Different response to --output, in two different situations

[krasnh]

DO NOT REMOVE OR SKIP THE ISSUE TEMPLATE

• I understand that I will be blocked if I intentionally remove or skip any mandatory* field

Checklist

• I'm reporting a bug unrelated to a specific site
• I've verified that I have updated yt-dlp to nightly or master (update instructions)
• I've checked that all provided URLs are playable in a browser with the same IP and same login details
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched known issues and the bugtracker for similar issues including closed ones. DO NOT post duplicates
• I've read the guidelines for opening an issue

Provide a description that is worded well enough to be understood

A name I don't expect:

1. -f bv+va --output '%(title)s - %(id)s'
   We get "*oBUuh3DIK_A.webm"

The correct name:
2. -f b --output '%(title)s - %(id)s'
We get "*oBUuh3DIK_A"

Provide verbose output that clearly demonstrates the problem

• Run your yt-dlp command with -vU flag added (yt-dlp -vU <your command line>)
• If using API, add 'verbose': True to YoutubeDL params instead
• Copy the WHOLE output (starting with [debug] Command-line config) and insert it below

Complete Verbose Output

[debug] Command-line config: ['oBUuh3DIK_A', '-o', '%(title)s - %(id)s', '--no-config', '-Uv']
[debug] Encodings: locale UTF-8, fs utf-8, pref UTF-8, out utf-8, error utf-8, screen utf-8
[debug] yt-dlp version nightly@2024.05.16.232713 from yt-dlp/yt-dlp-nightly-builds [6d8a53d87] (zip)
[debug] Python 3.10.8 (CPython x86_64 64bit) - Linux-6.8.0-pf1-x86_64-with-glibc2.38 (OpenSSL 1.1.1t  7 Feb 2023, glibc 2.38)
[debug] exe versions: ffmpeg 5.1.2 (setts), ffprobe 5.1.2
[debug] Optional libraries: certifi-2022.09.24, requests-2.28.1, sqlite3-3.39.4, urllib3-1.26.12
[debug] Proxy map: {}
[debug] Request Handlers: urllib
[debug] Extractor Plugins: YandexTranslateIE
[debug] Post-Processor Plugins: YandexTranslateAutoAddPP, YandexTranslateMergePP, YandexTranslateSubtitleFixPP
[debug] Loaded 1803 extractors
[debug] Fetching release info: https://api.github.com/repos/yt-dlp/yt-dlp-nightly-builds/releases/latest
Latest version: nightly@2024.05.16.232713 from yt-dlp/yt-dlp-nightly-builds
yt-dlp is up to date (nightly@2024.05.16.232713 from yt-dlp/yt-dlp-nightly-builds)
[youtube] Extracting URL: oBUuh3DIK_A
[youtube] oBUuh3DIK_A: Downloading webpage
[youtube] oBUuh3DIK_A: Downloading ios player API JSON
[youtube] oBUuh3DIK_A: Downloading android player API JSON
WARNING: [youtube] Skipping player responses from android clients (got player responses for video "aQvGIIdgFDM" instead of "oBUuh3DIK_A")
[debug] [youtube] Extracting signature function js_74a3a562_101
[debug] Loading youtube-sigfuncs.js_74a3a562_101 from cache
[debug] Loading youtube-nsig.74a3a562 from cache
[debug] [youtube] Decrypted nsig 8URNQt6HR25XQYY-1Yq => DsjKhepHzWpBOw
[debug] [youtube] Extracting signature function js_74a3a562_105
[debug] Loading youtube-sigfuncs.js_74a3a562_105 from cache
[debug] Loading youtube-nsig.74a3a562 from cache
[debug] [youtube] Decrypted nsig 6z66rnwK2pdozA9J54E => ikvu3HKFwoAXKg
[youtube] oBUuh3DIK_A: Downloading m3u8 information
[debug] Sort order given by extractor: quality, res, fps, hdr:12, source, vcodec:vp9.2, channels, acodec, lang, proto
[debug] Formats sorted by: hasvid, ie_pref, quality, res, fps, hdr:12(7), source, vcodec:vp9.2(10), channels, acodec, lang, proto, size, br, asr, vext, aext, hasaud, id
[debug] Default format spec: bestvideo*+bestaudio/best
