[Feature Request] Add more operations to format selection

[sgkoishi]

• I've verified and I assure that I'm running youtube-dl 2019.02.08
• At least skimmed through the README, most notably the FAQ and BUGS sections
• Searched the bugtracker for similar issues including closed ones
• Checked that provided video/audio/playlist URLs (if any) are alive and playable in a browser

What is the purpose of your issue?

• Bug report (encountered problems with youtube-dl)
• Site support request (request for adding support for a new site)
• Feature request (request for a new functionality)
• Question
• Other

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Enhancement of Format Selection

Format selection now allow the best/worst format to download. However, the format selection only support conditions (e.g. -f "best[height>=720]"), as a filter. In some special case, people may want to download video of most/least certain field (e.g. highest resolution, smallest size) rather than default "best/worst". Youtube-dl does not support this without manually specify numeric format code or knowing the exact value.

For example, the best quality for this youtube video is a medium(640x360) resolution while highest resolution is 1080p(1920x1080).

format code  extension  resolution note
249          webm       audio only DASH audio   62k , opus @ 50k, 1.43MiB
250          webm       audio only DASH audio   82k , opus @ 70k, 1.91MiB
140          m4a        audio only DASH audio  128k , m4a_dash container, mp4a.40.2@128k, 3.32MiB
171          webm       audio only DASH audio  144k , vorbis@128k, 3.55MiB
251          webm       audio only DASH audio  159k , opus @160k, 3.77MiB
160          mp4        256x144    144p   51k , avc1.4d400c, 30fps, video only, 501.84KiB
278          webm       256x144    144p   95k , webm container, vp9, 30fps, video only, 1.47MiB
133          mp4        426x240    240p  147k , avc1.4d4015, 30fps, video only, 1.08MiB
242          webm       426x240    240p  169k , vp9, 30fps, video only, 1.59MiB
134          mp4        640x360    360p  304k , avc1.4d401e, 30fps, video only, 2.04MiB
243          webm       640x360    360p  337k , vp9, 30fps, video only, 2.69MiB
135          mp4        854x480    480p  384k , avc1.4d401f, 30fps, video only, 3.10MiB
136          mp4        1280x720   720p  468k , avc1.4d401f, 30fps, video only, 5.18MiB
244          webm       854x480    480p  551k , vp9, 30fps, video only, 3.96MiB
137          mp4    --->1920x1080  1080p  597k , avc1.640028, 30fps, video only, 7.67MiB
247          webm       1280x720   720p  815k , vp9, 30fps, video only, 7.21MiB
248          webm   --->1920x1080  1080p 1064k , vp9, 30fps, video only, 13.02MiB
17           3gp        176x144    small   48k , mp4v.20.3, mp4a.40.2@ 24k (22050Hz), 1.26MiB
36           3gp        320x180    small  156k , mp4v.20.3, mp4a.40.2 (22050Hz), 4.08MiB
18           mp4    --->640x360    medium  361k , avc1.42001E, mp4a.40.2@ 96k (44100Hz), 9.44MiB (best)

If I want to download the highest resolution of this video, I had to manually specify 1080p or an extractor specific code(137, 248) now.

Requested new feature: add more operations of format selection.
Sample: To find highest resolution, use -f "best[height]" or -f "best[height=max]"

[JensKorte]

At the moment it is not possible to request the smallestFilesize. You could use worstvideo+worstaudio as a workaround. I don't know if it is the same as the smallest sum of (smallestVideo+smallestAudio).

I get the best video without any format option (248) for the video mentioned above. Why don't you just use -f bestvideo+bestaudio?

