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• Cutting and rejoining videos causes audio de-synchronization using ffmpeg [closed]

  10 décembre 2023, par Donotalo

  This is the original post. I'm not getting any answer there so I thought may be the programming community knows the answer.

  


  Main Post

  


  I'm trying to cut a video into pieces and rejoin them using ffmpeg on Windows 11 x64. Here's the details of ffmpeg :

  


  ffmpeg version 2023-11-22-git-0008e1c5d5-full_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --pkg-config=pkgconf --disable-w32threads
--disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp
--enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt
--enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2
--enable-libaribb24 --enable-libaribcaption --enable-libdav1d --enable-libdavs2 --enable-libuavs3d
--enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265
--enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl --enable-libopenjpeg --enable-libvpx
--enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi
--enable-libharfbuzz --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg
--enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc
--enable-dxva2 --enable-d3d11va --enable-libvpl --enable-libshaderc --enable-vulkan --enable-libplacebo
--enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt
--enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame
--enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc --enable-libgsm --enable-libopencore-amrnb
--enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite
--enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      58. 32.100 / 58. 32.100
  libavcodec     60. 34.100 / 60. 34.100
  libavformat    60. 17.100 / 60. 17.100
  libavdevice    60.  4.100 / 60.  4.100
  libavfilter     9. 13.100 /  9. 13.100
  libswscale      7.  6.100 /  7.  6.100
  libswresample   4. 13.100 /  4. 13.100
  libpostproc    57.  4.100 / 57.  4.100


  


  I've a video file in MKV format. I've cut it into 3 pieces using the following command :

  


  ffmpeg.exe -ss 0:0:0 -i input.mkv -t 0:54:15 -c:v hevc_amf -b:v 3M -c:s mov_text seg-01.mp4
ffmpeg.exe -ss 0:54:29 -i input.mkv -t 0:35:35 -c:v hevc_amf -b:v 3M -c:s mov_text seg-02.mp4
ffmpeg.exe -ss 1:30:12 -i input.mkv -t 0:4:10 -c:v hevc_amf -b:v 3M -c:s mov_text seg-03.mp4


  


  The audio is copied in all 3 pieces like original. Now I'm joining them using the following command :

  


  ffmpeg.exe -y -f concat -safe 0 -i .\join.txt -c:v hevc_amf -c:a copy -c:s copy -fflags +genpts out.mp4


  


  where, join.txt is :

  


  file seg-01.mp4
file seg-02.mp4
file seg-03.mp4


  


  ffmpeg throws the following warning :

  


  [mp4 @ 000002a5cf9cc040] Non-monotonic DTS in output stream 0:1; previous: 156240896, current: 156240084; changing to 156240897.
This may result in incorrect timestamps in the output file.
[mp4 @ 000002a5cf9cc040] Non-monotonic DTS in output stream 0:1; previous: 258720980, current: 258720462; changing to 258720981.
This may result in incorrect timestamps in the output file.


  


  I've observed that audio is de-synchronized after the places where I cut.

  


  How to keep audio, video and subtitle synchronized after cutting and rejoining the video using ffmpeg ?

  


• Cannot seem to work with mp3 files in pydub

  14 janvier 2023, par NegativePotato

  I have been trying to open mp3 files on pydub, I have ffmpeg in path and whatnot, but I get errors whenever I attempt to use pydub with mp3 files. Wav files work fine of course.
This is my code for testing purposes (copied directly from online) :

  


  from os import path
from pydub import AudioSegment

# files                                                                         
src = "Meet.mp3"
dst = "test.wav"

# convert wav to mp3                                                            
sound = AudioSegment.from_mp3(src)
sound.export(dst, format="wav")


  


  And this is my output for that code :

  


  C:\Users\aiden\OneDrive\Desktop\VietnameseAudioConnector>py test.py&#xA;Traceback (most recent call last):&#xA;  File "C:\Users\aiden\OneDrive\Desktop\VietnameseAudioConnector\test.py", line 9, in <module>&#xA;    sound = AudioSegment.from_mp3(src)&#xA;            ^^^^^^^^^^^^^^^^^^^^^^^^^^&#xA;  File "C:\Users\aiden\AppData\Local\Programs\Python\Python311\Lib\site-packages\pydub\audio_segment.py", line 796, in from_mp3&#xA;    return cls.from_file(file, &#x27;mp3&#x27;, parameters=parameters)&#xA;           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^&#xA;  File "C:\Users\aiden\AppData\Local\Programs\Python\Python311\Lib\site-packages\pydub\audio_segment.py", line 773, in from_file&#xA;    raise CouldntDecodeError(&#xA;pydub.exceptions.CouldntDecodeError: Decoding failed. ffmpeg returned error code: 1&#xA;&#xA;Output from ffmpeg/avlib:&#xA;&#xA;ffmpeg version 2023-01-12-git-fc263f073e-full_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers&#xA;  built with gcc 12.2.0 (Rev7, Built by MSYS2 project)&#xA;  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libdav1d --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint&#xA;  libavutil      57. 43.100 / 57. 43.100&#xA;  libavcodec     59. 56.100 / 59. 56.100&#xA;  libavformat    59. 35.100 / 59. 35.100&#xA;  libavdevice    59.  8.101 / 59.  8.101&#xA;  libavfilter     8. 53.100 /  8. 53.100&#xA;  libswscale      6.  8.112 /  6.  8.112&#xA;  libswresample   4.  9.100 /  4.  9.100&#xA;  libpostproc    56.  7.100 / 56.  7.100&#xA;[mp3 @ 000002d24d29e500] Failed to read frame size: Could not seek to 44209.&#xA;Meet.mp3: Invalid argument&#xA;</module>