[info] oBUuh3DIK_A: Downloading 1 format(s): 243+251
[debug] Invoking http downloader on "https://rr8---sn-gxuog0-axqe.googlevideo.com/videoplayback?expire=1715957218&ei=ghlHZpGtJPuA0u8PvNufsAo&ip=&id=o-AK8TxJ7tzTFwuTtOnFMSu6fhbr-s5PYpIIDbwD7gXl-5&itag=243&source=youtube&requiressl=yes&xpc=EgVo2aDSNQ%3D%3D&mh=Ro&mm=31%2C29&mn=sn-gxuog0-axqe%2Csn-axq7sn7s&ms=au%2Crdu&mv=m&mvi=8&pl=21&initcwndbps=1856250&vprv=1&svpuc=1&mime=video%2Fwebm&rqh=1&gir=yes&clen=9340169&dur=278.840&lmt=1559401363730576&mt=1715935264&fvip=4&keepalive=yes&c=IOS&txp=5432432&sparams=expire%2Cei%2Cip%2Cid%2Citag%2Csource%2Crequiressl%2Cxpc%2Cvprv%2Csvpuc%2Cmime%2Crqh%2Cgir%2Cclen%2Cdur%2Clmt&sig=AJfQdSswRgIhAPEJpW2v8mDzRo4wT2Q41hcL0-QQK4X5GKJFl4goV8apAiEAvheX2DVIZYoY1MUJ26BAFlFddGe3HHE___pauOqnl1U%3D&lsparams=mh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps&lsig=AHWaYeowRQIhAL5pIOE0kRofQqZsB_mh-khET3n2FcK9M-sq2c175RpQAiA13-473Rzpobxu39VfKS69Owk9evBKped7-W-WKSyr3A%3D%3D"
[download] Destination: Винни-Пух Пятачок Ослик Иа. Песни из мультиков. Вспомним детство! Подписывайтесь - ссылка под видео - oBUuh3DIK_A.f243.webm
[download] 100% of    8.91MiB in 00:00:04 at 2.04MiB/s
[debug] Invoking http downloader on "https://rr8---sn-gxuog0-axqe.googlevideo.com/videoplayback?expire=1715957218&ei=ghlHZuD1Aeunv_IP-dKJiAI&ip=&id=o-ALeb5Mva2jBhSKN9ZDU7O8GwPxRNh6kpkyS14MPIwn72&itag=251&source=youtube&requiressl=yes&xpc=EgVo2aDSNQ%3D%3D&mh=Ro&mm=31%2C29&mn=sn-gxuog0-axqe%2Csn-axq7sn7s&ms=au%2Crdu&mv=m&mvi=8&pl=21&initcwndbps=1856250&bui=AWRWj2QrGiHhNJQfm4SUorrjzEvOYaGi2b8fkfux696eO3wyAly_1jBgYC2Y3_ZVGwYfwwLobw3Mmp0e&spc=UWF9f4vLCgqoPLYxgcyY6dGlPREaHuyPCuAQIj0mpx37sExTANRMkHQ&vprv=1&svpuc=1&mime=audio%2Fwebm&ns=jRp6gvjuWuJTlhsy-Z8ospMQ&rqh=1&gir=yes&clen=4556315&dur=278.861&lmt=1559387980437469&mt=1715935264&fvip=4&keepalive=yes&c=WEB&sefc=1&txp=5432432&n=ikvu3HKFwoAXKg&sparams=expire%2Cei%2Cip%2Cid%2Citag%2Csource%2Crequiressl%2Cxpc%2Cbui%2Cspc%2Cvprv%2Csvpuc%2Cmime%2Cns%2Crqh%2Cgir%2Cclen%2Cdur%2Clmt&lsparams=mh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps&lsig=AHWaYeowRQIgPxbkoAmtKD6n6ABkJa0SNSR6okVAjXNv8Lc-O4XcrF4CIQDjeu5DbilRLat8cV5vd3WhI3MrC1Yv3S3xs49eu_rLVg%3D%3D&sig=AJfQdSswRAIgE_4Y07ZDBYto7lLr57zeCBIwMleT-1CHYOEPLDOcUIICIEM7-TyiAiwgaV8u2BkFuCqjUqtZKrWqmYH45v51rl44"
[download] Destination: Винни-Пух Пятачок Ослик Иа. Песни из мультиков. Вспомним детство! Подписывайтесь - ссылка под видео - oBUuh3DIK_A.f251.webm
[download] 100% of    4.35MiB in 00:00:02 at 1.77MiB/s
[Merger] Merging formats into "Винни-Пух Пятачок Ослик Иа. Песни из мультиков. Вспомним детство! Подписывайтесь - ссылка под видео - oBUuh3DIK_A.webm"
[debug] ffmpeg command line: ffmpeg -y -loglevel repeat+info -i 'file:Винни-Пух Пятачок Ослик Иа. Песни из мультиков. Вспомним детство! Подписывайтесь - ссылка под видео - oBUuh3DIK_A.f243.webm' -i 'file:Винни-Пух Пятачок Ослик Иа. Песни из мультиков. Вспомним детство! Подписывайтесь - ссылка под видео - oBUuh3DIK_A.f251.webm' -c copy -map 0:v:0 -map 1:a:0 -movflags +faststart 'file:Винни-Пух Пятачок Ослик Иа. Песни из мультиков. Вспомним детство! Подписывайтесь - ссылка под видео - oBUuh3DIK_A.temp.webm'
Deleting original file Винни-Пух Пятачок Ослик Иа. Песни из мультиков. Вспомним детство! Подписывайтесь - ссылка под видео - oBUuh3DIK_A.f243.webm (pass -k to keep)
Deleting original file Винни-Пух Пятачок Ослик Иа. Песни из мультиков. Вспомним детство! Подписывайтесь - ссылка под видео - oBUuh3DIK_A.f251.webm (pass -k to keep)


