bestvideo doesn't always select best video

[Yhonay]

For this video:
https://www.youtube.com/watch?v=InxwGZ_PgC4
-f bestvideo[ext=mp4]+bestaudio downloads 240p version (while there is 1080p available)

$ youtube-dl -F https://www.youtube.com/watch?v=InxwGZ_PgC4
[youtube] InxwGZ_PgC4: Downloading webpage
[youtube] InxwGZ_PgC4: Extracting video information
WARNING: video doesn't have subtitles
[youtube] InxwGZ_PgC4: Downloading DASH manifest
[info] Available formats for InxwGZ_PgC4:
format code  extension  resolution note
140          m4a        audio only DASH audio  129k , m4a_dash container, aac  @128k (44100Hz), 4.20MiB
171          webm       audio only DASH audio  138k , audio@128k (44100Hz), 4.19MiB
141          m4a        audio only DASH audio  256k , m4a_dash container, aac  @256k (44100Hz), 8.35MiB
134          mp4        640x360    DASH video   28k , 30fps, video only, 766.85KiB
242          webm       426x240    DASH video   29k , 1fps, video only, 859.75KiB
135          mp4        854x480    DASH video   39k , 30fps, video only, 1.05MiB
243          webm       640x360    DASH video   44k , 1fps, video only, 1.26MiB
136          mp4        1280x720   DASH video   56k , 30fps, video only, 1.59MiB
160          mp4        256x144    DASH video   64k , 15fps, video only, 1.15MiB
244          webm       854x480    DASH video   69k , 1fps, video only, 1.90MiB
137          mp4        1920x1080  DASH video   83k , 30fps, video only, 2.37MiB
133          mp4        426x240    DASH video  111k , 30fps, video only, 2.13MiB
247          webm       1280x720   DASH video  118k , 1fps, video only, 2.98MiB
248          webm       1920x1080  DASH video  176k , 1fps, video only, 4.36MiB
17           3gp        176x144    
36           3gp        320x240    
5            flv        400x240    
43           webm       640x360    
18           mp4        640x360    
22           mp4        1280x720   (best)

[Tailszefox]

Probably related (though I'll open a different bug report if needed): with no argument and thus no request for a particular format, youtube-dl produces a warning:

$ youtube-dl https://www.youtube.com/watch\?v\=InxwGZ_PgC4                                                                                                                                                                              
[youtube] InxwGZ_PgC4: Downloading webpage
[youtube] InxwGZ_PgC4: Extracting video information
[youtube] InxwGZ_PgC4: Downloading DASH manifest
WARNING: You have requested formats uncompatible for merge. The formats will be merged into mkv
[download] Destination: GUMI 'I (Love)' Original Song-InxwGZ_PgC4.f248.webm
[download] 100% of 4.36MiB in 00:12
[download] Destination: GUMI 'I (Love)' Original Song-InxwGZ_PgC4.f141.m4a
[download] 100% of 8.35MiB in 00:07
[ffmpeg] Merging formats into "GUMI 'I (Love)' Original Song-InxwGZ_PgC4.mkv"
Deleting original file GUMI 'I (Love)' Original Song-InxwGZ_PgC4.f248.webm (pass -k to keep)
Deleting original file GUMI 'I (Love)' Original Song-InxwGZ_PgC4.f141.m4a (pass -k to keep)

This isn't specific to this video:

$ youtube-dl https://www.youtube.com/watch\?v\=Wcpk052_VDQ                                                                                                                                                                              
[youtube] Wcpk052_VDQ: Downloading webpage
[youtube] Wcpk052_VDQ: Extracting video information
[youtube] Wcpk052_VDQ: Downloading DASH manifest
WARNING: You have requested formats uncompatible for merge. The formats will be merged into mkv
[download] Destination: Sonic 06 Makes Sonic Boom Look Like Sonic 06 (Part 14)-Wcpk052_VDQ.f303.webm

Potentially related as well (I was about to open a new bug report for this one, but I would guess the root cause is the same): unless I'm not understanding how to use it correctly, the --max-quality option seems to be ignored:

$ youtube-dl --max-quality 99 https://www.youtube.com/watch\?v\=InxwGZ_PgC4                                                                                                                                                                    
[youtube] InxwGZ_PgC4: Downloading webpage
[youtube] InxwGZ_PgC4: Extracting video information
[youtube] InxwGZ_PgC4: Downloading DASH manifest
WARNING: You have requested formats uncompatible for merge. The formats will be merged into mkv
[download] Destination: GUMI 'I (Love)' Original Song-InxwGZ_PgC4.f248.webm

[jaimeMF]

@Tailszefox see #5456 (comment) for why we output the warning (if you always want mp4 files you can use -f bestvideo[ext=mp4]+bestaudio[ext=m4a]/best). About --max-quality: probably it only works if you use -f best, but I would recommend using filters (like -f best[height<=720]). Feel free to open a new issue for that.

[Tailszefox]

@jaimeMF Yeah, I see why the warning is necessary. I just find it odd that the new default options make it necessary. I mean, a program that emits a warning when using default options just looks weird to me, since default options are supposed to be the normal mode of operation, and thus shouldn't cause any warning.

The warning itself is also a bit confusing in this case, since it says You have requested, emphasis on "You"; despite the fact that the user didn't request anything in particular and just used the default options.

That might just be a matter of preference, though, and it's easy to avoid it with the proper arguments, so it's not a big issue. Again, I just find it odd, but it's clearly not problematic. In any case, it's not related to this issue, then, my apologies.

I'll open a new issue for --max-quality, since it used to work before without setting -f.