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• Converting files before merging with FFMPEG

  25 mars 2022, par user1748217

  I'm trying to merge a series of files with the same format (taken from a camera) with another of a different format (an outro).

  


  TARGET file ffprobe output :

  


     Duration: 00:00:21.60, start: 0.000000, bitrate: 1847 kb/s

   Stream #0:0[0x1](eng): 
   Video: h264 (Main) (avc1 / 0x31637661), 
          yuv420p(progressive), 
          1280x720, 
          1050 kb/s, 
          30 fps, 
          30 tbr, 
          30k tbn (default)

   Stream #0:1[0x2](eng): 
   Audio: pcm_s16le (sowt / 0x74776F73), 
          32000 Hz, 
          1 channels, 
          s16,  
          512 kb/s (default)


  


  OUTRO file ffprobe output :

  


     Duration: 00:00:13.03, start: 0.000000, bitrate: 21890 kb/s

   Stream #0:0[0x1](eng): 
   Video: h264 (High) (avc1 / 0x31637661), 
          yuv420p(progressive), 
          1920x1080 [SAR 1:1 DAR 16:9], 
          21492 kb/s, 
          24 fps, 
          24 tbr, 
          24k tbn (default)

   Stream #0:1[0x2](eng): 
   Audio: aac (LC) (mp4a / 0x6134706D), 
          48000 Hz, 
          stereo, 
          fltp, 
          316 kb/s (default)


  


  ... and I'm trying to convert the outro to match the others using :

  


  ffmpeg -i outro.mp4 \ 
       -c:v h264 \
       -s 1280x720 \
       -pix_fmt yuv420p \
       -framerate 30 \ 
       -r 30 \
       -c:a pcm_s16le \
       -ac 1 \ 
       -b:a 512k \
       -ar 32000 \ 
       outro.mov


  


  After the transcode the outro plays fine.
but then I merge the files with :

  


  ffmpeg -f concat -safe 0 -i videos.txt -c copy merged.mov -y


  


  In the merged output the outro video is messed up, though the audio on it is ok.
  
It seems like the outro plays way too fast (milliseconds) but I'm not sure as the original/source outro video fades to black at the end and the "corrupted" merged outro "pauses" on the last frame prior to fading.

  


  I noticed the outro has a lower FPS than the other files (24 FPS vs 30 on the others). When I run ffprobe on the outro after the conversion, it reads ...

  


   Stream #0:0[0x1](eng): 
 Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 
        1280x720 [SAR 1:1 DAR 16:9], 
        1031 kb/s, 
        24 fps, 
        24 tbr, 
        12288 tbn (default)


  


  ... so the FPS is still 24 ? How come ? Is this my problem ? What am I missing ? How do I get this to convert so I can join it seamlessly ?

  


  Thanks in advance.

  


  UPDATE :

  


  adding -r 30 (Thanks @Kesh) on the conversion got the FPS to match but but unfortunately it didn't fix the merge issue :-(

  


  audio is all good however...

  


  ... If I add the "pre-converted" file to the end of the concat list then series of files I'm trying to match play video fine but the "pre-converted" file plays video through in roughly a second.

  


  If I add the "pre-converted" file to the start of the list then it plays fine, but the rest play video far too slow.

  


• image to video conversion with transition effect

  24 avril 2015, par DroidWorm Narendra

  I am successfully able to convert a sequence of images into a video referring the link https://github.com/guardianproject/SSCVideoProto.

  But now my requirement is to put some transition effects like fade in / fade out to be shown in video with the change of every image.

  Is it possible to do using FFMPEG or should I use something else for that ?

  Refer
  ffmpeg convert a series of images to video - with crossfade or any other transition between every two frames

  for more details.

  Please direct me.

• FFmpeg image2 output : Control JPG image quality when using mjpeg_qsv

  11 avril 2022, par clic

  My FFmpeg command ouputs a series of JPG images. Simplified :

  


  


  ffmpeg -f dshow -video_size 3840x2160 -framerate 25 -i "video=My
Webcam" -qscale:v 5 -vcodec mjpeg_qsv "C :\out\%d.jpg"

  


  


  I want to use -vcodec mjpeg_qsv to leverage GPU acceleration. Usually (without "_qsv") I can control JPG image quality by using qscale:v , but it seems to have no effect in combination with mjpeg_qsv.

  


  Is it even possible to control JPG image quality when using mjpeg_qsv ? If yes, any ideas how ? Thanks !