[Python] yt-dlp returns non-existent format_id when extracting formats via Python

I'm a Python beginner. I am using yt-dlp via Python to select the best video format with a target resolution.
However, I sometimes get a format_id that does not actually exist in the -F output. My 'yt-dlp' is up to date.

My script:

import os
import subprocess
import glob
import sys
import yt_dlp

def download_best_video (url, target_height):
ydl_opts = {
'quiet': True,
'forcejson': True,
'dump': True
}

with yt_dlp.YoutubeDL(ydl_opts) as ydl:
info_dict = ydl.extract_info(url, download=False)

formats = info_dict.get('formats', [])

# get maximum bit rate format
max_bitrate = 0
max_bitrate_format_id = None
for format in formats:
height = format.get('height')
bitrate = format.get('tbr')
if height == target_height and bitrate > max_bitrate:
max_bitrate = bitrate
max_bitrate_format_id = format.get('format_id')

if max_bitrate_format_id == None:
return

# download
script_path = os.path.abspath(__file__)
script_dir = os.path.dirname(script_path)

print(script_dir)

args = ["yt-dlp", "--ignore-no-formats-error", "-f", f"{max_bitrate_format_id}+ba[ext=m4a]",
"--write-sub", "--embed-subs", "--sub-lang", "ja", "--embed-metadata", "--paths", script_dir, url]

print("cmd:", " ".join(args))

subprocess.run(args)

# delete subtitle file
vtt_files = glob.glob(os.path.join(script_dir, "*.vtt"))
for vtt_file in vtt_files:
os.remove(vtt_file)

heights = [720, 1080, 1440, 1920, 2160, 2560, 3840]
print(f"available heights: {heights}")
target_height_str = input("height = ")

target_height = None
try:
target_height = int(target_height_str)
except ValueError:
sys.exit()

if (not(heights.__contains__(target_height))):
sys.exit()

url_Texts = input("URL > ")
urls = url_Texts.split()

for url in urls:
try:
download_best_video(url, target_height)
except Exception as e:
continue


Output:

PS C:\Users\user> & C:/Users/user/AppData/Local/Programs/Python/Python313/python.exe "d:/Download/Download Best Video.py"
available heights: [720, 1080, 1440, 1920, 2160, 2560, 3840]
height = 1440
URL > https://www.youtube.com/watch?v=wJwUjuKr_54
d:\Download
cmd: yt-dlp --ignore-no-formats-error -f 623+ba[ext=m4a] --write-sub --embed-subs --sub-lang ja --embed-metadata --paths d:\Download https://www.youtube.com/watch?v=wJwUjuKr_54
[youtube] Extracting URL: https://www.youtube.com/watch?v=wJwUjuKr_54
[youtube] wJwUjuKr_54: Downloading webpage
[youtube] wJwUjuKr_54: Downloading tv simply player API JSON
[youtube] wJwUjuKr_54: Downloading tv client config
[youtube] wJwUjuKr_54: Downloading tv player API JSON
[info] wJwUjuKr_54: Downloading subtitles: ja
WARNING: Requested format is not available
Deleting existing file d:\Download\LE SSERAFIM(르세라핌) 'CRAZY' (4K) ｜ STUDIO CHOOM ORIGINAL [wJwUjuKr_54].ja.vtt
[info] Writing video subtitles to: d:\Download\LE SSERAFIM(르세라핌) 'CRAZY' (4K) ｜ STUDIO CHOOM ORIGINAL [wJwUjuKr_54].ja.vtt
[download] Destination: d:\Download\LE SSERAFIM(르세라핌) 'CRAZY' (4K) ｜ STUDIO CHOOM ORIGINAL [wJwUjuKr_54].ja.vtt
[download] 100% of 3.45KiB in 00:00:00 at 15.56KiB/s
ERROR: [youtube] wJwUjuKr_54: No video formats found!


Format list of the video　(I have only included the formats for 1440p.):

C:\Users\user>yt-dlp -F https://www.youtube.com/watch?v=wJwUjuKr_54
[youtube] Extracting URL: https://www.youtube.com/watch?v=wJwUjuKr_54
[youtube] wJwUjuKr_54: Downloading webpage
[youtube] wJwUjuKr_54: Downloading tv simply player API JSON
[youtube] wJwUjuKr_54: Downloading tv client config
[youtube] wJwUjuKr_54: Downloading tv player API JSON
[info] Available formats for wJwUjuKr_54:
ID EXT RESOLUTION FPS CH │ FILESIZE TBR PROTO │ VCODEC VBR ACODEC ABR ASR MORE INFO
───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
(omit)
308 webm 2560x1440 60 │ 275.48MiB 12195k https │ vp9 12195k video only 1440p60, webm_dash
400 mp4 2560x1440 60 │ 145.44MiB 6439k https │ av01.0.12M.08 6439k video only 1440p60, mp4_dash
(omit)


The command

yt-dlp --ignore-no-formats-error -f 623+ba[ext=m4a] --write-sub --embed-subs --sub-lang ja --embed-metadata --paths d:\Download https://www.youtube.com/watch?v=wJwUjuKr_54


was generated by my script, but format 623 does not exist in the -F output. Why is this happening? This script used to work fine until recently.

By the way, I am aware that I could use a command like:

yt-dlp -f "bv[height=1440]" URL


However, I don’t use this approach, because for some reason it does not always select the highest quality format. That is why I wrote my own script to choose the format with the maximum bitrate at the desired height.

D:\Download>yt-dlp -f bv[height=1440]+ba[ext=m4a] https://www.youtube.com/watch?v=wJwUjuKr_54
[youtube] Extracting URL: https://www.youtube.com/watch?v=wJwUjuKr_54
[youtube] wJwUjuKr_54: Downloading webpage
[youtube] wJwUjuKr_54: Downloading tv simply player API JSON
[youtube] wJwUjuKr_54: Downloading tv client config
[youtube] wJwUjuKr_54: Downloading tv player API JSON
[info] wJwUjuKr_54: Downloading 1 format(s): 400+140
[download] Destination: LE SSERAFIM(르세라핌) 'CRAZY' (4K) ｜ STUDIO CHOOM ORIGINAL [wJwUjuKr_54].f400.mp4
[download] 100% of 145.44MiB in 00:00:17 at 8.16MiB/s
[download] Destination: LE SSERAFIM(르세라핌) 'CRAZY' (4K) ｜ STUDIO CHOOM ORIGINAL [wJwUjuKr_54].f140.m4a
[download] 100% of 2.93MiB in 00:00:00 at 6.25MiB/s


For example, at 1440p the best quality should be format 308, but yt-dlp instead selects 400.

Why does 'yt-dlp' return a format_id that does not actually exist in the yt-dlp -F output? And how can I make sure to only select real, downloadable formats?

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