Newest 'ffmpeg' Questions - Stack Overflow

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• How to merge the raw pcm data of two channels ?

  15 mai 2019, par maximedupre

  I have two Float32Arrays containing the raw pcm data of the left and right channel. Is it possible to create a Float32Array that combines both channel? If so, how would I do that? Can I simply concatenate the arrays?

  Cheers!

• How to add a caption with video using ffmpeg ?

  15 mai 2019, par Sandson Costa

  I have a video in.mkv which is dual audio and has built-in subtitles. I want to convert it to output.mp4 and I used the following command:

  ffmpeg -rtbufsize 150M -i entrada.mkv' -acodec aac -map 0:0 -map 0:2 -vcodec h264 -c:s mov_text -map 0:3 "saída.mp4"
  

  With this command I was able to add a caption, but it was not recorded in any video, so I had a good choice. Video is not a video being part of the video itself.

  How I do? Image

  I tried the command

  ffmpeg.exe -rtbufsize 150M -i 'entrada.mkv' -acodec aac -map 0:0 -map 0:2 -vcodec h264 -vf:0:3 "saída.mp4"
  

  But there is the mistake

  At least one output file must be specified
  

• FFmpeg gets stuck after printing Warning : EOF timestamp not reliable

  15 mai 2019, par yoda89

  I am trying to create a video, with a bunch of different inputs consisting of set of sequence of images, along with few other images and a video (might be more than one) to overlay on top of those.

  The duration of the final video output is supposed to be equal to the duration of the longest input (while shorter inputs will just loop till that duration).

  While the command is working for most cases. In some cases I see the warning EOF timestamp not reliable, and afterthat FFmpeg gets stuck indefinately.This happens with some particular cases of inputs, and also seem to vary with different versions of ffmpeg, i tried with ffmpeg versions 4.1, 4.0.4 and 3.4.1. It seems to be only working with 4.0.4, while it fails on other versions.

  I am sharing an example command along with assets for windows, for which I am encountering this problem

  Below is the Command:

      ffmpeg -i assets\w_re_p_3\w_re_p_3_%d.jpg -loop 1 -i assets\text_0.png -loop 1 -i assets\text_1.png -loop 1 -i assets\text_2.png -loop 1 -i assets\text_3.png -loop 1 -i assets\text_4.png -loop 1 -i assets\text_5.png -loop 1 -i assets\text_6.png -loop 1 -i assets\text_7.png -lavfi "[0:v]loop=loop=-1:size=121:start=1[lip0];[1:v]scale=w=693:h=155[si_1];[lip0][si_1]overlay=x=13:y=13:shortest=1[over_0];[2:v]scale=w=693:h=45[si_2];[over_0][si_2]overlay=x=13:y=871:shortest=1[over_1];[3:v]scale=w=693:h=155[si_3];[over_1][si_3]overlay=x=13:y=236:shortest=1[over_2];[4:v]scale=w=693:h=40[si_4];[over_2][si_4]overlay=x=13:y=1089:shortest=1[over_3];[5:v]scale=w=693:h=84[si_5];[over_3][si_5]overlay=x=13:y=1141:shortest=1[over_4];[6:v]scale=w=693:h=31[si_6];[over_4][si_6]overlay=x=13:y=1207:shortest=1[over_5];[7:v]scale=w=693:h=85[si_7];[over_5][si_7]overlay=x=13:y=982:shortest=1[over_6];[8:v]scale=w=693:h=52[si_8];[over_6][si_8]overlay=x=13:y=148:shortest=1[over_7];movie=filename=assets\\\\cmedia_cropped.mp4:loop=1,setpts=N/(FRAME_RATE*TB)[mov_0];[mov_0]scale=w=720:h=487[sm_0];[over_7][sm_0]overlay=x=0:y=357:shortest=1" card_output.mp4
  

  Below is the link of all the assets being used in the command:

  https://www.dropbox.com/sh/6bwo4fg5de3fjwz/AAA471jUtLZGtti3hakT1bgfa?dl=0

  The final output should look something like this:

  https://www.dropbox.com/s/s92t6qij2lrl2j7/card_output1.mp4?dl=0

  Please, I dont understand the reason behind it. Is there anyway that I can improve my command so that I dont have to face this problem. Any help would be appreciated.

• Intel QuickSync and Nvenc at same Time on Ubuntu Server

  15 mai 2019, par Ahmet Gürer

  Im setting up a new Ubuntu Server with an Intel i7 6700k and Nvidia Gpu 1080ti. Is it possible to use Intel iGPU and Nvidia Gpu at same time on transcoding?

  Example: Stream 1 transcoding with iGPU Stream 2 transcoding with nvenc

  I will use it at same time. Is that possible?

  • I Installed Nvidia Cuda Drivers and Intel SDK
  • Activated iGPU and Nvidia GPU
  • Try to start with iGPU but get the error that Driver not found

• PHP : How to stream blank video ?

  15 mai 2019, par Marc

  How do I create and stream a blank video with duration pass to url like this:

  It should play a black screen video for 8 seconds. Is this possible?