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• ffmpeg concatenated file does not play as expected

  28 janvier 2018, par Trewq

  I am trying create a video by concatenating in this order :

  video1.mp4 & video_from_static_image.mp4 & video1.mp4

  video1.mp4 is a simple video file. video_from_static_image.mp4 was created from the a.png image like this :

  ffmpeg  -y -framerate 25 -f image2  -loop 1 -i a.png -c:v libx264 -profile:v main -pix_fmt yuv420p -t 2 -r 25  video_from_static_image.mp4

  I create the final concatenated file through this command :

  ffmpeg -y -f concat -safe 0 -i mylist.txt -c copy final_concat.mp4

  I get the following message during the concat process :

  [mp4 @ 0x7fee6b815e00] Non-monotonous DTS in output stream 0:0; previous: 120678, current: 65722; changing to 120679. This may result in incorrect timestamps in the output file.

  The complete output when running the above command is here

  When I play final_concat.mp4 it has problems with video_from_static_image.mp4 and it seems to skip it (and other variations resulted in playing for a short while). I’ve tried a bunch of things, but I believe they all point to the DTS error above.

  BTW, all the video files are pretty small (< 1MB). Here are details about the version I am using :

  $ ffmpeg -version
ffmpeg version 3.3.4 Copyright (c) 2000-2017 the FFmpeg developers
built with Apple LLVM version 7.3.0 (clang-703.0.31)
configuration: --prefix=/usr/local/Cellar/ffmpeg/3.3.4 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libvpx --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma --enable-vda
libavutil      55. 58.100 / 55. 58.100
libavcodec     57. 89.100 / 57. 89.100
libavformat    57. 71.100 / 57. 71.100
libavdevice    57.  6.100 / 57.  6.100
libavfilter     6. 82.100 /  6. 82.100
libavresample   3.  5.  0 /  3.  5.  0
libswscale      4.  6.100 /  4.  6.100
libswresample   2.  7.100 /  2.  7.100
libpostproc    54.  5.100 / 54.  5.100

• FFmpeg : Frame sizes of the generated video are extremely larger than the expected [closed]

  8 février 2021, par bbasaran

  I am recording frames (screen buffer) as NumPy arrays during the game which runs on the resolution of "400x225". Each frame array is a size of 270.1 kB.

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  After saving those frames, I create an mp4 file with the following bash command (The game runs in 35 FPS (frames/second)) :

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  ffmpeg -r 35 -f image2 -i frame%05d.png -vcodec libx264 -crf 1 video.mp4


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  Then I have used a tool to generate a CSV file of frame data from the video created with the command above. The output is here below. The weird this is that, if we sum those first 35 frames (video was recorded with "-r 35" parameter because game runs in 35 FPS), we get approximately 18k kbit.

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  18k kbit/sec bitrate is super high for a 400x225 video. What am I doing wrong while generating the video ? I appreciate any help, thanks !

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• Constant Frame Rate Video extracting more frames than expected - FFMPEG

  22 septembre 2023, par superand12

  I'm trying to extract 1 frame per second in a 3 second video that has a video frame rate of 30 fps.

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  ffmpeg -i 3seconds.mp4 -r 1 -q:v 2 output_%04d.jpg

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  I noticed that this command was returning 5 frames instead of 3. I then run this command to figure out that there are iframes in the video (not sure if thats the reason).

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  ffprobe -v error -select_streams v:0 -show_frames -show_entries frame=pict_type -of csv 3seconds.mp4

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  This may have been redundant but adding this filter flag gave me exactly 3 frames. Unclear about the underlying frame selection process.

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  ffmpeg -i 3seconds.mp4 -filter:v fps=1 -r 1 -q:v 2 output_%04d.jpg

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  Video info :

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  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '3seconds.mp4': Metadata: major_brand     : isom minor_version   : 512 compatible_brands: isomiso2avc1mp41 encoder         : Lavf58.20.100 Duration: 00:00:03.07, start: 0.000000, bitrate: 2753 kb/s Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc), 1920x1080 [SAR 1:1 DAR 16:9], 2747 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default) Metadata: handler_name    : GoPro AVC vendor_id       : [0][0][0][0] timecode        : 19:56:41:04 Stream #0:1(eng): Data: none (tmcd / 0x64636D74), 0 kb/s Metadata: handler_name    : GoPro AVC timecode        : 19:56:41:04

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