[Feature Request] Change playback speed of downloaded files

[Vitruvia]

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Dear developers of youtube-dl,

In the first place, thank you for making this excellent tool. It has enabled me to listen to quality audio during my commutes.

I'd just like to ask if it is possible to include an option to save the video/audio in a faster speed, thus mimicking youtube's function of increasing the playback speed of their videos.

I thought of helping with this, but I'm quite a beginner. I've been learning to code for only 3 months (with python 3), so I don't know if I could be of any help. If you think there is anything I can do, just let me know.

[dstftw]

Use player's playback speed options.

[Vitruvia]

That is assuming my car player has such option; it doesn't. I'm looking for a way to circunvent this by putting audios in my iphone and changing playback speed there, but I haven't found a practical way of doing it yet.

[mrkmndz]

For your own use, your best bet is probably just to use ffmpeg directly afterward https://trac.ffmpeg.org/wiki/How%20to%20speed%20up%20/%20slow%20down%20a%20video

[CharlSteynberg]

Cool tip @mrkmndz
I don't know if the following feature already exists in youtube-dl -but here's an idea:
Using a filter-argument, maybe it could be used to pass filter options through to ffmpeg?
The command could then look something like:
youtube-dl --extract-audio --filter-atempo=0.5 https://www.example.com/...

-awesome cli tool btw, thanks for making it and maintaining, appreciated

[andrew-ma]

i'm working on this now (but never done any real coding project or any open source). Theoretically, it would be like --ffmpeg-filter FILTER where FILTER is 'atempo=0.5' I just need a way to detect if input is a video or audio because ffmpeg -filter:(v|a). And also i would need to add it to options.py

general.add_option( '--ffmpeg-filter', metavar='FILTER', dest='ffmpeg_filter', help='Apply ffmpeg filter to downloaded file. Example: --ffmpeg-filter \'atempo=0.5\'.')

[uhhmaybe]

Just use a podcast app that allows you to upload your own files and then speed adjust them using that on the fly as fast or slow as you want. For example, both Overcast and Pocket Casts can do this, plus they have the ability to do things like trim silences and boost the voice. Way better than trying to roll your own solution.

[andrew-ma]

I mean it kinda is useful if you want to make a quick nightcore lmao

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On October 5, 2018 3:25:53 AM uhhmaybe ***@***.***> wrote: Just use a podcast app that allows you to upload your own files and then speed adjust them using that on the fly as fast or slow as you want. For example, both Overcast and Pocket Casts can do this. — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[ashleyharvey]

@andrew-ma are you still working on this?

I dug into the arguments of ffmpeg and youtube-dl a bit, and found you can execute a command on a downloaded file after the fact using --exec, for example: youtube-dl -v "https://www.youtube.com/watch?v=SOME_URL" --restrict-filenames --extract-audio --exec 'ffmpeg -i {} -af "atempo=2.0" -vn processed_{}'.

But, this is obviously less elegant than having the option built-in to youtube-dl.

[xxKeith20xx]

To increase both audio and video, I ran this on the download from youtube-dl, as a separate command:

ffmpeg -i input.mp4 -filter_complex "[0:v]setpts=0.5*PTS[v];[0:a]atempo=1.5[a]" -map "[v]" -map "[a]" output.mp4

The 1.5 above representing the playback rate.