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• FFmpeg create boomerang GIF effect from video trimmed Flutter

  3 septembre 2022, par nicover

  I have a 45seconds video file which I want to create a boomerang GIF from a trimmed part of the video, let's say from 20s to 23s.

  


  I tried to run in flutter a basic GIF command :

  


  " -i $videoInput -filter_complex ${"[0]reverse[r];[0][r]concat=n=2:v=1:a=0"} $gifOutput";


  


  But it was crashing every time without a short video file (OOM) :

  


  INFO: frame=  362 fps= 15 q=-0.0 size=  162048kB time=00:00:12.06 bitrate=110074.4kbits/s speed=0.514x
INFO: Skipping NAL unit 62
INFO: Skipping NAL unit 62
INFO: Skipping NAL unit 62
INFO: Skipping NAL unit 62
 * thread #50, queue = 'com.apple.root.default-qos', stop reason = EXC_RESOURCE RESOURCE_TYPE_MEMORY (limit=3072 MB, unused=0x0)
    frame #0: 0x0000000250474d60 libsystem_platform.dylib`__bzero + 64
libsystem_platform.dylib`__bzero:
->  0x250474d60 <+64>: dc     zva, x3
    0x250474d64 <+68>: add    x3, x3, #0x40
    0x250474d68 <+72>: subs   x2, x2, #0x40
    0x250474d6c <+76>: b.hi   0x250474d60               ; <+64>
Target 0: (Runner) stopped.


  


  Questions :

  


  


  • Can the video be trimmed and the boomerang GIF created in the same command ?

    


  


  • Can the GIF in the same command be scaled down (as compression for low res files) ?

    


  


  • Can preset like veryfast or medium be used for GIF creation or only for video ?

    


  


  


  Thanks in advance for any help

  


• merge segments with ffmpeg causes small cracks in the audio

  14 octobre 2019, par Paulo Medeiros

  To speed up the delivery of videos on my platform I split the uploaded medias into segments of up to 120 seconds and process them simultaneously on several machines.

  After processing, I put the pieces back together with "-f concat".

  Unfortunately, new media is generated with small cracks in the audio (they occur exactly at the junction). I haven’t found a filter / command yet to end the problem. Does anybody know how to solve this ?

  Note : I am using ffmpeg 3.4.1

  This is the command I make to split the media :

  ffmpeg -hide_banner -fflags +genpts -avoid_negative_ts make_zero -y -v error -i /video/somevideo.mov -map 0:v? -map 0:a? -c copy -f segment -segment_time 120 -segment_format matroska -reset_timestamps 1 -segment_list_type ffconcat -segment_list /video/segment_map.ffcat /video/segment%03d

  A short example of the command used to process a segment

  some variables change according to the resolution

  ffmpeg -y -hide_banner -v error -probesize 10M -analyzeduration 10M -itsoffset 0.066 -i /video/segment000 -c:v libx264 -preset fast -profile:v high -crf 23 -r 117375/3916 -maxrate 1500000 -bufsize 2250000 -g 58 -keyint_min 58 -sc_threshold 0 -bf 3 -b_strategy 2 -refs 10 -vf scale="iw*sar:ih,scale=trunc(oh*a/2)*2:540" -pix_fmt yuv420p -max_muxing_queue_size 5000 -strict -2 -c:a aac -b:a 128000 -ar 44100  -f mp4 /video/transcode/segment000

  to finalize how do I join the segments

  ffmpeg -hide_banner -v error -f concat -safe 0 -y -i /video/transcode/segment_map.ffcat -c copy -movflags +faststart /video/transcoded.mp4

• How to update this script to generate HLS video with different resolution streams ? [closed]

  1er décembre 2023, par Andy Z

  I have the following FFmpeg script :

  


  ffmpeg -i video.mp4 -i video.vtt \
 -map 0:v -map 0:a:0 -map 1 \
 -s:v:0 1080x1920 -c:v:0 h264 -b:v:0 500K \
 -c:a:0 copy -c:a:1 copy -c:a:2 copy -c:s webvtt \
 -f hls -hls_playlist_type vod -var_stream_map "v:0,a:0,s:0" \
 -master_pl_name video.m3u8 -hls_time 6 -hls_list_size 0 -hls_allow_cache 1 -start_number 1 \
 -hls_segment_filename "output/hls/%v/seg-%d.ts" output/hls/%v/index.m3u8


  


  Currently it only produces one 1080x1920 stream, how do I produce more lower resolution ones so it can adjust based on client bandwidth ?

  


  Also, I've noticed that it doesn't add the reference to the VTT file to the master HLS playlist ; I had to add this manually but is there a way to make FFmpeg do it for me ?

  


  #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="English",DEFAULT=YES,AUTOSELECT=YES,FORCED=NO,LANGUAGE="en",CHARACTERISTICS="public.accessibility.transcribes-spoken-dialog",URI="0/index_vtt.m3u8"


  


  I've tried this, but I get an argument error :

  


  ffmpeg -i video.mp4 -i video.vtt \
 -map 0:v -map 0:a:0 -map 1 \
 -s:v:0 1080x1920 -c:v:0 h264 -b:v:0 500K \
 -s:v:1 720x1280 -c:v:1 h264 -b:v:1 300K \
 -s:v:2 480x854 -c:v:2 h264 -b:v:2 150K \
 -c:a:0 copy -c:a:1 copy -c:a:2 copy -c:s webvtt \
 -f hls -hls_playlist_type vod -var_stream_map "v:0,a:0,s:0 v:1,a:1 s:1 v:2,a:2 s:2" \
 -master_pl_name video.m3u8 -hls_time 6 -hls_list_size 0 -hls_allow_cache 1 -start_number 1 \
 -hls_segment_filename "output/hls/%v/seg-%d.ts" output/hls/%v/index.m3u8