11][a12][a13][a14][a15][a16][a17][a18][a19][a20][a21][a22]amix=23,loudnorm[final]" -map "[final]" -metadata title="example.com - a title" ./recFiles/rec28314068fe97c6_1659163923005.webm

  


  


  all the numbers are calculated and correct but it doesn't seems so in the output file.
some streams are out of sync ( sometimes all of them )

  


  my ffmpeg version is :
ffmpeg version n4.4.1-2-gcc33e73618

  


  can anyone please help me with this ? i can't see what's wrong.. it should work

  


• Using Flutter FFMPEG_KIT to convert a sequence of RGBA images into a mp4 video

  30 avril 2023, par jdevp2

  I’m trying to convert a sequence of RGBA byte images into an MP4 video by using Flutter FFMPEGKit package. The following is the code snippet but it gives me an error. I’m not sure what is the correct option that I should use to convert a set of rawrgba images to a video. I appreciate any help.

  


   static Future<void> videoEncoder() async {&#xA;    appTempDir = &#x27;${(await getTemporaryDirectory()).path}/workPath&#x27;;&#xA;   &#xA;    FFmpegKit.execute(&#xA;           &#x27;-hide_banner -y -f rawvideo -pix_fmt rgba -i appTempDir/input%d.rgba -c:v mpeg4  -r 12 appTempDir/output.mp4&#x27;)&#xA;     .then((session) async {&#xA;       final returnCode = await session.getReturnCode();&#xA;      if (ReturnCode.isSuccess(returnCode)) {&#xA;        print(&#x27;SUCCESS&#x27;);&#xA;      } else if (ReturnCode.isCancel(returnCode)) {&#xA;        print(&#x27;CANCEL&#x27;);&#xA;      } else {&#xA;        print(&#x27;ERROR&#x27;);&#xA;      }&#xA;    });&#xA;  }&#xA;}&#xA;</void>

  


  The image rgba data is saved via the following code snippet.

  


  Utils.getBuffer(renderKey).then((value) async {
        ui.Image buffer = value;
        final data =
            await buffer!.toByteData(format: ui.ImageByteFormat.rawRgba);
        Uint8List uData = data!.buffer.asUint8List();
        VideoUtil.saveImageFileToDirectory(uData, 'input$frameNum.rgba');
        frameNum++;
        });


  


• Using HEVC with Alpha to Compose Moviepy Video

  3 avril, par James Grace

  I'm using moviepy, PIL and numpy and trying to compile a video with 3 components : A background image that is a PNG with no transparency, an Overlay Video that is a HEVC with Alpha, and a primary clip that is produced with a collection of PNG images with transparency.

  


  The video is composed with background + overlay video + main video.

  


  The problem I'm having is that the overlay video has a black background, so the background image is covered completely. Moviepy is able to import the HEVC video successfully by it seems as though the Alpha channel is lost on import.

  


  Any ideas ?

  


  Here's my code :

  


  from PIL import Image
import moviepy.editor as mpe
import numpy as np

def CompileVideo() :

    frames = ["list_of_png_files_with_transparency"]
    fps = 30.0
    clips = [mpe.ImageClip(np.asarray(Image.open(frame))).set_duration(1 / int(fps)) for frame in frames]
    ad_clip = mpe.concatenate_videoclips(clips, method="compose")
    bg_clip = mpe.ImageClip(np.asarray(Image.open("path_to_background_file_no_transparency"))).set_duration(ad_clip.duration)

    overlay_clip = mpe.VideoFileClip("path_to_HEVC_with_Alpha.mov")

    comp = [bg_clip, overlay_clip, ad_clip]

    final = mpe.CompositeVideoClip(comp).set_duration(ad_clip.duration)
    final.write_videofile("output.mp4", fps=fps)