[debug] Command-line config: ['-f', 'b', 'oBUuh3DIK_A', '-o', '%(title)s - %(id)s', '--no-config', '-Uv']
[debug] Encodings: locale UTF-8, fs utf-8, pref UTF-8, out utf-8, error utf-8, screen utf-8
[debug] yt-dlp version nightly@2024.05.16.232713 from yt-dlp/yt-dlp-nightly-builds [6d8a53d87] (zip)
[debug] Python 3.10.8 (CPython x86_64 64bit) - Linux-6.8.0-pf1-x86_64-with-glibc2.38 (OpenSSL 1.1.1t  7 Feb 2023, glibc 2.38)
[debug] exe versions: ffmpeg 5.1.2 (setts), ffprobe 5.1.2
[debug] Optional libraries: certifi-2022.09.24, requests-2.28.1, sqlite3-3.39.4, urllib3-1.26.12
[debug] Proxy map: {}
[debug] Request Handlers: urllib
[debug] Extractor Plugins: YandexTranslateIE
[debug] Post-Processor Plugins: YandexTranslateAutoAddPP, YandexTranslateMergePP, YandexTranslateSubtitleFixPP
[debug] Loaded 1803 extractors
[debug] Fetching release info: https://api.github.com/repos/yt-dlp/yt-dlp-nightly-builds/releases/latest
Latest version: nightly@2024.05.16.232713 from yt-dlp/yt-dlp-nightly-builds
yt-dlp is up to date (nightly@2024.05.16.232713 from yt-dlp/yt-dlp-nightly-builds)
[youtube] Extracting URL: oBUuh3DIK_A
[youtube] oBUuh3DIK_A: Downloading webpage
[youtube] oBUuh3DIK_A: Downloading ios player API JSON
[youtube] oBUuh3DIK_A: Downloading android player API JSON
WARNING: [youtube] Skipping player responses from android clients (got player responses for video "aQvGIIdgFDM" instead of "oBUuh3DIK_A")
[debug] [youtube] Extracting signature function js_74a3a562_105
[debug] Loading youtube-sigfuncs.js_74a3a562_105 from cache
[debug] Loading youtube-nsig.74a3a562 from cache
[debug] [youtube] Decrypted nsig lxIy3PJytBPklPHdjyh => gjU2hFaU4NusXw
[debug] Loading youtube-nsig.74a3a562 from cache
[debug] [youtube] Decrypted nsig qkzRVhbXyS6yUFt-otF => 35OtP0tZ55o-kA
[debug] [youtube] Extracting signature function js_74a3a562_101
[debug] Loading youtube-sigfuncs.js_74a3a562_101 from cache
[youtube] oBUuh3DIK_A: Downloading m3u8 information
[debug] Sort order given by extractor: quality, res, fps, hdr:12, source, vcodec:vp9.2, channels, acodec, lang, proto
[debug] Formats sorted by: hasvid, ie_pref, quality, res, fps, hdr:12(7), source, vcodec:vp9.2(10), channels, acodec, lang, proto, size, br, asr, vext, aext, hasaud, id
[info] oBUuh3DIK_A: Downloading 1 format(s): 18
[debug] Invoking http downloader on "https://rr8---sn-gxuog0-axqe.googlevideo.com/videoplayback?expire=1715957246&ei=nhlHZr6GJ7KQv_IPjpSs4AE&ip=&id=o-AOZTY8Pdzxwuit3CIdANmW1T9dvgj-Xpa-nUck5cHXG7&itag=18&source=youtube&requiressl=yes&xpc=EgVo2aDSNQ%3D%3D&mh=Ro&mm=31%2C29&mn=sn-gxuog0-axqe%2Csn-axq7sn7s&ms=au%2Crdu&mv=m&mvi=8&pl=21&initcwndbps=1856250&bui=AWRWj2RJI4SwAGhjrigXBSd1U6WmjCuM45cQPqqoXElL_juAMoIR2qPfRBZGCs12vZZm64bsL7hVLshc&spc=UWF9fw1cZ4JrZTe6ibfUtz8yYdoT47q8VikGtotm4Xpq0VKLhSia9BdsFalf&vprv=1&svpuc=1&mime=video%2Fmp4&ns=auPUgkjHW0FvS1Dwfa2GgaUQ&rqh=1&cnr=14&ratebypass=yes&dur=278.894&lmt=1665358852464066&mt=1715935264&fvip=4&c=WEB&sefc=1&txp=1438434&n=gjU2hFaU4NusXw&sparams=expire%2Cei%2Cip%2Cid%2Citag%2Csource%2Crequiressl%2Cxpc%2Cbui%2Cspc%2Cvprv%2Csvpuc%2Cmime%2Cns%2Crqh%2Ccnr%2Cratebypass%2Cdur%2Clmt&lsparams=mh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps&lsig=AHWaYeowRQIhAI4PV4sAzEpfK9UOmUAq7G8YNWdHuQRidesdj6cObZKaAiBesqMdhQafogfWLKnvIC0JouxfZvzueLYNCkz2UO7fLQ%3D%3D&sig=AJfQdSswRQIhAPR5Wu92hNL2hFvSogWkHgd3DcIy3GZvKd65NHOa26HjAiAAsbX-1R79heOXkXjvxBUlNtKY7ZRaBRohbebPdXeeWw%3D%3D"
[download] Destination: Винни-Пух Пятачок Ослик Иа. Песни из мультиков. Вспомним детство! Подписывайтесь - ссылка под видео - oBUuh3DIK_A
[download] 100% of   15.97MiB in 00:00:07 at 2.00MiB/s

