youtube-dl to decent small size audio

DynV · 03-07-2020, 02:56 AM

I'm currently using

Quote:

youtube-dl --extract-audio --audio-format opus --audio-quality 8

and when looking at VLC codec info (Ctrl-J) and media statistics (other tab (from same window)) it show it's an Opus 32 bit 48 KHz and I estimate from the content bitrate fluctuation that its average is 150 Kbps (Is there a better way to get its average?) but I'd like something with a smaller file size. When I stream AAC 32 Kbps (radio), I like the (sound) quality; perhaps Opus would be a similar quality at that bitrate, or even better? I tried

Quote:

youtube-dl -f 'bestaudio' --audio-format opus --audio-quality 8

and the result is (sounds) horrible.

I've noticed multiple videos have audio starting from around what I think is 50 Kbps since it's mentioned

Quote:

opus @ 50k

in the resolution note column but if the quality is as good, or better, than AAC, I don't need something that good; as mentioned above AAC 32 Kbps is fine by me.

How can I get a decent small size audio from Youtube?

Thank you kindly

ondoho · 03-07-2020, 03:50 AM

It sounds confusing.
You want less than 32kbps audio, and NOT opus? Am I understanding this correctly?
Basically youtube-dl works in this way:

it looks for all audio/video formats
it chooses the best available (possibly with restrictions added on the command line, but be careful, more than 1 restriction quickly leads to no suitable format available!)
it downloads the file(s)
possibly it muxes the chosen audio & video track together

To my knowledge it does NOT transcode anything by default, but there's a switch '--recode-video' you might want to look at (there's no --recode-audio, strangely. You might need to do that manually after downloading).
You really need to read youtube-dl's extensive man page.

For any of this to work with youtube-dl, a recent ffmpeg is a soft dependency.

DynV · 03-07-2020, 08:56 AM

Considering

Quote:

Originally Posted by DynV

When I stream AAC 32 Kbps (radio), I like the (sound) quality [...] as mentioned above AAC 32 Kbps is fine by me.

(underlining just added) and if

Quote:

Originally Posted by DynV

[...] Opus would be a similar quality at that bitrate, or even better[...]

is the case, then

Quote:

Originally Posted by DynV

I've noticed multiple videos have audio starting from around what I think is [Opus] 50 Kbps [...]

would be at a quality considerably more than I need, and I'd prefer for it to end up at the sufficient quality is it mean it save a non-negligible amount of storage space.

It doesn't seem there's a man page for the program on my system but

Quote:

--help

has a long output, which I tried my best to understand. I forgot to mention in the OP that I attempted multiple #s for the 2nd command and, while the file size do change (depending on the #), they all sounded considerably less (good) than what's sufficient for me (AAC 32 Kbps).

If Opus is indeed better than AAC, I'd like for this process to occur:

if there's an Opus between 24 & 32 Kbps, for it to be downloaded
if there's an AAC between 32 & 48 Kbps, for it to be downloaded
otherwise the best audio be downloaded then converted to the Opus equivalent of AAC 32 Kbps

teckk · 03-07-2020, 10:57 AM

http://manpages.ubuntu.com/manpages/...tube-dl.1.html

Use the -F switch to find the available formats.

Code:

youtube-dl -F https://www.youtube.com/watch?v=hXZ2AfBkPD4
[youtube] hXZ2AfBkPD4: Downloading webpage
[youtube] hXZ2AfBkPD4: Downloading video info webpage
[youtube] hXZ2AfBkPD4: Downloading MPD manifest
[info] Available formats for hXZ2AfBkPD4:
format code  extension  resolution note
139          m4a        audio only DASH audio   50k , m4a_dash container, mp4a.40.5@ 48k (22050Hz)
140          m4a        audio only DASH audio  130k , m4a_dash container, mp4a.40.2@128k (44100Hz)
251          webm       audio only DASH audio  136k , webm_dash container, opus @160k (48000Hz)
278          webm       256x144    DASH video   95k , webm_dash container, vp9, 30fps, video only
160          mp4        256x144    DASH video  108k , mp4_dash container, avc1.4d400b, 30fps, video only
242          webm       426x240    DASH video  220k , webm_dash container, vp9, 30fps, video only
133          mp4        426x240    DASH video  242k , mp4_dash container, avc1.4d400c, 30fps, video only
243          webm       640x360    DASH video  405k , webm_dash container, vp9, 30fps, video only
134          mp4        640x360    DASH video  508k , mp4_dash container, avc1.4d401e, 30fps, video only
244          webm       854x480    DASH video  752k , webm_dash container, vp9, 30fps, video only
135          mp4        854x480    DASH video 1155k , mp4_dash container, avc1.4d4014, 30fps, video only
247          webm       1280x720   DASH video 1505k , webm_dash container, vp9, 30fps, video only
136          mp4        1280x720   DASH video 1629k , mp4_dash container, avc1.4d401f, 30fps, video only
18           mp4        640x360    360p  374k , avc1.42001E, mp4a.40.2@ 96k (44100Hz), 17.68MiB
22           mp4        1280x720   720p  782k , avc1.64001F, mp4a.40.2@192k (44100Hz) (best)

Format 139, 50k, m4a is the smallest available for that video.
If you want it smaller, lower bitrate, then run it through ffmpeg

Quote:

If Opus is indeed better than AAC, I'd like for this process to occur:
1. if there's an Opus between 24 & 32 Kbps, for it to be downloaded
2. if there's an AAC between 32 & 48 Kbps, for it to be downloaded
3. otherwise the best audio be downloaded then converted to the Opus equivalent of AAC 32 Kbps

Make yourself a bash script to do what you are wanting with ffmpeg then.
youtube-dl is python and it uses ffmpeg as it's backend to reencode.

