Please allow passing of -ss and -to (-t) to ffmpeg

[tyll]

It's nice that you can dump youtube videos into audio and even have it convert using ffmpeg. What would be nice is to allow youtube-dl to pass START and STOP (duration) through to either ffmpeg or whatever is used as alternative.

Reason behind my request:

Some movies have some talking before or after the music-video (or whatever I watch). I would really like to avoid using youtube-dl AND ffmpeg afterwards only to convert one file. It would be a huge benefit to have this offered by youtube-dl. So I only need to deal with youtube-dl alone.

Reported in Red Hat Bugzilla:
https://bugzilla.redhat.com/show_bug.cgi?id=1065746

[jaimeMF]

For a few versions, youtube-dl has the --exec option which allows you to execute arbitrary commands after each file has been downloaded. This can be used for you usercase:

1. Create the file cut.sh and make it executable:

   #!/bin/sh
   
   start=$1
   duration=$2
   file="$3"
   tempfile="$file.tmp"
   mv "$file" "$tempfile"
   
   ffmpeg -y -i "$tempfile" -ss "$start" -t "$duration" -c copy "$file"
   
   rm "$tempfile"

2. Then run, for example, youtube-dl test:youtube_1 --exec "./cut.sh 20 40 {}". You can even use options like --extract-audio. You may want to give it a proper name to the script and put it in your $PATH, so that you can call it from everywhere.

I thinks that's enough and youtube-dl shouldn't have special support for it, for a few reasons:

• You can adapt it to any options you need.
• You can use any program you want, you are not limited to ffmpeg/avconv.
• We could of course ad an option --ffmpeg-options which would add the arguments in the ffmpeg command (before the output filename). But this can't be done in the existing postprocessors (for example if you combine the --add-metadata and --embed-subtitles options, ffmpeg would be run twice with -ss 20 -t 40 which is not the expected behaviour). So it would need its own postprocessor, which would be equivalent to the script I posted.

This is just my opinion, so if you (or someone else) thinks that we should really add support for passing these options, I don't mind reopening the issue.