  


  Sorry if this ends up being obvious, I am new to using python. Thank you for the help !

  


• Converting `webm` to `mov` format using ffmpeg loses transparency - how can I keep it ?

  10 mars 2023, par M.A Shahbazi

  I am trying to convert a webm video to mov format without losing quality and transparency using the following command :

  


  ffmpeg -c:v libvpx-vp9 -i input.webm ouput.mov


  


  The video gets converted, but it loses transparency and the background of video is black.

  


  I also tried the following command :

  


  ffmpeg -c:v png -i input.webm output.mov


  


  But it gives me the following error output :

  


    libavutil      58.  3.100 / 58.  3.100
  libavcodec     60.  4.100 / 60.  4.100
  libavformat    60.  4.100 / 60.  4.100
  libavdevice    60.  2.100 / 60.  2.100
  libavfilter     9.  4.100 /  9.  4.100
  libswscale      7.  2.100 /  7.  2.100
  libswresample   4. 11.100 /  4. 11.100
  libpostproc    57.  2.100 / 57.  2.100
[png @ 0000028041ca7000] Invalid PNG signature 0x824983420031F031.
[matroska,webm @ 0000028041c91240] Could not find codec parameters for stream 0 (Video: png, none(pc, progressive), 800x800): unspecified pixel format
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Input #0, matroska,webm, from 'hero.webm':
  Metadata:
    COMPATIBLE_BRANDS: qt
    creation_time   : 2023-02-23T10:43:46.703800Z
    MAJOR_BRAND     : qt
    MINOR_VERSION   : 537199360
    ENCODER         : Lavf59.35.100
  Duration: 00:00:09.00, start: 0.000000, bitrate: 1378 kb/s
  Stream #0:0: Video: png, none(pc, progressive), 800x800, SAR 1:1 DAR 1:1, 24 fps, 24 tbr, 1k tbn
    Metadata:
      alpha_mode      : 1
      ENCODER         : Lavc59.56.100 libvpx-vp9
      DURATION        : 00:00:09.000000000
Stream mapping:
  Stream #0:0 -> #0:0 (png (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[png @ 0000028041ca7680] Invalid PNG signature 0x824983420031F031.
Error while decoding stream #0:0: Invalid data found when processing input
Cannot determine format of input stream 0:0 after EOF
Error marking filters as finished
Conversion failed!


  


  How can I maintain transparency when converting from webm to mov format ?

  


  Here's the video info in case it can be helpful :

  


  {
    "streams": [
        {
            "index": 0,
            "codec_name": "vp9",
            "codec_long_name": "Google VP9",
            "profile": "Profile 0",
            "codec_type": "video",
            "codec_tag_string": "[0][0][0][0]",
            "codec_tag": "0x0000",
            "width": 800,
            "height": 800,
            "coded_width": 800,
            "coded_height": 800,
            "closed_captions": 0,
            "film_grain": 0,
            "has_b_frames": 0,
            "sample_aspect_ratio": "1:1",
            "display_aspect_ratio": "1:1",
            "pix_fmt": "yuv420p",
            "level": -99,
            "color_range": "tv",
            "field_order": "progressive",
            "refs": 1,
            "r_frame_rate": "24/1",
            "avg_frame_rate": "24/1",
            "time_base": "1/1000",
            "start_pts": 0,
            "start_time": "0.000000",
            "disposition": {
                "default": 0,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0,
                "captions": 0,
                "descriptions": 0,
                "metadata": 0,
                "dependent": 0,
                "still_image": 0
            },
            "tags": {
                "alpha_mode": "1",
                "ENCODER": "Lavc59.56.100 libvpx-vp9",
                "DURATION": "00:00:09.000000000"
            }
        }
    ],
    "format": {
        "filename": ".\\hero.webm",
        "nb_streams": 1,
        "nb_programs": 0,
        "format_name": "matroska,webm",
        "format_long_name": "Matroska / WebM",
        "start_time": "0.000000",
        "duration": "9.000000",
        "size": "1550466",
        "bit_rate": "1378192",
        "probe_score": 100,
        "tags": {
            "COMPATIBLE_BRANDS": "qt  ",
            "creation_time": "2023-02-23T10:43:46.703800Z",
            "MAJOR_BRAND": "qt  ",
            "MINOR_VERSION": "537199360",
            "ENCODER": "Lavf59.35.100"
        }
    }
}