[Grub4K]

You always should append .%(ext)s to the output template, otherwise it might cause even more problems (Like when the name contains a .).

• In the first case, yt-dlp implicitly appends an extension for processing so ffmpeg can merge the files
• In the second case, it will download straight to the file, so it can use the filename as given

Why do you want to download without the extension in the first place?

[dirkf]

Presumably the merge process is applying the extension even though it wasn't specified in the output template.

Actually, as the first log shows, yt-dlp is forcing the {format_id}.webm extension to avoid having one format overwrite the other (function correct_ext(), I think), the merge command is using a temp.webm extension for the output, and that is being renamed by just removing the temp. part (because dl_filename passed to the post_process() is that temp filename when no file has been downloaded).

Would the answer to this be a documentation note that an output template with no %(ext)s is likely to cause unexpected behaviour except in very simple cases, like downloading one combined format video with a specific filename?

[pukkandan]

I swear there is an open issue for this, but I can't find it

[krasnh]

but I can't find it

And I was looking for it. I was also surprised that for the entire existence of "yt-dlp", I was the first one who encountered this problem. :)

upd. If this is not a problem but a feature, it is advisable to mention it in the readme.

[dirkf]

This old upstream issue, with its relatives, is somewhat similar: user who specified a fixed --output value (in particular, without %(ext)s) was surprised when the final file had a .webm or .mkv extension as a side-effect of merging.