[YouTube] Incorrect detection of best format

[temp190248671]

Checklist

• I'm reporting a broken site support issue
• I've verified that I'm running youtube-dl version 2019.11.05
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar bug reports including closed ones
• I've read bugs section in FAQ

Verbose log

youtube-dl.exe -v --list-formats https://www.youtube.com/watch?v=88aN6mYjJTQ
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['-v', '--list-formats', 'https://www.youtube.com/watch?v=88aN6mYjJTQ']
[debug] Encodings: locale cp1252, fs mbcs, out cp850, pref cp1252
[debug] youtube-dl version 2019.11.05
[debug] Python version 3.4.4 (CPython) - Windows-10-10.0.18362
[debug] exe versions: none
[debug] Proxy map: {}
[youtube] 88aN6mYjJTQ: Downloading webpage
[youtube] 88aN6mYjJTQ: Downloading video info webpage
[youtube] {18} signature length 109, html5 player vfl3Ub7Lu
[youtube] {313} signature length 105, html5 player vfl3Ub7Lu
[youtube] {266} signature length 109, html5 player vfl3Ub7Lu
[youtube] {264} signature length 105, html5 player vfl3Ub7Lu
[youtube] {271} signature length 109, html5 player vfl3Ub7Lu
[youtube] {137} signature length 109, html5 player vfl3Ub7Lu
[youtube] {248} signature length 109, html5 player vfl3Ub7Lu
[youtube] {136} signature length 109, html5 player vfl3Ub7Lu
[youtube] {247} signature length 105, html5 player vfl3Ub7Lu
[youtube] {135} signature length 105, html5 player vfl3Ub7Lu
[youtube] {244} signature length 109, html5 player vfl3Ub7Lu
[youtube] {134} signature length 105, html5 player vfl3Ub7Lu
[youtube] {243} signature length 109, html5 player vfl3Ub7Lu
[youtube] {133} signature length 105, html5 player vfl3Ub7Lu
[youtube] {242} signature length 105, html5 player vfl3Ub7Lu
[youtube] {160} signature length 109, html5 player vfl3Ub7Lu
[youtube] {278} signature length 109, html5 player vfl3Ub7Lu
[youtube] {140} signature length 109, html5 player vfl3Ub7Lu
[youtube] {249} signature length 109, html5 player vfl3Ub7Lu
[youtube] {250} signature length 109, html5 player vfl3Ub7Lu
[youtube] {251} signature length 109, html5 player vfl3Ub7Lu
[info] Available formats for 88aN6mYjJTQ:
format code  extension  resolution note
249          webm       audio only tiny   51k , opus @ 50k (48000Hz), 1.12MiB
250          webm       audio only tiny   67k , opus @ 70k (48000Hz), 1.47MiB
140          m4a        audio only tiny  128k , m4a_dash container, mp4a.40.2@128k (44100Hz), 2.93MiB
251          webm       audio only tiny  134k , opus @160k (48000Hz), 2.92MiB
278          webm       256x144    144s  108k , webm container, vp9, 30fps, video only, 2.26MiB
160          mp4        256x144    144s  116k , avc1.4d400c, 30fps, video only, 2.56MiB
133          mp4        424x240    240s  253k , avc1.4d4015, 30fps, video only, 5.66MiB
242          webm       424x240    240s  257k , vp9, 30fps, video only, 5.04MiB
243          webm       640x360    360s  474k , vp9, 30fps, video only, 9.49MiB
134          mp4        640x360    360s  634k , avc1.4d401e, 30fps, video only, 10.34MiB
244          webm       848x480    480s  867k , vp9, 30fps, video only, 17.07MiB
135          mp4        848x480    480s 1161k , avc1.4d401f, 30fps, video only, 19.66MiB
247          webm       1280x720   720s 1706k , vp9, 30fps, video only, 34.40MiB
136          mp4        1280x720   720s 2314k , avc1.4d401f, 30fps, video only, 37.20MiB
248          webm       1920x1080  1080s 2971k , vp9, 30fps, video only, 61.08MiB
137          mp4        1920x1080  1080s 4342k , avc1.640028, 30fps, video only, 66.13MiB
264          mp4        2560x1440  1440s 9200k , avc1.640032, 30fps, video only, 134.85MiB
271          webm       2560x1440  1440s 9285k , vp9, 30fps, video only, 183.87MiB
266          mp4        3840x2048  2160s 12787k , avc1.640033, 30fps, video only, 236.25MiB
313          webm       3840x2160  2160s 19124k , vp9, 30fps, video only, 402.59MiB
18           mp4        640x360    360s  585k , avc1.42001E, mp4a.40.2@ 96k (44100Hz), 13.49MiB (best)

Description

Trying to download https://www.youtube.com/watch?v=88aN6mYjJTQ at default settings, which is supposed to be best quality, downloads a video at total garbage quality. You can see in the output of --list-formats above how it is incorrectly detecting format 18 as best instead of 313+140/251, or at least 266.

[temp192486711]

Oh, it seems I forgot to install ffmpeg, that is why it did not pick the split bestvideo+bestaudio. Big facepalm here..