Repository: yt-dlp
Issue: No audio is redirected to the standard output when using the "-o -" parameter (standard output redirection parameter) together with the "--live-from-start" parameter
Labels: enhancement,triage,core:post-processor,core:downloader

### DO NOT REMOVE OR SKIP THE ISSUE TEMPLATE

- [X] I understand that I will be **blocked** if I *intentionally* remove or skip any mandatory\* field

### Checklist

- [X] I'm reporting a bug unrelated to a specific site
- [X] I've verified that I have **updated yt-dlp to nightly or master** ([update instructions](https://github.com/yt-dlp/yt-dlp#update-channels))
- [X] I've checked that all provided URLs are playable in a browser with the same IP and same login details
- [X] I've checked that all URLs and arguments with special characters are [properly quoted or escaped](https://github.com/yt-dlp/yt-dlp/wiki/FAQ#video-url-contains-an-ampersand--and-im-getting-some-strange-output-1-2839-or-v-is-not-recognized-as-an-internal-or-external-command)
- [X] I've searched [known issues](https://github.com/yt-dlp/yt-dlp/issues/3766) and the [bugtracker](https://github.com/yt-dlp/yt-dlp/issues?q=) for similar issues **including closed ones**. DO NOT post duplicates
- [X] I've read the [guidelines for opening an issue](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#opening-an-issue)

### Provide a description that is worded well enough to be understood

Audio is not redirected to the standard output during a live stream when the "--live-from-start" parameter is used in conjunction with the "-o -" parameter (standard output redirection parameter), if a live and ongoing stream is being broadcast.

Complete cmd line:

    yt-dlp "https://www.youtube.com/watch?v=jiJN7-2qkks&pp=ygUPbGl2ZSBzdHJlYW0gMjRo" -vU --live-from-start --merge-output-format mkv -o - | mpv -

### Provide verbose output that clearly demonstrates the problem

- [X] 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
- [X] Copy the WHOLE output (starting with `[debug] Command-line config`) and insert it below