DynV · 03-07-2020, 12:43 PM

I plan to download playlists so doing it manually, using -F would take a long time. I was hoping for some assistance with automated -f as in the OP 2nd quote. Since youtube-dl has ffmpeg integrated, perhaps there's a way to go through it? I was hoping --audio-format opus --audio-quality 8 would do so.

Also if a bash script would be necessary, perhaps I can get assistance with that? I understand if you don't want to.

DynV · 03-08-2020, 09:32 PM

Is there a way the selection can be done automatically as in post #3 list (at its bottom) ?

ondoho · 03-09-2020, 01:34 AM

This sounds too convoluted to ask youtube-dl to find the suitable format - consider that not all formats are always available for every download.
I think your best bet is to let youtube-dl do its thing (download best quality available), then convert into whatever it is you want in a second step.

pan64 · 03-09-2020, 02:06 AM

Quote:

Originally Posted by DynV

Is there a way the selection can be done automatically as in post #3 list (at its bottom) ?

obviously there is a way to do that:
1. get the list as it was explained
2. select the one you prefer (if you know how to do that and what to do if missing...)
3. run youtube-dl and specify the format you need.

from the other hand you may try to download and install the latest version and see this page: https://github.com/ytdl-org/youtube-...rmat-selection

DynV · 03-09-2020, 03:03 AM

By automatically I meant without doing -F previously, as in -f 'INSERT_APPROPRIATE_STRING_HERE', to do the as in post #3 list (at its bottom).

pan64 · 03-09-2020, 06:46 AM

so read the link I posted all the relevant options are listed and explained. You can choose your preferred solution.

DynV · 03-09-2020, 07:10 AM

I did read it even before starting this thread but I don't know how to do what I want (post #3 list). I'd think something like

Quote:

youtube-dl -f 'bestaudio[ext=opus][abr>=24][abr<=32]/bestaudio[ext=aac][abr>=32][abr<=48]/bestaudio'

would work but I'm not confident at all so I asked here.

boughtonp · 03-09-2020, 08:34 AM

Quote:

Originally Posted by DynV

I'd think something like [example] would work

What happened when you tried it?

pan64 · 03-09-2020, 12:09 PM

you can also specify the file size and the tool will choose depending on that....

teckk · 03-09-2020, 12:38 PM

Oh, never notices that before

Code:

man youtube-dl | grep -A1 "\-filesize"

DynV · 03-09-2020, 07:13 PM

Quote:

Originally Posted by boughtonp

What happened when you tried it?

Please note in the following there's a 2nd attempt, which I increased the maximum limit to capture the 50 Kbps Opus

Quote:

me@me-computer:~/Downloads$ youtube-dl -f 'bestaudio[ext=opus][abr>=24][abr<=50]/bestaudio[ext=aac][abr>=32][abr<=48]/bestaudio' https://www.youtube.com/watch?v=oPB4gk-SSEs
[youtube] oPB4gk-SSEs: Downloading webpage
[youtube] oPB4gk-SSEs: Downloading video info webpage
[download] Destination: Lemmy ,Slash & Dave Grohl - Ace Of Spades-oPB4gk-SSEs.webm
[download] 100% of 2.90MiB in 00:00
me@me-computer:~/Downloads$ mediainfo --Inform="General;%BitRate/String%" Lemmy\ \,Slash\ \&\ Dave\ Grohl\ -\ Ace\ Of\ Spades-oPB4gk-SSEs.webm
123 kb/s
me@me-computer:~/Downloads$ youtube-dl -F https://www.youtube.com/watch?v=oPB4gk-SSEs | grep -P '^\d+\s{2,}\w+\s{2,}audio only\s.*$'
249 webm audio only tiny 52k , opus @ 50k (48000Hz), 1.09MiB
250 webm audio only tiny 67k , opus @ 70k (48000Hz), 1.46MiB
140 m4a audio only tiny 128k , m4a_dash container, mp4a.40.2@128k (44100Hz), 2.99MiB
251 webm audio only tiny 130k , opus @160k (48000Hz), 2.90MiB
me@me-computer:~/Downloads$ rm Lemmy\ \,Slash\ \&\ Dave\ Grohl\ -\ Ace\ Of\ Spades-oPB4gk-SSEs.webm
me@me-computer:~/Downloads$ youtube-dl -f 'bestaudio[ext=opus][abr>=24][abr<60]/bestaudio[ext=aac][abr>=32][abr<=48]/bestaudio' https://www.youtube.com/watch?v=oPB4gk-SSEs
[youtube] oPB4gk-SSEs: Downloading webpage
[youtube] oPB4gk-SSEs: Downloading video info webpage
[download] Destination: Lemmy ,Slash & Dave Grohl - Ace Of Spades-oPB4gk-SSEs.webm
[download] 100% of 2.90MiB in 00:01
me@me-computer:~/Downloads$ mediainfo --Inform="General;%BitRate/String%" Lemmy\ \,Slash\ \&\ Dave\ Grohl\ -\ Ace\ Of\ Spades-oPB4gk-SSEs.webm
123 kb/s

I thought mediainfo might not work properly so I opened the file in VLC and in the window Current Media Information tab Statistics tree Input/Read entry Input bitrate, it fluctuated at a bit over 120 Kbps.

Quote:

Originally Posted by pan64

you can also specify the file size and the tool will choose depending on that....

That would also depend on the duration, and since I plan on downloading playlists, with the vast majority of the time which included videos have varying non-negligable durations, and often with a decent variation (ie: longest >= 150% shortest). The playlist can also contain videos with different audio only, which I assume would affect the file size.