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  1. Member
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    Mar 2011
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    Paris, France
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    Hello,

    I need to 1) create a 10s silent video from a picture, 2) edit a "soundful" video (ie. it has audio and video), and 3) join the two files.

    Using the following commands, the joined video has no audio the input video is fine, so it's the last command that's wrong:

    Code:
    REM 1. Make video from picture:
    c:\ffmpeg -loop 1 -i pic.png -t 10 -vf scale=720:404  -c:v libx264 -pix_fmt yuv420p -c:a aac -ar 44100 -b:a 96k -ac 2 -threads 2 -f mp4 01.pic.mp4
    
    REM 2. Edit video:
    c:\ffmpeg -i input.mp4 -ss 0:13:08.280  -to 0:13:49.600 -vf scale=720:404  -c:v libx264 -pix_fmt yuv420p -c:a aac -ar 44100 -b:a 96k -ac 2 -threads 2 -f mp4 02.video.mp4
    
    REM 3. Join two video files:
    (for %%i in (*.mp4) do @echo file '%%i') > input.txt
    c:\ffmpeg -safe 0 -f concat -i input.txt -c copy joined.mp4
    
    c:\ffmpeg --version
    ffmpeg version 2023-11-05-git-44a0148fad-essentials_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers
    What command should I use to join them correctly?

    Thank you.

    --
    Edit: Here's how to doctor the silent video file so it has an audio stream (it might be possible to get it right the first time):
    Code:
    c:\ffmpeg -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=44100 -i 01.pic.mp4 -c:v copy -c:a aac -shortest 01.pic.silent.mp4
    Last edited by yetanotherlogin; 5th Feb 2024 at 11:49.
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  2. The framerate from video 1 and 2 must be the same.
    For video 1:
    ffmpeg -framerate x -i pic.npg -t 10 (where x is the framerate from video 2).
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  3. Member
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    I didn't set the framerate in either. Why does it matter, and is it the cause of the problem I had?
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  4. the second video has a frame rate.
    Check it with mediainfo.
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  5. Member
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    Mar 2011
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    Here's what ffprobe says about the two videos:

    Code:
    Vid1
    Duration: 00:00:10.00, start: 0.000000, bitrate: 29 kb/s
    Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 720x404, 26 kb/s, 25 fps, 25 tbr, 12800 tbn (default)
    
    Vid2  
    Duration: 00:00:41.32, start: 0.000000, bitrate: 397 kb/s
    Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 720x404 [SAR 404:405 DAR 16:9], 295 kb/s, 25 fps, 25 tbr, 12800 tbn (default)
    I'll add a "-framerate" option to avoid this error. Thanks.
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