User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:93.0) Gecko/20100101 Firefox/93.0

Steps to reproduce:

I tried to stream an episode of a series on the ZDF mediathek with firefox flatpak.

Actual results:

The video freezed every few minutes and after the screen the start picture is shown.

The debug information of the ZDF player gives the following information:
ZDF-Player Debug-Information
Version: ZDF-Player 2.18.1-stable
Type: html5-hls
Dimensions: 659x370.683349609375
Resolution: 1280x720
Quality: auto
Protocol: https
MimeType: application/x-mpegURL
Volume: 100%
Duration: 1715.74s
CurrentTime: 710.77s
Buffer: 189.23s
Adaptive: aktiv
AdaptiveQuality: 5 of 5
ArticleUrl: https://www.zdf.de/serien/nix-festes/offiziell-am-arsch-100.html
UserAgent: Mozilla/5.0 (X11; Linux x86_64; rv:93.0) Gecko/20100101 Firefox/93.0

The flatpak information is:
Firefox - Mozilla Firefox Web Browser

     Kennung: org.mozilla.firefox
         Ref: app/org.mozilla.firefox/x86_64/stable
 Architektur: x86_64
       Zweig: stable
     Version: 93.0
     License: MPL-2.0
    Ursprung: flathub
    Sammlung: org.flathub.Stable
Installation: user
 Installiert: 234,4 MB

Laufzeitumgebung: org.freedesktop.Platform/x86_64/20.08
Sdk: org.freedesktop.Sdk/x86_64/20.08

      Commit: 8f41e404106b16c0d1e6a7611ef5778aab35f5879234768f38ef180cec76c929
      Parent: 2c0be76338290e0056b25371cbb8c68a7396e5b1b5a5619ccf609e01c420d3b9
     Subject: Export org.mozilla.firefox
        Date: 2021-10-05 12:49:22 +0000

On the console I get the following messages:
[Child 73, MediaDecoderStateMachine #1] WARNING: Decoder=7f5303a76400 Decode error: NS_ERROR_DOM_MEDIA_DECODE_ERR (0x806e0004) - virtual mozilla::MediaResult mozilla::FFmpegVideoDecoder<58>::DoDecode(mozilla::MediaRawData *, uint8_t *, int, bool *, MediaDataDecoder::DecodedData &): avcodec_send_packet error: -1313558101: file /builds/worker/checkouts/gecko/dom/media/MediaDecoderStateMachine.cpp:3541
[Child 73, MediaDecoderStateMachine #1] WARNING: Decoder=7f5303a76400 Decode error: NS_ERROR_DOM_MEDIA_DECODE_ERR (0x806e0004) - virtual mozilla::MediaResult mozilla::FFmpegVideoDecoder<58>::DoDecode(mozilla::MediaRawData *, uint8_t *, int, bool *, MediaDataDecoder::DecodedData &): avcodec_send_packet error: -1313558101: file /builds/worker/checkouts/gecko/dom/media/MediaDecoderStateMachine.cpp:3541

Expected results:

The video runs smoothly.

I couldn't reproduce that on my Ubuntu 20.04. Would you mind to help me capture debug log by using MOZ_LOG=MediaDecoder:5,PlatformDecoderModule:5? In addition, I wonder if this issue still happens on the latest Nightly?
Thank you.

Terminal output of firefox for the given bug report.

Correct terminal output for given bug report.

Would you help me check if there is ffmpeg-full installed in your computer? There is a similar issue before and I suspect that is the same issue. Thank you.

(In reply to Alastor Wu [:alwu][PTO until Nov.1] from comment #4)

Would you help me check if there is ffmpeg-full installed in your computer? There is a similar issue before and I suspect that is the same issue. Thank you.

No, the ´ffmpeg-full´ flatpak extension was not installed at that time.

If you install ffmpeg-full does that help improve playback quality? Alternatively, does a non-flatpak version of Firefox suffer from the same issue?

Yes, installing ffmpeg-full does solve the issue but my opinion the handling of such media files is suboptimal as I would expect one of the following two scenarios if ffmpeg-full is not installed: either the video can´t be played at all (such as in my SUSE firefox installation without any propitiatory codecs) or the video does play without major problems (even though the hardware load may be higher and the playback may be choppy).
Compared to these two scenarios, I consider the actual case of a video playback breaking down every few minutes worse, as it is neither working flawlessly nor failing completely and gives you the feeling of "it kinda works but somehow it doesn´t. But I can´t point out the problem".
But if you disagree, you can feel free to close this issue. I won´t have any hard feeling.

Thanks for the reply. Sadly, this is a licensing issue rather than a technical one. We're not able to package the full-ffmpeg with the flatpak build. However, I appreciate the feedback that you'd prefer no playback at all until you've installed the full ffmpeg, and will pass it on.