[kurtontheway]

Could not get 137+140 with the option "bestvideo+bestaudio"..
youtube-dl -F "https://www.youtube.com/watch?v=XiVeuftm5go&t=4s"

format code	extension	resolution note
139	m4a	audio only DASH audio 52k , m4a_dash container, mp4a.40.5@ 48k (22050Hz), 4.58MiB
140	m4a	audio only DASH audio 131k , m4a_dash container, mp4a.40.2@128k (44100Hz), 12.22MiB
160	mp4	256x144 DASH video 108k , mp4_dash container, avc1.4d400b, 30fps, video only
133	mp4	426x240 DASH video 242k , mp4_dash container, avc1.4d400c, 30fps, video only
134	mp4	640x360 DASH video 325k , mp4_dash container, avc1.4d401e, 30fps, video only, 5.82MiB
135	mp4	854x480 DASH video 1155k , mp4_dash container, avc1.4d4014, 30fps, video only
137	mp4	1920x1080 DASH video 2197k , mp4_dash container, avc1.640028, 30fps, video only, 45.22MiB
136	mp4	1280x720 DASH video 2310k , mp4_dash container, avc1.4d4016, 30fps, video only
17	3gp	176x144 small 45k , mp4v.20.3, mp4a.40.2@ 24k (22050Hz), 4.39MiB
36	3gp	320x180 small 130k , mp4v.20.3, mp4a.40.2 (22050Hz), 12.57MiB
43	webm	640x360 medium , vp8.0, vorbis@128k, 24.67MiB
18	mp4	640x360 medium 295k , avc1.42001E, mp4a.40.2@ 96k (44100Hz), 28.36MiB
22	mp4	1280x720 hd720 947k , avc1.64001F, mp4a.40.2@192k (44100Hz) (best)

[JensKorte]

You are right. I checked for "best" and not for bestvideo. I guess bestvideo uses the highest videobitrate which results in 136 with lower resolution, like you wrote.

youtube-dl --get-url -f "bestvideo[height>1000],bestaudio" "https://www.youtube.com/watch?v=XiVeuftm5go&t=4s" # is a workaround
Result: Video: itag/137/ Audio: itag/140

[ChildishGiant]

Here the "best" option is 360p even though there's a 1080p option. Is this still

[inferiorhumanorgans]

At the moment it is not possible to request the smallestFilesize. You could use worstvideo+worstaudio as a workaround. I don't know if it is the same as the smallest sum of (smallestVideo+smallestAudio).

$ youtube-dl -F https://youtube.com/watch?v=8ha4bkni3zg
[youtube] 8ha4bkni3zg: Downloading webpage
[info] Available formats for 8ha4bkni3zg:
format code  extension  resolution note
249          webm       audio only tiny   51k , opus @ 50k (48000Hz), 11.78MiB
250          webm       audio only tiny   64k , opus @ 70k (48000Hz), 12.64MiB
251          webm       audio only tiny  117k , opus @160k (48000Hz), 22.86MiB
140          m4a        audio only tiny  132k , m4a_dash container, mp4a.40.2@128k (44100Hz), 30.32MiB
278          webm       256x144    144p   96k , webm container, vp9, 30fps, video only, 20.04MiB
160          mp4        256x144    144p  111k , avc1.4d400c, 30fps, video only, 16.15MiB
242          webm       426x240    240p  193k , vp9, 30fps, video only, 40.96MiB
133          mp4        426x240    240p  245k , avc1.4d4015, 30fps, video only, 35.31MiB
243          webm       640x360    360p  414k , vp9, 30fps, video only, 89.14MiB
134          mp4        640x360    360p  505k , avc1.4d401e, 30fps, video only, 67.33MiB
244          webm       854x480    480p  766k , vp9, 30fps, video only, 163.07MiB
135          mp4        854x480    480p  818k , avc1.4d401f, 30fps, video only, 107.59MiB
247          webm       1280x720   720p 1524k , vp9, 30fps, video only, 323.88MiB
136          mp4        1280x720   720p 2313k , avc1.4d401f, 30fps, video only, 319.69MiB
18           mp4        640x360    360p  697k , avc1.42001E, mp4a.40.2@ 96k (44100Hz), 163.21MiB
22           mp4        1280x720   720p 1494k , avc1.64001F, mp4a.40.2@192k (44100Hz) (best)
$ youtube-dl --get-format -f "worstvideo[height=720]+bestaudio" https://youtube.com/watch?v=8ha4bkni3zg
247 - 1280x720 (720p)+140 - audio only (tiny)

A smallest file size operator would hopefully get 136+140 instead.