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• What resolution would be best for processing videos in firebase functions ? [closed]

  11 janvier 2020, par Nathan

  I’m making an app that is mainly used for sharing videos of maximum 30 seconds long. One video example could be a screen recording of someone’s computer screen or a game. I have this code that checks whether the uploaded video that has just been uploaded to firebase storage has been processed or not and if it hasn’t then I use ffmpeg to process the video (change the resolution etc.) with this command :

  const promise = spawn('./ffmpeg', ['-i', tempFilePath, '-vf', 'scale=1280:720', targetTempFilePath]);

  Now with these commands, the firebase function is giving me a timeout error when I upload 30 second clips since I’m only converting the video to 720. I was just wondering what compression settings would be sufficient enough for the video to :

  1. Be still a high enough quality in my app
  2. Not take ages processing the video in the function (10-20 second clips works perfectly well).

  I know the better option would be to use Googles App engine or something similar to process videos but I’d prefer it to avoid that at the moment, if I can’t process videos to a good enough quality without sacrificing efficiency then I will go to something like Google’s App engine, just need some advice and some pointers for it otherwise.

  EDIT :

  I’ve seen instagram compresses their videos to a resolution of 640x640 ? Would that be reasonable or is it dependent on the original clip’s resolution ?

  Thanks

• ffmpeg - less frames getting extracted than expected

  20 juin 2021, par Vrajesh Doshi

  


  ffmpeg -i instagram.mp4 -vf fps=29.97 thumb%06d.jpg -hide_banner

  
 


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'instagram.mp4' : Metadata :
 major_brand : isom
 minor_version : 512
 compatible_brands : isomiso2avc1mp41
 encoder : Lavf55.19.104 Duration : 00:00:13.61, start : 0.000000, bitrate : 1163 kb/s
 Stream #0:0(und) : Video : h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 640x640 [SAR 1:1 DAR 1:1], 1099 kb/s, 29.97 fps,
 29.97 tbr, 11988 tbn, 59.94 tbc (default)
 Metadata :
 handler_name : VideoHandler
 Stream #0:1(und) : Audio : aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 64 kb/s (default)
 Metadata :
 handler_name : SoundHandler Stream mapping : Stream #0:0 -> #0:0 (h264 (native) -> mjpeg (native)) Press [q] to stop, [?] for help [swscaler @ 0x55b2b53cf440] deprecated pixel format used, make sure
 you did set range correctly Output #0, image2, to 'thumb%06d.jpg' :
  
 Metadata :
 major_brand : isom
 minor_version : 512
 compatible_brands : isomiso2avc1mp41
 encoder : Lavf57.83.100
 Stream #0:0(und) : Video : mjpeg, yuvj420p(pc), 640x640 [SAR 1:1 DAR 1:1], q=2-31, 200 kb/s, 29.97 fps, 29.97 tbn, 29.97 tbc (default)
 Metadata :
 handler_name : VideoHandler
 encoder : Lavc57.107.100 mjpeg
 Side data :
 cpb : bitrate max/min/avg : 0/0/200000 buffer size : 0 vbv_delay : -1 frame= 405 fps=231 q=24.8 Lsize=N/A time=00:00:13.51 bitrate=N/A speed=7.72x video:5961kB audio:0kB subtitle:0kB other streams:0kB
 global headers:0kB muxing overhead : unknown

  


  



  The video duration is 13.61 seconds and frame rate is 29.97. So I was expecting 13.61 * 29.97 = 407.8917 i.e. 407 frames. But have got 405 frames. I am new to ffmpeg, need help to correctly get all 407 frames.

  



  I had also tried following command,

  



  ffmpeg -i instagram.mp4 thumb%06d.jpg -hide_banner


  



  but the output was same 405 frames.

  



  Possibly the start 2 frames are missing.

  



  I need to display the frames generated in the base video timeline. And on clicking on the frame I need to exactly seek the video to the frame position using HTML5 currentTime. Since the first 2 frames are not getting available, exact mapping is not getting possible.

  



  Please guide.

  


• FFmpeg : animate image size to match music loudness

  22 juillet 2019, par skitzo

  This is for a script to generate Instagram video content. I have a script that merges an audio clip, video clip, and a logo centered throughout the whole output video’s duration.

  Goal : make the logo change size to match the audio waveform. The logo should look like it’s reacting to the beat.

  How can I achieve this using FFmpeg ? I don’t know if FFmpeg has this capability. Perhaps I could

  1. Use another library to get a volume array of the audio clip

  2. Generate an array of image sizes for the logo based on that volume array

  3. Read that array with FFmpeg ?

  1 and 2 are definitely possible but I don’t know how to approach step 3.

  Here’s the current command in my script that merges audio, video, logo, and crops the video into a square.

  ffmpeg -i video_path -i logo_path -i audio_path -filter_complex "[0:v]scale=-2:720,crop=500:500[bg];[bg][1:v] overlay=(W-w)/2:(H-h)/2" -      pix_fmt yuv420p -map 0:v -map 2:a -shortest out_path