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  1. Hello,

    I want to shorten the playing time of an MP4 file [duration=68 minutes]. The contents are not that long but the speakers speak in a slow pace. If I increase playing speed to 1.2, the video plays well and audio is fine too.

    Can I do something to make video play faster without changing playing speed in PotPlayer?

    Thanks.
    Sword is no substitute for kitchen-knife.
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  2. You could increase the audio pitch without change the video.
    This can be done with clever Ffmpeg-GUI.
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  3. Originally Posted by ProWo View Post
    You could increase the audio pitch without change the video.
    This can be done with clever Ffmpeg-GUI.
    Thanks.

    One question:
    Will it not put video audio out of sync?
    Sword is no substitute for kitchen-knife.
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  4. Download the newest beta here:
    https://files.videohelp.com/u/292773/clever_ffmpeg_gui_newest_beta.7z

    Then load your mp4, click main, click Convert Audio stream, Continue, type 1.2 in the coefficient field, select pitch only below, leave all other settings as they are, click convert.

    Image
    [Attachment 61385 - Click to enlarge]


    When done, click Multiplex, all necessary streams are already loaded (the new created audio stream is shown in green color), deselect the old audio stream, select mp4 as container (if it is not already selected), click Multiplex.

    Image
    [Attachment 61386 - Click to enlarge]


    All done!
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  5. Originally Posted by ProWo View Post
    Thanks for the step-by-step guide.

    It has changed male voices into female voices but the duration has remained 67 minutes!
    I want to cut down the duration by a factor of 1.2 or 1.25.

    Is it possible?
    Last edited by ConverterCrazy; 21st Oct 2021 at 08:19. Reason: reapeat words
    Sword is no substitute for kitchen-knife.
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  6. Originally Posted by ConverterCrazy View Post
    Thanks for the step-by-step guide.
    It has changed male voices into female voices but the duration has remained 67 minutes!
    I want to cut down the duration by a factor of 1.2 or 1.25.
    Is it possible?
    To shorten the video, you need to recode it.
    As a result, you will probably end up with a non-compliant framerate.
    The video may then only play on the computer.
    But it is possible.
    To be more precise, we need more information.
    Post a mediainfo report (text mode) here.
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  7. Here it is:

    General
    Complete name : C:\Working Folder\Video\Understanding No Blasphemy.mp4
    Format : MPEG-4
    Format profile : Base Media
    Codec ID : isom (isom/iso2/avc1/mp41)
    File size : 202 MiB
    Duration : 1 h 7 min
    Overall bit rate : 416 kb/s
    Description :
    Writing application : Lavf59.6.100

    Video
    ID : 1
    Format : AVC
    Format/Info : Advanced Video Codec
    Format profile : Main@L2.1
    Format settings : CABAC / 1 Ref Frames
    Format settings, CABAC : Yes
    Format settings, Reference frames : 1 frame
    Codec ID : avc1
    Codec ID/Info : Advanced Video Coding
    Duration : 1 h 7 min
    Bit rate : 281 kb/s
    Width : 426 pixels
    Height : 240 pixels
    Display aspect ratio : 16:9
    Frame rate mode : Constant
    Frame rate : 30.000 FPS
    Color space : YUV
    Chroma subsampling : 4:2:0
    Bit depth : 8 bits
    Scan type : Progressive
    Bits/(Pixel*Frame) : 0.092
    Stream size : 136 MiB (68%)
    Title : ISO Media file produced by Google Inc. Created on: 10/19/2021.
    Color range : Limited
    Color primaries : BT.709
    Transfer characteristics : BT.709
    Matrix coefficients : BT.709
    Codec configuration box : avcC

    Audio
    ID : 2
    Format : AAC LC
    Format/Info : Advanced Audio Codec Low Complexity
    Codec ID : mp4a-40-2
    Duration : 1 h 7 min
    Bit rate mode : Constant
    Bit rate : 128 kb/s
    Channel(s) : 2 channels
    Channel layout : L R
    Sampling rate : 44.1 kHz
    Frame rate : 43.066 FPS (1024 SPF)
    Compression mode : Lossy
    Stream size : 62.0 MiB (31%)
    Title : ISO Media file produced by Google Inc.
    Language : English
    Default : Yes
    Alternate group : 1


    As seen here, the duration is 67 minutes which I want to reduce to 50 minutes.
    Sword is no substitute for kitchen-knife.
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  8. The video currently has a frame rate of 30.
    If you want to shorten the video by a factor of 1.3, it must be encoded at 39fps.
    This shortens the time from 67 min to 51.53 min.
    To achieve this, load your video, click main, click convert video stream, click continue, enter all data as on the picture, click convert.

    Image
    [Attachment 61387 - Click to enlarge]


    If done, click Convert Audio stream, Continue, type 1.3 in the coefficient field, select lenght only below, leave all other settings as they are, click convert.

    Image
    [Attachment 61388 - Click to enlarge]


    Mux afterwards as indicated above.
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  9. Thanks.

    Will do ASAP.
    Sword is no substitute for kitchen-knife.
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  10. Originally Posted by ProWo View Post
    The video currently has a frame rate of 30.
    If you want to shorten the video by a factor of 1.3, it must be encoded at 39fps.
    This shortens the time from 67 min to 51.53 min.
    To achieve this, load your video, click main, click convert video stream, click continue, enter all data as on the picture, click convert.

    If done, click Convert Audio stream, Continue, type 1.3 in the coefficient field, select lenght only below, leave all other settings as they are, click convert.

    Mux afterwards as indicated above.


    Thanks a ton.
    Sword is no substitute for kitchen-knife.
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