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• Convert audio download with youtube-dl to flac ?

  28 janvier 2020, par Urasam

  Is it possible to download a YouTube video as e.g. mp3 and then convert it to flac with ffmpeg ? I can specify the arguments that ffmpeg shall use after the download with —postprocessor-args but I don’t know how to get the file name there.

  --postprocessor-args "-i downloadedfile.xxx -c:a flac downloadedfile.flac"

  This would be the argument I want to use. Is this possible ?

• Raspivid & Avconv add watermark and save .mp4 from Youtube output stream

  25 octobre 2017, par walolinux

  I have this ffmpeg command working with a USB webcam in my raspberry pi :

  ffmpeg -thread_queue_size 512 -f v4l2 -video_size 1280x720 -i /dev/video0 -f lavfi -i anullsrc=cl=stereo:r=44100 -map 0:v -map 1:a -r 30 -aspect 16:9 -c:v h264 -preset veryfast -crf 25 -pix_fmt yuv420p -g 60 -maxrate:v 820k -bufsize:v 820k -profile:v baseline -c:a aac -b:a 128k -strict experimental -flags +global_header -vf "movie=logo.png [watermark]; [in][watermark] overlay=main_w-overlay_w-5:main_h-overlay_h-5 [out]" -f tee "[f=flv]rtmp://a.rtmp.youtube.com/live2/XXX|video.flv"

  This command adds a watermark (logo), saves mp4 to disk and broadcast to youtube the stream. It is working, but my raspberry pi hangs because it gets out of memory (CPU and RAM).

  This is why i have changed my USB webcam to raspicam 2.1.

  Now i am trying to do the same but using raspivid and avconv. But this is the only command i have already managed to use :

  raspivid -o - -t 0 -vf -hf -fps 30 -b 6000000 | avconv -re -ar 44100 -ac 2 -acodec pcm_s16le -f s16le -ac 2 -i /dev/zero -f h264 -i - -vcodec copy -acodec aac -ab 128k -g 50 -strict experimental -f flv rtmp://a.rtmp.youtube.com/live2/XXX

  I am looking to replicate functionality but with raspicam 2.1.

  Thanks.

• Streaming windows desktop to Youtube with ffmpeg [closed]

  23 mai 2021, par rarahim

  I've been spending days trying to stream my live desktop to Youtube using ffmpeg. There are too many questions and answers on SO about this topic but none really works for me, or perhaps because working with ffmpeg is non-trivial task with it's never ending list of available options.

  


  So far, what sort of works for me is using the following (which is a mixture of what was gathered from various sources) :

  


  


  ffmpeg -threads:v 2 -threads:a 8 -filter_threads 2 -thread_queue_size
5096 -f dshow -i video="screen-capture-recorder" -f dshow -i
audio="Stereo Mix (Realtek High Definition Audio)" -pix_fmt yuv420p
-c:v libx264 -qp:v 19 -profile:v high -rc:v cbr_ld_hq -level:v 4.2 -r:v 60 -g:v 120 -bf:v 3 -refs:v 16 -f flv rtmp ://a.rtmp.youtube.com/live2/KEY

  


  


  My questions are :

  


  


  1. how do i only stream video ? i do not want to stream audio, simply removing '-f dshow -i audio="Stereo Mix (Realtek High Definition Audio)"' causes it to fail

     


  


  2. after a while, ffmpeg starts to hog my memory causing my system to slow down terribly, what causes this and how can i fix it ?

     


  


  3. my video feed when viewed from Youtube keeps buffering rather frequently, how can this be fixed/improved ?

     


  


  


  Thanks.

  


  UPDATE :
I've managed to somewhat figure out a workaround for these issues. Not sure if these are the right solutions but they work for now.

  


  


  1. Youtube apparently requires streams to have audio component. So instead of just removing the audio device form the options, i had to put in "-f lavfi -i anullsrc" to use null audio device.

     


  


  2. The memory hog issue was improved by adding "-framerate 10" and "-r 10" to the input and output options, this reduces target frame rate to 10fps.

     


  


  3. The overall stream performance seem to be indirectly improved by doing the above actions.

     


  


  


  So finally the working simplified version of my ffmpeg command is :

  


  


  ffmpeg -framerate 10 -f dshow -i video="screen-capture-recorder" -f
lavfi -i anullsrc -vcodec libx264 -preset:v ultrafast -pix_fmt yuv420p
-f flv -r 10 rtmp ://a.rtmp.youtube.com/live2/KEY

  


  


  I'm updating here in case it might be useful to someone at some point in the future.