### Complete Verbose Output

```shell
[debug] Command-line config: ['https://www.youtube.com/watch?v=jiJN7-2qkks&pp=ygUPbGl2ZSBzdHJlYW0gMjRo', '-vU', '--live-from-start', '--merge-output-format', 'mkv', '-o', '-']
[debug] Encodings: locale UTF-8, fs utf-8, pref UTF-8, out utf-8, error utf-8, screen utf-8
[debug] yt-dlp version stable@2024.04.09 from yt-dlp/yt-dlp [ff0779267] (pip)
[debug] Python 3.10.6 (CPython x86_64 64bit) - Linux-6.5.13-7-MANJARO-x86_64-with-glibc2.39 (OpenSSL 3.2.1 30 Jan 2024, glibc 2.39)
[debug] exe versions: ffmpeg 6.1.1 (setts), ffprobe 6.1.1, rtmpdump 2.4
[debug] Optional libraries: Cryptodome-3.20.0, brotli-1.1.0, certifi-2024.02.02, mutagen-1.47.0, requests-2.31.0, sqlite3-3.45.1, urllib3-2.2.1, websockets-12.0
[debug] Proxy map: {}
[debug] Request Handlers: urllib, requests, websockets
[debug] Loaded 1810 extractors
[debug] Fetching release info: https://api.github.com/repos/yt-dlp/yt-dlp/releases/latest
Latest version: stable@2024.04.09 from yt-dlp/yt-dlp
yt-dlp is up to date (stable@2024.04.09 from yt-dlp/yt-dlp)
[youtube] Extracting URL: https://www.youtube.com/watch?v=jiJN7-2qkks&pp=ygUPbGl2ZSBzdHJlYW0gMjRo
[youtube] jiJN7-2qkks: Downloading webpage
[youtube] jiJN7-2qkks: Downloading ios player API JSON
[youtube] jiJN7-2qkks: Downloading android player API JSON
[youtube] jiJN7-2qkks: Downloading MPD manifest
[youtube] jiJN7-2qkks: Downloading MPD manifest
[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: best/bestvideo+bestaudio
[info] jiJN7-2qkks: Downloading 1 format(s): 248+140
WARNING: You have requested downloading multiple formats to stdout but the formats are incompatible for simultaneous download. The formats will be streamed one after the other
[debug] Invoking dashsegments downloader on "https://manifest.googlevideo.com/api/manifest/dash/expire/1712784215/ei/964WZqm9JYuL-LAPscimIA/ip/104.234.224.134/id/jiJN7-2qkks.1/source/yt_live_broadcast/requiressl/yes/xpc/EgVo2aDSNQ%3D%3D/as/fmp4_audio_clear%2Cwebm_audio_clear%2Cwebm2_audio_clear%2Cfmp4_sd_hd_clear%2Cwebm2_sd_hd_clear/spc/UWF9f7ER_ppnRr5C7IVNXg-JRQOboduvDkXt/vprv/1/pacing/0/itag_bl/376%2C377%2C384%2C385%2C612%2C613%2C617%2C619%2C623%2C628%2C655%2C656%2C660%2C662%2C666%2C671/keepalive/yes/itag/0/playlist_type/DVR/sparams/expire%2Cei%2Cip%2Cid%2Csource%2Crequiressl%2Cxpc%2Cas%2Cspc%2Cvprv%2Citag%2Cplaylist_type/sig/AJfQdSswRQIgf21SgP_9Pqd9nRWqxufLcxpcloGhFWV8NXPHiVFdwnECIQD3X6mE-Ls2BAycGttVa-6w0vgrcSDo1wq3v2eY1gZuow%3D%3D"
[dashsegments] Total fragments: unknown (live)
[download] Destination: -
[debug] File locking is not supported. Proceeding without locking
[debug] [youtube] [jiJN7-2qkks] Generating fragments for format 248
[download]    1.03MiB at  280.76KiB/s (00:00:02) (frag 1/569) (+) Video --vid=1 (*) (vp9 1920x1080 30.000fps)
VO: [gpu] 1920x1080 yuv420p
[mkv] Invalid EBML length at position 1085295
[mkv] Corrupt file detected. Trying to resync starting from position 1085295...
[mkv] Cluster found at 1085771.
[mkv] Invalid EBML length at position 2107406
[mkv] Corrupt file detected. Trying to resync starting from position 2107406...
[mkv] Cluster found at 2107883.
[download] 100% of    4.12MiB in 00:00:07 at 593.31KiB/s
[debug] Invoking dashsegments downloader on "https://manifest.googlevideo.com/api/manifest/dash/expire/1712784215/ei/964WZqm9JYuL-LAPscimIA/ip/104.234.224.134/id/jiJN7-2qkks.1/source/yt_live_broadcast/requiressl/yes/xpc/EgVo2aDSNQ%3D%3D/as/fmp4_audio_clear%2Cwebm_audio_clear%2Cwebm2_audio_clear%2Cfmp4_sd_hd_clear%2Cwebm2_sd_hd_clear/spc/UWF9f7ER_ppnRr5C7IVNXg-JRQOboduvDkXt/vprv/1/pacing/0/itag_bl/376%2C377%2C384%2C385%2C612%2C613%2C617%2C619%2C623%2C628%2C655%2C656%2C660%2C662%2C666%2C671/keepalive/yes/itag/0/playlist_type/DVR/sparams/expire%2Cei%2Cip%2Cid%2Csource%2Crequiressl%2Cxpc%2Cas%2Cspc%2Cvprv%2Citag%2Cplaylist_type/sig/AJfQdSswRQIgf21SgP_9Pqd9nRWqxufLcxpcloGhFWV8NXPHiVFdwnECIQD3X6mE-Ls2BAycGttVa-6w0vgrcSDo1wq3v2eY1gZuow%3D%3D"
[dashsegments] Total fragments: unknown (live)
[download] Destination: -
[debug] [youtube] [jiJN7-2qkks] Generating fragments for format 140
Exiting... (Quit)
[download]   79.77KiB at    5.89KiB/s (00:00:01) (frag 1/570)
```